* [PATCH v8.1] xSplice v1 design and implementation.
@ 2016-04-13 22:01 Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 01/27] Revert "libxc/libxl/python/xenstat/ocaml: Use new XEN_VERSION hypercall" Konrad Rzeszutek Wilk
` (27 more replies)
0 siblings, 28 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Hey!
Changelog:
v8: since http://lists.xen.org/archives/html/xen-devel/2016-04/msg01873.html
- Posting the _RIGHT_ set of patches.
v7: http://lists.xen.org/archives/html/xen-devel/2016-04/msg01476.html
- Ingested newer version of x86/mm: Introduce modify_xen_mappings()
- Implemented faster symbol table lookup (NEW)
- Carried out tests on large CPU machine (240CPUs)
- Made the struct xsplice_patch_func work on ARM32 and changed its size
(64bit it is 64bytes, 32bit is 52 bytes - and the offset is different too)
- Changed a bunch of printk to dprintk, adjusted XENLOG_ levels.
- Resurrected the XENVER_build_id.
- Reverted VERSION_op.
v6: http://lists.xen.org/archives/html/xen-devel/2016-04/msg00871.html
- Acted on all comments from Andrew, Julien, and Jan.
- Got help from Andrew on one of them over the weekend.
- Dropped: xsplice: Add .xsplice.hooks functions and test-case,
xsplice: Add support for shadow variables.
v5: http://lists.xen.org/archives/html/xen-devel/2016-03/msg03286.html
- Acted at all comments from Jan.
v4: http://lists.xen.org/archives/html/xen-devel/2016-03/msg01776.html
- Lots of review. Lots of rework. Some patches checked in.
v3: http://www.gossamer-threads.com/lists/xen/devel/418262
and
http://lists.xenproject.org/archives/html/xen-devel/2016-02/msg04106.html
- Act on all reviews.
- Redo the flow of patches
v2: http://lists.xen.org/archives/html/xen-devel/2016-01/msg01597.html
- Updated code/docs/design with review comments.
- Make xen also have an PT_NOTE
- Added more of Ross's patches
- Combined build-id patchset with this.
(since the RFC and the Seattle Xen presentation)
- Finished off some of the work around the build-id.
- Settled on the preemption mechanism.
- Cleaned the patches a lot up, broke them up to easy
review for maintainers.
v1: http://lists.xenproject.org/archives/html/xen-devel/2015-09/msg02116.html
- Put all the design comments in the code
Prototype: http://lists.xenproject.org/archives/html/xen-devel/2015-10/msg02595.html
[Posting by Ross]
- Took all reviews into account.
- Redid the patches
*Tools Maintainers*
Since v7, two new patches, please review:
XENVER_build_id/libxc: Provide ld-embedded build-id
libxl: info: Display build_id of the hypervisor.
*Maintainers*
Legend:
* - See below
R - Reviewed
R+ - Reviewed by two folks
A - Acked by maintainer of the area (hypervisor or toolstack)
* Revert "libxc/libxl/python/xenstat/ocaml: Use new
* Revert "HYPERCALL_version_op. New hypercall mirroring
A xsplice: Design document
R xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op
AR libxc: Implementation of XEN_XSPLICE_op in libxc
AR xen-xsplice: Tool to manipulate xsplice payloads
AR arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables lookup.
[Julien Acked the ARM part]
AR arm/x86/vmap: Add vmalloc_xen, vfree_xen and vm_init_type
[Julien Acked the ARM part]
R+ x86/mm: Introduce modify_xen_mappings()
R xsplice: Add helper elf routines
R xsplice: Implement payload loading
* R xsplice: Implement support for applying/reverting/replacing patches.
R x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version'.
R xsplice,symbols: Implement symbol name resolution on address.
* xsplice, symbols: Implement fast symbol names -> virtual addresses lookup
R x86, xsplice: Print payload's symbol name and payload name in backtraces
R xsplice: Add support for bug frames.
R xsplice: Add support for exception tables.
R xsplice: Add support for alternatives
AR build_id: Provide ld-embedded build-ids
[Julien Acked the ARM part]
AR xsplice: Print build_id in keyhandler and on bootup.
* XENVER_build_id/libxc: Provide ld-embedded build-id
* libxl: info: Display build_id of the hypervisor.
R xsplice: Stacking build-id dependency checking.
R xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE
R xsplice: Prevent duplicate payloads from being loaded.
R MAINTAINERS/xsplice: Add myself and Ross as the maintainers.
Since v7, the
[PATCH v8.1 01/27] Revert "libxc/libxl/python/xenstat/ocaml: Use new
[PATCH v8.1 02/27] Revert "HYPERCALL_version_op. New hypercall mirroring
[PATCH v8.1 15/27] xsplice, symbols: Implement fast symbol names ->
[PATCH v8.1 22/27] XENVER_build_id/libxc: Provide ld-embedded build-id
[PATCH v8.1 23/27] libxl: info: Display build_id of the hypervisor.
haven't been reviewed (they are new). Thought honestly the reverts don't really
need a review.
Julien, Stefano, I dropped Julien's Ack on
[PATCH v8.1 11/27] xsplice: Implement payload loading
as Jan's expressed a desire not to have BITS_PER_LONG exposed
in the public headers. I've put CONFIG_ARM_32 in there. On IRC
Stefano was OK (relucantly) with it.
Patchset has been tested on ARM (tweaking the Kconfig to build xSplice and then
booting and using it under ARM CubieTruck - granted there is no patching
yet but the hypercalls work), ARM64 (only built it), and x86 (legacy and EFI)
*VERSION_OP being reverted?*
Ian (thank you taking the stressful role of tiebreaker) pointed out that
at the end of the day - less code from a maintaince perspective is easier.
Hence the revert. We can always revisit this in Xen 4.8 :-)
*Are there any TODOs left from v5,v6,v7 reviews?*
Just how the sysctl.h definition for 'struct xsplice_patch_func' should be:
#define XSPLICE_PAYLOAD_VERSION 1
/*
* .xsplice.funcs structure layout defined in the `Payload format`
* section in the xSplice design document.
*
* The size should be exactly 64 bytes (64) or 52 bytes (32).
*
* We guard this with __XEN__ as toolstacks do not need to use it.
*/
#ifdef __XEN__
struct xsplice_patch_func {
const char *name; /* Name of function to be patched. */
#if CONFIG_ARM_32
uint32_t new_addr;
uint32_t old_addr;
#else
uint64_t new_addr;
uint64_t old_addr; /* Can be zero and name will be looked up. */
#endif
uint32_t new_size;
uint32_t old_size;
uint8_t version; /* MUST be XSPLICE_PAYLOAD_VERSION. */
uint8_t pad[31]; /* MUST be zero filled. */
};
typedef struct xsplice_patch_func xsplice_patch_func_t;
#endif
Please note the __XEN__ so even if toolstack does include the public/sysctl.h
it won't find it the structure.
With this I am able to compile early-test-cases-prototype-work xSplice on ARM32.
*What is xSplice?*
A mechanism to binarily patch the running hypervisor with new
opcodes that have come about due to primarily security updates.
*What will this patchset do once I've it*
Patch the hypervisor.
*Why are you emailing me?*
Please please review as many patches as possible.
*OK, what do you have?*
They are located at a git tree:
git://xenbits.xen.org/people/konradwilk/xen.git xsplice.v8.drop_VERSION_op
(Copying from Ross's email):
Much of the work is implementing a basic version of the Linux kernel module
loader. The code:
* Loading of xSplice ELF payloads.
* Copying allocated sections into a new executable region of memory.
* Resolving symbols.
* Applying relocations.
* Patching of altinstructions.
* Special handling of bug frames and exception tables.
* Unloading of xSplice ELF payloads.
* Compiling a sample xSplice ELF payload
* Resolving symbols
* Using build-id dependencies
* Support for shadow variable framework
* Support for executing ELF payload functions on load/unload.
The other main bit of this work is applying and reverting the patches safely.
As implemented, the code is patched with each CPU waiting in the
return-to-guest path (i.e. with no stack) or on the cpu-idle path
which appears to be the safest way of patching. While it is safe we should
still (in the next wave of patches) to verify to not patch cetain critical
sections (say the code doing the patching)
All of the following should work:
* Applying patches safely.
* Reverting patches safely.
* Replacing patches safely (e.g. reverting any applied patches and applying
a new patch).
* Bug frames as part of modules. This means adding or
changing WARN, ASSERT, BUG, and run_in_exception_handler works correctly.
Line number only changes _are ignored_.
* Exception tables as part of modules. E.g. wrmsr_safe and copy_to_user work
correctly when used in a patch module.
* Stacking of patches on top of each other
* Resolving symbols (even of patches)
*Limitations*
The above is enough to fully implement an update system where multiple source
patches are combined (using combinediff) and built into a single binary
which then atomically replaces any existing loaded patches
(this is why Ross added a REPLACE operation). This is the approach used
by kPatch and kGraft.
Multiple completely independent patches can also be loaded but unexpected
interactions may occur.
As it stands, the patches are statically linked which means that independent
patches cannot be linked against one another (e.g. if one introduces a
new symbol). Using the combinediff approach above fixes this.
Backtraces containing functions from a patch module do not show the symbol name.
There is no checking that a patch which is loaded is built for the
correct hypervisor (need to use build-id).
Binary patching works at the function level.
*Testing*
You can use the example code included in this patchset:
# xl info | grep extra
xen_extra : -unstable
# xen-xsplice load /usr/lib/debug/xen_hello_world.xsplice
Uploading /usr/lib/debug/xen_hello_world.xsplice (2071 bytes)
Performing check: completed
Performing apply:. completed
# xl info | grep extra
xen_extra : Hello World
# xen-xsplice revert xen_hello_world
Performing revert:. completed
# xen-xsplice unload xen_hello_world
Performing unload: completed
# xl info | grep extra
xen_extra : -unstable
Or you can use git://xenbits.xen.org/people/konradwilk/xsplice-build-tools.git
which generates the ELF payloads.
This link has a nice description of how to use the tool:
http://lists.xenproject.org/archives/html/xen-devel/2015-10/msg02595.html
.gitignore | 5 +
Config.mk | 12 +
MAINTAINERS | 10 +
docs/misc/xsplice.markdown | 1116 +++++++++++++++++++
tools/flask/policy/policy/modules/xen/xen.te | 9 +-
tools/libxc/include/xenctrl.h | 94 +-
tools/libxc/xc_core.c | 35 +-
tools/libxc/xc_dom_boot.c | 12 +-
tools/libxc/xc_domain.c | 3 +-
tools/libxc/xc_misc.c | 355 ++++++
tools/libxc/xc_private.c | 60 +-
tools/libxc/xc_private.h | 18 +-
tools/libxc/xc_resume.c | 3 +-
tools/libxc/xc_sr_save.c | 9 +-
tools/libxc/xg_save_restore.h | 6 +-
tools/libxl/libxl.c | 108 +-
tools/libxl/libxl.h | 6 +
tools/libxl/libxl_types.idl | 1 +
tools/libxl/xl_cmdimpl.c | 1 +
tools/misc/Makefile | 4 +
tools/misc/xen-xsplice.c | 463 ++++++++
tools/ocaml/libs/xc/xenctrl_stubs.c | 39 +-
tools/python/xen/lowlevel/xc/xc.c | 30 +-
tools/xenstat/libxenstat/src/xenstat.c | 12 +-
tools/xentrace/xenctx.c | 3 +-
xen/Makefile | 8 +-
xen/arch/arm/Makefile | 5 +-
xen/arch/arm/kernel.c | 2 +-
xen/arch/arm/mm.c | 2 +-
xen/arch/arm/setup.c | 4 +
xen/arch/arm/traps.c | 40 +-
xen/arch/arm/xen.lds.S | 15 +-
xen/arch/arm/xsplice.c | 87 ++
xen/arch/x86/Makefile | 58 +-
xen/arch/x86/alternative.c | 42 +-
xen/arch/x86/boot/mkelf32.c | 129 ++-
xen/arch/x86/domain.c | 2 +
xen/arch/x86/extable.c | 41 +-
xen/arch/x86/hvm/hvm.c | 1 -
xen/arch/x86/mm.c | 77 +-
xen/arch/x86/setup.c | 28 +-
xen/arch/x86/test/Makefile | 85 ++
xen/arch/x86/test/xen_bye_world.c | 34 +
xen/arch/x86/test/xen_bye_world_func.c | 24 +
xen/arch/x86/test/xen_hello_world.c | 33 +
xen/arch/x86/test/xen_hello_world_func.c | 38 +
xen/arch/x86/test/xen_replace_world.c | 34 +
xen/arch/x86/test/xen_replace_world_func.c | 24 +
xen/arch/x86/traps.c | 45 +-
xen/arch/x86/x86_64/compat/entry.S | 2 -
xen/arch/x86/x86_64/entry.S | 2 -
xen/arch/x86/xen.lds.S | 28 +
xen/arch/x86/xsplice.c | 264 +++++
xen/common/Kconfig | 28 +
xen/common/Makefile | 3 +
xen/common/compat/kernel.c | 2 -
xen/common/kernel.c | 226 ++--
xen/common/symbols-dummy.c | 6 +
xen/common/symbols.c | 118 +-
xen/common/sysctl.c | 6 +
xen/common/version.c | 70 ++
xen/common/virtual_region.c | 148 +++
xen/common/vmap.c | 202 ++--
xen/common/vsprintf.c | 19 +-
xen/common/xsplice.c | 1541 ++++++++++++++++++++++++++
xen/common/xsplice_elf.c | 495 +++++++++
xen/drivers/acpi/osl.c | 2 +-
xen/include/asm-x86/alternative.h | 4 +
xen/include/asm-x86/current.h | 10 +-
xen/include/asm-x86/uaccess.h | 2 +
xen/include/public/arch-arm.h | 2 -
xen/include/public/sysctl.h | 193 ++++
xen/include/public/version.h | 82 +-
xen/include/public/xen.h | 1 -
xen/include/xen/elfstructs.h | 7 +
xen/include/xen/hypercall.h | 4 -
xen/include/xen/mm.h | 2 +
xen/include/xen/symbols.h | 11 +
xen/include/xen/version.h | 1 +
xen/include/xen/virtual_region.h | 47 +
xen/include/xen/vmap.h | 21 +-
xen/include/xen/xsplice.h | 146 +++
xen/include/xen/xsplice_elf.h | 58 +
xen/include/xsm/dummy.h | 21 -
xen/include/xsm/xsm.h | 6 -
xen/tools/symbols.c | 93 +-
xen/xsm/dummy.c | 1 -
xen/xsm/flask/hooks.c | 40 +-
xen/xsm/flask/policy/access_vectors | 25 +-
89 files changed, 6496 insertions(+), 715 deletions(-)
Andrew Cooper (1):
x86/mm: Introduce modify_xen_mappings()
Konrad Rzeszutek Wilk (17):
Revert "libxc/libxl/python/xenstat/ocaml: Use new XEN_VERSION hypercall"
Revert "HYPERCALL_version_op. New hypercall mirroring XENVER_ but sane."
xsplice: Design document
xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op
libxc: Implementation of XEN_XSPLICE_op in libxc
xen-xsplice: Tool to manipulate xsplice payloads
arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables lookup.
arm/x86/vmap: Add vmalloc_xen, vfree_xen and vm_init_type
x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version'.
xsplice, symbols: Implement fast symbol names -> virtual addresses lookup
build_id: Provide ld-embedded build-ids
xsplice: Print build_id in keyhandler and on bootup.
XENVER_build_id/libxc: Provide ld-embedded build-id
libxl: info: Display build_id of the hypervisor.
xsplice: Stacking build-id dependency checking.
xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE
MAINTAINERS/xsplice: Add myself and Ross as the maintainers.
Ross Lagerwall (9):
xsplice: Add helper elf routines
xsplice: Implement payload loading
xsplice: Implement support for applying/reverting/replacing patches.
xsplice,symbols: Implement symbol name resolution on address.
x86, xsplice: Print payload's symbol name and payload name in backtraces
xsplice: Add support for bug frames.
xsplice: Add support for exception tables.
xsplice: Add support for alternatives
xsplice: Prevent duplicate payloads from being loaded.
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 126+ messages in thread
* [PATCH v8.1 01/27] Revert "libxc/libxl/python/xenstat/ocaml: Use new XEN_VERSION hypercall"
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 02/27] Revert "HYPERCALL_version_op. New hypercall mirroring XENVER_ but sane." Konrad Rzeszutek Wilk
` (26 subsequent siblings)
27 siblings, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Konrad Rzeszutek Wilk
This reverts commit d275ec9ca8a86f7c9c213f3551194d471ce90fbd.
As we prefer to still utilize the old XENVER_ hypercall.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
tools/libxc/include/xenctrl.h | 32 +-------------
tools/libxc/xc_core.c | 35 ++++++++--------
tools/libxc/xc_dom_boot.c | 12 +-----
tools/libxc/xc_domain.c | 3 +-
tools/libxc/xc_private.c | 53 +++++++++++++++++++----
tools/libxc/xc_private.h | 7 ++--
tools/libxc/xc_resume.c | 3 +-
tools/libxc/xc_sr_save.c | 9 ++--
tools/libxc/xg_save_restore.h | 6 +--
tools/libxl/libxl.c | 77 +++++++++++++---------------------
tools/ocaml/libs/xc/xenctrl_stubs.c | 39 ++++++++++-------
tools/python/xen/lowlevel/xc/xc.c | 30 ++++++-------
tools/xenstat/libxenstat/src/xenstat.c | 12 +++---
tools/xentrace/xenctx.c | 3 +-
14 files changed, 146 insertions(+), 175 deletions(-)
diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index f5a034a..42f201b 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -1536,37 +1536,7 @@ int xc_tbuf_set_evt_mask(xc_interface *xch, uint32_t mask);
int xc_domctl(xc_interface *xch, struct xen_domctl *domctl);
int xc_sysctl(xc_interface *xch, struct xen_sysctl *sysctl);
-/**
- * This function returns the size of buffer to be allocated for
- * the cmd. The cmd are XEN_VERSION_*.
- */
-ssize_t xc_version_len(xc_interface *xch, unsigned int cmd);
-
-/**
- * This function retrieves the information from the version_op hypercall.
- * The len is the size of the arg buffer. If arg is NULL, will not
- * perform hypercall - instead will just return the size of arg
- * buffer that is needed.
- *
- * Note that prior to Xen 4.7 this would return 0 for success and
- * negative value (-1) for error (with the error in errno). In Xen 4.7
- * and later for success it will return an positive value which is the
- * number of bytes copied in arg.
- *
- * It can also return -1 with various errno values:
- * - EPERM - not permitted.
- * - ENOBUFS - the len was to short, output in arg truncated.
- * - ENOSYS - not implemented.
- *
- * @parm xch a handle to an open hypervisor interface
- * @parm cmd XEN_VERSION_* value
- * @param arg Pointer to xen_version_op_buf_t or xen_version_op_val_t
- * @param len Size of arg
- * @return size of bytes copied in arg on success, -1 on failure (and
- * errno will contain the error)
- *
- */
-int xc_version(xc_interface *xch, unsigned int cmd, void *arg, size_t len);
+int xc_version(xc_interface *xch, int cmd, void *arg);
int xc_flask_op(xc_interface *xch, xen_flask_op_t *op);
diff --git a/tools/libxc/xc_core.c b/tools/libxc/xc_core.c
index cfeba6b..d792566 100644
--- a/tools/libxc/xc_core.c
+++ b/tools/libxc/xc_core.c
@@ -270,43 +270,42 @@ elfnote_fill_xen_version(xc_interface *xch,
*xen_version)
{
int rc;
- xen_version_op_val_t val = 0;
memset(xen_version, 0, sizeof(*xen_version));
- rc = xc_version(xch, XEN_VERSION_version, &val, sizeof(val));
+ rc = xc_version(xch, XENVER_version, NULL);
if ( rc < 0 )
return rc;
- xen_version->major_version = val >> 16;
- xen_version->minor_version = val & ((1 << 16) - 1);
+ xen_version->major_version = rc >> 16;
+ xen_version->minor_version = rc & ((1 << 16) - 1);
- rc = xc_version(xch, XEN_VERSION_extraversion,
- xen_version->extra_version,
- sizeof(xen_version->extra_version));
+ rc = xc_version(xch, XENVER_extraversion,
+ &xen_version->extra_version);
if ( rc < 0 )
return rc;
- rc = xc_version(xch, XEN_VERSION_capabilities,
- xen_version->capabilities,
- sizeof(xen_version->capabilities));
+ rc = xc_version(xch, XENVER_compile_info,
+ &xen_version->compile_info);
if ( rc < 0 )
return rc;
- rc = xc_version(xch, XEN_VERSION_changeset, xen_version->changeset,
- sizeof(xen_version->changeset));
+ rc = xc_version(xch,
+ XENVER_capabilities, &xen_version->capabilities);
if ( rc < 0 )
return rc;
- rc = xc_version(xch, XEN_VERSION_platform_parameters,
- &xen_version->platform_parameters,
- sizeof(xen_version->platform_parameters));
+ rc = xc_version(xch, XENVER_changeset, &xen_version->changeset);
if ( rc < 0 )
return rc;
- val = 0;
- rc = xc_version(xch, XEN_VERSION_pagesize, &val, sizeof(val));
+ rc = xc_version(xch, XENVER_platform_parameters,
+ &xen_version->platform_parameters);
if ( rc < 0 )
return rc;
- xen_version->pagesize = val;
+
+ rc = xc_version(xch, XENVER_pagesize, NULL);
+ if ( rc < 0 )
+ return rc;
+ xen_version->pagesize = rc;
return 0;
}
diff --git a/tools/libxc/xc_dom_boot.c b/tools/libxc/xc_dom_boot.c
index bbff72e..791041b 100644
--- a/tools/libxc/xc_dom_boot.c
+++ b/tools/libxc/xc_dom_boot.c
@@ -112,19 +112,11 @@ int xc_dom_compat_check(struct xc_dom_image *dom)
int xc_dom_boot_xen_init(struct xc_dom_image *dom, xc_interface *xch, domid_t domid)
{
- xen_version_op_val_t val = 0;
-
- if ( xc_version(xch, XEN_VERSION_version, &val, sizeof(val)) < 0 )
- {
- xc_dom_panic(xch, XC_INTERNAL_ERROR, "can't get Xen version!");
- return -1;
- }
- dom->xen_version = val;
dom->xch = xch;
dom->guest_domid = domid;
- if ( xc_version(xch, XEN_VERSION_capabilities, dom->xen_caps,
- sizeof(dom->xen_caps)) < 0 )
+ dom->xen_version = xc_version(xch, XENVER_version, NULL);
+ if ( xc_version(xch, XENVER_capabilities, &dom->xen_caps) < 0 )
{
xc_dom_panic(xch, XC_INTERNAL_ERROR, "can't get xen capabilities");
return -1;
diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
index 9ebd1d6..050216e 100644
--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -2084,8 +2084,7 @@ int xc_map_domain_meminfo(xc_interface *xch, int domid,
_di.guest_width = minfo->guest_width;
/* Get page table levels (see get_platform_info() in xg_save_restore.h */
- if ( xc_version(xch, XEN_VERSION_capabilities, xen_caps,
- sizeof(xen_caps)) < 0 )
+ if ( xc_version(xch, XENVER_capabilities, &xen_caps) )
{
PERROR("Could not get Xen capabilities (for page table levels)");
return -1;
diff --git a/tools/libxc/xc_private.c b/tools/libxc/xc_private.c
index 631ad91..c41e433 100644
--- a/tools/libxc/xc_private.c
+++ b/tools/libxc/xc_private.c
@@ -457,23 +457,58 @@ int xc_sysctl(xc_interface *xch, struct xen_sysctl *sysctl)
return do_sysctl(xch, sysctl);
}
-ssize_t xc_version_len(xc_interface *xch, unsigned int cmd)
+int xc_version(xc_interface *xch, int cmd, void *arg)
{
- return do_version_op(xch, cmd, NULL, 0);
-}
-
-int xc_version(xc_interface *xch, unsigned int cmd, void *arg, size_t sz)
-{
- DECLARE_HYPERCALL_BOUNCE(arg, sz, XC_HYPERCALL_BUFFER_BOUNCE_OUT);
+ DECLARE_HYPERCALL_BOUNCE(arg, 0, XC_HYPERCALL_BUFFER_BOUNCE_OUT); /* Size unknown until cmd decoded */
+ size_t sz;
int rc;
- if ( xc_hypercall_bounce_pre(xch, arg) )
+ switch ( cmd )
+ {
+ case XENVER_version:
+ sz = 0;
+ break;
+ case XENVER_extraversion:
+ sz = sizeof(xen_extraversion_t);
+ break;
+ case XENVER_compile_info:
+ sz = sizeof(xen_compile_info_t);
+ break;
+ case XENVER_capabilities:
+ sz = sizeof(xen_capabilities_info_t);
+ break;
+ case XENVER_changeset:
+ sz = sizeof(xen_changeset_info_t);
+ break;
+ case XENVER_platform_parameters:
+ sz = sizeof(xen_platform_parameters_t);
+ break;
+ case XENVER_get_features:
+ sz = sizeof(xen_feature_info_t);
+ break;
+ case XENVER_pagesize:
+ sz = 0;
+ break;
+ case XENVER_guest_handle:
+ sz = sizeof(xen_domain_handle_t);
+ break;
+ case XENVER_commandline:
+ sz = sizeof(xen_commandline_t);
+ break;
+ default:
+ ERROR("xc_version: unknown command %d\n", cmd);
+ return -EINVAL;
+ }
+
+ HYPERCALL_BOUNCE_SET_SIZE(arg, sz);
+
+ if ( (sz != 0) && xc_hypercall_bounce_pre(xch, arg) )
{
PERROR("Could not bounce buffer for version hypercall");
return -ENOMEM;
}
- rc = do_version_op(xch, cmd, HYPERCALL_BUFFER(arg), sz);
+ rc = do_xen_version(xch, cmd, HYPERCALL_BUFFER(arg));
if ( sz != 0 )
xc_hypercall_bounce_post(xch, arg);
diff --git a/tools/libxc/xc_private.h b/tools/libxc/xc_private.h
index 5be8fdd..aa8daf1 100644
--- a/tools/libxc/xc_private.h
+++ b/tools/libxc/xc_private.h
@@ -214,12 +214,11 @@ void xc__hypercall_buffer_cache_release(xc_interface *xch);
* Hypercall interfaces.
*/
-static inline long do_version_op(xc_interface *xch, int cmd,
- xc_hypercall_buffer_t *dest, ssize_t len)
+static inline int do_xen_version(xc_interface *xch, int cmd, xc_hypercall_buffer_t *dest)
{
DECLARE_HYPERCALL_BUFFER_ARGUMENT(dest);
- return xencall3(xch->xcall, __HYPERVISOR_version_op,
- cmd, HYPERCALL_BUFFER_AS_ARG(dest), len);
+ return xencall2(xch->xcall, __HYPERVISOR_xen_version,
+ cmd, HYPERCALL_BUFFER_AS_ARG(dest));
}
static inline int do_physdev_op(xc_interface *xch, int cmd, void *op, size_t len)
diff --git a/tools/libxc/xc_resume.c b/tools/libxc/xc_resume.c
index 2b6c308..c169204 100644
--- a/tools/libxc/xc_resume.c
+++ b/tools/libxc/xc_resume.c
@@ -56,8 +56,7 @@ static int modify_returncode(xc_interface *xch, uint32_t domid)
return 0;
/* HVM guests have host address width. */
- if ( xc_version(xch, XEN_VERSION_capabilities, caps,
- sizeof(caps)) < 0 )
+ if ( xc_version(xch, XENVER_capabilities, &caps) != 0 )
{
PERROR("Could not get Xen capabilities");
return -1;
diff --git a/tools/libxc/xc_sr_save.c b/tools/libxc/xc_sr_save.c
index 291fe9f..f98c827 100644
--- a/tools/libxc/xc_sr_save.c
+++ b/tools/libxc/xc_sr_save.c
@@ -9,7 +9,7 @@
static int write_headers(struct xc_sr_context *ctx, uint16_t guest_type)
{
xc_interface *xch = ctx->xch;
- xen_version_op_val_t xen_version;
+ int32_t xen_version = xc_version(xch, XENVER_version, NULL);
struct xc_sr_ihdr ihdr =
{
.marker = IHDR_MARKER,
@@ -21,16 +21,15 @@ static int write_headers(struct xc_sr_context *ctx, uint16_t guest_type)
{
.type = guest_type,
.page_shift = XC_PAGE_SHIFT,
+ .xen_major = (xen_version >> 16) & 0xffff,
+ .xen_minor = (xen_version) & 0xffff,
};
- if ( xc_version(xch, XEN_VERSION_version, &xen_version,
- sizeof(xen_version)) < 0 )
+ if ( xen_version < 0 )
{
PERROR("Unable to obtain Xen Version");
return -1;
}
- dhdr.xen_major = (xen_version >> 16) & 0xffff;
- dhdr.xen_minor = (xen_version) & 0xffff;
if ( write_exact(ctx->fd, &ihdr, sizeof(ihdr)) )
{
diff --git a/tools/libxc/xg_save_restore.h b/tools/libxc/xg_save_restore.h
index 007875f..303081d 100644
--- a/tools/libxc/xg_save_restore.h
+++ b/tools/libxc/xg_save_restore.h
@@ -57,12 +57,10 @@ static inline int get_platform_info(xc_interface *xch, uint32_t dom,
xen_capabilities_info_t xen_caps = "";
xen_platform_parameters_t xen_params;
- if (xc_version(xch, XEN_VERSION_platform_parameters, &xen_params,
- sizeof(xen_params)) < 0)
+ if (xc_version(xch, XENVER_platform_parameters, &xen_params) != 0)
return 0;
- if (xc_version(xch, XEN_VERSION_capabilities, xen_caps,
- sizeof(xen_caps)) < 0)
+ if (xc_version(xch, XENVER_capabilities, &xen_caps) != 0)
return 0;
if (xc_maximum_ram_page(xch, max_mfn))
diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index d232473..eec899d 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -5353,71 +5353,50 @@ libxl_numainfo *libxl_get_numainfo(libxl_ctx *ctx, int *nr)
return ret;
}
-
-static int libxl__xc_version_wrapper(libxl__gc *gc, unsigned int cmd,
- char *buf, ssize_t len, char **dst)
-{
- int r;
-
- r = xc_version(CTX->xch, cmd, buf, len);
- if ( r == -EPERM ) {
- buf[0] = '\0';
- } else if ( r < 0 ) {
- return r;
- }
- *dst = libxl__strdup(NOGC, buf);
- return 0;
-}
-
const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx)
{
GC_INIT(ctx);
- char *buf;
- xen_version_op_val_t val = 0;
+ union {
+ xen_extraversion_t xen_extra;
+ xen_compile_info_t xen_cc;
+ xen_changeset_info_t xen_chgset;
+ xen_capabilities_info_t xen_caps;
+ xen_platform_parameters_t p_parms;
+ xen_commandline_t xen_commandline;
+ } u;
+ long xen_version;
libxl_version_info *info = &ctx->version_info;
if (info->xen_version_extra != NULL)
goto out;
- if (xc_version(CTX->xch, XEN_VERSION_pagesize, &val, sizeof(val)) < 0)
- goto out;
+ xen_version = xc_version(ctx->xch, XENVER_version, NULL);
+ info->xen_version_major = xen_version >> 16;
+ info->xen_version_minor = xen_version & 0xFF;
- info->pagesize = val;
- /* 4K buffer. */
- buf = libxl__zalloc(gc, info->pagesize);
+ xc_version(ctx->xch, XENVER_extraversion, &u.xen_extra);
+ info->xen_version_extra = libxl__strdup(NOGC, u.xen_extra);
- val = 0;
- if (xc_version(CTX->xch, XEN_VERSION_version, &val, sizeof(val)) < 0)
- goto out;
- info->xen_version_major = val >> 16;
- info->xen_version_minor = val & 0xFF;
+ xc_version(ctx->xch, XENVER_compile_info, &u.xen_cc);
+ info->compiler = libxl__strdup(NOGC, u.xen_cc.compiler);
+ info->compile_by = libxl__strdup(NOGC, u.xen_cc.compile_by);
+ info->compile_domain = libxl__strdup(NOGC, u.xen_cc.compile_domain);
+ info->compile_date = libxl__strdup(NOGC, u.xen_cc.compile_date);
- if (libxl__xc_version_wrapper(gc, XEN_VERSION_extraversion, buf,
- info->pagesize, &info->xen_version_extra) < 0)
- goto out;
+ xc_version(ctx->xch, XENVER_capabilities, &u.xen_caps);
+ info->capabilities = libxl__strdup(NOGC, u.xen_caps);
- info->compiler = libxl__strdup(NOGC, "");
- info->compile_by = libxl__strdup(NOGC, "");
- info->compile_domain = libxl__strdup(NOGC, "");
- info->compile_date = libxl__strdup(NOGC, "");
+ xc_version(ctx->xch, XENVER_changeset, &u.xen_chgset);
+ info->changeset = libxl__strdup(NOGC, u.xen_chgset);
- if (libxl__xc_version_wrapper(gc, XEN_VERSION_capabilities, buf,
- info->pagesize, &info->capabilities) < 0)
- goto out;
+ xc_version(ctx->xch, XENVER_platform_parameters, &u.p_parms);
+ info->virt_start = u.p_parms.virt_start;
- if (libxl__xc_version_wrapper(gc, XEN_VERSION_changeset, buf,
- info->pagesize, &info->changeset) < 0)
- goto out;
-
- val = 0;
- if (xc_version(CTX->xch, XEN_VERSION_platform_parameters, &val,
- sizeof(val)) < 0)
- goto out;
+ info->pagesize = xc_version(ctx->xch, XENVER_pagesize, NULL);
- info->virt_start = val;
+ xc_version(ctx->xch, XENVER_commandline, &u.xen_commandline);
+ info->commandline = libxl__strdup(NOGC, u.xen_commandline);
- (void)libxl__xc_version_wrapper(gc, XEN_VERSION_commandline, buf,
- info->pagesize, &info->commandline);
out:
GC_FREE;
return info;
diff --git a/tools/ocaml/libs/xc/xenctrl_stubs.c b/tools/ocaml/libs/xc/xenctrl_stubs.c
index 22741d5..5477df3 100644
--- a/tools/ocaml/libs/xc/xenctrl_stubs.c
+++ b/tools/ocaml/libs/xc/xenctrl_stubs.c
@@ -853,21 +853,21 @@ CAMLprim value stub_xc_version_version(value xch)
CAMLparam1(xch);
CAMLlocal1(result);
xen_extraversion_t extra;
- xen_version_op_val_t packed;
+ long packed;
int retval;
caml_enter_blocking_section();
- retval = xc_version(_H(xch), XEN_VERSION_version, &packed, sizeof(packed));
+ packed = xc_version(_H(xch), XENVER_version, NULL);
caml_leave_blocking_section();
- if (retval < 0)
+ if (packed < 0)
failwith_xc(_H(xch));
caml_enter_blocking_section();
- retval = xc_version(_H(xch), XEN_VERSION_extraversion, &extra, sizeof(extra));
+ retval = xc_version(_H(xch), XENVER_extraversion, &extra);
caml_leave_blocking_section();
- if (retval < 0)
+ if (retval)
failwith_xc(_H(xch));
result = caml_alloc_tuple(3);
@@ -884,28 +884,37 @@ CAMLprim value stub_xc_version_compile_info(value xch)
{
CAMLparam1(xch);
CAMLlocal1(result);
+ xen_compile_info_t ci;
+ int retval;
+
+ caml_enter_blocking_section();
+ retval = xc_version(_H(xch), XENVER_compile_info, &ci);
+ caml_leave_blocking_section();
+
+ if (retval)
+ failwith_xc(_H(xch));
result = caml_alloc_tuple(4);
- Store_field(result, 0, caml_copy_string(""));
- Store_field(result, 1, caml_copy_string(""));
- Store_field(result, 2, caml_copy_string(""));
- Store_field(result, 3, caml_copy_string(""));
+ Store_field(result, 0, caml_copy_string(ci.compiler));
+ Store_field(result, 1, caml_copy_string(ci.compile_by));
+ Store_field(result, 2, caml_copy_string(ci.compile_domain));
+ Store_field(result, 3, caml_copy_string(ci.compile_date));
CAMLreturn(result);
}
-static value xc_version_single_string(value xch, int code, void *info, ssize_t len)
+static value xc_version_single_string(value xch, int code, void *info)
{
CAMLparam1(xch);
int retval;
caml_enter_blocking_section();
- retval = xc_version(_H(xch), code, info, len);
+ retval = xc_version(_H(xch), code, info);
caml_leave_blocking_section();
- if (retval < 0)
+ if (retval)
failwith_xc(_H(xch));
CAMLreturn(caml_copy_string((char *)info));
@@ -916,8 +925,7 @@ CAMLprim value stub_xc_version_changeset(value xch)
{
xen_changeset_info_t ci;
- return xc_version_single_string(xch, XEN_VERSION_changeset,
- &ci, sizeof(ci));
+ return xc_version_single_string(xch, XENVER_changeset, &ci);
}
@@ -925,8 +933,7 @@ CAMLprim value stub_xc_version_capabilities(value xch)
{
xen_capabilities_info_t ci;
- return xc_version_single_string(xch, XEN_VERSION_capabilities,
- &ci, sizeof(ci));
+ return xc_version_single_string(xch, XENVER_capabilities, &ci);
}
diff --git a/tools/python/xen/lowlevel/xc/xc.c b/tools/python/xen/lowlevel/xc/xc.c
index 812a905..8411789 100644
--- a/tools/python/xen/lowlevel/xc/xc.c
+++ b/tools/python/xen/lowlevel/xc/xc.c
@@ -1204,40 +1204,34 @@ static PyObject *pyxc_xeninfo(XcObject *self)
xen_capabilities_info_t xen_caps;
xen_platform_parameters_t p_parms;
xen_commandline_t xen_commandline;
- xen_version_op_val_t xen_version;
- xen_version_op_val_t xen_pagesize;
+ long xen_version;
+ long xen_pagesize;
char str[128];
- if ( xc_version(self->xc_handle, XEN_VERSION_version, &xen_version,
- sizeof(xen_version)) < 0 )
- return pyxc_error_to_exception(self->xc_handle);
+ xen_version = xc_version(self->xc_handle, XENVER_version, NULL);
- if ( xc_version(self->xc_handle, XEN_VERSION_extraversion, &xen_extra,
- sizeof(xen_extra)) < 0 )
+ if ( xc_version(self->xc_handle, XENVER_extraversion, &xen_extra) != 0 )
return pyxc_error_to_exception(self->xc_handle);
- memset(&xen_cc, 0, sizeof(xen_cc));
+ if ( xc_version(self->xc_handle, XENVER_compile_info, &xen_cc) != 0 )
+ return pyxc_error_to_exception(self->xc_handle);
- if ( xc_version(self->xc_handle, XEN_VERSION_changeset, &xen_chgset,
- sizeof(xen_chgset)) < 0 )
+ if ( xc_version(self->xc_handle, XENVER_changeset, &xen_chgset) != 0 )
return pyxc_error_to_exception(self->xc_handle);
- if ( xc_version(self->xc_handle, XEN_VERSION_capabilities, &xen_caps,
- sizeof(xen_caps)) < 0 )
+ if ( xc_version(self->xc_handle, XENVER_capabilities, &xen_caps) != 0 )
return pyxc_error_to_exception(self->xc_handle);
- if ( xc_version(self->xc_handle, XEN_VERSION_platform_parameters,
- &p_parms, sizeof(p_parms)) < 0 )
+ if ( xc_version(self->xc_handle, XENVER_platform_parameters, &p_parms) != 0 )
return pyxc_error_to_exception(self->xc_handle);
- if ( xc_version(self->xc_handle, XEN_VERSION_commandline,
- &xen_commandline, sizeof(xen_commandline)) < 0 )
+ if ( xc_version(self->xc_handle, XENVER_commandline, &xen_commandline) != 0 )
return pyxc_error_to_exception(self->xc_handle);
snprintf(str, sizeof(str), "virt_start=0x%"PRI_xen_ulong, p_parms.virt_start);
- if ( xc_version(self->xc_handle, XEN_VERSION_pagesize, &xen_pagesize,
- sizeof(xen_pagesize)) < 0 )
+ xen_pagesize = xc_version(self->xc_handle, XENVER_pagesize, NULL);
+ if (xen_pagesize < 0 )
return pyxc_error_to_exception(self->xc_handle);
return Py_BuildValue("{s:i,s:i,s:s,s:s,s:i,s:s,s:s,s:s,s:s,s:s,s:s,s:s}",
diff --git a/tools/xenstat/libxenstat/src/xenstat.c b/tools/xenstat/libxenstat/src/xenstat.c
index efb68b5..3495f3f 100644
--- a/tools/xenstat/libxenstat/src/xenstat.c
+++ b/tools/xenstat/libxenstat/src/xenstat.c
@@ -621,18 +621,20 @@ unsigned long long xenstat_network_tdrop(xenstat_network * network)
/* Collect Xen version information */
static int xenstat_collect_xen_version(xenstat_node * node)
{
- xen_version_op_val_t vnum = 0;
+ long vnum = 0;
xen_extraversion_t version;
/* Collect Xen version information if not already collected */
if (node->handle->xen_version[0] == '\0') {
/* Get the Xen version number and extraversion string */
- if (xc_version(node->handle->xc_handle,
- XEN_VERSION_version, &vnum, sizeof(vnum)) < 0)
+ vnum = xc_version(node->handle->xc_handle,
+ XENVER_version, NULL);
+
+ if (vnum < 0)
return 0;
- if (xc_version(node->handle->xc_handle, XEN_VERSION_extraversion,
- &version, sizeof(version)) < 0)
+ if (xc_version(node->handle->xc_handle, XENVER_extraversion,
+ &version) < 0)
return 0;
/* Format the version information as a string and store it */
snprintf(node->handle->xen_version, VERSION_SIZE, "%ld.%ld%s",
diff --git a/tools/xentrace/xenctx.c b/tools/xentrace/xenctx.c
index cd280fc..e647179 100644
--- a/tools/xentrace/xenctx.c
+++ b/tools/xentrace/xenctx.c
@@ -1000,8 +1000,7 @@ static void dump_ctx(int vcpu)
guest_word_size = (cpuctx.msr_efer & 0x400) ? 8 :
guest_protected_mode ? 4 : 2;
/* HVM guest context records are always host-sized */
- if (xc_version(xenctx.xc_handle, XEN_VERSION_capabilities,
- &xen_caps, sizeof(xen_caps)) < 0) {
+ if (xc_version(xenctx.xc_handle, XENVER_capabilities, &xen_caps) != 0) {
perror("xc_version");
return;
}
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 02/27] Revert "HYPERCALL_version_op. New hypercall mirroring XENVER_ but sane."
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 01/27] Revert "libxc/libxl/python/xenstat/ocaml: Use new XEN_VERSION hypercall" Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-14 16:14 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 03/27] xsplice: Design document Konrad Rzeszutek Wilk
` (25 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Konrad Rzeszutek Wilk
This reverts commit 2716d875379d538c1dfccad78a99ca7db2e09f90.
As it was decided that the existing XENVER hypercall - while having
grown organically over the years can still be expanded.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
tools/flask/policy/policy/modules/xen/xen.te | 7 +-
xen/arch/arm/traps.c | 1 -
xen/arch/x86/hvm/hvm.c | 1 -
xen/arch/x86/x86_64/compat/entry.S | 2 -
xen/arch/x86/x86_64/entry.S | 2 -
xen/common/compat/kernel.c | 2 -
xen/common/kernel.c | 212 +++++----------------------
xen/include/public/arch-arm.h | 2 -
xen/include/public/version.h | 72 +--------
xen/include/public/xen.h | 1 -
xen/include/xen/hypercall.h | 4 -
xen/include/xsm/dummy.h | 21 ---
xen/include/xsm/xsm.h | 6 -
xen/xsm/dummy.c | 1 -
xen/xsm/flask/hooks.c | 35 -----
xen/xsm/flask/policy/access_vectors | 21 +--
16 files changed, 43 insertions(+), 347 deletions(-)
diff --git a/tools/flask/policy/policy/modules/xen/xen.te b/tools/flask/policy/policy/modules/xen/xen.te
index a551756..2a2630d 100644
--- a/tools/flask/policy/policy/modules/xen/xen.te
+++ b/tools/flask/policy/policy/modules/xen/xen.te
@@ -76,12 +76,11 @@ allow dom0_t xen_t:xen2 {
get_cpu_featureset
};
-# Allow dom0 to use all XENVER_ subops and VERSION subops that have checks.
+# Allow dom0 to use all XENVER_ subops that have checks.
# Note that dom0 is part of domain_type so this has duplicates.
allow dom0_t xen_t:version {
xen_extraversion xen_compile_info xen_capabilities
xen_changeset xen_pagesize xen_guest_handle xen_commandline
- extraversion capabilities changeset pagesize guest_handle commandline
};
allow dom0_t xen_t:mmu memorymap;
@@ -148,12 +147,10 @@ if (guest_writeconsole) {
# pmu_ctrl is for)
allow domain_type xen_t:xen2 pmu_use;
-# For normal guests all possible except XENVER_commandline, VERSION_changeset,
-# and VERSION_commandline
+# For normal guests all possible except XENVER_commandline.
allow domain_type xen_t:version {
xen_extraversion xen_compile_info xen_capabilities
xen_changeset xen_pagesize xen_guest_handle
- extraversion capabilities pagesize guest_handle
};
###############################################################################
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 1516abd..9abfc3c 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -1274,7 +1274,6 @@ static arm_hypercall_t arm_hypercall_table[] = {
HYPERCALL(multicall, 2),
HYPERCALL(platform_op, 1),
HYPERCALL_ARM(vcpu_op, 3),
- HYPERCALL(version_op, 3),
};
#ifndef NDEBUG
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index f24126d..f41aedd 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4054,7 +4054,6 @@ static const struct {
COMPAT_CALL(platform_op),
COMPAT_CALL(mmuext_op),
HYPERCALL(xenpmu_op),
- HYPERCALL(version_op),
HYPERCALL(arch_1)
};
diff --git a/xen/arch/x86/x86_64/compat/entry.S b/xen/arch/x86/x86_64/compat/entry.S
index 0ff6818..6ca4a54 100644
--- a/xen/arch/x86/x86_64/compat/entry.S
+++ b/xen/arch/x86/x86_64/compat/entry.S
@@ -399,7 +399,6 @@ ENTRY(compat_hypercall_table)
.quad do_tmem_op
.quad do_ni_hypercall /* reserved for XenClient */
.quad do_xenpmu_op /* 40 */
- .quad do_version_op
.rept __HYPERVISOR_arch_0-((.-compat_hypercall_table)/8)
.quad compat_ni_hypercall
.endr
@@ -451,7 +450,6 @@ ENTRY(compat_hypercall_args_table)
.byte 1 /* do_tmem_op */
.byte 0 /* reserved for XenClient */
.byte 2 /* do_xenpmu_op */ /* 40 */
- .byte 3 /* do_version_op */
.rept __HYPERVISOR_arch_0-(.-compat_hypercall_args_table)
.byte 0 /* compat_ni_hypercall */
.endr
diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index 6866e8f..d0f3259 100644
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -735,7 +735,6 @@ ENTRY(hypercall_table)
.quad do_tmem_op
.quad do_ni_hypercall /* reserved for XenClient */
.quad do_xenpmu_op /* 40 */
- .quad do_version_op
.rept __HYPERVISOR_arch_0-((.-hypercall_table)/8)
.quad do_ni_hypercall
.endr
@@ -787,7 +786,6 @@ ENTRY(hypercall_args_table)
.byte 1 /* do_tmem_op */
.byte 0 /* reserved for XenClient */
.byte 2 /* do_xenpmu_op */ /* 40 */
- .byte 3 /* do_version_op */
.rept __HYPERVISOR_arch_0-(.-hypercall_args_table)
.byte 0 /* do_ni_hypercall */
.endr
diff --git a/xen/common/compat/kernel.c b/xen/common/compat/kernel.c
index 7a7ca53..df93fdd 100644
--- a/xen/common/compat/kernel.c
+++ b/xen/common/compat/kernel.c
@@ -39,8 +39,6 @@ CHECK_TYPE(capabilities_info);
CHECK_TYPE(domain_handle);
-CHECK_TYPE(version_op_val);
-
#define xennmi_callback compat_nmi_callback
#define xennmi_callback_t compat_nmi_callback_t
diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index af2674d..a4a3c36 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -221,47 +221,6 @@ void __init do_initcalls(void)
#endif
-static int get_features(struct domain *d, xen_feature_info_t *fi)
-{
- switch ( fi->submap_idx )
- {
- case 0:
- fi->submap = (1U << XENFEAT_memory_op_vnode_supported);
- if ( paging_mode_translate(d) )
- fi->submap |=
- (1U << XENFEAT_writable_page_tables) |
- (1U << XENFEAT_auto_translated_physmap);
- if ( is_hardware_domain(d) )
- fi->submap |= 1U << XENFEAT_dom0;
-#ifdef CONFIG_X86
- if ( VM_ASSIST(d, pae_extended_cr3) )
- fi->submap |= (1U << XENFEAT_pae_pgdir_above_4gb);
- switch ( d->guest_type )
- {
- case guest_type_pv:
- fi->submap |= (1U << XENFEAT_mmu_pt_update_preserve_ad) |
- (1U << XENFEAT_highmem_assist) |
- (1U << XENFEAT_gnttab_map_avail_bits);
- break;
- case guest_type_pvh:
- fi->submap |= (1U << XENFEAT_hvm_safe_pvclock) |
- (1U << XENFEAT_supervisor_mode_kernel) |
- (1U << XENFEAT_hvm_callback_vector);
- break;
- case guest_type_hvm:
- fi->submap |= (1U << XENFEAT_hvm_safe_pvclock) |
- (1U << XENFEAT_hvm_callback_vector) |
- (1U << XENFEAT_hvm_pirqs);
- break;
- }
-#endif
- break;
- default:
- return -EINVAL;
- }
- return 0;
-}
-
/*
* Simple hypercalls.
*/
@@ -339,14 +298,47 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
case XENVER_get_features:
{
xen_feature_info_t fi;
- int rc;
+ struct domain *d = current->domain;
if ( copy_from_guest(&fi, arg, 1) )
return -EFAULT;
- rc = get_features(current->domain, &fi);
- if ( rc )
- return rc;
+ switch ( fi.submap_idx )
+ {
+ case 0:
+ fi.submap = (1U << XENFEAT_memory_op_vnode_supported);
+ if ( VM_ASSIST(d, pae_extended_cr3) )
+ fi.submap |= (1U << XENFEAT_pae_pgdir_above_4gb);
+ if ( paging_mode_translate(d) )
+ fi.submap |=
+ (1U << XENFEAT_writable_page_tables) |
+ (1U << XENFEAT_auto_translated_physmap);
+ if ( is_hardware_domain(d) )
+ fi.submap |= 1U << XENFEAT_dom0;
+#ifdef CONFIG_X86
+ switch ( d->guest_type )
+ {
+ case guest_type_pv:
+ fi.submap |= (1U << XENFEAT_mmu_pt_update_preserve_ad) |
+ (1U << XENFEAT_highmem_assist) |
+ (1U << XENFEAT_gnttab_map_avail_bits);
+ break;
+ case guest_type_pvh:
+ fi.submap |= (1U << XENFEAT_hvm_safe_pvclock) |
+ (1U << XENFEAT_supervisor_mode_kernel) |
+ (1U << XENFEAT_hvm_callback_vector);
+ break;
+ case guest_type_hvm:
+ fi.submap |= (1U << XENFEAT_hvm_safe_pvclock) |
+ (1U << XENFEAT_hvm_callback_vector) |
+ (1U << XENFEAT_hvm_pirqs);
+ break;
+ }
+#endif
+ break;
+ default:
+ return -EINVAL;
+ }
if ( __copy_to_guest(arg, &fi, 1) )
return -EFAULT;
@@ -389,122 +381,6 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
return -ENOSYS;
}
-/* Computed by capabilities_cache_init. */
-static xen_capabilities_info_t __read_mostly cached_cap;
-static unsigned int __read_mostly cached_cap_len;
-
-/*
- * Similar to HYPERVISOR_xen_version but with a sane interface
- * (has a length, one can probe for the length) and with one less sub-ops:
- * missing XENVER_compile_info.
- */
-DO(version_op)(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) arg,
- unsigned int len)
-{
- union {
- xen_version_op_val_t val;
- xen_feature_info_t fi;
- } u = {};
- unsigned int sz = 0;
- const void *ptr = NULL;
- int rc = xsm_version_op(XSM_OTHER, cmd);
-
- if ( rc )
- return rc;
-
- /*
- * The HYPERVISOR_xen_version sub-ops differ in that some return the value,
- * and some copy it on back on argument. We follow the same rule for all
- * sub-ops: return the number of bytes written, or negative errno on
- * failure, and always copy the result in arg. Yeey sanity!
- */
- switch ( cmd )
- {
- case XEN_VERSION_version:
- sz = sizeof(xen_version_op_val_t);
- u.val = (xen_major_version() << 16) | xen_minor_version();
- break;
-
- case XEN_VERSION_extraversion:
- sz = strlen(xen_extra_version()) + 1;
- ptr = xen_extra_version();
- break;
-
- case XEN_VERSION_capabilities:
- sz = cached_cap_len;
- ptr = cached_cap;
- break;
-
- case XEN_VERSION_changeset:
- sz = strlen(xen_changeset()) + 1;
- ptr = xen_changeset();
- break;
-
- case XEN_VERSION_platform_parameters:
- sz = sizeof(xen_version_op_val_t);
- u.val = HYPERVISOR_VIRT_START;
- break;
-
- case XEN_VERSION_get_features:
- sz = sizeof(xen_feature_info_t);
-
- if ( guest_handle_is_null(arg) )
- break;
-
- if ( copy_from_guest(&u.fi, arg, 1) )
- {
- rc = -EFAULT;
- break;
- }
- rc = get_features(current->domain, &u.fi);
- break;
-
- case XEN_VERSION_pagesize:
- sz = sizeof(xen_version_op_val_t);
- u.val = PAGE_SIZE;
- break;
-
- case XEN_VERSION_guest_handle:
- sz = ARRAY_SIZE(current->domain->handle);
- ptr = current->domain->handle;
- break;
-
- case XEN_VERSION_commandline:
- sz = strlen(saved_cmdline) + 1;
- ptr = saved_cmdline;
- break;
-
- default:
- rc = -ENOSYS;
- }
-
- if ( rc )
- return rc;
-
- /*
- * This hypercall also allows the client to probe. If it provides
- * a NULL arg we will return the size of the space it has to
- * allocate for the specific sub-op.
- */
- ASSERT(sz);
- if ( guest_handle_is_null(arg) )
- return sz;
-
- if ( !rc )
- {
- unsigned int bytes = min(sz, len);
-
- if ( copy_to_guest(arg, ptr ? : &u, bytes) )
- rc = -EFAULT;
-
- /* We return len (truncate) worth of data even if we fail. */
- if ( !rc && sz > len )
- rc = -ENOBUFS;
- }
-
- return rc == 0 ? sz : rc;
-}
-
DO(nmi_op)(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
{
struct xennmi_callback cb;
@@ -542,20 +418,6 @@ DO(ni_hypercall)(void)
return -ENOSYS;
}
-static int __init capabilities_cache_init(void)
-{
- /*
- * Pre-populate the cache so we do not have to worry about
- * simultaneous invocations on safe_strcat by guests and the cache
- * data becoming garbage.
- */
- arch_get_xen_caps(&cached_cap);
- cached_cap_len = strlen(cached_cap) + 1;
-
- return 0;
-}
-__initcall(capabilities_cache_init);
-
/*
* Local variables:
* mode: C
diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h
index 5f90718..870bc3b 100644
--- a/xen/include/public/arch-arm.h
+++ b/xen/include/public/arch-arm.h
@@ -128,8 +128,6 @@
* * VCPUOP_register_vcpu_info
* * VCPUOP_register_runstate_memory_area
*
- * HYPERVISOR_version_op
- * All generic sub-operations
*
* Other notes on the ARM ABI:
*
diff --git a/xen/include/public/version.h b/xen/include/public/version.h
index 78961c9..24a582f 100644
--- a/xen/include/public/version.h
+++ b/xen/include/public/version.h
@@ -30,16 +30,7 @@
#include "xen.h"
-/*
- * There are two hypercalls mentioned in here. The XENVER_ are for
- * HYPERCALL_xen_version (17), while VERSION_ are for the
- * HYPERCALL_version_op (41).
- *
- * The subops are very similar except that the later hypercall has a
- * sane interface.
- *
- * NB. All XENVER_ ops return zero on success, except XENVER_{version,pagesize}
- */
+/* NB. All ops return zero on success, except XENVER_{version,pagesize} */
/* arg == NULL; returns major:minor (16:16). */
#define XENVER_version 0
@@ -96,67 +87,6 @@ typedef struct xen_feature_info xen_feature_info_t;
#define XENVER_commandline 9
typedef char xen_commandline_t[1024];
-/*
- * The HYPERCALL_version_op has a set of sub-ops which mirror the
- * sub-ops of HYPERCALL_xen_version. However this hypercall differs
- * radically from the former:
- * - It returns the amount of bytes copied, or
- * - It will return -XEN_EPERM if the sub-op is denied to the guest.
- * (Albeit XEN_VERSION_version, XEN_VERSION_platform_parameters, and
- * XEN_VERSION_get_features will always return an value as guest cannot
- * survive without this information).
- * - It will return the requested data in arg.
- * - It requires an third argument (len) for the length of the
- * arg. Naturally the arg has to fit the requested data otherwise
- * -XEN_ENOBUFS is returned.
- *
- * It also offers a mechanism to probe for the amount of bytes an
- * sub-op will require. Having the arg have a NULL handle will
- * return the number of bytes requested for the operation.
- * Or a negative value if an error is encountered.
- */
-
-typedef uint64_t xen_version_op_val_t;
-DEFINE_XEN_GUEST_HANDLE(xen_version_op_val_t);
-
-/*
- * arg == xen_version_op_val_t. Encoded as major:minor (31..16:15..0), while
- * 63..32 are zero.
- */
-#define XEN_VERSION_version 0
-
-/* arg == char[]. Contains NUL terminated utf-8 string. */
-#define XEN_VERSION_extraversion 1
-
-/* arg == char[]. Contains NUL terminated utf-8 string. */
-#define XEN_VERSION_capabilities 3
-
-/* arg == char[]. Contains NUL terminated utf-8 string. */
-#define XEN_VERSION_changeset 4
-
-/* arg == xen_version_op_val_t. */
-#define XEN_VERSION_platform_parameters 5
-
-/*
- * arg = xen_feature_info_t - shares the same structure
- * as the XENVER_get_features.
- */
-#define XEN_VERSION_get_features 6
-
-/* arg == xen_version_op_val_t. */
-#define XEN_VERSION_pagesize 7
-
-/*
- * arg == void.
- *
- * The toolstack fills it out for guest consumption. It is intended to hold
- * the UUID of the guest.
- */
-#define XEN_VERSION_guest_handle 8
-
-/* arg = char[]. Contains NUL terminated utf-8 string. */
-#define XEN_VERSION_commandline 9
-
#endif /* __XEN_PUBLIC_VERSION_H__ */
/*
diff --git a/xen/include/public/xen.h b/xen/include/public/xen.h
index 97a5ae5..617020b 100644
--- a/xen/include/public/xen.h
+++ b/xen/include/public/xen.h
@@ -115,7 +115,6 @@ DEFINE_XEN_GUEST_HANDLE(xen_ulong_t);
#define __HYPERVISOR_tmem_op 38
#define __HYPERVISOR_xc_reserved_op 39 /* reserved for XenClient */
#define __HYPERVISOR_xenpmu_op 40
-#define __HYPERVISOR_version_op 41 /* supersedes xen_version (17) */
/* Architecture-specific hypercall definitions. */
#define __HYPERVISOR_arch_0 48
diff --git a/xen/include/xen/hypercall.h b/xen/include/xen/hypercall.h
index e8d2b81..0c8ae0e 100644
--- a/xen/include/xen/hypercall.h
+++ b/xen/include/xen/hypercall.h
@@ -147,10 +147,6 @@ do_xenoprof_op(int op, XEN_GUEST_HANDLE_PARAM(void) arg);
extern long
do_xenpmu_op(unsigned int op, XEN_GUEST_HANDLE_PARAM(xen_pmu_params_t) arg);
-extern long
-do_version_op(unsigned int cmd,
- XEN_GUEST_HANDLE_PARAM(void) arg, unsigned int len);
-
#ifdef CONFIG_COMPAT
extern int
diff --git a/xen/include/xsm/dummy.h b/xen/include/xsm/dummy.h
index e5dad35..abbe282 100644
--- a/xen/include/xsm/dummy.h
+++ b/xen/include/xsm/dummy.h
@@ -751,24 +751,3 @@ static XSM_INLINE int xsm_xen_version (XSM_DEFAULT_ARG uint32_t op)
return xsm_default_action(XSM_PRIV, current->domain, NULL);
}
}
-
-static XSM_INLINE int xsm_version_op (XSM_DEFAULT_ARG uint32_t op)
-{
- XSM_ASSERT_ACTION(XSM_OTHER);
- switch ( op )
- {
- case XEN_VERSION_version:
- case XEN_VERSION_platform_parameters:
- case XEN_VERSION_get_features:
- /* These MUST always be accessible to any guest by default. */
- return 0;
- case XEN_VERSION_extraversion:
- case XEN_VERSION_capabilities:
- case XEN_VERSION_pagesize:
- case XEN_VERSION_guest_handle:
- /* These can be accessible to a guest. */
- return xsm_default_action(XSM_HOOK, current->domain, NULL);
- default:
- return xsm_default_action(XSM_PRIV, current->domain, NULL);
- }
-}
diff --git a/xen/include/xsm/xsm.h b/xen/include/xsm/xsm.h
index 3cfd953..8ed8ee5 100644
--- a/xen/include/xsm/xsm.h
+++ b/xen/include/xsm/xsm.h
@@ -197,7 +197,6 @@ struct xsm_operations {
int (*pmu_op) (struct domain *d, unsigned int op);
#endif
int (*xen_version) (uint32_t cmd);
- int (*version_op) (uint32_t cmd);
};
#ifdef CONFIG_XSM
@@ -741,11 +740,6 @@ static inline int xsm_xen_version (xsm_default_t def, uint32_t op)
return xsm_ops->xen_version(op);
}
-static inline int xsm_version_op (xsm_default_t def, uint32_t op)
-{
- return xsm_ops->version_op(op);
-}
-
#endif /* XSM_NO_WRAPPERS */
#ifdef CONFIG_MULTIBOOT
diff --git a/xen/xsm/dummy.c b/xen/xsm/dummy.c
index 776dd09..9791ad4 100644
--- a/xen/xsm/dummy.c
+++ b/xen/xsm/dummy.c
@@ -163,5 +163,4 @@ void xsm_fixup_ops (struct xsm_operations *ops)
set_to_dummy_if_null(ops, pmu_op);
#endif
set_to_dummy_if_null(ops, xen_version);
- set_to_dummy_if_null(ops, version_op);
}
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 233612e..6295768 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -1664,40 +1664,6 @@ static int flask_xen_version (uint32_t op)
}
}
-static int flask_version_op (uint32_t op)
-{
- u32 dsid = domain_sid(current->domain);
-
- switch ( op )
- {
- case XEN_VERSION_version:
- case XEN_VERSION_platform_parameters:
- case XEN_VERSION_get_features:
- /* These MUST always be accessible to any guest by default. */
- return 0;
- case XEN_VERSION_extraversion:
- return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
- VERSION__EXTRAVERSION, NULL);
- case XEN_VERSION_capabilities:
- return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
- VERSION__CAPABILITIES, NULL);
- case XEN_VERSION_changeset:
- return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
- VERSION__CHANGESET, NULL);
- case XEN_VERSION_pagesize:
- return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
- VERSION__PAGESIZE, NULL);
- case XEN_VERSION_guest_handle:
- return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
- VERSION__GUEST_HANDLE, NULL);
- case XEN_VERSION_commandline:
- return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
- VERSION__COMMANDLINE, NULL);
- default:
- return -EPERM;
- }
-}
-
long do_flask_op(XEN_GUEST_HANDLE_PARAM(xsm_op_t) u_flask_op);
int compat_flask_op(XEN_GUEST_HANDLE_PARAM(xsm_op_t) u_flask_op);
@@ -1837,7 +1803,6 @@ static struct xsm_operations flask_ops = {
.pmu_op = flask_pmu_op,
#endif
.xen_version = flask_xen_version,
- .version_op = flask_version_op,
};
static __init void flask_init(void)
diff --git a/xen/xsm/flask/policy/access_vectors b/xen/xsm/flask/policy/access_vectors
index 0ebb56b..bdb7b89 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -500,14 +500,12 @@ class security
del_ocontext
}
-# Class version is used to describe the XENVER_ and VERSION hypercall.
+# Class version is used to describe the XENVER_ hypercall.
# Almost all sub-ops are described here - in the default case all of them should
-# be allowed except the XENVER_commandline, VERSION_commandline, and
-# VERSION_changeset.
+# be allowed except the XENVER_commandline.
#
# The ones that are omitted are XENVER_version, XENVER_platform_parameters,
-# XENVER_get_features, XEN_VERSION_version, XEN_VERSION_platform_parameters,
-# and XEN_VERSION_get_features - as they MUST always be returned to a guest.
+# and XENVER_get_features - as they MUST always be returned to a guest.
#
class version
{
@@ -525,17 +523,4 @@ class version
xen_guest_handle
# Xen command line.
xen_commandline
-# --- VERSION hypercall ---
-# Extra informations (-unstable).
- extraversion
-# Such as "xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64".
- capabilities
-# Source code changeset.
- changeset
-# Page size the hypervisor uses.
- pagesize
-# An value that the control stack can choose.
- guest_handle
-# Xen command line.
- commandline
}
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 03/27] xsplice: Design document
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 01/27] Revert "libxc/libxl/python/xenstat/ocaml: Use new XEN_VERSION hypercall" Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 02/27] Revert "HYPERCALL_version_op. New hypercall mirroring XENVER_ but sane." Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 04/27] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op Konrad Rzeszutek Wilk
` (24 subsequent siblings)
27 siblings, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Keir Fraser, Tim Deegan, Ian Jackson, Jan Beulich, Konrad Rzeszutek Wilk
A mechanism is required to binarily patch the running hypervisor with new
opcodes that have come about due to primarily security updates.
This document describes the design of the API that would allow us to
upload to the hypervisor binary patches.
This document has been shaped by the input from:
Martin Pohlack <mpohlack@amazon.de>
Jan Beulich <jbeulich@suse.com>
Thank you!
Input-from: Martin Pohlack <mpohlack@amazon.de>
Input-from: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Tim Deegan <tim@xen.org>
v1-2: review
v3: Split document in v1 and v2 (todo) to simplify implementation goals.
- Add const on some structures. Truncate size to uint16_t where it makes sense.
- Convert 'id' to 'name', Add Ross's comments about what is implemented.
- Wei's and Ross's reviews.
- Jan's review comments.
- Jan's review comments.
s/int32_t state/uint32_t state/ now that return code is in seperate
field (rc). Add various other types, such as R_X86_64_PC64 in the list.
Mention the need for compiler check.
v4:
- Drop the LOADED->CHECKED state and go directly to CHECKED state. Drop
LOADED.
v5: Julien mentioned ARM 32-bit would not use ELF64, so make the .xsplice.func
use uintXX_t types instead of ELF ones. Remove the OUT on idx subfield.
Mention that 'nr' being zero can be used for probing the number of payloads.
Update what 'idx' means.
v6: Update what 'idx' means again!
Move the "Interdependencies section" to make it easier to in the design
doc the movement of text (when the patch implements it).
Add also 'version' field to payload.
---
---
docs/misc/xsplice.markdown | 1044 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 1044 insertions(+)
create mode 100644 docs/misc/xsplice.markdown
diff --git a/docs/misc/xsplice.markdown b/docs/misc/xsplice.markdown
new file mode 100644
index 0000000..d4e7d75
--- /dev/null
+++ b/docs/misc/xsplice.markdown
@@ -0,0 +1,1044 @@
+# xSplice Design v1
+
+## Rationale
+
+A mechanism is required to binarily patch the running hypervisor with new
+opcodes that have come about due to primarily security updates.
+
+This document describes the design of the API that would allow us to
+upload to the hypervisor binary patches.
+
+The document is split in four sections:
+
+ * Detailed descriptions of the problem statement.
+ * Design of the data structures.
+ * Design of the hypercalls.
+ * Implementation notes that should be taken into consideration.
+
+
+## Glossary
+
+ * splice - patch in the binary code with new opcodes
+ * trampoline - a jump to a new instruction.
+ * payload - telemetries of the old code along with binary blob of the new
+ function (if needed).
+ * reloc - telemetries contained in the payload to construct proper trampoline.
+
+## History
+
+The document has gone under various reviews and only covers v1 design.
+
+The end of the document has a section titled `Not Yet Done` which
+outlines ideas and design for the future version of this work.
+
+## Multiple ways to patch
+
+The mechanism needs to be flexible to patch the hypervisor in multiple ways
+and be as simple as possible. The compiled code is contiguous in memory with
+no gaps - so we have no luxury of 'moving' existing code and must either
+insert a trampoline to the new code to be executed - or only modify in-place
+the code if there is sufficient space. The placement of new code has to be done
+by hypervisor and the virtual address for the new code is allocated dynamically.
+
+This implies that the hypervisor must compute the new offsets when splicing
+in the new trampoline code. Where the trampoline is added (inside
+the function we are patching or just the callers?) is also important.
+
+To lessen the amount of code in hypervisor, the consumer of the API
+is responsible for identifying which mechanism to employ and how many locations
+to patch. Combinations of modifying in-place code, adding trampoline, etc
+has to be supported. The API should allow read/write any memory within
+the hypervisor virtual address space.
+
+We must also have a mechanism to query what has been applied and a mechanism
+to revert it if needed.
+
+## Workflow
+
+The expected workflows of higher-level tools that manage multiple patches
+on production machines would be:
+
+ * The first obvious task is loading all available / suggested
+ hotpatches when they are available.
+ * Whenever new hotpatches are installed, they should be loaded too.
+ * One wants to query which modules have been loaded at runtime.
+ * If unloading is deemed safe (see unloading below), one may want to
+ support a workflow where a specific hotpatch is marked as bad and
+ unloaded.
+
+## Patching code
+
+The first mechanism to patch that comes in mind is in-place replacement.
+That is replace the affected code with new code. Unfortunately the x86
+ISA is variable size which places limits on how much space we have available
+to replace the instructions. That is not a problem if the change is smaller
+than the original opcode and we can fill it with nops. Problems will
+appear if the replacement code is longer.
+
+The second mechanism is by ti replace the call or jump to the
+old function with the address of the new function.
+
+A third mechanism is to add a jump to the new function at the
+start of the old function. N.B. The Xen hypervisor implements the third
+mechanism. See `Trampoline (e9 opcode)` section for more details.
+
+### Example of trampoline and in-place splicing
+
+As example we will assume the hypervisor does not have XSA-132 (see
+*domctl/sysctl: don't leak hypervisor stack to toolstacks*
+4ff3449f0e9d175ceb9551d3f2aecb59273f639d) and we would like to binary patch
+the hypervisor with it. The original code looks as so:
+
+<pre>
+ 48 89 e0 mov %rsp,%rax
+ 48 25 00 80 ff ff and $0xffffffffffff8000,%rax
+</pre>
+
+while the new patched hypervisor would be:
+
+<pre>
+ 48 c7 45 b8 00 00 00 00 movq $0x0,-0x48(%rbp)
+ 48 c7 45 c0 00 00 00 00 movq $0x0,-0x40(%rbp)
+ 48 c7 45 c8 00 00 00 00 movq $0x0,-0x38(%rbp)
+ 48 89 e0 mov %rsp,%rax
+ 48 25 00 80 ff ff and $0xffffffffffff8000,%rax
+</pre>
+
+This is inside the arch_do_domctl. This new change adds 21 extra
+bytes of code which alters all the offsets inside the function. To alter
+these offsets and add the extra 21 bytes of code we might not have enough
+space in .text to squeeze this in.
+
+As such we could simplify this problem by only patching the site
+which calls arch_do_domctl:
+
+<pre>
+do_domctl:
+ e8 4b b1 05 00 callq ffff82d08015fbb9 <arch_do_domctl>
+</pre>
+
+with a new address for where the new `arch_do_domctl` would be (this
+area would be allocated dynamically).
+
+Astute readers will wonder what we need to do if we were to patch `do_domctl`
+- which is not called directly by hypervisor but on behalf of the guests via
+the `compat_hypercall_table` and `hypercall_table`.
+Patching the offset in `hypercall_table` for `do_domctl:
+(ffff82d080103079 <do_domctl>:)
+
+<pre>
+
+ ffff82d08024d490: 79 30
+ ffff82d08024d492: 10 80 d0 82 ff ff
+
+</pre>
+
+with the new address where the new `do_domctl` is possible. The other
+place where it is used is in `hvm_hypercall64_table` which would need
+to be patched in a similar way. This would require an in-place splicing
+of the new virtual address of `arch_do_domctl`.
+
+In summary this example patched the callee of the affected function by
+ * allocating memory for the new code to live in,
+ * changing the virtual address in all the functions which called the old
+ code (computing the new offset, patching the callq with a new callq).
+ * changing the function pointer tables with the new virtual address of
+ the function (splicing in the new virtual address). Since this table
+ resides in the .rodata section we would need to temporarily change the
+ page table permissions during this part.
+
+However it has drawbacks - the safety checks which have to make sure
+the function is not on the stack - must also check every caller. For some
+patches this could mean - if there were an sufficient large amount of
+callers - that we would never be able to apply the update.
+
+Having the patching done at predetermined instances where the stacks
+are not deep mostly solves this problem.
+
+### Example of different trampoline patching.
+
+An alternative mechanism exists where we can insert a trampoline in the
+existing function to be patched to jump directly to the new code. This
+lessens the locations to be patched to one but it puts pressure on the
+CPU branching logic (I-cache, but it is just one unconditional jump).
+
+For this example we will assume that the hypervisor has not been compiled
+with fe2e079f642effb3d24a6e1a7096ef26e691d93e (XSA-125: *pre-fill structures
+for certain HYPERVISOR_xen_version sub-ops*) which mem-sets an structure
+in `xen_version` hypercall. This function is not called **anywhere** in
+the hypervisor (it is called by the guest) but referenced in the
+`compat_hypercall_table` and `hypercall_table` (and indirectly called
+from that). Patching the offset in `hypercall_table` for the old
+`do_xen_version` (ffff82d080112f9e <do_xen_version>)
+
+</pre>
+ ffff82d08024b270 <hypercall_table>:
+ ...
+ ffff82d08024b2f8: 9e 2f 11 80 d0 82 ff ff
+
+</pre>
+
+with the new address where the new `do_xen_version` is possible. The other
+place where it is used is in `hvm_hypercall64_table` which would need
+to be patched in a similar way. This would require an in-place splicing
+of the new virtual address of `do_xen_version`.
+
+An alternative solution would be to patch insert a trampoline in the
+old `do_xen_version' function to directly jump to the new `do_xen_version`.
+
+<pre>
+ ffff82d080112f9e do_xen_version:
+ ffff82d080112f9e: 48 c7 c0 da ff ff ff mov $0xffffffffffffffda,%rax
+ ffff82d080112fa5: 83 ff 09 cmp $0x9,%edi
+ ffff82d080112fa8: 0f 87 24 05 00 00 ja ffff82d0801134d2 ; do_xen_version+0x534
+</pre>
+
+with:
+
+<pre>
+ ffff82d080112f9e do_xen_version:
+ ffff82d080112f9e: e9 XX YY ZZ QQ jmpq [new do_xen_version]
+</pre>
+
+which would lessen the amount of patching to just one location.
+
+In summary this example patched the affected function to jump to the
+new replacement function which required:
+ * allocating memory for the new code to live in,
+ * inserting trampoline with new offset in the old function to point to the
+ new function.
+ * Optionally we can insert in the old function a trampoline jump to an function
+ providing an BUG_ON to catch errant code.
+
+The disadvantage of this are that the unconditional jump will consume a small
+I-cache penalty. However the simplicity of the patching and higher chance
+of passing safety checks make this a worthwhile option.
+
+This patching has a similar drawback as inline patching - the safety
+checks have to make sure the function is not on the stack. However
+since we are replacing at a higher level (a full function as opposed
+to various offsets within functions) the checks are simpler.
+
+Having the patching done at predetermined instances where the stacks
+are not deep mostly solves this problem as well.
+
+### Security
+
+With this method we can re-write the hypervisor - and as such we **MUST** be
+diligent in only allowing certain guests to perform this operation.
+
+Furthermore with SecureBoot or tboot, we **MUST** also verify the signature
+of the payload to be certain it came from a trusted source and integrity
+was intact.
+
+As such the hypercall **MUST** support an XSM policy to limit what the guest
+is allowed to invoke. If the system is booted with signature checking the
+signature checking will be enforced.
+
+## Design of payload format
+
+The payload **MUST** contain enough data to allow us to apply the update
+and also safely reverse it. As such we **MUST** know:
+
+ * The locations in memory to be patched. This can be determined dynamically
+ via symbols or via virtual addresses.
+ * The new code that will be patched in.
+
+This binary format can be constructed using an custom binary format but
+there are severe disadvantages of it:
+
+ * The format might need to be changed and we need an mechanism to accommodate
+ that.
+ * It has to be platform agnostic.
+ * Easily constructed using existing tools.
+
+As such having the payload in an ELF file is the sensible way. We would be
+carrying the various sets of structures (and data) in the ELF sections under
+different names and with definitions.
+
+Note that every structure has padding. This is added so that the hypervisor
+can re-use those fields as it sees fit.
+
+Earlier design attempted to ineptly explain the relations of the ELF sections
+to each other without using proper ELF mechanism (sh_info, sh_link, data
+structures using Elf types, etc). This design will explain the structures
+and how they are used together and not dig in the ELF format - except mention
+that the section names should match the structure names.
+
+The xSplice payload is a relocatable ELF binary. A typical binary would have:
+
+ * One or more .text sections.
+ * Zero or more read-only data sections.
+ * Zero or more data sections.
+ * Relocations for each of these sections.
+
+It may also have some architecture-specific sections. For example:
+
+ * Alternatives instructions.
+ * Bug frames.
+ * Exception tables.
+ * Relocations for each of these sections.
+
+The xSplice core code loads the payload as a standard ELF binary, relocates it
+and handles the architecture-specifc sections as needed. This process is much
+like what the Linux kernel module loader does.
+
+The payload contains a section (xsplice_patch_func) with an array of structures
+describing the functions to be patched:
+
+<pre>
+struct xsplice_patch_func {
+ const char *name;
+ uint64_t new_addr;
+ uint64_t old_addr;
+ uint32_t new_size;
+ uint32_t old_size;
+ uint8_t version;
+ uint8_t pad[31];
+};
+</pre>
+
+The size of the structure is 64 bytes.
+
+* `name` is the symbol name of the old function. Only used if `old_addr` is
+ zero, otherwise will be used during dynamic linking (when hypervisor loads
+ the payload).
+
+* `old_addr` is the address of the function to be patched and is filled in at
+ payload generation time if hypervisor function address is known. If unknown,
+ the value *MUST* be zero and the hypervisor will attempt to resolve the address.
+
+* `new_addr` is the address of the function that is replacing the old
+ function. The address is filled in during relocation. The value **MUST** be
+ the address of the new function in the file.
+
+* `old_size` and `new_size` contain the sizes of the respective functions in bytes.
+ The value of `old_size` **MUST** not be zero.
+
+* `version` is to be one.
+
+* `pad` **MUST** be zero.
+
+The size of the `xsplice_patch_func` array is determined from the ELF section
+size.
+
+When applying the patch the hypervisor iterates over each `xsplice_patch_func`
+structure and the core code inserts a trampoline at `old_addr` to `new_addr`.
+The `new_addr` is altered when the ELF payload is loaded.
+
+When reverting a patch, the hypervisor iterates over each `xsplice_patch_func`
+and the core code copies the data from the undo buffer (private internal copy)
+to `old_addr`.
+
+## Hypercalls
+
+We will employ the sub operations of the system management hypercall (sysctl).
+There are to be four sub-operations:
+
+ * upload the payloads.
+ * listing of payloads summary uploaded and their state.
+ * getting an particular payload summary and its state.
+ * command to apply, delete, or revert the payload.
+
+Most of the actions are asynchronous therefore the caller is responsible
+to verify that it has been applied properly by retrieving the summary of it
+and verifying that there are no error codes associated with the payload.
+
+We **MUST** make some of them asynchronous due to the nature of patching
+it requires every physical CPU to be lock-step with each other.
+The patching mechanism while an implementation detail, is not an short
+operation and as such the design **MUST** assume it will be an long-running
+operation.
+
+The sub-operations will spell out how preemption is to be handled (if at all).
+
+Furthermore it is possible to have multiple different payloads for the same
+function. As such an unique name per payload has to be visible to allow proper manipulation.
+
+The hypercall is part of the `xen_sysctl`. The top level structure contains
+one uint32_t to determine the sub-operations and one padding field which
+*MUST* always be zero.
+
+<pre>
+struct xen_sysctl_xsplice_op {
+ uint32_t cmd; /* IN: XEN_SYSCTL_XSPLICE_*. */
+ uint32_t pad; /* IN: Always zero. */
+ union {
+ ... see below ...
+ } u;
+};
+
+</pre>
+while the rest of hypercall specific structures are part of the this structure.
+
+### Basic type: struct xen_xsplice_name
+
+Most of the hypercalls employ an shared structure called `struct xen_xsplice_name`
+which contains:
+
+ * `name` - pointer where the string for the name is located.
+ * `size` - the size of the string
+ * `pad` - padding - to be zero.
+
+The structure is as follow:
+
+<pre>
+/*
+ * Uniquely identifies the payload. Should be human readable.
+ * Includes the NUL terminator
+ */
+#define XEN_XSPLICE_NAME_SIZE 128
+struct xen_xsplice_name {
+ XEN_GUEST_HANDLE_64(char) name; /* IN, pointer to name. */
+ uint16_t size; /* IN, size of name. May be upto
+ XEN_XSPLICE_NAME_SIZE. */
+ uint16_t pad[3]; /* IN: MUST be zero. */
+};
+</pre>
+
+### XEN_SYSCTL_XSPLICE_UPLOAD (0)
+
+Upload a payload to the hypervisor. The payload is verified
+against basic checks and if there are any issues the proper return code
+will be returned. The payload is not applied at this time - that is
+controlled by *XEN_SYSCTL_XSPLICE_ACTION*.
+
+The caller provides:
+
+ * A `struct xen_xsplice_name` called `name` which has the unique name.
+ * `size` the size of the ELF payload (in bytes).
+ * `payload` the virtual address of where the ELF payload is.
+
+The `name` could be an UUID that stays fixed forever for a given
+payload. It can be embedded into the ELF payload at creation time
+and extracted by tools.
+
+The return value is zero if the payload was succesfully uploaded.
+Otherwise an -XEN_EXX return value is provided. Duplicate `name` are not supported.
+
+The `payload` is the ELF payload as mentioned in the `Payload format` section.
+
+The structure is as follow:
+
+<pre>
+struct xen_sysctl_xsplice_upload {
+ xen_xsplice_name_t name; /* IN, name of the patch. */
+ uint64_t size; /* IN, size of the ELF file. */
+ XEN_GUEST_HANDLE_64(uint8) payload; /* IN: ELF file. */
+};
+</pre>
+
+### XEN_SYSCTL_XSPLICE_GET (1)
+
+Retrieve an status of an specific payload. This caller provides:
+
+ * A `struct xen_xsplice_name` called `name` which has the unique name.
+ * A `struct xen_xsplice_status` structure. The member values will
+ be over-written upon completion.
+
+Upon completion the `struct xen_xsplice_status` is updated.
+
+ * `status` - indicates the current status of the payload:
+ * *XSPLICE_STATUS_CHECKED* (1) loaded and the ELF payload safety checks passed.
+ * *XSPLICE_STATUS_APPLIED* (2) loaded, checked, and applied.
+ * No other value is possible.
+ * `rc` - -XEN_EXX type errors encountered while performing the last
+ XSPLICE_ACTION_* operation. The normal values can be zero or -XEN_EAGAIN which
+ respectively mean: success or operation in progress. Other values
+ imply an error occurred. If there is an error in `rc`, `status` will **NOT**
+ have changed.
+
+The return value of the hypercall is zero on success and -XEN_EXX on failure.
+(Note that the `rc`` value can be different from the return value, as in
+rc=-XEN_EAGAIN and return value can be 0).
+
+For example, supposing there is an payload:
+
+<pre>
+ status: XSPLICE_STATUS_CHECKED
+ rc: 0
+</pre>
+
+We apply an action - XSPLICE_ACTION_REVERT - to revert it (which won't work
+as we have not even applied it. Afterwards we will have:
+
+<pre>
+ status: XSPLICE_STATUS_CHECKED
+ rc: -XEN_EINVAL
+</pre>
+
+It has failed but it remains loaded.
+
+This operation is synchronous and does not require preemption.
+
+The structure is as follow:
+
+<pre>
+struct xen_xsplice_status {
+#define XSPLICE_STATUS_CHECKED 1
+#define XSPLICE_STATUS_APPLIED 2
+ uint32_t state; /* OUT: XSPLICE_STATE_*. */
+ int32_t rc; /* OUT: 0 if no error, otherwise -XEN_EXX. */
+};
+
+struct xen_sysctl_xsplice_get {
+ xen_xsplice_name_t name; /* IN, the name of the payload. */
+ xen_xsplice_status_t status; /* IN/OUT: status of the payload. */
+};
+</pre>
+
+### XEN_SYSCTL_XSPLICE_LIST (2)
+
+Retrieve an array of abbreviated status and names of payloads that are loaded in the
+hypervisor.
+
+The caller provides:
+
+ * `version`. Version of the payload. Caller should re-use the field provided by
+ the hypervisor. If the value differs the data is stale.
+ * `idx` index iterator. The index into the hypervisor's payload count. It is
+ recommended that on first invocation zero be used so that `nr` (which the
+ hypervisor will update with the remaining payload count) be provided.
+ Also the hypervisor will provide `version` with the most current value.
+ * `nr` the max number of entries to populate. Can be zero which will result
+ in the hypercall being a probing one and return the number of payloads
+ (and update the `version`).
+ * `pad` - *MUST* be zero.
+ * `status` virtual address of where to write `struct xen_xsplice_status`
+ structures. Caller *MUST* allocate up to `nr` of them.
+ * `name` - virtual address of where to write the unique name of the payload.
+ Caller *MUST* allocate up to `nr` of them. Each *MUST* be of
+ **XEN_XSPLICE_NAME_SIZE** size. Note that **XEN_XSPLICE_NAME_SIZE** includes
+ the NUL terminator.
+ * `len` - virtual address of where to write the length of each unique name
+ of the payload. Caller *MUST* allocate up to `nr` of them. Each *MUST* be
+ of sizeof(uint32_t) (4 bytes).
+
+If the hypercall returns an positive number, it is the number (upto `nr`
+provided to the hypercall) of the payloads returned, along with `nr` updated
+with the number of remaining payloads, `version` updated (it may be the same
+across hypercalls - if it varies the data is stale and further calls could
+fail). The `status`, `name`, and `len`' are updated at their designed index
+value (`idx`) with the returned value of data.
+
+If the hypercall returns -XEN_E2BIG the `nr` is too big and should be
+lowered.
+
+If the hypercall returns an zero value there are no more payloads.
+
+Note that due to the asynchronous nature of hypercalls the control domain might
+have added or removed a number of payloads making this information stale. It is
+the responsibility of the toolstack to use the `version` field to check
+between each invocation. if the version differs it should discard the stale
+data and start from scratch. It is OK for the toolstack to use the new
+`version` field.
+
+The `struct xen_xsplice_status` structure contains an status of payload which includes:
+
+ * `status` - indicates the current status of the payload:
+ * *XSPLICE_STATUS_CHECKED* (1) loaded and the ELF payload safety checks passed.
+ * *XSPLICE_STATUS_APPLIED* (2) loaded, checked, and applied.
+ * No other value is possible.
+ * `rc` - -XEN_EXX type errors encountered while performing the last
+ XSPLICE_ACTION_* operation. The normal values can be zero or -XEN_EAGAIN which
+ respectively mean: success or operation in progress. Other values
+ imply an error occurred. If there is an error in `rc`, `status` will **NOT**
+ have changed.
+
+The structure is as follow:
+
+<pre>
+struct xen_sysctl_xsplice_list {
+ uint32_t version; /* OUT: Hypervisor stamps value.
+ If varies between calls, we are
+ getting stale data. */
+ uint32_t idx; /* IN: Index into hypervisor list. */
+ uint32_t nr; /* IN: How many status, names, and len
+ should be filled out. Can be zero to get
+ amount of payloads and version.
+ OUT: How many payloads left. */
+ uint32_t pad; /* IN: Must be zero. */
+ XEN_GUEST_HANDLE_64(xen_xsplice_status_t) status; /* OUT. Must have enough
+ space allocate for nr of them. */
+ XEN_GUEST_HANDLE_64(char) id; /* OUT: Array of names. Each member
+ MUST XEN_XSPLICE_NAME_SIZE in size.
+ Must have nr of them. */
+ XEN_GUEST_HANDLE_64(uint32) len; /* OUT: Array of lengths of name's.
+ Must have nr of them. */
+};
+</pre>
+
+### XEN_SYSCTL_XSPLICE_ACTION (3)
+
+Perform an operation on the payload structure referenced by the `name` field.
+The operation request is asynchronous and the status should be retrieved
+by using either **XEN_SYSCTL_XSPLICE_GET** or **XEN_SYSCTL_XSPLICE_LIST** hypercall.
+
+The caller provides:
+
+ * A 'struct xen_xsplice_name` `name` containing the unique name.
+ * `cmd` the command requested:
+ * *XSPLICE_ACTION_CHECK* (1) check that the payload will apply properly.
+ This also verfies the payload - which may require SecureBoot firmware
+ calls. This is the initial state an payload is in.
+ * *XSPLICE_ACTION_UNLOAD* (2) unload the payload.
+ Any further hypercalls against the `name` will result in failure unless
+ **XEN_SYSCTL_XSPLICE_UPLOAD** hypercall is perfomed with same `name`.
+ * *XSPLICE_ACTION_REVERT* (3) revert the payload. If the operation takes
+ more time than the upper bound of time the `rc` in `xen_xsplice_status'
+ retrieved via **XEN_SYSCTL_XSPLICE_GET** will be -XEN_EBUSY.
+ * *XSPLICE_ACTION_APPLY* (4) apply the payload. If the operation takes
+ more time than the upper bound of time the `rc` in `xen_xsplice_status'
+ retrieved via **XEN_SYSCTL_XSPLICE_GET** will be -XEN_EBUSY.
+ * *XSPLICE_ACTION_REPLACE* (5) revert all applied payloads and apply this
+ payload. If the operation takes more time than the upper bound of time
+ the `rc` in `xen_xsplice_status' retrieved via **XEN_SYSCTL_XSPLICE_GET**
+ will be -XEN_EBUSY.
+ * `time` the upper bound of time (ms) the cmd should take. Zero means infinite.
+ If within the time the operation does not succeed the operation would go in
+ error state.
+ * `pad` - *MUST* be zero.
+
+The return value will be zero unless the provided fields are incorrect.
+
+The structure is as follow:
+
+<pre>
+#define XSPLICE_ACTION_CHECK 1
+#define XSPLICE_ACTION_UNLOAD 2
+#define XSPLICE_ACTION_REVERT 3
+#define XSPLICE_ACTION_APPLY 4
+#define XSPLICE_ACTION_REPLACE 5
+struct xen_sysctl_xsplice_action {
+ xen_xsplice_name_t name; /* IN, name of the patch. */
+ uint32_t cmd; /* IN: XSPLICE_ACTION_* */
+ uint32_t time; /* IN: Zero if no timeout. */
+ /* Or upper bound of time (ms) */
+ /* for operation to take. */
+};
+
+</pre>
+
+## State diagrams of XSPLICE_ACTION commands.
+
+There is a strict ordering state of what the commands can be.
+The XSPLICE_ACTION prefix has been dropped to easy reading and
+does not include the XSPLICE_STATES:
+
+<pre>
+ /->\
+ \ /
+ UNLOAD <--- CHECK ---> REPLACE|APPLY --> REVERT --\
+ \ |
+ \-------------------<-------------/
+
+</pre>
+## State transition table of XSPLICE_ACTION commands and XSPLICE_STATUS.
+
+Note that:
+
+ - The CHECKED state is the starting one achieved with *XEN_SYSCTL_XSPLICE_UPLOAD* hypercall.
+ - The REVERT operation on success will automatically move to the CHECKED state.
+ - There are two STATES: CHECKED and APPLIED.
+ - There are five actions (aka commands): CHECK, APPLY, REPLACE, REVERT, and UNLOAD.
+
+The state transition table of valid states and action states:
+
+<pre>
+
++---------+---------+--------------------------------+-------+--------+
+| ACTION | Current | Result | Next STATE: |
+| ACTION | STATE | |CHECKED|APPLIED |
++---------+----------+-------------------------------+-------+--------+
+| CHECK | CHECKED | Check payload (once more, no) | x | |
+| | | errors) | | |
++---------+---------+--------------------------------+-------+--------+
+| CHECK | CHECKED | Check payload (once more, with | | |
+| | | errors) | | |
++---------+---------+--------------------------------+-------+--------+
+| UNLOAD | CHECKED | Unload payload. Always works. | | |
+| | | No next states. | | |
++---------+---------+--------------------------------+-------+--------+
+| APPLY | CHECKED | Apply payload (success). | | x |
++---------+---------+--------------------------------+-------+--------+
+| APPLY | CHECKED | Apply payload (error|timeout) | x | |
++---------+---------+--------------------------------+-------+--------+
+| REPLACE | CHECKED | Revert payloads and apply new | | x |
+| | | payload with success. | | |
++---------+---------+--------------------------------+-------+--------+
+| REPLACE | CHECKED | Revert payloads and apply new | x | |
+| | | payload with error. | | |
++---------+---------+--------------------------------+-------+--------+
+| REVERT | APPLIED | Revert payload (success). | x | |
++---------+---------+--------------------------------+-------+--------+
+| REVERT | APPLIED | Revert payload (error|timeout) | | x |
++---------+---------+--------------------------------+-------+--------+
+</pre>
+
+All the other state transitions are invalid.
+
+## Sequence of events.
+
+The normal sequence of events is to:
+
+ 1. *XEN_SYSCTL_XSPLICE_UPLOAD* to upload the payload. If there are errors *STOP* here.
+ 2. *XEN_SYSCTL_XSPLICE_GET* to check the `->rc`. If *-XEN_EAGAIN* spin. If zero go to next step.
+ 3. *XEN_SYSCTL_XSPLICE_ACTION* with *XSPLICE_ACTION_APPLY* to apply the patch.
+ 4. *XEN_SYSCTL_XSPLICE_GET* to check the `->rc`. If in *-XEN_EAGAIN* spin. If zero exit with success.
+
+
+## Addendum
+
+Implementation quirks should not be discussed in a design document.
+
+However these observations can provide aid when developing against this
+document.
+
+
+### Alternative assembler
+
+Alternative assembler is a mechanism to use different instructions depending
+on what the CPU supports. This is done by providing multiple streams of code
+that can be patched in - or if the CPU does not support it - padded with
+`nop` operations. The alternative assembler macros cause the compiler to
+expand the code to place a most generic code in place - emit a special
+ELF .section header to tag this location. During run-time the hypervisor
+can leave the areas alone or patch them with an better suited opcodes.
+
+Note that patching functions that copy to or from guest memory requires
+to support alternative support. For example this can be due to SMAP
+(specifically *stac* and *clac* operations) which is enabled on Broadwell
+and later architectures. It may be related to other alternative instructions.
+
+### When to patch
+
+During the discussion on the design two candidates bubbled where
+the call stack for each CPU would be deterministic. This would
+minimize the chance of the patch not being applied due to safety
+checks failing. Safety checks such as not patching code which
+is on the stack - which can lead to corruption.
+
+#### Rendezvous code instead of stop_machine for patching
+
+The hypervisor's time rendezvous code runs synchronously across all CPUs
+every second. Using the stop_machine to patch can stall the time rendezvous
+code and result in NMI. As such having the patching be done at the tail
+of rendezvous code should avoid this problem.
+
+However the entrance point for that code is
+do_softirq->timer_softirq_action->time_calibration
+which ends up calling on_selected_cpus on remote CPUs.
+
+The remote CPUs receive CALL_FUNCTION_VECTOR IPI and execute the
+desired function.
+
+#### Before entering the guest code.
+
+Before we call VMXResume we check whether any soft IRQs need to be executed.
+This is a good spot because all Xen stacks are effectively empty at
+that point.
+
+To randezvous all the CPUs an barrier with an maximum timeout (which
+could be adjusted), combined with forcing all other CPUs through the
+hypervisor with IPIs, can be utilized to execute lockstep instructions
+on all CPUs.
+
+The approach is similar in concept to stop_machine and the time rendezvous
+but is time-bound. However the local CPU stack is much shorter and
+a lot more deterministic.
+
+This is implemented in the Xen Project hypervisor.
+
+### Compiling the hypervisor code
+
+Hotpatch generation often requires support for compiling the target
+with -ffunction-sections / -fdata-sections. Changes would have to
+be done to the linker scripts to support this.
+
+### Generation of xSplice ELF payloads
+
+The design of that is not discussed in this design.
+
+This is implemented in a seperate tool which lives in a seperate
+GIT repo.
+
+Currently it resides at https://github.com/rosslagerwall/xsplice-build
+
+### Exception tables and symbol tables growth
+
+We may need support for adapting or augmenting exception tables if
+patching such code. Hotpatches may need to bring their own small
+exception tables (similar to how Linux modules support this).
+
+If supporting hotpatches that introduce additional exception-locations
+is not important, one could also change the exception table in-place
+and reorder it afterwards.
+
+As found almost every patch (XSA) to a non-trivial function requires
+additional entries in the exception table and/or the bug frames.
+
+This is implemented in the Xen Project hypervisor.
+
+### .rodata sections
+
+The patching might require strings to be updated as well. As such we must be
+also able to patch the strings as needed. This sounds simple - but the compiler
+has a habit of coalescing strings that are the same - which means if we in-place
+alter the strings - other users will be inadvertently affected as well.
+
+This is also where pointers to functions live - and we may need to patch this
+as well. And switch-style jump tables.
+
+To guard against that we must be prepared to do patching similar to
+trampoline patching or in-line depending on the flavour. If we can
+do in-line patching we would need to:
+
+ * alter `.rodata` to be writeable.
+ * inline patch.
+ * alter `.rodata` to be read-only.
+
+If are doing trampoline patching we would need to:
+
+ * allocate a new memory location for the string.
+ * all locations which use this string will have to be updated to use the
+ offset to the string.
+ * mark the region RO when we are done.
+
+The trampoline patching is implemented in the Xen Project hypervisor.
+
+### .bss and .data sections.
+
+In place patching writable data is not suitable as it is unclear what should be done
+depending on the current state of data. As such it should not be attempted.
+
+However, functions which are being patched can bring in changes to strings
+(.data or .rodata section changes), or even to .bss sections.
+
+As such the ELF payload can introduce new .rodata, .bss, and .data sections.
+Patching in the new function will end up also patching in the new .rodata
+section and the new function will reference the new string in the new
+.rodata section.
+
+This is implemented in the Xen Project hypervisor.
+
+### Security
+
+Only the privileged domain should be allowed to do this operation.
+
+
+# Not Yet Done
+
+This is for further development of xSplice.
+
+## TODO Goals
+
+The implementation must also have a mechanism for (in no particular order):
+
+ * Be able to lookup in the Xen hypervisor the symbol names of functions from the ELF payload.
+ * Be able to patch .rodata, .bss, and .data sections.
+ * Deal with NMI/MCE checks during patching instead of ignoring them.
+ * Further safety checks (blacklist of which functions cannot be patched, check
+ the stack, make sure the payload is built with same compiler as hypervisor).
+ Specifically we want to make sure that xSplice codepaths cannot be patched.
+ * NOP out the code sequence if `new_size` is zero.
+ * Deal with other relocation types: R_X86_64_[8,16,32,32S], R_X86_64_PC[8,16,64] in payload file.
+ * An dependency mechanism for the payloads. To use that information to load:
+ - The appropiate payload. To verify that payload is built against the
+ hypervisor. This can be done via the `build-id`
+ or via providing an copy of the old code - so that the hypervisor can
+ verify it against the code in memory.
+ - To construct an appropiate order of payloads to load in case they
+ depend on each other.
+
+### Handle inlined __LINE__
+
+This problem is related to hotpatch construction
+and potentially has influence on the design of the hotpatching
+infrastructure in Xen.
+
+For example:
+
+We have file1.c with functions f1 and f2 (in that order). f2 contains a
+BUG() (or WARN()) macro and at that point embeds the source line number
+into the generated code for f2.
+
+Now we want to hotpatch f1 and the hotpatch source-code patch adds 2
+lines to f1 and as a consequence shifts out f2 by two lines. The newly
+constructed file1.o will now contain differences in both binary
+functions f1 (because we actually changed it with the applied patch) and
+f2 (because the contained BUG macro embeds the new line number).
+
+Without additional information, an algorithm comparing file1.o before
+and after hotpatch application will determine both functions to be
+changed and will have to include both into the binary hotpatch.
+
+Options:
+
+1. Transform source code patches for hotpatches to be line-neutral for
+ each chunk. This can be done in almost all cases with either
+ reformatting of the source code or by introducing artificial
+ preprocessor "#line n" directives to adjust for the introduced
+ differences.
+
+ This approach is low-tech and simple. Potentially generated
+ backtraces and existing debug information refers to the original
+ build and does not reflect hotpatching state except for actually
+ hotpatched functions but should be mostly correct.
+
+2. Ignoring the problem and living with artificially large hotpatches
+ that unnecessarily patch many functions.
+
+ This approach might lead to some very large hotpatches depending on
+ content of specific source file. It may also trigger pulling in
+ functions into the hotpatch that cannot reasonable be hotpatched due
+ to limitations of a hotpatching framework (init-sections, parts of
+ the hotpatching framework itself, ...) and may thereby prevent us
+ from patching a specific problem.
+
+ The decision between 1. and 2. can be made on a patch--by-patch
+ basis.
+
+3. Introducing an indirection table for storing line numbers and
+ treating that specially for binary diffing. Linux may follow
+ this approach.
+
+ We might either use this indirection table for runtime use and patch
+ that with each hotpatch (similarly to exception tables) or we might
+ purely use it when building hotpatches to ignore functions that only
+ differ at exactly the location where a line-number is embedded.
+
+For BUG(), WARN(), etc., the line number is embedded into the bug frame, not
+the function itself.
+
+Similar considerations are true to a lesser extent for __FILE__, but it
+could be argued that file renaming should be done outside of hotpatches.
+
+### xSplice interdependencies
+
+xSplice patches interdependencies are tricky.
+
+There are the ways this can be addressed:
+ * A single large patch that subsumes and replaces all previous ones.
+ Over the life-time of patching the hypervisor this large patch
+ grows to accumulate all the code changes.
+ * Hotpatch stack - where an mechanism exists that loads the hotpatches
+ in the same order they were built in. We would need an build-id
+ of the hypevisor to make sure the hot-patches are build against the
+ correct build.
+ * Payload containing the old code to check against that. That allows
+ the hotpatches to be loaded indepedently (if they don't overlap) - or
+ if the old code also containst previously patched code - even if they
+ overlap.
+
+The disadvantage of the first large patch is that it can grow over
+time and not provide an bisection mechanism to identify faulty patches.
+
+The hot-patch stack puts stricts requirements on the order of the patches
+being loaded and requires an hypervisor build-id to match against.
+
+The old code allows much more flexibility and an additional guard,
+but is more complex to implement.
+
+## Signature checking requirements.
+
+The signature checking requires that the layout of the data in memory
+**MUST** be same for signature to be verified. This means that the payload
+data layout in ELF format **MUST** match what the hypervisor would be
+expecting such that it can properly do signature verification.
+
+The signature is based on the all of the payloads continuously laid out
+in memory. The signature is to be appended at the end of the ELF payload
+prefixed with the string '~Module signature appended~\n', followed by
+an signature header then followed by the signature, key identifier, and signers
+name.
+
+Specifically the signature header would be:
+
+<pre>
+#define PKEY_ALGO_DSA 0
+#define PKEY_ALGO_RSA 1
+
+#define PKEY_ID_PGP 0 /* OpenPGP generated key ID */
+#define PKEY_ID_X509 1 /* X.509 arbitrary subjectKeyIdentifier */
+
+#define HASH_ALGO_MD4 0
+#define HASH_ALGO_MD5 1
+#define HASH_ALGO_SHA1 2
+#define HASH_ALGO_RIPE_MD_160 3
+#define HASH_ALGO_SHA256 4
+#define HASH_ALGO_SHA384 5
+#define HASH_ALGO_SHA512 6
+#define HASH_ALGO_SHA224 7
+#define HASH_ALGO_RIPE_MD_128 8
+#define HASH_ALGO_RIPE_MD_256 9
+#define HASH_ALGO_RIPE_MD_320 10
+#define HASH_ALGO_WP_256 11
+#define HASH_ALGO_WP_384 12
+#define HASH_ALGO_WP_512 13
+#define HASH_ALGO_TGR_128 14
+#define HASH_ALGO_TGR_160 15
+#define HASH_ALGO_TGR_192 16
+
+
+struct elf_payload_signature {
+ u8 algo; /* Public-key crypto algorithm PKEY_ALGO_*. */
+ u8 hash; /* Digest algorithm: HASH_ALGO_*. */
+ u8 id_type; /* Key identifier type PKEY_ID*. */
+ u8 signer_len; /* Length of signer's name */
+ u8 key_id_len; /* Length of key identifier */
+ u8 __pad[3];
+ __be32 sig_len; /* Length of signature data */
+};
+
+</pre>
+(Note that this has been borrowed from Linux module signature code.).
+
+
+### .bss and .data sections.
+
+In place patching writable data is not suitable as it is unclear what should be done
+depending on the current state of data. As such it should not be attempted.
+
+That said we should provide hook functions so that the existing data
+can be changed during payload application.
+
+
+### Inline patching
+
+The hypervisor should verify that the in-place patching would fit within
+the code or data.
+
+### Trampoline (e9 opcode)
+
+The e9 opcode used for jmpq uses a 32-bit signed displacement. That means
+we are limited to up to 2GB of virtual address to place the new code
+from the old code. That should not be a problem since Xen hypervisor has
+a very small footprint.
+
+However if we need - we can always add two trampolines. One at the 2GB
+limit that calls the next trampoline.
+
+Please note there is a small limitation for trampolines in
+function entries: The target function (+ trailing padding) must be able
+to accomodate the trampoline. On x86 with +-2 GB relative jumps,
+this means 5 bytes are required.
+
+Depending on compiler settings, there are several functions in Xen that
+are smaller (without inter-function padding).
+
+<pre>
+readelf -sW xen-syms | grep " FUNC " | \
+ awk '{ if ($3 < 5) print $3, $4, $5, $8 }'
+
+...
+3 FUNC LOCAL wbinvd_ipi
+3 FUNC LOCAL shadow_l1_index
+...
+</pre>
+A compile-time check for, e.g., a minimum alignment of functions or a
+runtime check that verifies symbol size (+ padding to next symbols) for
+that in the hypervisor is advised.
+
+The tool for generating payloads currently does perform a compile-time
+check to ensure that the function to be replaced is large enough.
+
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 04/27] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (2 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 03/27] xsplice: Design document Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-14 16:36 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 05/27] libxc: Implementation of XEN_XSPLICE_op in libxc Konrad Rzeszutek Wilk
` (23 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Wei Liu, Daniel De Graaf, Stefano Stabellini, Ian Jackson,
Konrad Rzeszutek Wilk
The implementation does not actually do any patching.
It just adds the framework for doing the hypercalls,
keeping track of ELF payloads, and the basic operations:
- query which payloads exist,
- query for specific payloads,
- check*1, apply*1, replace*1, and unload payloads.
*1: Which of course in this patch are nops.
The functionality is disabled on ARM until all arch
components are implemented.
Also by default it is disabled until the implementation
is in place.
We also use recursive spinlocks to so that the find_payload
function does not need to have a 'lock' and 'non-lock' variant.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
---
Cc: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Wei Liu <wei.liu2@citrix.com>
v2: Rebased on keyhandler: rework keyhandler infrastructure
v3: Fixed XSM.
- Removed REVERTED state.
Split status and error code.
Add REPLACE action.
Separate payload data from the payload structure.
s/XSPLICE_ID_../XSPLICE_NAME_../
- Add xsplice and CONFIG_XSPLICE build toption.
Fix code per Jan's review.
Update the sysctl.h (change bits to enum like)
- Rebase on Kconfig changes.
- Add missing pad checks. Re-order keyhandler.h to build on ARM.
- Rebase on build: hook the schedulers into Kconfig
- s/id/name/; s/payload_list_lock/payload_lock/
- Put #ifdef CONFIG_XSPLICE in header file per Doug review.
- Andrew review:
- use recursive spinlocks, change name to xsplice_op,
sprinkle new-lines, add local variable block, include
state diagram, squash two goto labels, use vzalloc instead of
alloc_xenheap_pages.
- change 'state' from int32 to uint32_t
- remove the err label out of xsplice_upload
- use void* instaed of uint8_t
- move code around to make it easier to read.
- Add vmap.h to compiler under ARM.
- Add missing Copyright in header file
- Dropped LOADED state, make the payload go in CHECKED.
v4: Made it only work on x86 per Julien's (ARM) maintainer request.
v5: Dropped the load->check state example in sysctl.h
Made the ->nr=0 call work. Remove rc=0 in lots of cases. Update
header from design doc.
v6: Update what 'idx' means. Don't drop lock in find_payload. Make
find_name copy data.
v7: Don't print -EINVAL when payload_cnt is zero (and toolstack provides
idx as zero). Change return code to -ENOSYS, so change callback setting
based on -ENOSYS and -EOPNOTSUPP.
Add extra printk in keyhandler.
Use if (..) else in xsplice_upload instead of two 'if'.
Remove #ifdef in XSM machinery.
Add Andrew's Reviewed-by.
Rebase on x86/cpu: Sysctl and common infrastructure for levelling context switching
and xen+tools: Export maximum host and guest cpu featuresets via SYSCTL
---
---
tools/flask/policy/policy/modules/xen/xen.te | 1 +
xen/common/Kconfig | 12 +
xen/common/Makefile | 1 +
xen/common/sysctl.c | 6 +
xen/common/xsplice.c | 404 +++++++++++++++++++++++++++
xen/include/public/sysctl.h | 166 +++++++++++
xen/include/xen/xsplice.h | 35 +++
xen/xsm/flask/hooks.c | 4 +
xen/xsm/flask/policy/access_vectors | 2 +
9 files changed, 631 insertions(+)
create mode 100644 xen/common/xsplice.c
create mode 100644 xen/include/xen/xsplice.h
diff --git a/tools/flask/policy/policy/modules/xen/xen.te b/tools/flask/policy/policy/modules/xen/xen.te
index 2a2630d..daa1315 100644
--- a/tools/flask/policy/policy/modules/xen/xen.te
+++ b/tools/flask/policy/policy/modules/xen/xen.te
@@ -74,6 +74,7 @@ allow dom0_t xen_t:xen2 {
get_symbol
get_cpu_levelling_caps
get_cpu_featureset
+ xsplice_op
};
# Allow dom0 to use all XENVER_ subops that have checks.
diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index ad9f7bf..fea33d3 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -188,4 +188,16 @@ config SCHED_DEFAULT
endmenu
+# Enable/Disable xsplice support
+config XSPLICE
+ bool "xSplice live patching support"
+ default n
+ depends on X86
+ ---help---
+ Allows a running Xen hypervisor to be dynamically patched using
+ binary patches without rebooting. This is primarily used to binarily
+ patch in the field an hypervisor with XSA fixes.
+
+ If unsure, say Y.
+
endmenu
diff --git a/xen/common/Makefile b/xen/common/Makefile
index 77de27e..910ac69 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -57,6 +57,7 @@ obj-y += vsprintf.o
obj-y += wait.o
obj-$(CONFIG_XENOPROF) += xenoprof.o
obj-y += xmalloc_tlsf.o
+obj-$(CONFIG_XSPLICE) += xsplice.o
obj-bin-$(CONFIG_X86) += $(foreach n,decompress bunzip2 unxz unlzma unlzo unlz4 earlycpio,$(n).init.o)
diff --git a/xen/common/sysctl.c b/xen/common/sysctl.c
index 253b7c8..d04d529 100644
--- a/xen/common/sysctl.c
+++ b/xen/common/sysctl.c
@@ -28,6 +28,7 @@
#include <xsm/xsm.h>
#include <xen/pmstat.h>
#include <xen/gcov.h>
+#include <xen/xsplice.h>
long do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
{
@@ -460,6 +461,11 @@ long do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
ret = tmem_control(&op->u.tmem_op);
break;
+ case XEN_SYSCTL_xsplice_op:
+ ret = xsplice_op(&op->u.xsplice);
+ copyback = (ret == -ENOSYS || ret == -EOPNOTSUPP) ? 0 : 1;
+ break;
+
default:
ret = arch_do_sysctl(op, u_sysctl);
copyback = 0;
diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c
new file mode 100644
index 0000000..04151e9
--- /dev/null
+++ b/xen/common/xsplice.c
@@ -0,0 +1,404 @@
+/*
+ * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
+ *
+ */
+
+#include <xen/err.h>
+#include <xen/guest_access.h>
+#include <xen/keyhandler.h>
+#include <xen/lib.h>
+#include <xen/list.h>
+#include <xen/mm.h>
+#include <xen/sched.h>
+#include <xen/smp.h>
+#include <xen/spinlock.h>
+#include <xen/vmap.h>
+#include <xen/xsplice.h>
+
+#include <asm/event.h>
+#include <public/sysctl.h>
+
+/* Protects against payload_list operations. */
+static DEFINE_SPINLOCK(payload_lock);
+static LIST_HEAD(payload_list);
+
+static unsigned int payload_cnt;
+static unsigned int payload_version = 1;
+
+struct payload {
+ uint32_t state; /* One of the XSPLICE_STATE_*. */
+ int32_t rc; /* 0 or -XEN_EXX. */
+ struct list_head list; /* Linked to 'payload_list'. */
+ char name[XEN_XSPLICE_NAME_SIZE]; /* Name of it. */
+};
+
+static int verify_name(const xen_xsplice_name_t *name, char *n)
+{
+ if ( !name->size || name->size > XEN_XSPLICE_NAME_SIZE )
+ return -EINVAL;
+
+ if ( name->pad[0] || name->pad[1] || name->pad[2] )
+ return -EINVAL;
+
+ if ( !guest_handle_okay(name->name, name->size) )
+ return -EINVAL;
+
+ if ( __copy_from_guest(n, name->name, name->size) )
+ return -EFAULT;
+
+ if ( n[name->size - 1] )
+ return -EINVAL;
+
+ return 0;
+}
+
+static int verify_payload(const xen_sysctl_xsplice_upload_t *upload, char *n)
+{
+ if ( verify_name(&upload->name, n) )
+ return -EINVAL;
+
+ if ( !upload->size )
+ return -EINVAL;
+
+ if ( upload->size > MB(2) )
+ return -EINVAL;
+
+ if ( !guest_handle_okay(upload->payload, upload->size) )
+ return -EFAULT;
+
+ return 0;
+}
+
+static struct payload *find_payload(const char *name)
+{
+ struct payload *data, *found = NULL;
+
+ ASSERT(spin_is_locked(&payload_lock));
+ list_for_each_entry ( data, &payload_list, list )
+ {
+ if ( !strcmp(data->name, name) )
+ {
+ found = data;
+ break;
+ }
+ }
+
+ return found;
+}
+
+static void free_payload(struct payload *data)
+{
+ ASSERT(spin_is_locked(&payload_lock));
+ list_del(&data->list);
+ payload_cnt--;
+ payload_version++;
+ xfree(data);
+}
+
+static int xsplice_upload(xen_sysctl_xsplice_upload_t *upload)
+{
+ struct payload *data = NULL, *found;
+ char n[XEN_XSPLICE_NAME_SIZE];
+ int rc;
+
+ rc = verify_payload(upload, n);
+ if ( rc )
+ return rc;
+
+ spin_lock(&payload_lock);
+
+ found = find_payload(n);
+ if ( IS_ERR(found) )
+ {
+ rc = PTR_ERR(found);
+ goto out;
+ }
+ else if ( found )
+ {
+ rc = -EEXIST;
+ goto out;
+ }
+
+ data = xzalloc(struct payload);
+ if ( !data )
+ {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ rc = 0;
+
+ memcpy(data->name, n, strlen(n));
+ data->state = XSPLICE_STATE_CHECKED;
+ INIT_LIST_HEAD(&data->list);
+
+ list_add_tail(&data->list, &payload_list);
+ payload_cnt++;
+ payload_version++;
+
+ out:
+ spin_unlock(&payload_lock);
+
+ if ( rc )
+ xfree(data);
+
+ return rc;
+}
+
+static int xsplice_get(xen_sysctl_xsplice_get_t *get)
+{
+ struct payload *data;
+ int rc;
+ char n[XEN_XSPLICE_NAME_SIZE];
+
+ rc = verify_name(&get->name, n);
+ if ( rc )
+ return rc;
+
+ spin_lock(&payload_lock);
+
+ data = find_payload(n);
+ if ( IS_ERR_OR_NULL(data) )
+ {
+ spin_unlock(&payload_lock);
+
+ if ( !data )
+ return -ENOENT;
+
+ return PTR_ERR(data);
+ }
+
+ get->status.state = data->state;
+ get->status.rc = data->rc;
+
+ spin_unlock(&payload_lock);
+
+ return 0;
+}
+
+static int xsplice_list(xen_sysctl_xsplice_list_t *list)
+{
+ xen_xsplice_status_t status;
+ struct payload *data;
+ unsigned int idx = 0, i = 0;
+ int rc = 0;
+
+ if ( list->nr > 1024 )
+ return -E2BIG;
+
+ if ( list->pad )
+ return -EINVAL;
+
+ if ( list->nr &&
+ (!guest_handle_okay(list->status, list->nr) ||
+ !guest_handle_okay(list->name, XEN_XSPLICE_NAME_SIZE * list->nr) ||
+ !guest_handle_okay(list->len, list->nr)) )
+ return -EINVAL;
+
+ spin_lock(&payload_lock);
+ if ( list->idx >= payload_cnt && payload_cnt )
+ {
+ spin_unlock(&payload_lock);
+ return -EINVAL;
+ }
+
+ if ( list->nr )
+ {
+ list_for_each_entry( data, &payload_list, list )
+ {
+ uint32_t len;
+
+ if ( list->idx > i++ )
+ continue;
+
+ status.state = data->state;
+ status.rc = data->rc;
+ len = strlen(data->name) + 1;
+
+ /* N.B. 'idx' != 'i'. */
+ if ( __copy_to_guest_offset(list->name, idx * XEN_XSPLICE_NAME_SIZE,
+ data->name, len) ||
+ __copy_to_guest_offset(list->len, idx, &len, 1) ||
+ __copy_to_guest_offset(list->status, idx, &status, 1) )
+ {
+ rc = -EFAULT;
+ break;
+ }
+
+ idx++;
+
+ if ( (idx >= list->nr) || hypercall_preempt_check() )
+ break;
+ }
+ }
+ list->nr = payload_cnt - i; /* Remaining amount. */
+ list->version = payload_version;
+ spin_unlock(&payload_lock);
+
+ /* And how many we have processed. */
+ return rc ? : idx;
+}
+
+static int xsplice_action(xen_sysctl_xsplice_action_t *action)
+{
+ struct payload *data;
+ char n[XEN_XSPLICE_NAME_SIZE];
+ int rc;
+
+ rc = verify_name(&action->name, n);
+ if ( rc )
+ return rc;
+
+ spin_lock(&payload_lock);
+
+ data = find_payload(n);
+ if ( IS_ERR_OR_NULL(data) )
+ {
+ spin_unlock(&payload_lock);
+
+ if ( !data )
+ return -ENOENT;
+
+ return PTR_ERR(data);
+ }
+
+ switch ( action->cmd )
+ {
+ case XSPLICE_ACTION_CHECK:
+ if ( data->state == XSPLICE_STATE_CHECKED )
+ {
+ /* No implementation yet. */
+ data->state = XSPLICE_STATE_CHECKED;
+ data->rc = 0;
+ }
+ break;
+
+ case XSPLICE_ACTION_UNLOAD:
+ if ( data->state == XSPLICE_STATE_CHECKED )
+ {
+ free_payload(data);
+ /* No touching 'data' from here on! */
+ data = NULL;
+ }
+ break;
+
+ case XSPLICE_ACTION_REVERT:
+ if ( data->state == XSPLICE_STATE_APPLIED )
+ {
+ /* No implementation yet. */
+ data->state = XSPLICE_STATE_CHECKED;
+ data->rc = 0;
+ }
+ break;
+
+ case XSPLICE_ACTION_APPLY:
+ if ( data->state == XSPLICE_STATE_CHECKED )
+ {
+ /* No implementation yet. */
+ data->state = XSPLICE_STATE_APPLIED;
+ data->rc = 0;
+ }
+ break;
+
+ case XSPLICE_ACTION_REPLACE:
+ if ( data->state == XSPLICE_STATE_CHECKED )
+ {
+ /* No implementation yet. */
+ data->state = XSPLICE_STATE_CHECKED;
+ data->rc = 0;
+ }
+ break;
+
+ default:
+ rc = -EOPNOTSUPP;
+ break;
+ }
+
+ spin_unlock(&payload_lock);
+
+ return rc;
+}
+
+int xsplice_op(xen_sysctl_xsplice_op_t *xsplice)
+{
+ int rc;
+
+ if ( xsplice->pad )
+ return -EINVAL;
+
+ switch ( xsplice->cmd )
+ {
+ case XEN_SYSCTL_XSPLICE_UPLOAD:
+ rc = xsplice_upload(&xsplice->u.upload);
+ break;
+
+ case XEN_SYSCTL_XSPLICE_GET:
+ rc = xsplice_get(&xsplice->u.get);
+ break;
+
+ case XEN_SYSCTL_XSPLICE_LIST:
+ rc = xsplice_list(&xsplice->u.list);
+ break;
+
+ case XEN_SYSCTL_XSPLICE_ACTION:
+ rc = xsplice_action(&xsplice->u.action);
+ break;
+
+ default:
+ rc = -EOPNOTSUPP;
+ break;
+ }
+
+ return rc;
+}
+
+static const char *state2str(uint32_t state)
+{
+#define STATE(x) [XSPLICE_STATE_##x] = #x
+ static const char *const names[] = {
+ STATE(CHECKED),
+ STATE(APPLIED),
+ };
+#undef STATE
+
+ if (state >= ARRAY_SIZE(names) || !names[state])
+ return "unknown";
+
+ return names[state];
+}
+
+static void xsplice_printall(unsigned char key)
+{
+ struct payload *data;
+
+ printk("'%u' pressed - Dumping all xsplice patches\n", key);
+
+ if ( !spin_trylock(&payload_lock) )
+ {
+ printk("Lock held. Try again.\n");
+ return;
+ }
+
+ list_for_each_entry ( data, &payload_list, list )
+ printk(" name=%s state=%s(%d)\n", data->name,
+ state2str(data->state), data->state);
+
+ spin_unlock(&payload_lock);
+}
+
+static int __init xsplice_init(void)
+{
+ register_keyhandler('x', xsplice_printall, "print xsplicing info", 1);
+ return 0;
+}
+__initcall(xsplice_init);
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/public/sysctl.h b/xen/include/public/sysctl.h
index 4596d20..090fd21 100644
--- a/xen/include/public/sysctl.h
+++ b/xen/include/public/sysctl.h
@@ -812,6 +812,170 @@ struct xen_sysctl_cpu_featureset {
typedef struct xen_sysctl_featureset xen_sysctl_featureset_t;
DEFINE_XEN_GUEST_HANDLE(xen_sysctl_featureset_t);
+/*
+ * XEN_SYSCTL_XSPLICE_op
+ *
+ * Refer to the docs/unstable/misc/xsplice.markdown
+ * for the design details of this hypercall.
+ *
+ * There are four sub-ops:
+ * XEN_SYSCTL_XSPLICE_UPLOAD (0)
+ * XEN_SYSCTL_XSPLICE_GET (1)
+ * XEN_SYSCTL_XSPLICE_LIST (2)
+ * XEN_SYSCTL_XSPLICE_ACTION (3)
+ *
+ * The normal sequence of sub-ops is to:
+ * 1) XEN_SYSCTL_XSPLICE_UPLOAD to upload the payload. If errors STOP.
+ * 2) XEN_SYSCTL_XSPLICE_GET to check the `->rc`. If -XEN_EAGAIN spin.
+ * If zero go to next step.
+ * 3) XEN_SYSCTL_XSPLICE_ACTION with XSPLICE_ACTION_APPLY to apply the patch.
+ * 4) XEN_SYSCTL_XSPLICE_GET to check the `->rc`. If in -XEN_EAGAIN spin.
+ * If zero exit with success.
+ */
+
+/*
+ * Structure describing an ELF payload. Uniquely identifies the
+ * payload. Should be human readable.
+ * Recommended length is upto XEN_XSPLICE_NAME_SIZE.
+ * Includes the NUL terminator.
+ */
+#define XEN_XSPLICE_NAME_SIZE 128
+struct xen_xsplice_name {
+ XEN_GUEST_HANDLE_64(char) name; /* IN: pointer to name. */
+ uint16_t size; /* IN: size of name. May be upto
+ XEN_XSPLICE_NAME_SIZE. */
+ uint16_t pad[3]; /* IN: MUST be zero. */
+};
+typedef struct xen_xsplice_name xen_xsplice_name_t;
+DEFINE_XEN_GUEST_HANDLE(xen_xsplice_name_t);
+
+/*
+ * Upload a payload to the hypervisor. The payload is verified
+ * against basic checks and if there are any issues the proper return code
+ * will be returned. The payload is not applied at this time - that is
+ * controlled by XEN_SYSCTL_XSPLICE_ACTION.
+ *
+ * The return value is zero if the payload was succesfully uploaded.
+ * Otherwise an EXX return value is provided. Duplicate `name` are not
+ * supported.
+ *
+ * The payload at this point is verified against basic checks.
+ *
+ * The `payload` is the ELF payload as mentioned in the `Payload format`
+ * section in the xSplice design document.
+ */
+#define XEN_SYSCTL_XSPLICE_UPLOAD 0
+struct xen_sysctl_xsplice_upload {
+ xen_xsplice_name_t name; /* IN, name of the patch. */
+ uint64_t size; /* IN, size of the ELF file. */
+ XEN_GUEST_HANDLE_64(uint8) payload; /* IN, the ELF file. */
+};
+typedef struct xen_sysctl_xsplice_upload xen_sysctl_xsplice_upload_t;
+DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_upload_t);
+
+/*
+ * Retrieve an status of an specific payload.
+ *
+ * Upon completion the `struct xen_xsplice_status` is updated.
+ *
+ * The return value is zero on success and XEN_EXX on failure. This operation
+ * is synchronous and does not require preemption.
+ */
+#define XEN_SYSCTL_XSPLICE_GET 1
+
+struct xen_xsplice_status {
+#define XSPLICE_STATE_CHECKED 1
+#define XSPLICE_STATE_APPLIED 2
+ uint32_t state; /* OUT: XSPLICE_STATE_*. */
+ int32_t rc; /* OUT: 0 if no error, otherwise -XEN_EXX. */
+};
+typedef struct xen_xsplice_status xen_xsplice_status_t;
+DEFINE_XEN_GUEST_HANDLE(xen_xsplice_status_t);
+
+struct xen_sysctl_xsplice_get {
+ xen_xsplice_name_t name; /* IN, name of the payload. */
+ xen_xsplice_status_t status; /* IN/OUT, state of it. */
+};
+typedef struct xen_sysctl_xsplice_get xen_sysctl_xsplice_get_t;
+DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_get_t);
+
+/*
+ * Retrieve an array of abbreviated status and names of payloads that are
+ * loaded in the hypervisor.
+ *
+ * If the hypercall returns an positive number, it is the number (up to `nr`)
+ * of the payloads returned, along with `nr` updated with the number of remaining
+ * payloads, `version` updated (it may be the same across hypercalls. If it
+ * varies the data is stale and further calls could fail). The `status`,
+ * `name`, and `len`' are updated at their designed index value (`idx`) with
+ * the returned value of data.
+ *
+ * If the hypercall returns E2BIG the `nr` is too big and should be
+ * lowered. The upper limit of `nr` is left to the implemention.
+ *
+ * Note that due to the asynchronous nature of hypercalls the domain might have
+ * added or removed the number of payloads making this information stale. It is
+ * the responsibility of the toolstack to use the `version` field to check
+ * between each invocation. if the version differs it should discard the stale
+ * data and start from scratch. It is OK for the toolstack to use the new
+ * `version` field.
+ */
+#define XEN_SYSCTL_XSPLICE_LIST 2
+struct xen_sysctl_xsplice_list {
+ uint32_t version; /* OUT: Hypervisor stamps value.
+ If varies between calls, we are
+ * getting stale data. */
+ uint32_t idx; /* IN: Index into hypervisor list. */
+ uint32_t nr; /* IN: How many status, name, and len
+ should fill out. Can be zero to get
+ amount of payloads and version.
+ OUT: How many payloads left. */
+ uint32_t pad; /* IN: Must be zero. */
+ XEN_GUEST_HANDLE_64(xen_xsplice_status_t) status; /* OUT. Must have enough
+ space allocate for nr of them. */
+ XEN_GUEST_HANDLE_64(char) name; /* OUT: Array of names. Each member
+ MUST XEN_XSPLICE_NAME_SIZE in size.
+ Must have nr of them. */
+ XEN_GUEST_HANDLE_64(uint32) len; /* OUT: Array of lengths of name's.
+ Must have nr of them. */
+};
+typedef struct xen_sysctl_xsplice_list xen_sysctl_xsplice_list_t;
+DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_list_t);
+
+/*
+ * Perform an operation on the payload structure referenced by the `name` field.
+ * The operation request is asynchronous and the status should be retrieved
+ * by using either XEN_SYSCTL_XSPLICE_GET or XEN_SYSCTL_XSPLICE_LIST hypercall.
+ */
+#define XEN_SYSCTL_XSPLICE_ACTION 3
+struct xen_sysctl_xsplice_action {
+ xen_xsplice_name_t name; /* IN, name of the patch. */
+#define XSPLICE_ACTION_CHECK 1
+#define XSPLICE_ACTION_UNLOAD 2
+#define XSPLICE_ACTION_REVERT 3
+#define XSPLICE_ACTION_APPLY 4
+#define XSPLICE_ACTION_REPLACE 5
+ uint32_t cmd; /* IN: XSPLICE_ACTION_*. */
+ uint32_t timeout; /* IN: Zero if no timeout. */
+ /* Or upper bound of time (ms) */
+ /* for operation to take. */
+};
+typedef struct xen_sysctl_xsplice_action xen_sysctl_xsplice_action_t;
+DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_action_t);
+
+struct xen_sysctl_xsplice_op {
+ uint32_t cmd; /* IN: XEN_SYSCTL_XSPLICE_*. */
+ uint32_t pad; /* IN: Always zero. */
+ union {
+ xen_sysctl_xsplice_upload_t upload;
+ xen_sysctl_xsplice_list_t list;
+ xen_sysctl_xsplice_get_t get;
+ xen_sysctl_xsplice_action_t action;
+ } u;
+};
+typedef struct xen_sysctl_xsplice_op xen_sysctl_xsplice_op_t;
+DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_op_t);
+
struct xen_sysctl {
uint32_t cmd;
#define XEN_SYSCTL_readconsole 1
@@ -839,6 +1003,7 @@ struct xen_sysctl {
#define XEN_SYSCTL_tmem_op 24
#define XEN_SYSCTL_get_cpu_levelling_caps 25
#define XEN_SYSCTL_get_cpu_featureset 26
+#define XEN_SYSCTL_xsplice_op 27
uint32_t interface_version; /* XEN_SYSCTL_INTERFACE_VERSION */
union {
struct xen_sysctl_readconsole readconsole;
@@ -866,6 +1031,7 @@ struct xen_sysctl {
struct xen_sysctl_tmem_op tmem_op;
struct xen_sysctl_cpu_levelling_caps cpu_levelling_caps;
struct xen_sysctl_cpu_featureset cpu_featureset;
+ struct xen_sysctl_xsplice_op xsplice;
uint8_t pad[128];
} u;
};
diff --git a/xen/include/xen/xsplice.h b/xen/include/xen/xsplice.h
new file mode 100644
index 0000000..b9f08cd
--- /dev/null
+++ b/xen/include/xen/xsplice.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
+ *
+ */
+
+#ifndef __XEN_XSPLICE_H__
+#define __XEN_XSPLICE_H__
+
+struct xen_sysctl_xsplice_op;
+
+#ifdef CONFIG_XSPLICE
+
+int xsplice_op(struct xen_sysctl_xsplice_op *);
+
+#else
+
+#include <xen/errno.h> /* For -ENOSYS */
+static inline int xsplice_op(struct xen_sysctl_xsplice_op *op)
+{
+ return -ENOSYS;
+}
+
+#endif /* CONFIG_XSPLICE */
+
+#endif /* __XEN_XSPLICE_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 6295768..c2df48f 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -814,6 +814,10 @@ static int flask_sysctl(int cmd)
case XEN_SYSCTL_get_cpu_featureset:
return domain_has_xen(current->domain, XEN2__GET_CPU_FEATURESET);
+ case XEN_SYSCTL_xsplice_op:
+ return avc_current_has_perm(SECINITSID_XEN, SECCLASS_XEN2,
+ XEN2__XSPLICE_OP, NULL);
+
default:
printk("flask_sysctl: Unknown op %d\n", cmd);
return -EPERM;
diff --git a/xen/xsm/flask/policy/access_vectors b/xen/xsm/flask/policy/access_vectors
index bdb7b89..e9ab149 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -97,6 +97,8 @@ class xen2
get_cpu_levelling_caps
# XEN_SYSCTL_get_cpu_featureset
get_cpu_featureset
+# XEN_SYSCTL_xsplice_op
+ xsplice_op
}
# Classes domain and domain2 consist of operations that a domain performs on
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 05/27] libxc: Implementation of XEN_XSPLICE_op in libxc
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (3 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 04/27] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 06/27] xen-xsplice: Tool to manipulate xsplice payloads Konrad Rzeszutek Wilk
` (22 subsequent siblings)
27 siblings, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Wei Liu, Stefano Stabellini, Ian Jackson, Konrad Rzeszutek Wilk
The underlaying toolstack code to do the basic
operations when using the XEN_XSPLICE_op syscalls:
- upload the payload,
- get status of an payload,
- list all the payloads,
- apply, check, replace, and revert the payload.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Wei Liu <wei.liu2@citrix.com>
v2: Actually set zero for the _pad entries.
v3: Split status into state and error code.
Add REPLACE action.
- Use timeout and utilize pads.
- Update per Wei's review.
- Extra space slipped in, remove it
v4: Add Wei's review, update comment and Ack.
v7: Sprinkle errno=-EINVAL on all the 'if (!len)', etc checks.
Added Reviewed-by from Andrew.
---
---
tools/libxc/include/xenctrl.h | 62 ++++++++
tools/libxc/xc_misc.c | 355 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 417 insertions(+)
diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index 42f201b..54431de 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -2610,6 +2610,68 @@ const uint32_t *xc_get_feature_deep_deps(uint32_t feature);
#endif
+int xc_xsplice_upload(xc_interface *xch,
+ char *name, unsigned char *payload, uint32_t size);
+
+int xc_xsplice_get(xc_interface *xch,
+ char *name,
+ xen_xsplice_status_t *status);
+
+/*
+ * The heart of this function is to get an array of xen_xsplice_status_t.
+ *
+ * However it is complex because it has to deal with the hypervisor
+ * returning some of the requested data or data being stale
+ * (another hypercall might alter the list).
+ *
+ * The parameters that the function expects to contain data from
+ * the hypervisor are: 'info', 'name', and 'len'. The 'done' and
+ * 'left' are also updated with the number of entries filled out
+ * and respectively the number of entries left to get from hypervisor.
+ *
+ * It is expected that the caller of this function will take the
+ * 'left' and use the value for 'start'. This way we have an
+ * cursor in the array. Note that the 'info','name', and 'len' will
+ * be updated at the subsequent calls.
+ *
+ * The 'max' is to be provided by the caller with the maximum
+ * number of entries that 'info', 'name', and 'len' arrays can
+ * be filled up with.
+ *
+ * Each entry in the 'name' array is expected to be of XEN_XSPLICE_NAME_SIZE
+ * length.
+ *
+ * Each entry in the 'info' array is expected to be of xen_xsplice_status_t
+ * structure size.
+ *
+ * Each entry in the 'len' array is expected to be of uint32_t size.
+ *
+ * The return value is zero if the hypercall completed successfully.
+ * Note that the return value is _not_ the amount of entries filled
+ * out - that is saved in 'done'.
+ *
+ * If there was an error performing the operation, the return value
+ * will contain an negative -EXX type value. The 'done' and 'left'
+ * will contain the number of entries that had been succesfully
+ * retrieved (if any).
+ */
+int xc_xsplice_list(xc_interface *xch, unsigned int max, unsigned int start,
+ xen_xsplice_status_t *info, char *name,
+ uint32_t *len, unsigned int *done,
+ unsigned int *left);
+
+/*
+ * The operations are asynchronous and the hypervisor may take a while
+ * to complete them. The `timeout` offers an option to expire the
+ * operation if it could not be completed within the specified time
+ * (in ms). Value of 0 means let hypervisor decide the best timeout.
+ */
+int xc_xsplice_apply(xc_interface *xch, char *name, uint32_t timeout);
+int xc_xsplice_revert(xc_interface *xch, char *name, uint32_t timeout);
+int xc_xsplice_unload(xc_interface *xch, char *name, uint32_t timeout);
+int xc_xsplice_check(xc_interface *xch, char *name, uint32_t timeout);
+int xc_xsplice_replace(xc_interface *xch, char *name, uint32_t timeout);
+
/* Compat shims */
#include "xenctrl_compat.h"
diff --git a/tools/libxc/xc_misc.c b/tools/libxc/xc_misc.c
index 7d997d9..8cd398b 100644
--- a/tools/libxc/xc_misc.c
+++ b/tools/libxc/xc_misc.c
@@ -696,6 +696,361 @@ int xc_hvm_inject_trap(
return rc;
}
+int xc_xsplice_upload(xc_interface *xch,
+ char *name,
+ unsigned char *payload,
+ uint32_t size)
+{
+ int rc;
+ DECLARE_SYSCTL;
+ DECLARE_HYPERCALL_BUFFER(char, local);
+ DECLARE_HYPERCALL_BOUNCE(name, 0 /* later */, XC_HYPERCALL_BUFFER_BOUNCE_IN);
+ xen_xsplice_name_t def_name = { .pad = { 0, 0, 0 } };
+
+ if ( !name || !payload )
+ {
+ errno = EINVAL;
+ return -1;
+ }
+
+ def_name.size = strlen(name) + 1;
+ if ( def_name.size > XEN_XSPLICE_NAME_SIZE )
+ {
+ errno = EINVAL;
+ return -1;
+ }
+
+ HYPERCALL_BOUNCE_SET_SIZE(name, def_name.size);
+
+ if ( xc_hypercall_bounce_pre(xch, name) )
+ return -1;
+
+ local = xc_hypercall_buffer_alloc(xch, local, size);
+ if ( !local )
+ {
+ xc_hypercall_bounce_post(xch, name);
+ return -1;
+ }
+ memcpy(local, payload, size);
+
+ sysctl.cmd = XEN_SYSCTL_xsplice_op;
+ sysctl.u.xsplice.cmd = XEN_SYSCTL_XSPLICE_UPLOAD;
+ sysctl.u.xsplice.pad = 0;
+ sysctl.u.xsplice.u.upload.size = size;
+ set_xen_guest_handle(sysctl.u.xsplice.u.upload.payload, local);
+
+ sysctl.u.xsplice.u.upload.name = def_name;
+ set_xen_guest_handle(sysctl.u.xsplice.u.upload.name.name, name);
+
+ rc = do_sysctl(xch, &sysctl);
+
+ xc_hypercall_buffer_free(xch, local);
+ xc_hypercall_bounce_post(xch, name);
+
+ return rc;
+}
+
+int xc_xsplice_get(xc_interface *xch,
+ char *name,
+ xen_xsplice_status_t *status)
+{
+ int rc;
+ DECLARE_SYSCTL;
+ DECLARE_HYPERCALL_BOUNCE(name, 0 /*adjust later */, XC_HYPERCALL_BUFFER_BOUNCE_IN);
+ xen_xsplice_name_t def_name = { .pad = { 0, 0, 0 } };
+
+ if ( !name )
+ {
+ errno = EINVAL;
+ return -1;
+ }
+
+ def_name.size = strlen(name) + 1;
+ if ( def_name.size > XEN_XSPLICE_NAME_SIZE )
+ {
+ errno = EINVAL;
+ return -1;
+ }
+
+ HYPERCALL_BOUNCE_SET_SIZE(name, def_name.size);
+
+ if ( xc_hypercall_bounce_pre(xch, name) )
+ return -1;
+
+ sysctl.cmd = XEN_SYSCTL_xsplice_op;
+ sysctl.u.xsplice.cmd = XEN_SYSCTL_XSPLICE_GET;
+ sysctl.u.xsplice.pad = 0;
+
+ sysctl.u.xsplice.u.get.status.state = 0;
+ sysctl.u.xsplice.u.get.status.rc = 0;
+
+ sysctl.u.xsplice.u.get.name = def_name;
+ set_xen_guest_handle(sysctl.u.xsplice.u.get.name.name, name);
+
+ rc = do_sysctl(xch, &sysctl);
+
+ xc_hypercall_bounce_post(xch, name);
+
+ memcpy(status, &sysctl.u.xsplice.u.get.status, sizeof(*status));
+
+ return rc;
+}
+
+/*
+ * The heart of this function is to get an array of xen_xsplice_status_t.
+ *
+ * However it is complex because it has to deal with the hypervisor
+ * returning some of the requested data or data being stale
+ * (another hypercall might alter the list).
+ *
+ * The parameters that the function expects to contain data from
+ * the hypervisor are: 'info', 'name', and 'len'. The 'done' and
+ * 'left' are also updated with the number of entries filled out
+ * and respectively the number of entries left to get from hypervisor.
+ *
+ * It is expected that the caller of this function will take the
+ * 'left' and use the value for 'start'. This way we have an
+ * cursor in the array. Note that the 'info','name', and 'len' will
+ * be updated at the subsequent calls.
+ *
+ * The 'max' is to be provided by the caller with the maximum
+ * number of entries that 'info', 'name', and 'len' arrays can
+ * be filled up with.
+ *
+ * Each entry in the 'name' array is expected to be of XEN_XSPLICE_NAME_SIZE
+ * length.
+ *
+ * Each entry in the 'info' array is expected to be of xen_xsplice_status_t
+ * structure size.
+ *
+ * Each entry in the 'len' array is expected to be of uint32_t size.
+ *
+ * The return value is zero if the hypercall completed successfully.
+ * Note that the return value is _not_ the amount of entries filled
+ * out - that is saved in 'done'.
+ *
+ * If there was an error performing the operation, the return value
+ * will contain an negative -EXX type value. The 'done' and 'left'
+ * will contain the number of entries that had been succesfully
+ * retrieved (if any).
+ */
+int xc_xsplice_list(xc_interface *xch, unsigned int max, unsigned int start,
+ xen_xsplice_status_t *info,
+ char *name, uint32_t *len,
+ unsigned int *done,
+ unsigned int *left)
+{
+ int rc;
+ DECLARE_SYSCTL;
+ /* The sizes are adjusted later - hence zero. */
+ DECLARE_HYPERCALL_BOUNCE(info, 0, XC_HYPERCALL_BUFFER_BOUNCE_OUT);
+ DECLARE_HYPERCALL_BOUNCE(name, 0, XC_HYPERCALL_BUFFER_BOUNCE_OUT);
+ DECLARE_HYPERCALL_BOUNCE(len, 0, XC_HYPERCALL_BUFFER_BOUNCE_OUT);
+ uint32_t max_batch_sz, nr;
+ uint32_t version = 0, retries = 0;
+ uint32_t adjust = 0;
+ ssize_t sz;
+
+ if ( !max || !info || !name || !len )
+ {
+ errno = EINVAL;
+ return -1;
+ }
+
+ sysctl.cmd = XEN_SYSCTL_xsplice_op;
+ sysctl.u.xsplice.cmd = XEN_SYSCTL_XSPLICE_LIST;
+ sysctl.u.xsplice.pad = 0;
+ sysctl.u.xsplice.u.list.version = 0;
+ sysctl.u.xsplice.u.list.idx = start;
+ sysctl.u.xsplice.u.list.pad = 0;
+
+ max_batch_sz = max;
+ /* Convience value. */
+ sz = sizeof(*name) * XEN_XSPLICE_NAME_SIZE;
+ *done = 0;
+ *left = 0;
+ do {
+ /*
+ * The first time we go in this loop our 'max' may be bigger
+ * than what the hypervisor is comfortable with - hence the first
+ * couple of loops may adjust the number of entries we will
+ * want filled (tracked by 'nr').
+ *
+ * N.B. This is a do { } while loop and the right hand side of
+ * the conditional when adjusting will evaluate to false (as
+ * *left is set to zero before the loop. Hence we need this
+ * adjust - even if we reset it at the start of the loop.
+ */
+ if ( adjust )
+ adjust = 0; /* Used when adjusting the 'max_batch_sz' or 'retries'. */
+
+ nr = min(max - *done, max_batch_sz);
+
+ sysctl.u.xsplice.u.list.nr = nr;
+ /* Fix the size (may vary between hypercalls). */
+ HYPERCALL_BOUNCE_SET_SIZE(info, nr * sizeof(*info));
+ HYPERCALL_BOUNCE_SET_SIZE(name, nr * nr);
+ HYPERCALL_BOUNCE_SET_SIZE(len, nr * sizeof(*len));
+ /* Move the pointer to proper offset into 'info'. */
+ (HYPERCALL_BUFFER(info))->ubuf = info + *done;
+ (HYPERCALL_BUFFER(name))->ubuf = name + (sz * *done);
+ (HYPERCALL_BUFFER(len))->ubuf = len + *done;
+ /* Allocate memory. */
+ rc = xc_hypercall_bounce_pre(xch, info);
+ if ( rc )
+ break;
+
+ rc = xc_hypercall_bounce_pre(xch, name);
+ if ( rc )
+ break;
+
+ rc = xc_hypercall_bounce_pre(xch, len);
+ if ( rc )
+ break;
+
+ set_xen_guest_handle(sysctl.u.xsplice.u.list.status, info);
+ set_xen_guest_handle(sysctl.u.xsplice.u.list.name, name);
+ set_xen_guest_handle(sysctl.u.xsplice.u.list.len, len);
+
+ rc = do_sysctl(xch, &sysctl);
+ /*
+ * From here on we MUST call xc_hypercall_bounce. If rc < 0 we
+ * end up doing it (outside the loop), so using a break is OK.
+ */
+ if ( rc < 0 && errno == E2BIG )
+ {
+ if ( max_batch_sz <= 1 )
+ break;
+ max_batch_sz >>= 1;
+ adjust = 1; /* For the loop conditional to let us loop again. */
+ /* No memory leaks! */
+ xc_hypercall_bounce_post(xch, info);
+ xc_hypercall_bounce_post(xch, name);
+ xc_hypercall_bounce_post(xch, len);
+ continue;
+ }
+ else if ( rc < 0 ) /* For all other errors we bail out. */
+ break;
+
+ if ( !version )
+ version = sysctl.u.xsplice.u.list.version;
+
+ if ( sysctl.u.xsplice.u.list.version != version )
+ {
+ /* We could make this configurable as parameter? */
+ if ( retries++ > 3 )
+ {
+ rc = -1;
+ errno = EBUSY;
+ break;
+ }
+ *done = 0; /* Retry from scratch. */
+ version = sysctl.u.xsplice.u.list.version;
+ adjust = 1; /* And make sure we continue in the loop. */
+ /* No memory leaks. */
+ xc_hypercall_bounce_post(xch, info);
+ xc_hypercall_bounce_post(xch, name);
+ xc_hypercall_bounce_post(xch, len);
+ continue;
+ }
+
+ /* We should never hit this, but just in case. */
+ if ( rc > nr )
+ {
+ errno = EOVERFLOW; /* Overflow! */
+ rc = -1;
+ break;
+ }
+ *left = sysctl.u.xsplice.u.list.nr; /* Total remaining count. */
+ /* Copy only up 'rc' of data' - we could add 'min(rc,nr) if desired. */
+ HYPERCALL_BOUNCE_SET_SIZE(info, (rc * sizeof(*info)));
+ HYPERCALL_BOUNCE_SET_SIZE(name, (rc * sz));
+ HYPERCALL_BOUNCE_SET_SIZE(len, (rc * sizeof(*len)));
+ /* Bounce the data and free the bounce buffer. */
+ xc_hypercall_bounce_post(xch, info);
+ xc_hypercall_bounce_post(xch, name);
+ xc_hypercall_bounce_post(xch, len);
+ /* And update how many elements of info we have copied into. */
+ *done += rc;
+ /* Update idx. */
+ sysctl.u.xsplice.u.list.idx = *done;
+ } while ( adjust || (*done < max && *left != 0) );
+
+ if ( rc < 0 )
+ {
+ xc_hypercall_bounce_post(xch, len);
+ xc_hypercall_bounce_post(xch, name);
+ xc_hypercall_bounce_post(xch, info);
+ }
+
+ return rc > 0 ? 0 : rc;
+}
+
+static int _xc_xsplice_action(xc_interface *xch,
+ char *name,
+ unsigned int action,
+ uint32_t timeout)
+{
+ int rc;
+ DECLARE_SYSCTL;
+ /* The size is figured out when we strlen(name) */
+ DECLARE_HYPERCALL_BOUNCE(name, 0, XC_HYPERCALL_BUFFER_BOUNCE_IN);
+ xen_xsplice_name_t def_name = { .pad = { 0, 0, 0 } };
+
+ def_name.size = strlen(name) + 1;
+
+ if ( def_name.size > XEN_XSPLICE_NAME_SIZE )
+ {
+ errno = EINVAL;
+ return -1;
+ }
+
+ HYPERCALL_BOUNCE_SET_SIZE(name, def_name.size);
+
+ if ( xc_hypercall_bounce_pre(xch, name) )
+ return -1;
+
+ sysctl.cmd = XEN_SYSCTL_xsplice_op;
+ sysctl.u.xsplice.cmd = XEN_SYSCTL_XSPLICE_ACTION;
+ sysctl.u.xsplice.pad = 0;
+ sysctl.u.xsplice.u.action.cmd = action;
+ sysctl.u.xsplice.u.action.timeout = timeout;
+
+ sysctl.u.xsplice.u.action.name = def_name;
+ set_xen_guest_handle(sysctl.u.xsplice.u.action.name.name, name);
+
+ rc = do_sysctl(xch, &sysctl);
+
+ xc_hypercall_bounce_post(xch, name);
+
+ return rc;
+}
+
+int xc_xsplice_apply(xc_interface *xch, char *name, uint32_t timeout)
+{
+ return _xc_xsplice_action(xch, name, XSPLICE_ACTION_APPLY, timeout);
+}
+
+int xc_xsplice_revert(xc_interface *xch, char *name, uint32_t timeout)
+{
+ return _xc_xsplice_action(xch, name, XSPLICE_ACTION_REVERT, timeout);
+}
+
+int xc_xsplice_unload(xc_interface *xch, char *name, uint32_t timeout)
+{
+ return _xc_xsplice_action(xch, name, XSPLICE_ACTION_UNLOAD, timeout);
+}
+
+int xc_xsplice_check(xc_interface *xch, char *name, uint32_t timeout)
+{
+ return _xc_xsplice_action(xch, name, XSPLICE_ACTION_CHECK, timeout);
+}
+
+int xc_xsplice_replace(xc_interface *xch, char *name, uint32_t timeout)
+{
+ return _xc_xsplice_action(xch, name, XSPLICE_ACTION_REPLACE, timeout);
+}
+
/*
* Local variables:
* mode: C
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 06/27] xen-xsplice: Tool to manipulate xsplice payloads
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (4 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 05/27] libxc: Implementation of XEN_XSPLICE_op in libxc Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 07/27] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables lookup Konrad Rzeszutek Wilk
` (21 subsequent siblings)
27 siblings, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Wei Liu, Stefano Stabellini, Ian Jackson, Konrad Rzeszutek Wilk
A simple tool that allows an system admin to perform
basic xsplice operations:
- Upload a xsplice file (with an unique name)
- List all the xsplice payloads loaded.
- Apply, revert, replace, or unload the payload using the
unique name.
- Do all two - upload, and apply the payload in one go (load).
Also will use the name of the file as the <name>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Wei Liu <wei.liu2@citrix.com>
v2:
- Removed REVERTED state.
- Fixed bugs handling XSPLICE_STATUS_PROGRESS.
- Split status into state and error.
Add REPLACE action.
v3:
- Utilize the timeout and use the default one (let the hypervisor
pick it).
- Change the s/all/load and infer the <id> from name of file.
- s/id/name/
- Don't use hypercall buffer in upload_func, instead do it in libxc
- Remove the debug printk.
- Remove goto's (per Wei's review)
- Use fprintf(stderr in error paths.
- Add local variable block.
- Syntax, expand comment, and don't overwrite rc if xc_xsplice_upload failed.
v4:
- Remove LOADED state. Only have CHECKED state.
---
---
.gitignore | 1 +
tools/misc/Makefile | 4 +
tools/misc/xen-xsplice.c | 463 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 468 insertions(+)
create mode 100644 tools/misc/xen-xsplice.c
diff --git a/.gitignore b/.gitignore
index 20ffa2d..39eb779 100644
--- a/.gitignore
+++ b/.gitignore
@@ -182,6 +182,7 @@ tools/misc/xen_cpuperf
tools/misc/xen-cpuid
tools/misc/xen-detect
tools/misc/xen-tmem-list-parse
+tools/misc/xen-xsplice
tools/misc/xenperf
tools/misc/xenpm
tools/misc/xen-hvmctx
diff --git a/tools/misc/Makefile b/tools/misc/Makefile
index a94dad9..3a5f842 100644
--- a/tools/misc/Makefile
+++ b/tools/misc/Makefile
@@ -32,6 +32,7 @@ INSTALL_SBIN += xenlockprof
INSTALL_SBIN += xenperf
INSTALL_SBIN += xenpm
INSTALL_SBIN += xenwatchdogd
+INSTALL_SBIN += xen-xsplice
INSTALL_SBIN += $(INSTALL_SBIN-y)
# Everything to be installed in a private bin/
@@ -103,6 +104,9 @@ xen-mfndump: xen-mfndump.o
xenwatchdogd: xenwatchdogd.o
$(CC) $(LDFLAGS) -o $@ $< $(LDLIBS_libxenctrl) $(APPEND_LDFLAGS)
+xen-xsplice: xen-xsplice.o
+ $(CC) $(LDFLAGS) -o $@ $< $(LDLIBS_libxenctrl) $(APPEND_LDFLAGS)
+
xen-lowmemd: xen-lowmemd.o
$(CC) $(LDFLAGS) -o $@ $< $(LDLIBS_libxenevtchn) $(LDLIBS_libxenctrl) $(LDLIBS_libxenstore) $(APPEND_LDFLAGS)
diff --git a/tools/misc/xen-xsplice.c b/tools/misc/xen-xsplice.c
new file mode 100644
index 0000000..fb9228e
--- /dev/null
+++ b/tools/misc/xen-xsplice.c
@@ -0,0 +1,463 @@
+/*
+ * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
+ */
+
+#include <fcntl.h>
+#include <libgen.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <xenctrl.h>
+#include <xenstore.h>
+
+static xc_interface *xch;
+
+void show_help(void)
+{
+ fprintf(stderr,
+ "xen-xsplice: Xsplice test tool\n"
+ "Usage: xen-xsplice <command> [args]\n"
+ " <name> An unique name of payload. Up to %d characters.\n"
+ "Commands:\n"
+ " help display this help\n"
+ " upload <name> <file> upload file <file> with <name> name\n"
+ " list list payloads uploaded.\n"
+ " apply <name> apply <name> patch.\n"
+ " revert <name> revert name <name> patch.\n"
+ " replace <name> apply <name> patch and revert all others.\n"
+ " unload <name> unload name <name> patch.\n"
+ " load <file> upload, check and apply <file>.\n"
+ " name is the <file> name\n",
+ XEN_XSPLICE_NAME_SIZE);
+}
+
+/* wrapper function */
+static int help_func(int argc, char *argv[])
+{
+ show_help();
+ return 0;
+}
+
+#define ARRAY_SIZE(a) (sizeof (a) / sizeof ((a)[0]))
+
+static const char *state2str(unsigned int state)
+{
+#define STATE(x) [XSPLICE_STATE_##x] = #x
+ static const char *const names[] = {
+ STATE(CHECKED),
+ STATE(APPLIED),
+ };
+#undef STATE
+ if (state >= ARRAY_SIZE(names) || !names[state])
+ return "unknown";
+
+ return names[state];
+}
+
+/* This value was choosen adhoc. It could be 42 too. */
+#define MAX_LEN 11
+static int list_func(int argc, char *argv[])
+{
+ unsigned int idx, done, left, i;
+ xen_xsplice_status_t *info = NULL;
+ char *name = NULL;
+ uint32_t *len = NULL;
+ int rc = ENOMEM;
+
+ if ( argc )
+ {
+ show_help();
+ return -1;
+ }
+ idx = left = 0;
+ info = malloc(sizeof(*info) * MAX_LEN);
+ if ( !info )
+ return rc;
+ name = malloc(sizeof(*name) * XEN_XSPLICE_NAME_SIZE * MAX_LEN);
+ if ( !name )
+ {
+ free(info);
+ return rc;
+ }
+ len = malloc(sizeof(*len) * MAX_LEN);
+ if ( !len ) {
+ free(name);
+ free(info);
+ return rc;
+ }
+
+ fprintf(stdout," ID | status\n"
+ "----------------------------------------+------------\n");
+ do {
+ done = 0;
+ /* The memset is done to catch errors. */
+ memset(info, 'A', sizeof(*info) * MAX_LEN);
+ memset(name, 'B', sizeof(*name * MAX_LEN * XEN_XSPLICE_NAME_SIZE));
+ memset(len, 'C', sizeof(*len) * MAX_LEN);
+ rc = xc_xsplice_list(xch, MAX_LEN, idx, info, name, len, &done, &left);
+ if ( rc )
+ {
+ fprintf(stderr, "Failed to list %d/%d: %d(%s)!\n",
+ idx, left, errno, strerror(errno));
+ break;
+ }
+ for ( i = 0; i < done; i++ )
+ {
+ unsigned int j;
+ uint32_t sz;
+ char *str;
+
+ sz = len[i];
+ str = name + (i * XEN_XSPLICE_NAME_SIZE);
+ for ( j = sz; j < XEN_XSPLICE_NAME_SIZE; j++ )
+ str[j] = '\0';
+
+ printf("%-40s| %s", str, state2str(info[i].state));
+ if ( info[i].rc )
+ printf(" (%d, %s)\n", -info[i].rc, strerror(-info[i].rc));
+ else
+ puts("");
+ }
+ idx += done;
+ } while ( left );
+
+ free(name);
+ free(info);
+ free(len);
+ return rc;
+}
+#undef MAX_LEN
+
+static int get_name(int argc, char *argv[], char *name)
+{
+ ssize_t len = strlen(argv[0]);
+ if ( len > XEN_XSPLICE_NAME_SIZE )
+ {
+ fprintf(stderr, "ID MUST be %d characters!\n", XEN_XSPLICE_NAME_SIZE);
+ errno = EINVAL;
+ return errno;
+ }
+ /* Don't want any funny strings from the stack. */
+ memset(name, 0, XEN_XSPLICE_NAME_SIZE);
+ strncpy(name, argv[0], len);
+ return 0;
+}
+
+static int upload_func(int argc, char *argv[])
+{
+ char *filename;
+ char name[XEN_XSPLICE_NAME_SIZE];
+ int fd = 0, rc;
+ struct stat buf;
+ unsigned char *fbuf;
+ ssize_t len;
+
+ if ( argc != 2 )
+ {
+ show_help();
+ return -1;
+ }
+
+ if ( get_name(argc, argv, name) )
+ return EINVAL;
+
+ filename = argv[1];
+ fd = open(filename, O_RDONLY);
+ if ( fd < 0 )
+ {
+ fprintf(stderr, "Could not open %s, error: %d(%s)\n",
+ filename, errno, strerror(errno));
+ return errno;
+ }
+ if ( stat(filename, &buf) != 0 )
+ {
+ fprintf(stderr, "Could not get right size %s, error: %d(%s)\n",
+ filename, errno, strerror(errno));
+ close(fd);
+ return errno;
+ }
+
+ len = buf.st_size;
+ fbuf = mmap(0, len, PROT_READ, MAP_PRIVATE, fd, 0);
+ if ( fbuf == MAP_FAILED )
+ {
+ fprintf(stderr,"Could not map: %s, error: %d(%s)\n",
+ filename, errno, strerror(errno));
+ close (fd);
+ return errno;
+ }
+ printf("Uploading %s (%zu bytes)\n", filename, len);
+ rc = xc_xsplice_upload(xch, name, fbuf, len);
+ if ( rc )
+ fprintf(stderr, "Upload failed: %s, error: %d(%s)!\n",
+ filename, errno, strerror(errno));
+
+ if ( munmap( fbuf, len) )
+ {
+ fprintf(stderr, "Could not unmap!? error: %d(%s)!\n",
+ errno, strerror(errno));
+ if ( !rc )
+ rc = errno;
+ }
+ close(fd);
+
+ return rc;
+}
+
+/* These MUST match to the 'action_options[]' array slots. */
+enum {
+ ACTION_APPLY = 0,
+ ACTION_REVERT = 1,
+ ACTION_UNLOAD = 2,
+ ACTION_REPLACE = 3,
+};
+
+struct {
+ int allow; /* State it must be in to call function. */
+ int expected; /* The state to be in after the function. */
+ const char *name;
+ int (*function)(xc_interface *xch, char *name, uint32_t timeout);
+ unsigned int executed; /* Has the function been called?. */
+} action_options[] = {
+ { .allow = XSPLICE_STATE_CHECKED,
+ .expected = XSPLICE_STATE_APPLIED,
+ .name = "apply",
+ .function = xc_xsplice_apply,
+ },
+ { .allow = XSPLICE_STATE_APPLIED,
+ .expected = XSPLICE_STATE_CHECKED,
+ .name = "revert",
+ .function = xc_xsplice_revert,
+ },
+ { .allow = XSPLICE_STATE_CHECKED,
+ .expected = -ENOENT,
+ .name = "unload",
+ .function = xc_xsplice_unload,
+ },
+ { .allow = XSPLICE_STATE_CHECKED,
+ .expected = XSPLICE_STATE_APPLIED,
+ .name = "replace",
+ .function = xc_xsplice_replace,
+ },
+};
+
+/* Go around 300 * 0.1 seconds = 30 seconds. */
+#define RETRIES 300
+/* aka 0.1 second */
+#define DELAY 100000
+
+int action_func(int argc, char *argv[], unsigned int idx)
+{
+ char name[XEN_XSPLICE_NAME_SIZE];
+ int rc, original_state;
+ xen_xsplice_status_t status;
+ unsigned int retry = 0;
+
+ if ( argc != 1 )
+ {
+ show_help();
+ return -1;
+ }
+
+ if ( idx >= ARRAY_SIZE(action_options) )
+ return -1;
+
+ if ( get_name(argc, argv, name) )
+ return EINVAL;
+
+ /* Check initial status. */
+ rc = xc_xsplice_get(xch, name, &status);
+ if ( rc )
+ {
+ fprintf(stderr, "%s failed to get status (rc=%d, %s)!\n",
+ name, -rc, strerror(-rc));
+ return -1;
+ }
+ if ( status.rc == -EAGAIN )
+ {
+ fprintf(stderr, "%s failed. Operation already in progress\n", name);
+ return -1;
+ }
+
+ if ( status.state == action_options[idx].expected )
+ {
+ printf("No action needed\n");
+ return 0;
+ }
+
+ /* Perform action. */
+ if ( action_options[idx].allow & status.state )
+ {
+ printf("Performing %s:", action_options[idx].name);
+ rc = action_options[idx].function(xch, name, 0);
+ if ( rc )
+ {
+ fprintf(stderr, "%s failed with %d(%s)\n", name, -rc, strerror(-rc));
+ return -1;
+ }
+ }
+ else
+ {
+ printf("%s: in wrong state (%s), expected (%s)\n",
+ name, state2str(status.state),
+ state2str(action_options[idx].expected));
+ return -1;
+ }
+
+ original_state = status.state;
+ do {
+ rc = xc_xsplice_get(xch, name, &status);
+ if ( rc )
+ {
+ rc = -errno;
+ break;
+ }
+
+ if ( status.state != original_state )
+ break;
+ if ( status.rc && status.rc != -EAGAIN )
+ {
+ rc = status.rc;
+ break;
+ }
+
+ printf(".");
+ fflush(stdout);
+ usleep(DELAY);
+ } while ( ++retry < RETRIES );
+
+ if ( retry >= RETRIES )
+ {
+ fprintf(stderr, "%s: Operation didn't complete after 30 seconds.\n", name);
+ return -1;
+ }
+ else
+ {
+ if ( rc == 0 )
+ rc = status.state;
+
+ if ( action_options[idx].expected == rc )
+ printf(" completed\n");
+ else if ( rc < 0 )
+ {
+ fprintf(stderr, "%s failed with %d(%s)\n", name, -rc, strerror(-rc));
+ return -1;
+ }
+ else
+ {
+ fprintf(stderr, "%s: in wrong state (%s), expected (%s)\n",
+ name, state2str(rc),
+ state2str(action_options[idx].expected));
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+static int load_func(int argc, char *argv[])
+{
+ int rc;
+ char *new_argv[2];
+ char *path, *name, *lastdot;
+
+ if ( argc != 1 )
+ {
+ show_help();
+ return -1;
+ }
+ /* <file> */
+ new_argv[1] = argv[0];
+
+ /* Synthesize the <id> */
+ path = strdup(argv[0]);
+
+ name = basename(path);
+ lastdot = strrchr(name, '.');
+ if ( lastdot != NULL )
+ *lastdot = '\0';
+ new_argv[0] = name;
+
+ rc = upload_func(2 /* <id> <file> */, new_argv);
+ if ( rc )
+ return rc;
+
+ rc = action_func(1 /* only <id> */, new_argv, ACTION_APPLY);
+ if ( rc )
+ action_func(1, new_argv, ACTION_UNLOAD);
+
+ free(path);
+ return rc;
+}
+
+/*
+ * These are also functions in action_options that are called in case
+ * none of the ones in main_options match.
+ */
+struct {
+ const char *name;
+ int (*function)(int argc, char *argv[]);
+} main_options[] = {
+ { "help", help_func },
+ { "list", list_func },
+ { "upload", upload_func },
+ { "load", load_func },
+};
+
+int main(int argc, char *argv[])
+{
+ int i, j, ret;
+
+ if ( argc <= 1 )
+ {
+ show_help();
+ return 0;
+ }
+ for ( i = 0; i < ARRAY_SIZE(main_options); i++ )
+ if (!strncmp(main_options[i].name, argv[1], strlen(argv[1])))
+ break;
+
+ if ( i == ARRAY_SIZE(main_options) )
+ {
+ for ( j = 0; j < ARRAY_SIZE(action_options); j++ )
+ if (!strncmp(action_options[j].name, argv[1], strlen(argv[1])))
+ break;
+
+ if ( j == ARRAY_SIZE(action_options) )
+ {
+ fprintf(stderr, "Unrecognised command '%s' -- try "
+ "'xen-xsplice help'\n", argv[1]);
+ return 1;
+ }
+ } else
+ j = ARRAY_SIZE(action_options);
+
+ xch = xc_interface_open(0,0,0);
+ if ( !xch )
+ {
+ fprintf(stderr, "failed to get the handler\n");
+ return 0;
+ }
+
+ if ( i == ARRAY_SIZE(main_options) )
+ ret = action_func(argc -2, argv + 2, j);
+ else
+ ret = main_options[i].function(argc -2, argv + 2);
+
+ xc_interface_close(xch);
+
+ return !!ret;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 07/27] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables lookup.
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (5 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 06/27] xen-xsplice: Tool to manipulate xsplice payloads Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-14 16:50 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 08/27] arm/x86/vmap: Add vmalloc_xen, vfree_xen and vm_init_type Konrad Rzeszutek Wilk
` (20 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Julien Grall, Stefano Stabellini, Keir Fraser, Jan Beulich,
Konrad Rzeszutek Wilk
During execution of the hypervisor we have two regions of
executable code - stext -> _etext, and _sinittext -> _einitext.
The later is not needed after bootup.
We also have various built-in macros and functions to search
in between those two swaths depending on the state of the system.
That is either for bug_frames, exceptions (x86) or symbol
names for the instruction.
With xSplice in the picture - we need a mechanism for new payloads
to searched as well for all of this.
Originally we had extra 'if (xsplice)...' but that gets
a bit tiring and does not hook up nicely.
This 'struct virtual_region' and virtual_region_list provide a
mechanism to search for the bug_frames, exception table,
and symbol names entries without having various calls in
other sub-components in the system.
Code which wishes to participate in bug_frames and exception table
entries search has to only use two public APIs:
- register_virtual_region
- unregister_virtual_region
to let the core code know.
If the ->lookup_symbol is not then the default internal symbol lookup
mechanism is used.
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Julien Grall <julien.grall@arm.com> [ARM]
---
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Julien Grall <julien.grall@arm.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
v4: New patch.
v5:
- Rename to virtual_region.
- Ditch the 'skip' function.
- Remove the _stext.
- Use RCU lists.
- Add a search function.
- Remove extern, add rcu_read_lock. remove __ from name.
v6: s/search_for_text/find_text_region/.
- Drop the uaccess.h need. Make setup_virtual_regions accept two parameters.
Remove #ifdef.
- Constify struct exception_table_entry.
- Remove some newlines.
- Change header file guard #define to proper name.
---
---
xen/arch/arm/setup.c | 4 ++
xen/arch/arm/traps.c | 39 +++++++----
xen/arch/x86/extable.c | 12 +++-
xen/arch/x86/setup.c | 6 ++
xen/arch/x86/traps.c | 40 ++++++-----
xen/common/Makefile | 1 +
xen/common/symbols.c | 11 ++-
xen/common/virtual_region.c | 148 +++++++++++++++++++++++++++++++++++++++
xen/include/xen/symbols.h | 9 +++
xen/include/xen/virtual_region.h | 47 +++++++++++++
10 files changed, 280 insertions(+), 37 deletions(-)
create mode 100644 xen/common/virtual_region.c
create mode 100644 xen/include/xen/virtual_region.h
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 6d205a9..09ff1ea 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -34,6 +34,7 @@
#include <xen/keyhandler.h>
#include <xen/cpu.h>
#include <xen/pfn.h>
+#include <xen/virtual_region.h>
#include <xen/vmap.h>
#include <xen/libfdt/libfdt.h>
#include <xen/acpi.h>
@@ -860,6 +861,9 @@ void __init start_xen(unsigned long boot_phys_offset,
system_state = SYS_STATE_active;
+ /* Must be done past setting system_state. */
+ unregister_init_virtual_region();
+
domain_unpause_by_systemcontroller(dom0);
/* Switch on to the dynamically allocated stack for the idle vcpu
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 9abfc3c..d9ffcc3 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -31,6 +31,7 @@
#include <xen/softirq.h>
#include <xen/domain_page.h>
#include <xen/perfc.h>
+#include <xen/virtual_region.h>
#include <public/sched.h>
#include <public/xen.h>
#include <asm/debugger.h>
@@ -101,6 +102,8 @@ integer_param("debug_stack_lines", debug_stack_lines);
void init_traps(void)
{
+ setup_virtual_regions(NULL, NULL);
+
/* Setup Hyp vector base */
WRITE_SYSREG((vaddr_t)hyp_traps_vector, VBAR_EL2);
@@ -1116,27 +1119,33 @@ void do_unexpected_trap(const char *msg, struct cpu_user_regs *regs)
int do_bug_frame(struct cpu_user_regs *regs, vaddr_t pc)
{
- const struct bug_frame *bug;
+ const struct bug_frame *bug = NULL;
const char *prefix = "", *filename, *predicate;
unsigned long fixup;
- int id, lineno;
- static const struct bug_frame *const stop_frames[] = {
- __stop_bug_frames_0,
- __stop_bug_frames_1,
- __stop_bug_frames_2,
- NULL
- };
+ int id = -1, lineno;
+ const struct virtual_region *region;
- for ( bug = __start_bug_frames, id = 0; stop_frames[id]; ++bug )
+ region = find_text_region(pc);
+ if ( region )
{
- while ( unlikely(bug == stop_frames[id]) )
- ++id;
+ for ( id = 0; id < BUGFRAME_NR; id++ )
+ {
+ const struct bug_frame *b;
+ unsigned int i;
- if ( ((vaddr_t)bug_loc(bug)) == pc )
- break;
+ for ( i = 0, b = region->frame[id].bugs;
+ i < region->frame[id].n_bugs; b++, i++ )
+ {
+ if ( ((vaddr_t)bug_loc(b)) == pc )
+ {
+ bug = b;
+ goto found;
+ }
+ }
+ }
}
-
- if ( !stop_frames[id] )
+ found:
+ if ( !bug )
return -ENOENT;
/* WARN, BUG or ASSERT: decode the filename pointer and line number. */
diff --git a/xen/arch/x86/extable.c b/xen/arch/x86/extable.c
index 89b5bcb..2a06cca 100644
--- a/xen/arch/x86/extable.c
+++ b/xen/arch/x86/extable.c
@@ -1,10 +1,12 @@
-#include <xen/config.h>
#include <xen/init.h>
+#include <xen/list.h>
#include <xen/perfc.h>
+#include <xen/rcupdate.h>
#include <xen/sort.h>
#include <xen/spinlock.h>
#include <asm/uaccess.h>
+#include <xen/virtual_region.h>
#define EX_FIELD(ptr, field) ((unsigned long)&(ptr)->field + (ptr)->field)
@@ -80,8 +82,12 @@ search_one_table(const struct exception_table_entry *first,
unsigned long
search_exception_table(unsigned long addr)
{
- return search_one_table(
- __start___ex_table, __stop___ex_table-1, addr);
+ const struct virtual_region *region = find_text_region(addr);
+
+ if ( region && region->ex )
+ return search_one_table(region->ex, region->ex_end - 1, addr);
+
+ return 0;
}
unsigned long
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 3696c31..22dc148 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -26,6 +26,7 @@
#include <xen/pfn.h>
#include <xen/nodemask.h>
#include <xen/tmem_xen.h>
+#include <xen/virtual_region.h>
#include <xen/watchdog.h>
#include <public/version.h>
#include <compat/platform.h>
@@ -515,6 +516,9 @@ static void noinline init_done(void)
system_state = SYS_STATE_active;
+ /* MUST be done prior to removing .init data. */
+ unregister_init_virtual_region();
+
domain_unpause_by_systemcontroller(hardware_domain);
/* Zero the .init code and data. */
@@ -617,6 +621,8 @@ void __init noreturn __start_xen(unsigned long mbi_p)
smp_prepare_boot_cpu();
sort_exception_tables();
+ setup_virtual_regions(__start___ex_table, __stop___ex_table);
+
/* Full exception support from here on in. */
loader = (mbi->flags & MBI_LOADERNAME)
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index c6c9227..f73f7f3 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -48,6 +48,7 @@
#include <xen/kexec.h>
#include <xen/trace.h>
#include <xen/paging.h>
+#include <xen/virtual_region.h>
#include <xen/watchdog.h>
#include <asm/system.h>
#include <asm/io.h>
@@ -1229,18 +1230,12 @@ static int emulate_forced_invalid_op(struct cpu_user_regs *regs)
void do_invalid_op(struct cpu_user_regs *regs)
{
- const struct bug_frame *bug;
+ const struct bug_frame *bug = NULL;
u8 bug_insn[2];
const char *prefix = "", *filename, *predicate, *eip = (char *)regs->eip;
unsigned long fixup;
- int id, lineno;
- static const struct bug_frame *const stop_frames[] = {
- __stop_bug_frames_0,
- __stop_bug_frames_1,
- __stop_bug_frames_2,
- __stop_bug_frames_3,
- NULL
- };
+ int id = -1, lineno;
+ const struct virtual_region *region;
DEBUGGER_trap_entry(TRAP_invalid_op, regs);
@@ -1257,16 +1252,29 @@ void do_invalid_op(struct cpu_user_regs *regs)
memcmp(bug_insn, "\xf\xb", sizeof(bug_insn)) )
goto die;
- for ( bug = __start_bug_frames, id = 0; stop_frames[id]; ++bug )
+ region = find_text_region(regs->eip);
+ if ( region )
{
- while ( unlikely(bug == stop_frames[id]) )
- ++id;
- if ( bug_loc(bug) == eip )
- break;
+ for ( id = 0; id < BUGFRAME_NR; id++ )
+ {
+ const struct bug_frame *b;
+ unsigned int i;
+
+ for ( i = 0, b = region->frame[id].bugs;
+ i < region->frame[id].n_bugs; b++, i++ )
+ {
+ if ( bug_loc(b) == eip )
+ {
+ bug = b;
+ goto found;
+ }
+ }
+ }
}
- if ( !stop_frames[id] )
- goto die;
+ found:
+ if ( !bug )
+ goto die;
eip += sizeof(bug_insn);
if ( id == BUGFRAME_run_fn )
{
diff --git a/xen/common/Makefile b/xen/common/Makefile
index 910ac69..1e4bc70 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -51,6 +51,7 @@ obj-y += time.o
obj-y += timer.o
obj-y += trace.o
obj-y += version.o
+obj-y += virtual_region.o
obj-y += vm_event.o
obj-y += vmap.o
obj-y += vsprintf.o
diff --git a/xen/common/symbols.c b/xen/common/symbols.c
index a59c59d..b18ddcd1 100644
--- a/xen/common/symbols.c
+++ b/xen/common/symbols.c
@@ -17,6 +17,7 @@
#include <xen/lib.h>
#include <xen/string.h>
#include <xen/spinlock.h>
+#include <xen/virtual_region.h>
#include <public/platform.h>
#include <xen/guest_access.h>
@@ -97,8 +98,7 @@ static unsigned int get_symbol_offset(unsigned long pos)
bool_t is_active_kernel_text(unsigned long addr)
{
- return (is_kernel_text(addr) ||
- (system_state < SYS_STATE_active && is_kernel_inittext(addr)));
+ return !!find_text_region(addr);
}
const char *symbols_lookup(unsigned long addr,
@@ -108,13 +108,18 @@ const char *symbols_lookup(unsigned long addr,
{
unsigned long i, low, high, mid;
unsigned long symbol_end = 0;
+ const struct virtual_region *region;
namebuf[KSYM_NAME_LEN] = 0;
namebuf[0] = 0;
- if (!is_active_kernel_text(addr))
+ region = find_text_region(addr);
+ if (!region)
return NULL;
+ if (region->symbols_lookup)
+ return region->symbols_lookup(addr, symbolsize, offset, namebuf);
+
/* do a binary search on the sorted symbols_addresses array */
low = 0;
high = symbols_num_syms;
diff --git a/xen/common/virtual_region.c b/xen/common/virtual_region.c
new file mode 100644
index 0000000..82487e6
--- /dev/null
+++ b/xen/common/virtual_region.c
@@ -0,0 +1,148 @@
+/*
+ * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
+ *
+ */
+
+#include <xen/init.h>
+#include <xen/kernel.h>
+#include <xen/rcupdate.h>
+#include <xen/spinlock.h>
+#include <xen/virtual_region.h>
+
+static struct virtual_region core = {
+ .list = LIST_HEAD_INIT(core.list),
+ .start = (unsigned long)_stext,
+ .end = (unsigned long)_etext,
+};
+
+/* Becomes irrelevant when __init sections are cleared. */
+static struct virtual_region core_init __initdata = {
+ .list = LIST_HEAD_INIT(core_init.list),
+ .start = (unsigned long)_sinittext,
+ .end = (unsigned long)_einittext,
+};
+
+/*
+ * RCU locking. Additions are done either at startup (when there is only
+ * one CPU) or when all CPUs are running without IRQs.
+ *
+ * Deletions are big tricky. We do it when xSplicing (all CPUs running
+ * without IRQs) or during bootup (when clearing the init).
+ *
+ * Hence we use list_del_rcu (which sports an memory fence) and a spinlock
+ * on deletion.
+ *
+ * All readers of virtual_region_list MUST use list list_for_each_entry_rcu.
+ *
+ */
+static LIST_HEAD(virtual_region_list);
+static DEFINE_SPINLOCK(virtual_region_lock);
+static DEFINE_RCU_READ_LOCK(rcu_virtual_region_lock);
+
+const struct virtual_region *find_text_region(unsigned long addr)
+{
+ const struct virtual_region *region;
+
+ rcu_read_lock(&rcu_virtual_region_lock);
+ list_for_each_entry_rcu( region, &virtual_region_list, list )
+ {
+ if ( addr >= region->start && addr < region->end )
+ {
+ rcu_read_unlock(&rcu_virtual_region_lock);
+ return region;
+ }
+ }
+ rcu_read_unlock(&rcu_virtual_region_lock);
+
+ return NULL;
+}
+
+void register_virtual_region(struct virtual_region *r)
+{
+ ASSERT(!local_irq_is_enabled());
+
+ list_add_tail_rcu(&r->list, &virtual_region_list);
+}
+
+static void remove_virtual_region(struct virtual_region *r)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&virtual_region_lock, flags);
+ list_del_rcu(&r->list);
+ spin_unlock_irqrestore(&virtual_region_lock, flags);
+ /*
+ * We do not need to invoke call_rcu.
+ *
+ * This is due to the fact that on the deletion we have made sure
+ * to use spinlocks (to guard against somebody else calling
+ * unregister_virtual_region) and list_deletion spiced with
+ * memory barrier.
+ *
+ * That protects us from corrupting the list as the readers all
+ * use list_for_each_entry_rcu which is safe against concurrent
+ * deletions.
+ */
+}
+
+void unregister_virtual_region(struct virtual_region *r)
+{
+ /* Expected to be called from xSplice - which has IRQs disabled. */
+ ASSERT(!local_irq_is_enabled());
+
+ remove_virtual_region(r);
+}
+
+void __init unregister_init_virtual_region(void)
+{
+ BUG_ON(system_state != SYS_STATE_active);
+
+ remove_virtual_region(&core_init);
+}
+
+void __init setup_virtual_regions(const struct exception_table_entry *start,
+ const struct exception_table_entry *end)
+{
+ size_t sz;
+ unsigned int i;
+ static const struct bug_frame *const __initconstrel bug_frames[] = {
+ __start_bug_frames,
+ __stop_bug_frames_0,
+ __stop_bug_frames_1,
+ __stop_bug_frames_2,
+#ifdef CONFIG_X86
+ __stop_bug_frames_3,
+#endif
+ NULL
+ };
+
+ for ( i = 1; bug_frames[i]; i++ )
+ {
+ const struct bug_frame *s;
+
+ s = bug_frames[i - 1];
+ sz = bug_frames[i] - s;
+
+ core.frame[i - 1].n_bugs = sz;
+ core.frame[i - 1].bugs = s;
+
+ core_init.frame[i - 1].n_bugs = sz;
+ core_init.frame[i - 1].bugs = s;
+ }
+
+ core_init.ex = core.ex = start;
+ core_init.ex_end = core.ex_end = end;
+
+ register_virtual_region(&core_init);
+ register_virtual_region(&core);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/xen/symbols.h b/xen/include/xen/symbols.h
index 1fa0537..f58e611 100644
--- a/xen/include/xen/symbols.h
+++ b/xen/include/xen/symbols.h
@@ -5,6 +5,15 @@
#define KSYM_NAME_LEN 127
+/*
+ * Typedef for the callback functions that symbols_lookup
+ * can call if virtual_region_list has an callback for it.
+ */
+typedef const char *symbols_lookup_t(unsigned long addr,
+ unsigned long *symbolsize,
+ unsigned long *offset,
+ char *namebuf);
+
/* Lookup an address. */
const char *symbols_lookup(unsigned long addr,
unsigned long *symbolsize,
diff --git a/xen/include/xen/virtual_region.h b/xen/include/xen/virtual_region.h
new file mode 100644
index 0000000..31826d1
--- /dev/null
+++ b/xen/include/xen/virtual_region.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
+ *
+ */
+
+#ifndef __XEN_VIRTUAL_REGION__
+#define __XEN_VIRTUAL_REGION__
+
+#include <xen/list.h>
+#include <xen/symbols.h>
+
+struct virtual_region
+{
+ struct list_head list;
+ unsigned long start; /* Virtual address start. */
+ unsigned long end; /* Virtual address end. */
+
+ /* If this is NULL the default lookup mechanism is used. */
+ symbols_lookup_t *symbols_lookup;
+
+ struct {
+ const struct bug_frame *bugs; /* The pointer to array of bug frames. */
+ size_t n_bugs; /* The number of them. */
+ } frame[BUGFRAME_NR];
+
+ const struct exception_table_entry *ex;
+ const struct exception_table_entry *ex_end;
+};
+
+const struct virtual_region *find_text_region(unsigned long addr);
+void setup_virtual_regions(const struct exception_table_entry *start,
+ const struct exception_table_entry *end);
+void unregister_init_virtual_region(void);
+void register_virtual_region(struct virtual_region *r);
+void unregister_virtual_region(struct virtual_region *r);
+
+#endif /* __XEN_VIRTUAL_REGION__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 08/27] arm/x86/vmap: Add vmalloc_xen, vfree_xen and vm_init_type
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (6 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 07/27] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables lookup Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-17 20:17 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 09/27] x86/mm: Introduce modify_xen_mappings() Konrad Rzeszutek Wilk
` (19 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Stefano Stabellini, Keir Fraser, Konrad Rzeszutek Wilk,
Ian Jackson, Tim Deegan, Julien Grall, Jan Beulich
For those users who want to use the virtual addresses that
are in the hypervisor's code/data/ region address space -
these three new functions allow that.
Implementation wise the vmap API keeps track of two virtual
address regions now:
a) VMAP_VIRT_START
b) Any provided virtual address space (need start and end).
The a) one is the default one and the existing behavior
for users of vmalloc, vmap, etc is the same.
If however one wishes to use the b) one only has to use
the vm_init_type to initialize and the vmalloc_type to utilize it.
This allows users (such as xSplice) to provide their own
mechanism to change the the page flags, and also use virtual
addresses closer to the hypervisor virtual addresses (at least
on x86) while not having to deal with the allocation of
pages.
For example of users, see patch titled "xsplice: Implement payload
loading", where we parse the payload's ELF relocations - which
is defined to be signed 32-bit (so max displacement is 2GB virtual
spacE). The displacement of the hypervisor virtual addresses to the
vmalloc (on x86) is more than 32-bits - which means that ELF relocations
would truncate the 34 and 33th bit. Hence this alternate API.
We also add add extra checks in case the b) range has not been initialized.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Suggested-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <julien.grall@arm.com> [ARM]
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Tim Deegan <tim@xen.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Julien Grall <julien.grall@arm.com>
v4: New patch.
v5: Update per Jan's comments.
v6: Drop the stray parentheses on typedefs.
Ditch the vunmap callback. Stash away the virtual addresses in lists.
Ditch the vmap callback. Just provide virtual address.
Ditch the vmalloc_range. Require users of alternative virtual address
to call vmap_init_type first.
v7: Don't expose the vmalloc_type and such. Instead provide an wrapper
called vmalloc_xen for those.
Rename the enum, change one of the names.
Moved the vunmap_type around in c file so we don't have to declare
it in the header.
---
---
xen/arch/arm/kernel.c | 2 +-
xen/arch/arm/mm.c | 2 +-
xen/arch/x86/mm.c | 2 +-
xen/common/vmap.c | 202 ++++++++++++++++++++++++++++++-------------------
xen/drivers/acpi/osl.c | 2 +-
xen/include/xen/vmap.h | 21 ++++-
6 files changed, 148 insertions(+), 83 deletions(-)
diff --git a/xen/arch/arm/kernel.c b/xen/arch/arm/kernel.c
index 61808ac..9871bd9 100644
--- a/xen/arch/arm/kernel.c
+++ b/xen/arch/arm/kernel.c
@@ -299,7 +299,7 @@ static __init int kernel_decompress(struct bootmodule *mod)
return -ENOMEM;
}
mfn = _mfn(page_to_mfn(pages));
- output = __vmap(&mfn, 1 << kernel_order_out, 1, 1, PAGE_HYPERVISOR);
+ output = __vmap(&mfn, 1 << kernel_order_out, 1, 1, PAGE_HYPERVISOR, VMAP_DEFAULT);
rc = perform_gunzip(output, input, size);
clean_dcache_va_range(output, output_size);
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 7065c3e..94ea054 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -807,7 +807,7 @@ void *ioremap_attr(paddr_t pa, size_t len, unsigned int attributes)
mfn_t mfn = _mfn(PFN_DOWN(pa));
unsigned int offs = pa & (PAGE_SIZE - 1);
unsigned int nr = PFN_UP(offs + len);
- void *ptr = __vmap(&mfn, nr, 1, 1, attributes);
+ void *ptr = __vmap(&mfn, nr, 1, 1, attributes, VMAP_DEFAULT);
if ( ptr == NULL )
return NULL;
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index bca7532..ca2d0bb 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -6124,7 +6124,7 @@ void __iomem *ioremap(paddr_t pa, size_t len)
unsigned int offs = pa & (PAGE_SIZE - 1);
unsigned int nr = PFN_UP(offs + len);
- va = __vmap(&mfn, nr, 1, 1, PAGE_HYPERVISOR_NOCACHE) + offs;
+ va = __vmap(&mfn, nr, 1, 1, PAGE_HYPERVISOR_NOCACHE, VMAP_DEFAULT) + offs;
}
return (void __force __iomem *)va;
diff --git a/xen/common/vmap.c b/xen/common/vmap.c
index 134eda0..eb477a4 100644
--- a/xen/common/vmap.c
+++ b/xen/common/vmap.c
@@ -10,40 +10,43 @@
#include <asm/page.h>
static DEFINE_SPINLOCK(vm_lock);
-static void *__read_mostly vm_base;
-#define vm_bitmap ((unsigned long *)vm_base)
+static void *__read_mostly vm_base[VMAP_REGION_NR];
+#define vm_bitmap(x) ((unsigned long *)vm_base[x])
/* highest allocated bit in the bitmap */
-static unsigned int __read_mostly vm_top;
+static unsigned int __read_mostly vm_top[VMAP_REGION_NR];
/* total number of bits in the bitmap */
-static unsigned int __read_mostly vm_end;
+static unsigned int __read_mostly vm_end[VMAP_REGION_NR];
/* lowest known clear bit in the bitmap */
-static unsigned int vm_low;
+static unsigned int vm_low[VMAP_REGION_NR];
-void __init vm_init(void)
+void __init vm_init_type(enum vmap_region type, void *start, void *end)
{
unsigned int i, nr;
unsigned long va;
- vm_base = (void *)VMAP_VIRT_START;
- vm_end = PFN_DOWN(arch_vmap_virt_end() - vm_base);
- vm_low = PFN_UP((vm_end + 7) / 8);
- nr = PFN_UP((vm_low + 7) / 8);
- vm_top = nr * PAGE_SIZE * 8;
+ ASSERT(!vm_base[type]);
- for ( i = 0, va = (unsigned long)vm_bitmap; i < nr; ++i, va += PAGE_SIZE )
+ vm_base[type] = start;
+ vm_end[type] = PFN_DOWN(end - start);
+ vm_low[type]= PFN_UP((vm_end[type] + 7) / 8);
+ nr = PFN_UP((vm_low[type] + 7) / 8);
+ vm_top[type] = nr * PAGE_SIZE * 8;
+
+ for ( i = 0, va = (unsigned long)vm_bitmap(type); i < nr; ++i, va += PAGE_SIZE )
{
struct page_info *pg = alloc_domheap_page(NULL, 0);
map_pages_to_xen(va, page_to_mfn(pg), 1, PAGE_HYPERVISOR);
clear_page((void *)va);
}
- bitmap_fill(vm_bitmap, vm_low);
+ bitmap_fill(vm_bitmap(type), vm_low[type]);
/* Populate page tables for the bitmap if necessary. */
- populate_pt_range(va, 0, vm_low - nr);
+ populate_pt_range(va, 0, vm_low[type] - nr);
}
-void *vm_alloc(unsigned int nr, unsigned int align)
+static void *vm_alloc_type(unsigned int nr, unsigned int align,
+ enum vmap_region t)
{
unsigned int start, bit;
@@ -52,27 +55,30 @@ void *vm_alloc(unsigned int nr, unsigned int align)
else if ( align & (align - 1) )
align &= -align;
+ if ( !vm_base[t] )
+ return NULL;
+
spin_lock(&vm_lock);
for ( ; ; )
{
struct page_info *pg;
- ASSERT(vm_low == vm_top || !test_bit(vm_low, vm_bitmap));
- for ( start = vm_low; start < vm_top; )
+ ASSERT(vm_low[t] == vm_top[t] || !test_bit(vm_low[t], vm_bitmap(t)));
+ for ( start = vm_low[t]; start < vm_top[t]; )
{
- bit = find_next_bit(vm_bitmap, vm_top, start + 1);
- if ( bit > vm_top )
- bit = vm_top;
+ bit = find_next_bit(vm_bitmap(t), vm_top[t], start + 1);
+ if ( bit > vm_top[t] )
+ bit = vm_top[t];
/*
* Note that this skips the first bit, making the
* corresponding page a guard one.
*/
start = (start + align) & ~(align - 1);
- if ( bit < vm_top )
+ if ( bit < vm_top[t] )
{
if ( start + nr < bit )
break;
- start = find_next_zero_bit(vm_bitmap, vm_top, bit + 1);
+ start = find_next_zero_bit(vm_bitmap(t), vm_top[t], bit + 1);
}
else
{
@@ -82,12 +88,12 @@ void *vm_alloc(unsigned int nr, unsigned int align)
}
}
- if ( start < vm_top )
+ if ( start < vm_top[t] )
break;
spin_unlock(&vm_lock);
- if ( vm_top >= vm_end )
+ if ( vm_top[t] >= vm_end[t] )
return NULL;
pg = alloc_domheap_page(NULL, 0);
@@ -96,23 +102,23 @@ void *vm_alloc(unsigned int nr, unsigned int align)
spin_lock(&vm_lock);
- if ( start >= vm_top )
+ if ( start >= vm_top[t] )
{
- unsigned long va = (unsigned long)vm_bitmap + vm_top / 8;
+ unsigned long va = (unsigned long)vm_bitmap(t) + vm_top[t] / 8;
if ( !map_pages_to_xen(va, page_to_mfn(pg), 1, PAGE_HYPERVISOR) )
{
clear_page((void *)va);
- vm_top += PAGE_SIZE * 8;
- if ( vm_top > vm_end )
- vm_top = vm_end;
+ vm_top[t] += PAGE_SIZE * 8;
+ if ( vm_top[t] > vm_end[t] )
+ vm_top[t] = vm_end[t];
continue;
}
}
free_domheap_page(pg);
- if ( start >= vm_top )
+ if ( start >= vm_top[t] )
{
spin_unlock(&vm_lock);
return NULL;
@@ -120,47 +126,56 @@ void *vm_alloc(unsigned int nr, unsigned int align)
}
for ( bit = start; bit < start + nr; ++bit )
- __set_bit(bit, vm_bitmap);
- if ( bit < vm_top )
- ASSERT(!test_bit(bit, vm_bitmap));
+ __set_bit(bit, vm_bitmap(t));
+ if ( bit < vm_top[t] )
+ ASSERT(!test_bit(bit, vm_bitmap(t)));
else
- ASSERT(bit == vm_top);
- if ( start <= vm_low + 2 )
- vm_low = bit;
+ ASSERT(bit == vm_top[t]);
+ if ( start <= vm_low[t] + 2 )
+ vm_low[t] = bit;
spin_unlock(&vm_lock);
- return vm_base + start * PAGE_SIZE;
+ return vm_base[t] + start * PAGE_SIZE;
+}
+
+void *vm_alloc(unsigned int nr, unsigned int align)
+{
+ return vm_alloc_type(nr, align, VMAP_DEFAULT);
}
-static unsigned int vm_index(const void *va)
+static unsigned int vm_index(const void *va, enum vmap_region type)
{
unsigned long addr = (unsigned long)va & ~(PAGE_SIZE - 1);
unsigned int idx;
+ unsigned long start = (unsigned long)vm_base[type];
+
+ if ( !start)
+ return 0;
- if ( addr < VMAP_VIRT_START + (vm_end / 8) ||
- addr >= VMAP_VIRT_START + vm_top * PAGE_SIZE )
+ if ( addr < start + (vm_end[type] / 8) ||
+ addr >= start + vm_top[type] * PAGE_SIZE )
return 0;
- idx = PFN_DOWN(va - vm_base);
- return !test_bit(idx - 1, vm_bitmap) &&
- test_bit(idx, vm_bitmap) ? idx : 0;
+ idx = PFN_DOWN(va - vm_base[type]);
+ return !test_bit(idx - 1, vm_bitmap(type)) &&
+ test_bit(idx, vm_bitmap(type)) ? idx : 0;
}
-static unsigned int vm_size(const void *va)
+static unsigned int vm_size(const void *va, enum vmap_region type)
{
- unsigned int start = vm_index(va), end;
+ unsigned int start = vm_index(va, type), end;
if ( !start )
return 0;
- end = find_next_zero_bit(vm_bitmap, vm_top, start + 1);
+ end = find_next_zero_bit(vm_bitmap(type), vm_top[type], start + 1);
- return min(end, vm_top) - start;
+ return min(end, vm_top[type]) - start;
}
-void vm_free(const void *va)
+static void vm_free_type(const void *va, enum vmap_region type)
{
- unsigned int bit = vm_index(va);
+ unsigned int bit = vm_index(va, type);
if ( !bit )
{
@@ -169,29 +184,54 @@ void vm_free(const void *va)
}
spin_lock(&vm_lock);
- if ( bit < vm_low )
+ if ( bit < vm_low[type] )
{
- vm_low = bit - 1;
- while ( !test_bit(vm_low - 1, vm_bitmap) )
- --vm_low;
+ vm_low[type] = bit - 1;
+ while ( !test_bit(vm_low[type] - 1, vm_bitmap(type)) )
+ --vm_low[type];
}
- while ( __test_and_clear_bit(bit, vm_bitmap) )
- if ( ++bit == vm_top )
+ while ( __test_and_clear_bit(bit, vm_bitmap(type)) )
+ if ( ++bit == vm_top[type] )
break;
spin_unlock(&vm_lock);
}
+void vm_free(const void *va)
+{
+ vm_free_type(va, VMAP_DEFAULT);
+}
+
+static void vunmap_type(const void *va, enum vmap_region type)
+{
+ unsigned int size = vm_size(va, type);
+#ifndef _PAGE_NONE
+ unsigned long addr = (unsigned long)va;
+
+ destroy_xen_mappings(addr, addr + PAGE_SIZE * size);
+#else /* Avoid tearing down intermediate page tables. */
+ map_pages_to_xen((unsigned long)va, 0, size, _PAGE_NONE);
+#endif
+ vm_free_type(va, type);
+}
+
+void vunmap(const void *va)
+{
+ vunmap_type(va, VMAP_DEFAULT);
+}
+
+
void *__vmap(const mfn_t *mfn, unsigned int granularity,
- unsigned int nr, unsigned int align, unsigned int flags)
+ unsigned int nr, unsigned int align, unsigned int flags,
+ enum vmap_region type)
{
- void *va = vm_alloc(nr * granularity, align);
+ void *va = vm_alloc_type(nr * granularity, align, type);
unsigned long cur = (unsigned long)va;
for ( ; va && nr--; ++mfn, cur += PAGE_SIZE * granularity )
{
if ( map_pages_to_xen(cur, mfn_x(*mfn), granularity, flags) )
{
- vunmap(va);
+ vunmap_type(va, type);
va = NULL;
}
}
@@ -201,22 +241,10 @@ void *__vmap(const mfn_t *mfn, unsigned int granularity,
void *vmap(const mfn_t *mfn, unsigned int nr)
{
- return __vmap(mfn, 1, nr, 1, PAGE_HYPERVISOR);
+ return __vmap(mfn, 1, nr, 1, PAGE_HYPERVISOR, VMAP_DEFAULT);
}
-void vunmap(const void *va)
-{
-#ifndef _PAGE_NONE
- unsigned long addr = (unsigned long)va;
-
- destroy_xen_mappings(addr, addr + PAGE_SIZE * vm_size(va));
-#else /* Avoid tearing down intermediate page tables. */
- map_pages_to_xen((unsigned long)va, 0, vm_size(va), _PAGE_NONE);
-#endif
- vm_free(va);
-}
-
-void *vmalloc(size_t size)
+static void *vmalloc_type(size_t size, enum vmap_region type)
{
mfn_t *mfn;
size_t pages, i;
@@ -238,11 +266,12 @@ void *vmalloc(size_t size)
mfn[i] = _mfn(page_to_mfn(pg));
}
- va = vmap(mfn, pages);
+ va = __vmap(mfn, 1, pages, 1, PAGE_HYPERVISOR, type);
if ( va == NULL )
goto error;
xfree(mfn);
+
return va;
error:
@@ -252,6 +281,16 @@ void *vmalloc(size_t size)
return NULL;
}
+void *vmalloc(size_t size)
+{
+ return vmalloc_type(size, VMAP_DEFAULT);
+}
+
+void *vmalloc_xen(size_t size)
+{
+ return vmalloc_type(size, VMAP_XEN);
+}
+
void *vzalloc(size_t size)
{
void *p = vmalloc(size);
@@ -266,7 +305,7 @@ void *vzalloc(size_t size)
return p;
}
-void vfree(void *va)
+void vfree_type(void *va, enum vmap_region type)
{
unsigned int i, pages;
struct page_info *pg;
@@ -275,7 +314,8 @@ void vfree(void *va)
if ( !va )
return;
- pages = vm_size(va);
+ pages = vm_size(va, type);
+
ASSERT(pages);
for ( i = 0; i < pages; i++ )
@@ -285,9 +325,19 @@ void vfree(void *va)
ASSERT(page);
page_list_add(page, &pg_list);
}
- vunmap(va);
+ vunmap_type(va, type);
while ( (pg = page_list_remove_head(&pg_list)) != NULL )
free_domheap_page(pg);
}
+
+void vfree(void *va)
+{
+ vfree_type(va, VMAP_DEFAULT);
+}
+
+void vfree_xen(void *va)
+{
+ vfree_type(va, VMAP_XEN);
+}
#endif
diff --git a/xen/drivers/acpi/osl.c b/xen/drivers/acpi/osl.c
index 8a28d87..9a49029 100644
--- a/xen/drivers/acpi/osl.c
+++ b/xen/drivers/acpi/osl.c
@@ -97,7 +97,7 @@ acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
if (IS_ENABLED(CONFIG_X86) && !((phys + size - 1) >> 20))
return __va(phys);
return __vmap(&mfn, PFN_UP(offs + size), 1, 1,
- ACPI_MAP_MEM_ATTR) + offs;
+ ACPI_MAP_MEM_ATTR, VMAP_DEFAULT) + offs;
}
return __acpi_map_table(phys, size);
}
diff --git a/xen/include/xen/vmap.h b/xen/include/xen/vmap.h
index 5671ac8..0fb78a2 100644
--- a/xen/include/xen/vmap.h
+++ b/xen/include/xen/vmap.h
@@ -4,16 +4,28 @@
#include <xen/mm.h>
#include <asm/page.h>
+enum vmap_region {
+ VMAP_DEFAULT,
+ VMAP_XEN,
+ VMAP_REGION_NR,
+};
+
+void vm_init_type(enum vmap_region type, void *start, void *end);
+
void *vm_alloc(unsigned int nr, unsigned int align);
void vm_free(const void *);
-void *__vmap(const mfn_t *mfn, unsigned int granularity,
- unsigned int nr, unsigned int align, unsigned int flags);
+void *__vmap(const mfn_t *mfn, unsigned int granularity, unsigned int nr,
+ unsigned int align, unsigned int flags, enum vmap_region);
void *vmap(const mfn_t *mfn, unsigned int nr);
void vunmap(const void *);
+
void *vmalloc(size_t size);
+void *vmalloc_xen(size_t size);
+
void *vzalloc(size_t size);
void vfree(void *va);
+void vfree_xen(void *va);
void __iomem *ioremap(paddr_t, size_t);
@@ -24,7 +36,10 @@ static inline void iounmap(void __iomem *va)
vunmap((void *)(addr & PAGE_MASK));
}
-void vm_init(void);
void *arch_vmap_virt_end(void);
+static inline void vm_init(void)
+{
+ vm_init_type(VMAP_DEFAULT, (void *)VMAP_VIRT_START, arch_vmap_virt_end());
+}
#endif /* __XEN_VMAP_H__ */
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 09/27] x86/mm: Introduce modify_xen_mappings()
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (7 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 08/27] arm/x86/vmap: Add vmalloc_xen, vfree_xen and vm_init_type Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-14 4:07 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 10/27] xsplice: Add helper elf routines Konrad Rzeszutek Wilk
` (18 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: George Dunlap, Jan Beulich, Konrad Rzeszutek Wilk
From: Andrew Cooper <andrew.cooper3@citrix.com>
To simply change the permissions on existing Xen mappings. The existing
destroy_xen_mappings() is altered to support a change the PTE permissions.
A new destroy_xen_mappings() is introduced, as the special case of not passing
_PAGE_PRESENT to modify_xen_mappings().
As cleanup (and an ideal functional test), the boot logic which remaps Xen's
code and data with reduced permissions is altered to use
modify_xen_mappings(), rather than map_pages_to_xen() passing the same mfn's
back in.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: George Dunlap <george.dunlap@eu.citrix.com>
v7: New
v8:
* Allow callers to pass PAGE_HYPERVISOR_xxx constants, for consistently with
similar functions.
* Replace one opencoded 0 with its logical equivalent, _PAGE_NONE.
* Add check for creating new mappings of 4K entries.
* Correct the continue logic. Invert the sense of the comment to match the
code.
* Added Reviewed-by George and Jan. Fix missing "are" in comment.
---
---
xen/arch/x86/mm.c | 75 +++++++++++++++++++++++++++++++++++++++++++++-------
xen/arch/x86/setup.c | 22 +++++++--------
xen/include/xen/mm.h | 2 ++
3 files changed, 76 insertions(+), 23 deletions(-)
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index ca2d0bb..73798c3 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5956,7 +5956,19 @@ int populate_pt_range(unsigned long virt, unsigned long mfn,
return map_pages_to_xen(virt, mfn, nr_mfns, MAP_SMALL_PAGES);
}
-void destroy_xen_mappings(unsigned long s, unsigned long e)
+/*
+ * Alter the permissions of a range of Xen virtual address space.
+ *
+ * Does not create new mappings, and does not modify the mfn in existing
+ * mappings, but will shatter superpages if necessary, and will destroy
+ * mappings if not passed _PAGE_PRESENT.
+ *
+ * The only flags considered are NX, RW and PRESENT. All other input flags
+ * are ignored.
+ *
+ * It is an error to call with present flags over an unpopulated range.
+ */
+void modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf)
{
bool_t locking = system_state > SYS_STATE_boot;
l2_pgentry_t *pl2e;
@@ -5964,6 +5976,10 @@ void destroy_xen_mappings(unsigned long s, unsigned long e)
unsigned int i;
unsigned long v = s;
+ /* Set of valid PTE bits which may be altered. */
+#define FLAGS_MASK (_PAGE_NX|_PAGE_RW|_PAGE_PRESENT)
+ nf &= FLAGS_MASK;
+
ASSERT(IS_ALIGNED(s, PAGE_SIZE));
ASSERT(IS_ALIGNED(e, PAGE_SIZE));
@@ -5973,6 +5989,9 @@ void destroy_xen_mappings(unsigned long s, unsigned long e)
if ( !(l3e_get_flags(*pl3e) & _PAGE_PRESENT) )
{
+ /* Confirm the caller isn't trying to create new mappings. */
+ ASSERT(!(nf & _PAGE_PRESENT));
+
v += 1UL << L3_PAGETABLE_SHIFT;
v &= ~((1UL << L3_PAGETABLE_SHIFT) - 1);
continue;
@@ -5984,8 +6003,12 @@ void destroy_xen_mappings(unsigned long s, unsigned long e)
l1_table_offset(v) == 0 &&
((e - v) >= (1UL << L3_PAGETABLE_SHIFT)) )
{
- /* PAGE1GB: whole superpage is destroyed. */
- l3e_write_atomic(pl3e, l3e_empty());
+ /* PAGE1GB: whole superpage is modified. */
+ l3_pgentry_t nl3e = !(nf & _PAGE_PRESENT) ? l3e_empty()
+ : l3e_from_pfn(l3e_get_pfn(*pl3e),
+ (l3e_get_flags(*pl3e) & ~FLAGS_MASK) | nf);
+
+ l3e_write_atomic(pl3e, nl3e);
v += 1UL << L3_PAGETABLE_SHIFT;
continue;
}
@@ -6016,6 +6039,9 @@ void destroy_xen_mappings(unsigned long s, unsigned long e)
if ( !(l2e_get_flags(*pl2e) & _PAGE_PRESENT) )
{
+ /* Confirm the caller isn't trying to create new mappings. */
+ ASSERT(!(nf & _PAGE_PRESENT));
+
v += 1UL << L2_PAGETABLE_SHIFT;
v &= ~((1UL << L2_PAGETABLE_SHIFT) - 1);
continue;
@@ -6026,8 +6052,12 @@ void destroy_xen_mappings(unsigned long s, unsigned long e)
if ( (l1_table_offset(v) == 0) &&
((e-v) >= (1UL << L2_PAGETABLE_SHIFT)) )
{
- /* PSE: whole superpage is destroyed. */
- l2e_write_atomic(pl2e, l2e_empty());
+ /* PSE: whole superpage is modified. */
+ l2_pgentry_t nl2e = !(nf & _PAGE_PRESENT) ? l2e_empty()
+ : l2e_from_pfn(l2e_get_pfn(*pl2e),
+ (l2e_get_flags(*pl2e) & ~FLAGS_MASK) | nf);
+
+ l2e_write_atomic(pl2e, nl2e);
v += 1UL << L2_PAGETABLE_SHIFT;
}
else
@@ -6055,13 +6085,27 @@ void destroy_xen_mappings(unsigned long s, unsigned long e)
}
else
{
+ l1_pgentry_t nl1e;
+
/* Ordinary 4kB mapping. */
pl1e = l2e_to_l1e(*pl2e) + l1_table_offset(v);
- l1e_write_atomic(pl1e, l1e_empty());
+
+ /* Confirm the caller isn't trying to create new mappings. */
+ if ( !(l1e_get_flags(*pl1e) & _PAGE_PRESENT) )
+ ASSERT(!(nf & _PAGE_PRESENT));
+
+ nl1e = !(nf & _PAGE_PRESENT) ? l1e_empty()
+ : l1e_from_pfn(l1e_get_pfn(*pl1e),
+ (l1e_get_flags(*pl1e) & ~FLAGS_MASK) | nf);
+
+ l1e_write_atomic(pl1e, nl1e);
v += PAGE_SIZE;
- /* If we are done with the L2E, check if it is now empty. */
- if ( (v != e) && (l1_table_offset(v) != 0) )
+ /*
+ * If we not destroying mappings, or are not done with the L2E,
+ * skip the empty&free check.
+ */
+ if ( (nf & _PAGE_PRESENT) || ((v != e) && (l1_table_offset(v) != 0)) )
continue;
pl1e = l2e_to_l1e(*pl2e);
for ( i = 0; i < L1_PAGETABLE_ENTRIES; i++ )
@@ -6076,8 +6120,12 @@ void destroy_xen_mappings(unsigned long s, unsigned long e)
}
}
- /* If we are done with the L3E, check if it is now empty. */
- if ( (v != e) && (l2_table_offset(v) + l1_table_offset(v) != 0) )
+ /*
+ * If we are not destroying mappings, or not done with the L3E,
+ * skip the empty&free check.
+ */
+ if ( (nf & _PAGE_PRESENT) ||
+ ((v != e) && (l2_table_offset(v) + l1_table_offset(v) != 0)) )
continue;
pl2e = l3e_to_l2e(*pl3e);
for ( i = 0; i < L2_PAGETABLE_ENTRIES; i++ )
@@ -6093,10 +6141,17 @@ void destroy_xen_mappings(unsigned long s, unsigned long e)
}
flush_area(NULL, FLUSH_TLB_GLOBAL);
+
+#undef FLAGS_MASK
}
#undef flush_area
+void destroy_xen_mappings(unsigned long s, unsigned long e)
+{
+ modify_xen_mappings(s, e, _PAGE_NONE);
+}
+
void __set_fixmap(
enum fixed_addresses idx, unsigned long mfn, unsigned long flags)
{
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 22dc148..5029568 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1220,23 +1220,19 @@ void __init noreturn __start_xen(unsigned long mbi_p)
if ( !using_2M_mapping() )
{
/* Mark .text as RX (avoiding the first 2M superpage). */
- map_pages_to_xen(XEN_VIRT_START + MB(2),
- PFN_DOWN(__pa(XEN_VIRT_START + MB(2))),
- PFN_DOWN(__2M_text_end -
- (const char *)(XEN_VIRT_START + MB(2))),
- PAGE_HYPERVISOR_RX);
+ modify_xen_mappings(XEN_VIRT_START + MB(2),
+ (unsigned long)&__2M_text_end,
+ PAGE_HYPERVISOR_RX);
/* Mark .rodata as RO. */
- map_pages_to_xen((unsigned long)&__2M_rodata_start,
- PFN_DOWN(__pa(__2M_rodata_start)),
- PFN_DOWN(__2M_rodata_end - __2M_rodata_start),
- PAGE_HYPERVISOR_RO);
+ modify_xen_mappings((unsigned long)&__2M_rodata_start,
+ (unsigned long)&__2M_rodata_end,
+ PAGE_HYPERVISOR_RO);
/* Mark .data and .bss as RW. */
- map_pages_to_xen((unsigned long)&__2M_rwdata_start,
- PFN_DOWN(__pa(__2M_rwdata_start)),
- PFN_DOWN(__2M_rwdata_end - __2M_rwdata_start),
- PAGE_HYPERVISOR_RW);
+ modify_xen_mappings((unsigned long)&__2M_rwdata_start,
+ (unsigned long)&__2M_rwdata_end,
+ PAGE_HYPERVISOR_RW);
/* Drop the remaining mappings in the shattered superpage. */
destroy_xen_mappings((unsigned long)&__2M_rwdata_end,
diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h
index d62394f..d4721fc 100644
--- a/xen/include/xen/mm.h
+++ b/xen/include/xen/mm.h
@@ -103,6 +103,8 @@ int map_pages_to_xen(
unsigned long mfn,
unsigned long nr_mfns,
unsigned int flags);
+/* Alter the permissions of a range of Xen virtual address space. */
+void modify_xen_mappings(unsigned long s, unsigned long e, unsigned int flags);
void destroy_xen_mappings(unsigned long v, unsigned long e);
/*
* Create only non-leaf page table entries for the
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 10/27] xsplice: Add helper elf routines
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (8 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 09/27] x86/mm: Introduce modify_xen_mappings() Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-17 20:55 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 11/27] xsplice: Implement payload loading Konrad Rzeszutek Wilk
` (17 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Keir Fraser, Tim Deegan, Ian Jackson, Jan Beulich, Konrad Rzeszutek Wilk
From: Ross Lagerwall <ross.lagerwall@citrix.com>
Add Elf routines and data structures in preparation for loading an
xSplice payload.
We make an assumption that the max number of sections an ELF payload
can have is 64. We can in future make this be dependent on the
names of the sections and verifying against a list, but for right now
this suffices.
Also we a whole lot of checks to make sure that the ELF payload
file is not corrupted nor that the offsets point past the file.
For most of the checks we print an message if the hypervisor is built
with debug enabled.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Reviewed-by: Andrew Cooper<andrew.cooper3@citrix.com>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Tim Deegan <tim@xen.org>
v2: - With the #define ELFSIZE in the ARM file we can use the common
#defines instead of using #ifdef CONFIG_ARM_32. Moved to another
patch.
- Add checks for ELF file.
- Add name to be printed.
- Add len for easier ELF checks.
- Expand on the checks. Add macro.
v3: Remove the return_ macro
- Add return_ macro back but make it depend on debug=y
- Per Andrew review: add local variable. Fix memory leak in
elf_resolve_sections, Remove macro and use dprintk. Fix alignment.
Use void* instead of uint8_t to handle raw payload.
v4 - Fix memory leak in elf_get_sym
- Add XSPLICE to printk/dprintk
v5: Sprinkle newlines.
v6: Squash the ELF header checks from 'xsplice: Implement payload loading' here,
Do better job at checking string sections and the users of them (sh_size),
Use XSPLICE as a string literal,
Move some checks outside the loop,
Make sure that SHT_STRTAB are really what they say
Sprinkle consts.
v7:
Check sh_entsize and sh_offset.
Added Andrew's Reviewed-by and Ian's Acked-by
Redo check on sh_entsize to not be !=
v8: Make all the dprintk(XENLOG_DEBUG be XENLOG_ERR
---
---
xen/common/Makefile | 1 +
xen/common/xsplice_elf.c | 360 ++++++++++++++++++++++++++++++++++++++++++
xen/include/xen/xsplice.h | 3 +
xen/include/xen/xsplice_elf.h | 51 ++++++
4 files changed, 415 insertions(+)
create mode 100644 xen/common/xsplice_elf.c
create mode 100644 xen/include/xen/xsplice_elf.h
diff --git a/xen/common/Makefile b/xen/common/Makefile
index 1e4bc70..afd84b6 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -59,6 +59,7 @@ obj-y += wait.o
obj-$(CONFIG_XENOPROF) += xenoprof.o
obj-y += xmalloc_tlsf.o
obj-$(CONFIG_XSPLICE) += xsplice.o
+obj-$(CONFIG_XSPLICE) += xsplice_elf.o
obj-bin-$(CONFIG_X86) += $(foreach n,decompress bunzip2 unxz unlzma unlzo unlz4 earlycpio,$(n).init.o)
diff --git a/xen/common/xsplice_elf.c b/xen/common/xsplice_elf.c
new file mode 100644
index 0000000..0d96b78
--- /dev/null
+++ b/xen/common/xsplice_elf.c
@@ -0,0 +1,360 @@
+/*
+ * Copyright (C) 2016 Citrix Systems R&D Ltd.
+ */
+
+#include <xen/errno.h>
+#include <xen/lib.h>
+#include <xen/xsplice_elf.h>
+#include <xen/xsplice.h>
+
+const struct xsplice_elf_sec *xsplice_elf_sec_by_name(const struct xsplice_elf *elf,
+ const char *name)
+{
+ unsigned int i;
+
+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
+ {
+ if ( !strcmp(name, elf->sec[i].name) )
+ return &elf->sec[i];
+ }
+
+ return NULL;
+}
+
+static int elf_verify_strtab(const struct xsplice_elf_sec *sec)
+{
+ const Elf_Shdr *s;
+ const uint8_t *contents;
+
+ s = sec->sec;
+
+ if ( s->sh_type != SHT_STRTAB )
+ return -EINVAL;
+
+ if ( !s->sh_size )
+ return -EOPNOTSUPP;
+
+ contents = (const uint8_t *)sec->data;
+
+ if ( contents[0] || contents[s->sh_size - 1] )
+ return -EINVAL;
+
+ return 0;
+}
+
+static int elf_resolve_sections(struct xsplice_elf *elf, const void *data)
+{
+ struct xsplice_elf_sec *sec;
+ unsigned int i;
+ Elf_Off delta;
+ int rc;
+
+ /* xsplice_elf_load sanity checked e_shnum. */
+ sec = xmalloc_array(struct xsplice_elf_sec, elf->hdr->e_shnum);
+ if ( !sec )
+ {
+ dprintk(XENLOG_ERR, XSPLICE"%s: Could not allocate memory for section table!\n",
+ elf->name);
+ return -ENOMEM;
+ }
+
+ elf->sec = sec;
+
+ delta = elf->hdr->e_shoff + elf->hdr->e_shnum * elf->hdr->e_shentsize;
+ if ( delta > elf->len )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section table is past end of payload!\n",
+ elf->name);
+ return -EINVAL;
+ }
+
+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
+ {
+ delta = elf->hdr->e_shoff + i * elf->hdr->e_shentsize;
+
+ sec[i].sec = (void *)data + delta;
+
+ delta = sec[i].sec->sh_offset;
+
+ /*
+ * N.B. elf_resolve_section_names, elf_get_sym skip this check as
+ * we do it here.
+ */
+ if ( delta && (delta + sec[i].sec->sh_size > elf->len) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section [%u] data is past end of payload!\n",
+ elf->name, i);
+ return -EINVAL;
+ }
+
+ sec[i].data = data + delta;
+ /* Name is populated in xsplice_elf_sections_name. */
+ sec[i].name = NULL;
+
+ if ( sec[i].sec->sh_type == SHT_SYMTAB )
+ {
+ if ( elf->symtab )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Unsupported multiple symbol tables!\n",
+ elf->name);
+ return -EOPNOTSUPP;
+ }
+
+ elf->symtab = &sec[i];
+
+ /*
+ * elf->symtab->sec->sh_link would point to the right section
+ * but we hadn't finished parsing all the sections.
+ */
+ if ( elf->symtab->sec->sh_link > elf->hdr->e_shnum )
+ {
+ dprintk(XENLOG_ERR, XSPLICE
+ "%s: Symbol table idx (%u) to strtab past end (%u)\n",
+ elf->name, elf->symtab->sec->sh_link,
+ elf->hdr->e_shnum);
+ return -EINVAL;
+ }
+ }
+ }
+
+ if ( !elf->symtab )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: No symbol table found!\n",
+ elf->name);
+ return -EINVAL;
+ }
+
+ if ( !elf->symtab->sec->sh_size ||
+ elf->symtab->sec->sh_entsize < sizeof(Elf_Sym) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Symbol table header is corrupted!\n",
+ elf->name);
+ return -EINVAL;
+ }
+
+ /*
+ * There can be multiple SHT_STRTAB (.shstrtab, .strtab) so pick one
+ * associated with the symbol table.
+ */
+ elf->strtab = &sec[elf->symtab->sec->sh_link];
+
+ rc = elf_verify_strtab(elf->strtab);
+ if ( rc )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: String table section is corrupted\n",
+ elf->name);
+ }
+
+ return rc;
+}
+
+static int elf_resolve_section_names(struct xsplice_elf *elf, const void *data)
+{
+ const char *shstrtab;
+ unsigned int i;
+ Elf_Off offset, delta;
+ struct xsplice_elf_sec *sec;
+ int rc;
+
+ /*
+ * The elf->sec[0 -> e_shnum] structures have been verified by
+ * elf_resolve_sections. Find file offset for section string table
+ * (normally called .shstrtab)
+ */
+ sec = &elf->sec[elf->hdr->e_shstrndx];
+
+ rc = elf_verify_strtab(sec);
+ if ( rc )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section string table is corrupted\n",
+ elf->name);
+ return rc;
+ }
+
+ /* Verified in elf_resolve_sections but just in case. */
+ offset = sec->sec->sh_offset;
+ ASSERT(offset < elf->len && (offset + sec->sec->sh_size <= elf->len));
+
+ shstrtab = data + offset;
+
+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
+ {
+ delta = elf->sec[i].sec->sh_name;
+
+ if ( delta && delta >= sec->sec->sh_size )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: shstrtab [%u] data is past end of payload!\n",
+ elf->name, i);
+ return -EINVAL;
+ }
+
+ elf->sec[i].name = shstrtab + delta;
+ }
+
+ return 0;
+}
+
+static int elf_get_sym(struct xsplice_elf *elf, const void *data)
+{
+ const struct xsplice_elf_sec *symtab_sec, *strtab_sec;
+ struct xsplice_elf_sym *sym;
+ unsigned int i, delta, offset, nsym;
+
+ symtab_sec = elf->symtab;
+ strtab_sec = elf->strtab;
+
+ /* Pointers arithmetic to get file offset. */
+ offset = strtab_sec->data - data;
+
+ /* Checked already in elf_resolve_sections, but just in case. */
+ ASSERT(offset == strtab_sec->sec->sh_offset);
+ ASSERT(offset < elf->len && (offset + strtab_sec->sec->sh_size <= elf->len));
+
+ /* symtab_sec->data was computed in elf_resolve_sections. */
+ ASSERT((symtab_sec->sec->sh_offset + data) == symtab_sec->data);
+
+ /* No need to check values as elf_resolve_sections did it. */
+ nsym = symtab_sec->sec->sh_size / symtab_sec->sec->sh_entsize;
+
+ sym = xmalloc_array(struct xsplice_elf_sym, nsym);
+ if ( !sym )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Could not allocate memory for symbols\n",
+ elf->name);
+ return -ENOMEM;
+ }
+
+ /* So we don't leak memory. */
+ elf->sym = sym;
+
+ for ( i = 1; i < nsym; i++ )
+ {
+ Elf_Sym *s = &((Elf_Sym *)symtab_sec->data)[i];
+
+ /* If st->name is STN_UNDEF zero, the check will always be true. */
+ delta = s->st_name;
+
+ if ( delta && (delta > strtab_sec->sec->sh_size) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Symbol [%u] data is past end of payload!\n",
+ elf->name, i);
+ return -EINVAL;
+ }
+
+ sym[i].sym = s;
+ sym[i].name = data + (delta + offset);
+ }
+ elf->nsym = nsym;
+
+ return 0;
+}
+
+static int xsplice_header_check(const struct xsplice_elf *elf)
+{
+ const Elf_Ehdr *hdr = elf->hdr;
+
+ if ( sizeof(*elf->hdr) > elf->len )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section header is bigger than payload!\n",
+ elf->name);
+ return -EINVAL;
+ }
+
+ if ( !IS_ELF(*hdr) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Not an ELF payload!\n", elf->name);
+ return -EINVAL;
+ }
+
+ if ( hdr->e_ident[EI_CLASS] != ELFCLASS64 ||
+ hdr->e_ident[EI_DATA] != ELFDATA2LSB ||
+ hdr->e_ident[EI_OSABI] != ELFOSABI_SYSV ||
+ hdr->e_type != ET_REL ||
+ hdr->e_phnum != 0 )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Invalid ELF payload!\n", elf->name);
+ return -EOPNOTSUPP;
+ }
+
+ if ( elf->hdr->e_shstrndx == SHN_UNDEF )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section name idx is undefined!?\n",
+ elf->name);
+ return -EINVAL;
+ }
+
+ /* Check that section name index is within the sections. */
+ if ( elf->hdr->e_shstrndx >= elf->hdr->e_shnum )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section name idx (%u) is past end of sections (%u)!\n",
+ elf->name, elf->hdr->e_shstrndx, elf->hdr->e_shnum);
+ return -EINVAL;
+ }
+
+ if ( elf->hdr->e_shnum > 64 )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Too many (%u) sections!\n",
+ elf->name, elf->hdr->e_shnum);
+ return -EINVAL;
+ }
+
+ if ( elf->hdr->e_shoff > elf->len )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Bogus e_shoff!\n", elf->name);
+ return -EINVAL;
+ }
+
+ if ( elf->hdr->e_shentsize < sizeof(Elf_Shdr) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section header size is %u! Expected %zu!?\n",
+ elf->name, elf->hdr->e_shentsize, sizeof(Elf_Shdr));
+ return -EINVAL;
+ }
+ return 0;
+}
+
+int xsplice_elf_load(struct xsplice_elf *elf, const void *data)
+{
+ int rc;
+
+ elf->hdr = data;
+
+ rc = xsplice_header_check(elf);
+ if ( rc )
+ return rc;
+
+ rc = elf_resolve_sections(elf, data);
+ if ( rc )
+ return rc;
+
+ rc = elf_resolve_section_names(elf, data);
+ if ( rc )
+ return rc;
+
+ rc = elf_get_sym(elf, data);
+ if ( rc )
+ return rc;
+
+ return 0;
+}
+
+void xsplice_elf_free(struct xsplice_elf *elf)
+{
+ xfree(elf->sec);
+ elf->sec = NULL;
+ xfree(elf->sym);
+ elf->sym = NULL;
+ elf->nsym = 0;
+ elf->name = NULL;
+ elf->len = 0;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/xen/xsplice.h b/xen/include/xen/xsplice.h
index b9f08cd..cd805a8 100644
--- a/xen/include/xen/xsplice.h
+++ b/xen/include/xen/xsplice.h
@@ -10,6 +10,9 @@ struct xen_sysctl_xsplice_op;
#ifdef CONFIG_XSPLICE
+/* Convenience define for printk. */
+#define XSPLICE "xsplice: "
+
int xsplice_op(struct xen_sysctl_xsplice_op *);
#else
diff --git a/xen/include/xen/xsplice_elf.h b/xen/include/xen/xsplice_elf.h
new file mode 100644
index 0000000..89acb77
--- /dev/null
+++ b/xen/include/xen/xsplice_elf.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2016 Citrix Systems R&D Ltd.
+ */
+
+#ifndef __XEN_XSPLICE_ELF_H__
+#define __XEN_XSPLICE_ELF_H__
+
+#include <xen/types.h>
+#include <xen/elfstructs.h>
+
+/* The following describes an Elf file as consumed by xSplice. */
+struct xsplice_elf_sec {
+ Elf_Shdr *sec; /* Hooked up in elf_resolve_sections.*/
+ const char *name; /* Human readable name hooked in
+ elf_resolve_section_names. */
+ const void *data; /* Pointer to the section (done by
+ elf_resolve_sections). */
+};
+
+struct xsplice_elf_sym {
+ Elf_Sym *sym;
+ const char *name;
+};
+
+struct xsplice_elf {
+ const char *name; /* Pointer to payload->name. */
+ size_t len; /* Length of the ELF file. */
+ const Elf_Ehdr *hdr; /* ELF file. */
+ struct xsplice_elf_sec *sec; /* Array of sections, allocated by us. */
+ struct xsplice_elf_sym *sym; /* Array of symbols , allocated by us. */
+ unsigned int nsym;
+ const struct xsplice_elf_sec *symtab;/* Pointer to .symtab section - aka to sec[x]. */
+ const struct xsplice_elf_sec *strtab;/* Pointer to .strtab section - aka to sec[y]. */
+};
+
+const struct xsplice_elf_sec *xsplice_elf_sec_by_name(const struct xsplice_elf *elf,
+ const char *name);
+int xsplice_elf_load(struct xsplice_elf *elf, const void *data);
+void xsplice_elf_free(struct xsplice_elf *elf);
+
+#endif /* __XEN_XSPLICE_ELF_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 11/27] xsplice: Implement payload loading
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (9 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 10/27] xsplice: Add helper elf routines Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-18 6:16 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 12/27] xsplice: Implement support for applying/reverting/replacing patches Konrad Rzeszutek Wilk
` (16 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Julien Grall, Stefano Stabellini, Keir Fraser, Jan Beulich,
Konrad Rzeszutek Wilk
From: Ross Lagerwall <ross.lagerwall@citrix.com>
Add support for loading xsplice payloads. This is somewhat similar to
the Linux kernel module loader, implementing the following steps:
- Verify the elf file.
- Parse the elf file.
- Allocate a region of memory mapped within a free area of
[xen_virt_end, XEN_VIRT_END].
- Copy allocated sections into the new region. Split them in three
regions - .text, .data, and .rodata. MUST have at least .text.
- Resolve section symbols. All other symbols must be absolute addresses.
(Note that patch titled "xsplice,symbols: Implement symbol name resolution
on address" implements that)
- Perform relocations.
- Secure the the regions (.text,.data,.rodata) with proper permissions.
We capitalize on the vmalloc callback API (see patch titled:
"rm/x86/vmap: Add vmalloc_xen, vfree_xen and vm_init_type") to allocate
a region of memory within the [xen_virt_end, XEN_VIRT_END] for the code.
We also use the "x86/mm: Introduce modify_xen_mappings()"
to change the virtual address page-table permissions.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Julien Grall <julien.grall@arm.com>
---
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Julien Grall <julien.grall@arm.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
v2: - Change the 'xsplice_patch_func' structure layout/size.
- Add more error checking. Fix memory leak.
- Move elf_resolve and elf_perform relocs in elf file.
- Print the payload address and pages in keyhandler.
v3:
- Make it build under ARM
- Build it without using the return_ macro.
- Add fixes from Ross.
- Add the _return macro back - but only use it during debug builds.
- Remove the macro, prefix arch_ on arch specific calls.
v4:
- Move alloc_payload to arch specific file.
- Use void* instead of uint8_t, use const
- Add copyrights
- Unroll the vmap code to add ASSERT. Change while to not incur
potential long error loop
- Use vmalloc/vfree cb APIs
- Secure .text pages to be RX instead of RWX.
v5:
- Fix allocation of virtual addresses only allowing one page to be allocated.
- Create .text, .data, and .rodata regions with different permissions.
- Make the find_space_t not a typedef to pointer to a function.
- Allocate memory in here.
v6: Drop parentheses on typedefs.
- s/an xSplice/a xSplice/
- Rebase on "vmap: Add vmalloc_cb"
- Rebase on "vmap: Add vmalloc_type and vm_init_type"
- s/uint8_t/void/ on load_addr
- Set xsplice_elf on stack without using memset.
v7:
- Changed the check on delta = elf->hdr->e_shoff + elf->hdr->e_shnum * elf->hdr->e_shentsize;
The sections can be right at the back of the file (different linker!), so the failing conditional
for 'if (delta >= elf->len)' is incorrect and should have been '>'.
- Changed dprintk(XENLOG_DEBUG to XENLOG_ERR, then back to DEBUG. Converted
some of the printk to dprintk.
- Rebase on " arm/x86/vmap: Add vmalloc_xen, vfree_xen and vm_init_type"
- Changed some of the printk XENLOG_ERR to XENLOG_DEBUG
- Check the idx in the relocation to make sure it is within bounds and
implemented.
- Use "x86/mm: Introduce modify_xen_mappings()"
- Introduce PRIxElfAddr
- Check for overflow in R_X86_64_PC32
- Return -EOPNOTSUPP if we don't support types in ELF64_R_TYPE
v8:
- Change dprintk and printk XENLOG_DEBUG to XENLOG_ERR
- Convert four of the printks in dprintk.
---
---
xen/arch/arm/Makefile | 1 +
xen/arch/arm/xsplice.c | 54 ++++++++++
xen/arch/x86/Makefile | 1 +
xen/arch/x86/xsplice.c | 188 +++++++++++++++++++++++++++++++++++
xen/common/xsplice.c | 226 +++++++++++++++++++++++++++++++++++++++++-
xen/common/xsplice_elf.c | 124 ++++++++++++++++++++++-
xen/include/xen/elfstructs.h | 4 +
xen/include/xen/xsplice.h | 29 ++++++
xen/include/xen/xsplice_elf.h | 9 +-
9 files changed, 631 insertions(+), 5 deletions(-)
create mode 100644 xen/arch/arm/xsplice.c
create mode 100644 xen/arch/x86/xsplice.c
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 0328b50..eae5cb3 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -40,6 +40,7 @@ obj-y += device.o
obj-y += decode.o
obj-y += processor.o
obj-y += smc.o
+obj-$(CONFIG_XSPLICE) += xsplice.o
#obj-bin-y += ....o
diff --git a/xen/arch/arm/xsplice.c b/xen/arch/arm/xsplice.c
new file mode 100644
index 0000000..4465244
--- /dev/null
+++ b/xen/arch/arm/xsplice.c
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2016 Citrix Systems R&D Ltd.
+ */
+#include <xen/lib.h>
+#include <xen/errno.h>
+#include <xen/xsplice_elf.h>
+#include <xen/xsplice.h>
+
+int arch_xsplice_verify_elf(const struct xsplice_elf *elf)
+{
+ return -ENOSYS;
+}
+
+int arch_xsplice_perform_rel(struct xsplice_elf *elf,
+ const struct xsplice_elf_sec *base,
+ const struct xsplice_elf_sec *rela)
+{
+ return -ENOSYS;
+}
+
+int arch_xsplice_perform_rela(struct xsplice_elf *elf,
+ const struct xsplice_elf_sec *base,
+ const struct xsplice_elf_sec *rela)
+{
+ return -ENOSYS;
+}
+
+void *arch_xsplice_alloc_payload(unsigned int pages)
+{
+ return NULL;
+}
+
+int arch_xsplice_secure(void *va, unsigned int pages, enum va_type type)
+{
+ return -ENOSYS;
+}
+
+void arch_xsplice_free_payload(void *va)
+{
+}
+
+void arch_xsplice_init(void)
+{
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 729065b..8a6a7d5 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -64,6 +64,7 @@ obj-y += vm_event.o
obj-y += xstate.o
obj-$(crash_debug) += gdbstub.o
+obj-$(CONFIG_XSPLICE) += xsplice.o
x86_emulate.o: x86_emulate/x86_emulate.c x86_emulate/x86_emulate.h
diff --git a/xen/arch/x86/xsplice.c b/xen/arch/x86/xsplice.c
new file mode 100644
index 0000000..3000ecb
--- /dev/null
+++ b/xen/arch/x86/xsplice.c
@@ -0,0 +1,188 @@
+/*
+ * Copyright (C) 2016 Citrix Systems R&D Ltd.
+ */
+
+#include <xen/errno.h>
+#include <xen/lib.h>
+#include <xen/mm.h>
+#include <xen/pfn.h>
+#include <xen/vmap.h>
+#include <xen/xsplice_elf.h>
+#include <xen/xsplice.h>
+
+int arch_xsplice_verify_elf(const struct xsplice_elf *elf)
+{
+
+ const Elf_Ehdr *hdr = elf->hdr;
+
+ if ( hdr->e_machine != EM_X86_64 )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Unsupported ELF Machine type!\n",
+ elf->name);
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
+int arch_xsplice_perform_rel(struct xsplice_elf *elf,
+ const struct xsplice_elf_sec *base,
+ const struct xsplice_elf_sec *rela)
+{
+ dprintk(XENLOG_ERR, XSPLICE "%s: SHT_REL relocation unsupported\n",
+ elf->name);
+ return -EOPNOTSUPP;
+}
+
+int arch_xsplice_perform_rela(struct xsplice_elf *elf,
+ const struct xsplice_elf_sec *base,
+ const struct xsplice_elf_sec *rela)
+{
+ const Elf_RelA *r;
+ unsigned int symndx, i;
+ uint64_t val;
+ uint8_t *dest;
+
+ if ( !rela->sec->sh_entsize || !rela->sec->sh_size ||
+ rela->sec->sh_entsize != sizeof(Elf_RelA) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section relative header is corrupted!\n",
+ elf->name);
+ return -EINVAL;
+ }
+
+ for ( i = 0; i < (rela->sec->sh_size / rela->sec->sh_entsize); i++ )
+ {
+ r = rela->data + i * rela->sec->sh_entsize;
+ if ( (unsigned long)r > (unsigned long)(elf->hdr + elf->len) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Relative entry %u in %s is past end!\n",
+ elf->name, i, rela->name);
+ return -EINVAL;
+ }
+
+ symndx = ELF64_R_SYM(r->r_info);
+ if ( symndx > elf->nsym )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Relative symbol wants symbol@%u which is past end!\n",
+ elf->name, symndx);
+ return -EINVAL;
+ }
+
+ dest = base->load_addr + r->r_offset;
+ val = r->r_addend + elf->sym[symndx].sym->st_value;
+
+ switch ( ELF64_R_TYPE(r->r_info) )
+ {
+ case R_X86_64_NONE:
+ break;
+
+ case R_X86_64_64:
+ *(uint64_t *)dest = val;
+ break;
+
+ case R_X86_64_PLT32:
+ /*
+ * Xen uses -fpic which normally uses PLT relocations
+ * except that it sets visibility to hidden which means
+ * that they are not used. However, when gcc cannot
+ * inline memcpy it emits memcpy with default visibility
+ * which then creates a PLT relocation. It can just be
+ * treated the same as R_X86_64_PC32.
+ */
+ /* Fall through */
+ case R_X86_64_PC32:
+ val -= (uint64_t)dest;
+ *(uint32_t *)dest = val;
+ if ( (s64)val != *(s32 *)dest )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Overflow in relocation %u in %s for %s!\n",
+ elf->name, i, rela->name, base->name);
+ return -EOVERFLOW;
+ }
+ break;
+
+ default:
+ dprintk(XENLOG_ERR, XSPLICE "%s: Unhandled relocation %lu\n",
+ elf->name, ELF64_R_TYPE(r->r_info));
+ return -EOPNOTSUPP;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * The function prepares a xSplice payload by allocating space which
+ * then can be used for loading the allocated sections, resolving symbols,
+ * performing relocations, etc.
+ */
+void *arch_xsplice_alloc_payload(unsigned int pages)
+{
+ unsigned int i;
+ void *p;
+
+ ASSERT(pages);
+
+ p = vmalloc_xen(pages * PAGE_SIZE);
+ WARN_ON(!p);
+ if ( p )
+ {
+ /* By default they are PAGE_HYPERVISOR aka PAGE_HYPERVISOR_RWX.*/
+ for ( i = 0; i < pages; i++ )
+ clear_page(p + (i * PAGE_SIZE) );
+ }
+ return p;
+}
+
+/*
+ * Once the resolving symbols, performing relocations, etc is complete
+ * we secure the memory by putting in the proper page table attributes
+ * for the desired type.
+ */
+int arch_xsplice_secure(void *va, unsigned int pages, enum va_type type)
+{
+ unsigned long start = (unsigned long)va;
+ int flag;
+
+ ASSERT(va);
+ ASSERT(pages);
+
+ if ( type == XSPLICE_VA_RX ) /* PAGE_HYPERVISOR_RX */
+ flag = _PAGE_PRESENT;
+ else if ( type == XSPLICE_VA_RW ) /* PAGE_HYPERVISOR_RW */
+ flag = _PAGE_RW | _PAGE_NX | _PAGE_PRESENT;
+ else /* PAGE_HYPERVISOR_RO */
+ flag = _PAGE_NX | _PAGE_PRESENT;
+
+ /* The ones we are allowed to modify are: _PAGE_NX|_PAGE_RW|_PAGE_PRESENT */
+ modify_xen_mappings(start, start + pages * PAGE_SIZE, flag);
+
+ return 0;
+}
+
+void arch_xsplice_free_payload(void *va)
+{
+ vfree_xen(va);
+}
+
+void arch_xsplice_init(void)
+{
+ void *start, *end;
+
+ start = (void *)xen_virt_end;
+ end = (void *)(XEN_VIRT_END - NR_CPUS * PAGE_SIZE);
+
+ BUG_ON(end <= start);
+
+ vm_init_type(VMAP_XEN, start, end);
+}
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c
index 04151e9..809b067 100644
--- a/xen/common/xsplice.c
+++ b/xen/common/xsplice.c
@@ -13,6 +13,7 @@
#include <xen/smp.h>
#include <xen/spinlock.h>
#include <xen/vmap.h>
+#include <xen/xsplice_elf.h>
#include <xen/xsplice.h>
#include <asm/event.h>
@@ -29,6 +30,13 @@ struct payload {
uint32_t state; /* One of the XSPLICE_STATE_*. */
int32_t rc; /* 0 or -XEN_EXX. */
struct list_head list; /* Linked to 'payload_list'. */
+ void *text_addr; /* Virtual address of .text. */
+ size_t text_size; /* .. and its size. */
+ void *rw_addr; /* Virtual address of .data. */
+ size_t rw_size; /* .. and its size (if any). */
+ void *ro_addr; /* Virtual address of .rodata. */
+ size_t ro_size; /* .. and its size (if any). */
+ size_t pages; /* Total pages for [text,rw,ro]_addr */
char name[XEN_XSPLICE_NAME_SIZE]; /* Name of it. */
};
@@ -86,19 +94,215 @@ static struct payload *find_payload(const char *name)
return found;
}
+/*
+ * Functions related to XEN_SYSCTL_XSPLICE_UPLOAD (see xsplice_upload), and
+ * freeing payload (XEN_SYSCTL_XSPLICE_ACTION:XSPLICE_ACTION_UNLOAD).
+ */
+
+static void free_payload_data(struct payload *payload)
+{
+ /* Set to zero until "move_payload". */
+ if ( !payload->text_addr )
+ return;
+
+ arch_xsplice_free_payload(payload->text_addr);
+
+ payload->text_addr = NULL;
+ payload->ro_addr = NULL;
+ payload->rw_addr = NULL;
+ payload->pages = 0;
+}
+
+/*
+* calc_section computes the size (taking into account section alignment).
+*
+* It also modifies sh_entsize with the offset of from the start of
+* virtual address space. This is used in move_payload to figure out the
+* destination location.
+*/
+static void calc_section(struct xsplice_elf_sec *sec, size_t *size)
+{
+ Elf_Shdr *s = sec->sec;
+ size_t align_size;
+
+ align_size = ROUNDUP(*size, s->sh_addralign);
+ s->sh_entsize = align_size;
+
+ *size = s->sh_size + align_size;
+}
+
+static int move_payload(struct payload *payload, struct xsplice_elf *elf)
+{
+ uint8_t *buf;
+ unsigned int i;
+ size_t size = 0;
+
+ /* Compute text regions. */
+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
+ {
+ if ( (elf->sec[i].sec->sh_flags & (SHF_ALLOC|SHF_EXECINSTR)) ==
+ (SHF_ALLOC|SHF_EXECINSTR) )
+ calc_section(&elf->sec[i], &payload->text_size);
+ }
+
+ /* Compute rw data. */
+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
+ {
+ if ( (elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
+ !(elf->sec[i].sec->sh_flags & SHF_EXECINSTR) &&
+ (elf->sec[i].sec->sh_flags & SHF_WRITE) )
+ calc_section(&elf->sec[i], &payload->rw_size);
+ }
+
+ /* Compute ro data. */
+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
+ {
+ if ( (elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
+ !(elf->sec[i].sec->sh_flags & SHF_EXECINSTR) &&
+ !(elf->sec[i].sec->sh_flags & SHF_WRITE) )
+ calc_section(&elf->sec[i], &payload->ro_size);
+ }
+
+ /* Do not accept wx. */
+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
+ {
+ if ( !(elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
+ (elf->sec[i].sec->sh_flags & SHF_EXECINSTR) &&
+ (elf->sec[i].sec->sh_flags & SHF_WRITE) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: No WX sections!\n", elf->name);
+ return -EINVAL;
+ }
+ }
+
+ /*
+ * Total of all three regions - RX, RW, and RO. We have to have
+ * keep them in seperate pages so we PAGE_ALIGN the RX and RW to have
+ * them on seperate pages. The last one will by default fall on its
+ * own page.
+ */
+ size = PAGE_ALIGN(payload->text_size) + PAGE_ALIGN(payload->rw_size) +
+ payload->ro_size;
+
+ size = PFN_UP(size);
+ buf = arch_xsplice_alloc_payload(size);
+ if ( !buf )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Could not allocate memory for payload!\n",
+ elf->name);
+ return -ENOMEM;
+ }
+ payload->pages = size;
+ payload->text_addr = buf;
+ payload->rw_addr = payload->text_addr + PAGE_ALIGN(payload->text_size);
+ payload->ro_addr = payload->rw_addr + PAGE_ALIGN(payload->rw_size);
+
+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
+ {
+ if ( elf->sec[i].sec->sh_flags & SHF_ALLOC )
+ {
+ if ( (elf->sec[i].sec->sh_flags & SHF_EXECINSTR) )
+ buf = payload->text_addr;
+ else if ( (elf->sec[i].sec->sh_flags & SHF_WRITE) )
+ buf = payload->rw_addr;
+ else
+ buf = payload->ro_addr;
+
+ elf->sec[i].load_addr = buf + elf->sec[i].sec->sh_entsize;
+
+ /* Don't copy NOBITS - such as BSS. */
+ if ( elf->sec[i].sec->sh_type != SHT_NOBITS )
+ {
+ memcpy(elf->sec[i].load_addr, elf->sec[i].data,
+ elf->sec[i].sec->sh_size);
+ dprintk(XENLOG_DEBUG, XSPLICE "%s: Loaded %s at 0x%p\n",
+ elf->name, elf->sec[i].name, elf->sec[i].load_addr);
+ }
+ }
+ }
+
+ return 0;
+}
+
+static int secure_payload(struct payload *payload, struct xsplice_elf *elf)
+{
+ int rc;
+ unsigned int text_pages, rw_pages, ro_pages;
+
+ text_pages = PFN_UP(payload->text_size);
+ ASSERT(text_pages);
+
+ rc = arch_xsplice_secure(payload->text_addr, text_pages, XSPLICE_VA_RX);
+ if ( rc )
+ return rc;
+
+ rw_pages = PFN_UP(payload->rw_size);
+ if ( rw_pages )
+ {
+ rc = arch_xsplice_secure(payload->rw_addr, rw_pages, XSPLICE_VA_RW);
+ if ( rc )
+ return rc;
+ }
+
+ ro_pages = PFN_UP(payload->ro_size);
+ if ( ro_pages )
+ {
+ rc = arch_xsplice_secure(payload->ro_addr, ro_pages, XSPLICE_VA_RO);
+ }
+
+ ASSERT(ro_pages + rw_pages + text_pages == payload->pages);
+
+ return rc;
+}
+
static void free_payload(struct payload *data)
{
ASSERT(spin_is_locked(&payload_lock));
list_del(&data->list);
payload_cnt--;
payload_version++;
+ free_payload_data(data);
xfree(data);
}
+static int load_payload_data(struct payload *payload, void *raw, size_t len)
+{
+ struct xsplice_elf elf = { .name = payload->name, .len = len };
+ int rc = 0;
+
+ rc = xsplice_elf_load(&elf, raw);
+ if ( rc )
+ goto out;
+
+ rc = move_payload(payload, &elf);
+ if ( rc )
+ goto out;
+
+ rc = xsplice_elf_resolve_symbols(&elf);
+ if ( rc )
+ goto out;
+
+ rc = xsplice_elf_perform_relocs(&elf);
+ if ( rc )
+ goto out;
+
+ rc = secure_payload(payload, &elf);
+
+ out:
+ if ( rc )
+ free_payload_data(payload);
+
+ /* Free our temporary data structure. */
+ xsplice_elf_free(&elf);
+
+ return rc;
+}
+
static int xsplice_upload(xen_sysctl_xsplice_upload_t *upload)
{
struct payload *data = NULL, *found;
char n[XEN_XSPLICE_NAME_SIZE];
+ void *raw_data = NULL;
int rc;
rc = verify_payload(upload, n);
@@ -126,9 +330,20 @@ static int xsplice_upload(xen_sysctl_xsplice_upload_t *upload)
goto out;
}
- rc = 0;
+ rc = -ENOMEM;
+ raw_data = vmalloc(upload->size);
+ if ( !raw_data )
+ goto out;
+
+ rc = -EFAULT;
+ if ( __copy_from_guest(raw_data, upload->payload, upload->size) )
+ goto out;
memcpy(data->name, n, strlen(n));
+ rc = load_payload_data(data, raw_data, upload->size);
+ if ( rc )
+ goto out;
+
data->state = XSPLICE_STATE_CHECKED;
INIT_LIST_HEAD(&data->list);
@@ -139,6 +354,8 @@ static int xsplice_upload(xen_sysctl_xsplice_upload_t *upload)
out:
spin_unlock(&payload_lock);
+ vfree(raw_data);
+
if ( rc )
xfree(data);
@@ -380,8 +597,9 @@ static void xsplice_printall(unsigned char key)
}
list_for_each_entry ( data, &payload_list, list )
- printk(" name=%s state=%s(%d)\n", data->name,
- state2str(data->state), data->state);
+ printk(" name=%s state=%s(%d) %p (.data=%p, .rodata=%p) using %zu pages.\n",
+ data->name, state2str(data->state), data->state, data->text_addr,
+ data->rw_addr, data->ro_addr, data->pages);
spin_unlock(&payload_lock);
}
@@ -389,6 +607,8 @@ static void xsplice_printall(unsigned char key)
static int __init xsplice_init(void)
{
register_keyhandler('x', xsplice_printall, "print xsplicing info", 1);
+
+ arch_xsplice_init();
return 0;
}
__initcall(xsplice_init);
diff --git a/xen/common/xsplice_elf.c b/xen/common/xsplice_elf.c
index 0d96b78..f59f011 100644
--- a/xen/common/xsplice_elf.c
+++ b/xen/common/xsplice_elf.c
@@ -101,7 +101,7 @@ static int elf_resolve_sections(struct xsplice_elf *elf, const void *data)
}
elf->symtab = &sec[i];
-
+ elf->symtab_idx = i;
/*
* elf->symtab->sec->sh_link would point to the right section
* but we hadn't finished parsing all the sections.
@@ -249,9 +249,127 @@ static int elf_get_sym(struct xsplice_elf *elf, const void *data)
return 0;
}
+int xsplice_elf_resolve_symbols(struct xsplice_elf *elf)
+{
+ unsigned int i;
+ int rc = 0;
+
+ /*
+ * The first entry of an ELF symbol table is the "undefined symbol index".
+ * aka reserved so we skip it.
+ */
+ ASSERT(elf->sym);
+
+ for ( i = 1; i < elf->nsym; i++ )
+ {
+ uint16_t idx = elf->sym[i].sym->st_shndx;
+
+ rc = 0;
+ switch ( idx )
+ {
+ case SHN_COMMON:
+ dprintk(XENLOG_ERR, XSPLICE "%s: Unexpected common symbol: %s\n",
+ elf->name, elf->sym[i].name);
+ rc = -EINVAL;
+ break;
+
+ case SHN_UNDEF:
+ dprintk(XENLOG_ERR, XSPLICE "%s: Unknown symbol: %s\n",
+ elf->name, elf->sym[i].name);
+ rc = -ENOENT;
+ break;
+
+ case SHN_ABS:
+ dprintk(XENLOG_DEBUG, XSPLICE "%s: Absolute symbol: %s => %#"PRIxElfAddr"\n",
+ elf->name, elf->sym[i].name, elf->sym[i].sym->st_value);
+ break;
+
+ default:
+ /* SHN_COMMON and SHN_ABS are above. */
+ if ( idx > SHN_LORESERVE )
+ rc = -EOPNOTSUPP;
+ /* SHN_UNDEF (0) above. */
+ else if ( idx > elf->hdr->e_shnum && idx < SHN_LORESERVE )
+ rc = -EINVAL;
+
+ if ( rc )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Unknown type=%#"PRIx16"\n",
+ elf->name, idx);
+ break;
+ }
+
+ if ( !(elf->sec[idx].sec->sh_flags & SHF_ALLOC) )
+ break;
+
+ elf->sym[i].sym->st_value += (unsigned long)elf->sec[idx].load_addr;
+ if ( elf->sym[i].name )
+ dprintk(XENLOG_DEBUG, XSPLICE "%s: Symbol resolved: %s => %#"PRIxElfAddr"(%s)\n",
+ elf->name, elf->sym[i].name,
+ elf->sym[i].sym->st_value, elf->sec[idx].name);
+ }
+
+ if ( rc )
+ break;
+ }
+
+ return rc;
+}
+
+int xsplice_elf_perform_relocs(struct xsplice_elf *elf)
+{
+ struct xsplice_elf_sec *rela, *base;
+ unsigned int i;
+ int rc = 0;
+
+ /*
+ * The first entry of an ELF symbol table is the "undefined symbol index".
+ * aka reserved so we skip it.
+ */
+ ASSERT(elf->sym);
+
+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
+ {
+ rela = &elf->sec[i];
+
+ if ( (rela->sec->sh_type != SHT_RELA) &&
+ (rela->sec->sh_type != SHT_REL) )
+ continue;
+
+ /* Is it a valid relocation section? */
+ if ( rela->sec->sh_info >= elf->hdr->e_shnum )
+ continue;
+
+ base = &elf->sec[rela->sec->sh_info];
+
+ /* Don't relocate non-allocated sections. */
+ if ( !(base->sec->sh_flags & SHF_ALLOC) )
+ continue;
+
+ if ( rela->sec->sh_link != elf->symtab_idx )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Relative link of %s is incorrect (%d, expected=%d)\n",
+ elf->name, rela->name, rela->sec->sh_link, elf->symtab_idx);
+ rc = -EINVAL;
+ break;
+ }
+
+ if ( rela->sec->sh_type == SHT_RELA )
+ rc = arch_xsplice_perform_rela(elf, base, rela);
+ else /* SHT_REL */
+ rc = arch_xsplice_perform_rel(elf, base, rela);
+
+ if ( rc )
+ break;
+ }
+
+ return rc;
+}
+
static int xsplice_header_check(const struct xsplice_elf *elf)
{
const Elf_Ehdr *hdr = elf->hdr;
+ int rc;
if ( sizeof(*elf->hdr) > elf->len )
{
@@ -276,6 +394,10 @@ static int xsplice_header_check(const struct xsplice_elf *elf)
return -EOPNOTSUPP;
}
+ rc = arch_xsplice_verify_elf(elf);
+ if ( rc )
+ return rc;
+
if ( elf->hdr->e_shstrndx == SHN_UNDEF )
{
dprintk(XENLOG_ERR, XSPLICE "%s: Section name idx is undefined!?\n",
diff --git a/xen/include/xen/elfstructs.h b/xen/include/xen/elfstructs.h
index 85f35ed..be55985 100644
--- a/xen/include/xen/elfstructs.h
+++ b/xen/include/xen/elfstructs.h
@@ -472,6 +472,8 @@ typedef struct {
#endif
#if defined(ELFSIZE) && (ELFSIZE == 32)
+#define PRIxElfAddr "08x"
+
#define Elf_Ehdr Elf32_Ehdr
#define Elf_Phdr Elf32_Phdr
#define Elf_Shdr Elf32_Shdr
@@ -497,6 +499,8 @@ typedef struct {
#define AuxInfo Aux32Info
#elif defined(ELFSIZE) && (ELFSIZE == 64)
+#define PRIxElfAddr "lx"
+
#define Elf_Ehdr Elf64_Ehdr
#define Elf_Phdr Elf64_Phdr
#define Elf_Shdr Elf64_Shdr
diff --git a/xen/include/xen/xsplice.h b/xen/include/xen/xsplice.h
index cd805a8..83e4f31 100644
--- a/xen/include/xen/xsplice.h
+++ b/xen/include/xen/xsplice.h
@@ -6,6 +6,9 @@
#ifndef __XEN_XSPLICE_H__
#define __XEN_XSPLICE_H__
+struct xsplice_elf;
+struct xsplice_elf_sec;
+struct xsplice_elf_sym;
struct xen_sysctl_xsplice_op;
#ifdef CONFIG_XSPLICE
@@ -15,6 +18,32 @@ struct xen_sysctl_xsplice_op;
int xsplice_op(struct xen_sysctl_xsplice_op *);
+/* Arch hooks. */
+int arch_xsplice_verify_elf(const struct xsplice_elf *elf);
+int arch_xsplice_perform_rel(struct xsplice_elf *elf,
+ const struct xsplice_elf_sec *base,
+ const struct xsplice_elf_sec *rela);
+int arch_xsplice_perform_rela(struct xsplice_elf *elf,
+ const struct xsplice_elf_sec *base,
+ const struct xsplice_elf_sec *rela);
+enum va_type {
+ XSPLICE_VA_RX, /* .text */
+ XSPLICE_VA_RW, /* .data */
+ XSPLICE_VA_RO, /* .rodata */
+};
+
+#include <xen/mm.h>
+void *arch_xsplice_alloc_payload(unsigned int pages);
+
+/*
+ * Function to secure the allocate pages (from arch_xsplice_alloc_payload)
+ * with the right page permissions.
+ */
+int arch_xsplice_secure(void *va, unsigned int pages, enum va_type types);
+
+void arch_xsplice_free_payload(void *va);
+
+void arch_xsplice_init(void);
#else
#include <xen/errno.h> /* For -ENOSYS */
diff --git a/xen/include/xen/xsplice_elf.h b/xen/include/xen/xsplice_elf.h
index 89acb77..6892f59 100644
--- a/xen/include/xen/xsplice_elf.h
+++ b/xen/include/xen/xsplice_elf.h
@@ -15,6 +15,8 @@ struct xsplice_elf_sec {
elf_resolve_section_names. */
const void *data; /* Pointer to the section (done by
elf_resolve_sections). */
+ void *load_addr; /* A pointer to the allocated destination.
+ Done by load_payload_data. */
};
struct xsplice_elf_sym {
@@ -29,8 +31,10 @@ struct xsplice_elf {
struct xsplice_elf_sec *sec; /* Array of sections, allocated by us. */
struct xsplice_elf_sym *sym; /* Array of symbols , allocated by us. */
unsigned int nsym;
- const struct xsplice_elf_sec *symtab;/* Pointer to .symtab section - aka to sec[x]. */
+ const struct xsplice_elf_sec *symtab;/* Pointer to .symtab section - aka to
+ sec[symtab_idx]. */
const struct xsplice_elf_sec *strtab;/* Pointer to .strtab section - aka to sec[y]. */
+ unsigned int symtab_idx;
};
const struct xsplice_elf_sec *xsplice_elf_sec_by_name(const struct xsplice_elf *elf,
@@ -38,6 +42,9 @@ const struct xsplice_elf_sec *xsplice_elf_sec_by_name(const struct xsplice_elf *
int xsplice_elf_load(struct xsplice_elf *elf, const void *data);
void xsplice_elf_free(struct xsplice_elf *elf);
+int xsplice_elf_resolve_symbols(struct xsplice_elf *elf);
+int xsplice_elf_perform_relocs(struct xsplice_elf *elf);
+
#endif /* __XEN_XSPLICE_ELF_H__ */
/*
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 12/27] xsplice: Implement support for applying/reverting/replacing patches.
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (10 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 11/27] xsplice: Implement payload loading Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-19 6:27 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 13/27] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version' Konrad Rzeszutek Wilk
` (15 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Kevin Tian, Stefano Stabellini, Keir Fraser,
Suravee Suthikulpanit, Konrad Rzeszutek Wilk, Jun Nakajima,
Julien Grall, Jan Beulich, Boris Ostrovsky
From: Ross Lagerwall <ross.lagerwall@citrix.com>
Implement support for the apply, revert and replace actions.
To perform and action on a payload, the hypercall sets up a data
structure to schedule the work. A hook is added in the reset_stack_and_jump
to check for work and execute it if needed (specifically we check an
per-cpu flag to make this as quick as possible).
In this way, patches can be applied with all CPUs idle and without
stacks. The first CPU to run check_for_xsplice_work() becomes the
master and triggers a reschedule softirq to trigger all the other CPUs
to enter check_for_xsplice_work() with no stack. Once all CPUs
have rendezvoused, all CPUs disable IRQs and NMIs are ignored.
The system is then quiscient and the master performs the action.
After this, all CPUs enable IRQs and NMIs are re-enabled.
Note that it is unsafe to patch do_nmi and the xSplice internal functions.
Patching functions on NMI/MCE path is liable to end in disaster.
This is not addressed in this patch and is mentioned in the
design doc as a further TODO.
The action to perform is one of:
- APPLY: For each function in the module, store the first 5 bytes of the
old function and replace it with a jump to the new function.
- REVERT: Copy the previously stored bytes into the first 5 bytes of the
old function.
- REPLACE: Revert each applied module and then apply the new module.
To prevent a deadlock with any other barrier in the system, the master
will wait for up to 30ms before timing out.
Measurements found that the patch application to take about 100 μs on a
72 CPU system, whether idle or fully loaded.
We also add an BUILD_ON to make sure that the size of the structure
of the payload is not inadvertly changed and that the offsets are
correct on both 32 and 64-bit hypervisor (ARM32 and ARM64).
To make this work, we make the public header use architecture
neutral members (xen_ulong_t) but for per-architecture have to
fiddle with padding.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
--
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Julien Grall <julien.grall@arm.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Jun Nakajima <jun.nakajima@intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
v2: - Pluck the 'struct xsplice_patch_func' in this patch.
- Modify code per review comments.
- Add more data in the keyboard handler.
- Redo the patching code, split it in functions.
v3: - Add return_ macro for debug builds.
- Move s/payload_list_lock/payload_list/ to earlier patch
- Remove const and use ELF types for xsplice_patch_func
- Add check routine to do simple sanity checks for various
sections.
- s/%p/PRIx64/ as ARM builds complain.
- Move code around. Add more dprintk. Add XSPLICE in front of all
printks/dprintk.
Put the NMIs back if we fail patching.
Add per-cpu to lessen contention for global structure.
Extract from xsplice_do_single patching code into xsplice_do_action
Squash xsplice_do_single and check_for_xsplice_work together to
have all rendezvous in one place.
Made XSPLICE_ACTION_REPLACE work again (wrong list iterator)
s/find_special_sections/prepare_payload/
Use list_del_init and INIT_LIST_HEAD for applied_list
v4:
- Add comment, adjust spacing for "Timed out on CPU semaphore"
- Added CR0.WP manipulations when altering the .text of hypervisor.
- Added fix from Andrew for CR0.WP manipulation.
v5: - Made xsplice_patch_func use uintXX_t instead of ELF_ types to easy
making it work under ARM (32bit). Add more BUILD-BUG-ON checks.
- Add more BUILD_ON checks. Sprinkle newlines.
v6: Rebase on "arm/x86: Alter nmi_callback_t typedef"
- Drop the recursive spinlock usage.
- Move NMI callbacks in arch specific.
- Fold the 'check_for_xsplice_work' in reset_stack_and_jump
- Add arch specific check for .xsplice.funcs.
- Seperate external and internal structure of .xsplice.funcs.
- Changed per Jan's review
- Modified the .xsplice.funcs checks
v7:
- Modified old_ptr to void* instead of uint8_t*
- Modified the xsplice_patch_func_internal for ARM32 to have padding.
- Used #if BITS_PER_LONG == 64 for the xsplice_patch_func_internal along
with ifndef CONFIG_ARM for the undo (which may be different size on ARM64)
v8:
- Add "is empty" if special sections are in fact empty.
- Added Andrew's Reviewed-by:
- Rebase on v7.2 of x86/mm: Introduce modify_xen_mappings()
- Change some of printk to dprintk and some of the dprintk to printk.
- Make the xsplice_patch_func (and the internal) structure have uint32_t
(instead of uint64_t) if BITS_PER_LONG==32. This makes the size and
offset different so note that in the design and common code.
- Add #undef ACTION
- Guard struct xsplice_patch_func in sysctl.h with __XEN__ as toolstacks
will fail to compile. We do have BITS_PER_LONG defined in xc_bitops.h but
that will go away (and also that macro uses sizeof and the pre-processor
will choke on that).
- Dropped Julien's Acked as I replaced BITS_PER_LONG/CONFIG_ARM_32.
(Stefano is OK with it, but would prefer BITS_PER_LONG, Jan does not want
BITS_PER_LONG).
---
docs/misc/xsplice.markdown | 8 +-
xen/arch/arm/xsplice.c | 33 +++
xen/arch/x86/domain.c | 2 +
xen/arch/x86/xsplice.c | 88 +++++++-
xen/common/xsplice.c | 473 +++++++++++++++++++++++++++++++++++++++++-
xen/include/asm-x86/current.h | 10 +-
xen/include/public/sysctl.h | 27 +++
xen/include/xen/xsplice.h | 47 +++++
8 files changed, 670 insertions(+), 18 deletions(-)
diff --git a/docs/misc/xsplice.markdown b/docs/misc/xsplice.markdown
index d4e7d75..7a19b60 100644
--- a/docs/misc/xsplice.markdown
+++ b/docs/misc/xsplice.markdown
@@ -289,8 +289,13 @@ describing the functions to be patched:
<pre>
struct xsplice_patch_func {
const char *name;
+#if BITS_PER_LONG == 32
+ uint32_t new_addr;
+ uint32_t old_addr;
+#else
uint64_t new_addr;
uint64_t old_addr;
+#endif
uint32_t new_size;
uint32_t old_size;
uint8_t version;
@@ -298,7 +303,8 @@ struct xsplice_patch_func {
};
</pre>
-The size of the structure is 64 bytes.
+The size of the structure is 64 bytes or 52 bytes if compiled under 32-bit
+hypervisors.
* `name` is the symbol name of the old function. Only used if `old_addr` is
zero, otherwise will be used during dynamic linking (when hypervisor loads
diff --git a/xen/arch/arm/xsplice.c b/xen/arch/arm/xsplice.c
index 4465244..5491317 100644
--- a/xen/arch/arm/xsplice.c
+++ b/xen/arch/arm/xsplice.c
@@ -6,6 +6,39 @@
#include <xen/xsplice_elf.h>
#include <xen/xsplice.h>
+void arch_xsplice_patching_enter(void)
+{
+}
+
+void arch_xsplice_patching_leave(void)
+{
+}
+
+int arch_xsplice_verify_func(const struct xsplice_patch_func_internal *func)
+{
+ return -ENOSYS;
+}
+
+void arch_xsplice_apply_jmp(struct xsplice_patch_func_internal *func)
+{
+}
+
+void arch_xsplice_revert_jmp(const struct xsplice_patch_func_internal *func)
+{
+}
+
+void arch_xsplice_post_action(void)
+{
+}
+
+void arch_xsplice_mask(void)
+{
+}
+
+void arch_xsplice_unmask(void)
+{
+}
+
int arch_xsplice_verify_elf(const struct xsplice_elf *elf)
{
return -ENOSYS;
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index e93ff20..2d7932f 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -36,6 +36,7 @@
#include <xen/cpu.h>
#include <xen/wait.h>
#include <xen/guest_access.h>
+#include <xen/xsplice.h>
#include <public/sysctl.h>
#include <public/hvm/hvm_vcpu.h>
#include <asm/regs.h>
@@ -120,6 +121,7 @@ static void idle_loop(void)
(*pm_idle)();
do_tasklet();
do_softirq();
+ check_for_xsplice_work(); /* Must be last. */
}
}
diff --git a/xen/arch/x86/xsplice.c b/xen/arch/x86/xsplice.c
index 3000ecb..a180af8 100644
--- a/xen/arch/x86/xsplice.c
+++ b/xen/arch/x86/xsplice.c
@@ -10,6 +10,82 @@
#include <xen/xsplice_elf.h>
#include <xen/xsplice.h>
+#include <asm/nmi.h>
+
+#define PATCH_INSN_SIZE 5
+
+void arch_xsplice_patching_enter(void)
+{
+ /* Disable WP to allow changes to read-only pages. */
+ write_cr0(read_cr0() & ~X86_CR0_WP);
+}
+
+void arch_xsplice_patching_leave(void)
+{
+ /* Reinstate WP. */
+ write_cr0(read_cr0() | X86_CR0_WP);
+}
+
+int arch_xsplice_verify_func(const struct xsplice_patch_func_internal *func)
+{
+ /* No NOP patching yet. */
+ if ( !func->new_size )
+ return -EOPNOTSUPP;
+
+ if ( func->old_size < PATCH_INSN_SIZE )
+ return -EINVAL;
+
+ return 0;
+}
+
+void arch_xsplice_apply_jmp(struct xsplice_patch_func_internal *func)
+{
+ int32_t val;
+ uint8_t *old_ptr;
+
+ BUILD_BUG_ON(PATCH_INSN_SIZE > sizeof(func->u.undo));
+ BUILD_BUG_ON(PATCH_INSN_SIZE != (1 + sizeof val));
+
+ old_ptr = func->old_addr;
+ memcpy(func->u.undo, old_ptr, PATCH_INSN_SIZE);
+
+ *old_ptr++ = 0xe9; /* Relative jump */
+ val = func->new_addr - func->old_addr - PATCH_INSN_SIZE;
+ memcpy(old_ptr, &val, sizeof val);
+}
+
+void arch_xsplice_revert_jmp(const struct xsplice_patch_func_internal *func)
+{
+ memcpy(func->old_addr, func->u.undo, PATCH_INSN_SIZE);
+}
+
+/* Serialise the CPU pipeline. */
+void arch_xsplice_post_action(void)
+{
+ cpuid_eax(0);
+}
+
+static nmi_callback_t *saved_nmi_callback;
+/*
+ * Note that because of this NOP code the do_nmi is not safely patchable.
+ * Also if we do receive 'real' NMIs we have lost them. Ditto for MCE.
+ */
+static int mask_nmi_callback(const struct cpu_user_regs *regs, int cpu)
+{
+ /* TODO: Handle missing NMI/MCE.*/
+ return 1;
+}
+
+void arch_xsplice_mask(void)
+{
+ saved_nmi_callback = set_nmi_callback(mask_nmi_callback);
+}
+
+void arch_xsplice_unmask(void)
+{
+ set_nmi_callback(saved_nmi_callback);
+}
+
int arch_xsplice_verify_elf(const struct xsplice_elf *elf)
{
@@ -148,12 +224,12 @@ int arch_xsplice_secure(void *va, unsigned int pages, enum va_type type)
ASSERT(va);
ASSERT(pages);
- if ( type == XSPLICE_VA_RX ) /* PAGE_HYPERVISOR_RX */
- flag = _PAGE_PRESENT;
- else if ( type == XSPLICE_VA_RW ) /* PAGE_HYPERVISOR_RW */
- flag = _PAGE_RW | _PAGE_NX | _PAGE_PRESENT;
- else /* PAGE_HYPERVISOR_RO */
- flag = _PAGE_NX | _PAGE_PRESENT;
+ if ( type == XSPLICE_VA_RX )
+ flag = PAGE_HYPERVISOR_RX;
+ else if ( type == XSPLICE_VA_RW )
+ flag = PAGE_HYPERVISOR_RW;
+ else
+ flag = PAGE_HYPERVISOR_RO;
/* The ones we are allowed to modify are: _PAGE_NX|_PAGE_RW|_PAGE_PRESENT */
modify_xen_mappings(start, start + pages * PAGE_SIZE, flag);
diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c
index 809b067..9e6697e 100644
--- a/xen/common/xsplice.c
+++ b/xen/common/xsplice.c
@@ -3,6 +3,7 @@
*
*/
+#include <xen/cpu.h>
#include <xen/err.h>
#include <xen/guest_access.h>
#include <xen/keyhandler.h>
@@ -11,18 +12,28 @@
#include <xen/mm.h>
#include <xen/sched.h>
#include <xen/smp.h>
+#include <xen/softirq.h>
#include <xen/spinlock.h>
#include <xen/vmap.h>
+#include <xen/wait.h>
#include <xen/xsplice_elf.h>
#include <xen/xsplice.h>
#include <asm/event.h>
#include <public/sysctl.h>
-/* Protects against payload_list operations. */
+/*
+ * Protects against payload_list operations and also allows only one
+ * caller in schedule_work.
+ */
static DEFINE_SPINLOCK(payload_lock);
static LIST_HEAD(payload_list);
+/*
+ * Patches which have been applied.
+ */
+static LIST_HEAD(applied_list);
+
static unsigned int payload_cnt;
static unsigned int payload_version = 1;
@@ -37,9 +48,35 @@ struct payload {
void *ro_addr; /* Virtual address of .rodata. */
size_t ro_size; /* .. and its size (if any). */
size_t pages; /* Total pages for [text,rw,ro]_addr */
+ struct list_head applied_list; /* Linked to 'applied_list'. */
+ struct xsplice_patch_func_internal *funcs; /* The array of functions to patch. */
+ unsigned int nfuncs; /* Nr of functions to patch. */
char name[XEN_XSPLICE_NAME_SIZE]; /* Name of it. */
};
+/* Defines an outstanding patching action. */
+struct xsplice_work
+{
+ atomic_t semaphore; /* Used for rendezvous. */
+ atomic_t irq_semaphore; /* Used to signal all IRQs disabled. */
+ uint32_t timeout; /* Timeout to do the operation. */
+ struct payload *data; /* The payload on which to act. */
+ volatile bool_t do_work; /* Signals work to do. */
+ volatile bool_t ready; /* Signals all CPUs synchronized. */
+ unsigned int cmd; /* Action request: XSPLICE_ACTION_* */
+};
+
+/* There can be only one outstanding patching action. */
+static struct xsplice_work xsplice_work;
+
+/*
+ * Indicate whether the CPU needs to consult xsplice_work structure.
+ * We want an per-cpu data structure otherwise the check_for_xsplice_work
+ * would hammer a global xsplice_work structure on every guest VMEXIT.
+ * Having an per-cpu lessens the load.
+ */
+static DEFINE_PER_CPU(bool_t, work_to_do);
+
static int verify_name(const xen_xsplice_name_t *name, char *n)
{
if ( !name->size || name->size > XEN_XSPLICE_NAME_SIZE )
@@ -255,6 +292,98 @@ static int secure_payload(struct payload *payload, struct xsplice_elf *elf)
return rc;
}
+static int check_special_sections(const struct xsplice_elf *elf)
+{
+ unsigned int i;
+ static const char *const names[] = { ".xsplice.funcs" };
+ unsigned int count[ARRAY_SIZE(names)] = { 0 };
+
+ for ( i = 0; i < ARRAY_SIZE(names); i++ )
+ {
+ const struct xsplice_elf_sec *sec;
+
+ sec = xsplice_elf_sec_by_name(elf, names[i]);
+ if ( !sec )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: %s is missing!\n",
+ elf->name, names[i]);
+ return -EINVAL;
+ }
+
+ if ( !sec->sec->sh_size )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: %s is empty!\n",
+ elf->name, names[i]);
+ return -EINVAL;
+ }
+ count[i]++;
+ }
+
+ for ( i = 0; i < ARRAY_SIZE(names); i++ )
+ {
+ if ( count[i] > 1 )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: %s was seen more than once!\n",
+ elf->name, names[i]);
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+static int prepare_payload(struct payload *payload,
+ struct xsplice_elf *elf)
+{
+ const struct xsplice_elf_sec *sec;
+ unsigned int i;
+ struct xsplice_patch_func_internal *f;
+
+ sec = xsplice_elf_sec_by_name(elf, ".xsplice.funcs");
+ ASSERT(sec);
+ if ( sec->sec->sh_size % sizeof(*payload->funcs) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong size of .xsplice.funcs!\n",
+ elf->name);
+ return -EINVAL;
+ }
+
+ payload->funcs = sec->load_addr;
+ payload->nfuncs = sec->sec->sh_size / sizeof(*payload->funcs);
+
+ for ( i = 0; i < payload->nfuncs; i++ )
+ {
+ int rc;
+ unsigned int j;
+
+ f = &(payload->funcs[i]);
+
+ if ( f->version != XSPLICE_PAYLOAD_VERSION )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong version (%u). Expected %d!\n",
+ elf->name, f->version, XSPLICE_PAYLOAD_VERSION);
+ return -EOPNOTSUPP;
+ }
+
+ if ( !f->new_addr || !f->new_size )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Address or size fields are zero!\n",
+ elf->name);
+ return -EINVAL;
+ }
+
+ rc = arch_xsplice_verify_func(f);
+ if ( rc )
+ return rc;
+
+ for ( j = 0; j < ARRAY_SIZE(f->u.pad); j++ )
+ if ( f->u.pad[j] )
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static void free_payload(struct payload *data)
{
ASSERT(spin_is_locked(&payload_lock));
@@ -286,6 +415,14 @@ static int load_payload_data(struct payload *payload, void *raw, size_t len)
if ( rc )
goto out;
+ rc = check_special_sections(&elf);
+ if ( rc )
+ goto out;
+
+ rc = prepare_payload(payload, &elf);
+ if ( rc )
+ goto out;
+
rc = secure_payload(payload, &elf);
out:
@@ -346,6 +483,7 @@ static int xsplice_upload(xen_sysctl_xsplice_upload_t *upload)
data->state = XSPLICE_STATE_CHECKED;
INIT_LIST_HEAD(&data->list);
+ INIT_LIST_HEAD(&data->applied_list);
list_add_tail(&data->list, &payload_list);
payload_cnt++;
@@ -456,6 +594,295 @@ static int xsplice_list(xen_sysctl_xsplice_list_t *list)
return rc ? : idx;
}
+/*
+ * The following functions get the CPUs into an appropriate state and
+ * apply (or revert) each of the payload's functions. This is needed
+ * for XEN_SYSCTL_XSPLICE_ACTION operation (see xsplice_action).
+ */
+
+static int apply_payload(struct payload *data)
+{
+ unsigned int i;
+
+ printk(XENLOG_INFO XSPLICE "%s: Applying %u functions.\n",
+ data->name, data->nfuncs);
+
+ arch_xsplice_patching_enter();
+
+ for ( i = 0; i < data->nfuncs; i++ )
+ arch_xsplice_apply_jmp(&data->funcs[i]);
+
+ arch_xsplice_patching_leave();
+
+ list_add_tail(&data->applied_list, &applied_list);
+
+ return 0;
+}
+
+static int revert_payload(struct payload *data)
+{
+ unsigned int i;
+
+ printk(XENLOG_INFO XSPLICE "%s: Reverting.\n", data->name);
+
+ arch_xsplice_patching_enter();
+
+ for ( i = 0; i < data->nfuncs; i++ )
+ arch_xsplice_revert_jmp(&data->funcs[i]);
+
+ arch_xsplice_patching_leave();
+
+ list_del_init(&data->applied_list);
+
+ return 0;
+}
+
+/*
+ * This function is executed having all other CPUs with no stack (we may
+ * have cpu_idle on it) and IRQs disabled. We guard against NMI by temporarily
+ * installing our NOP NMI handler.
+ */
+static void xsplice_do_action(void)
+{
+ int rc;
+ struct payload *data, *other, *tmp;
+
+ data = xsplice_work.data;
+ /*
+ * Now this function should be the only one on any stack.
+ * No need to lock the payload list or applied list.
+ */
+ switch ( xsplice_work.cmd )
+ {
+ case XSPLICE_ACTION_APPLY:
+ rc = apply_payload(data);
+ if ( rc == 0 )
+ data->state = XSPLICE_STATE_APPLIED;
+ break;
+
+ case XSPLICE_ACTION_REVERT:
+ rc = revert_payload(data);
+ if ( rc == 0 )
+ data->state = XSPLICE_STATE_CHECKED;
+ break;
+
+ case XSPLICE_ACTION_REPLACE:
+ rc = 0;
+ /* N.B: Use 'applied_list' member, not 'list'. */
+ list_for_each_entry_safe_reverse ( other, tmp, &applied_list, applied_list )
+ {
+ other->rc = revert_payload(other);
+ if ( other->rc == 0 )
+ other->state = XSPLICE_STATE_CHECKED;
+ else
+ {
+ rc = -EINVAL;
+ break;
+ }
+ }
+
+ if ( rc == 0 )
+ {
+ rc = apply_payload(data);
+ if ( rc == 0 )
+ data->state = XSPLICE_STATE_APPLIED;
+ }
+ break;
+
+ default:
+ ASSERT_UNREACHABLE();
+ break;
+ }
+
+ /* We must set rc as xsplice_action sets it to -EAGAIN when kicking of. */
+ data->rc = rc;
+}
+
+static int schedule_work(struct payload *data, uint32_t cmd, uint32_t timeout)
+{
+ ASSERT(spin_is_locked(&payload_lock));
+
+ /* Fail if an operation is already scheduled. */
+ if ( xsplice_work.do_work )
+ return -EBUSY;
+
+ if ( !get_cpu_maps() )
+ {
+ printk(XENLOG_ERR XSPLICE "%s: unable to get cpu_maps lock!\n",
+ data->name);
+ return -EBUSY;
+ }
+
+ xsplice_work.cmd = cmd;
+ xsplice_work.data = data;
+ xsplice_work.timeout = timeout ?: MILLISECS(30);
+
+ dprintk(XENLOG_DEBUG, XSPLICE "%s: timeout is %"PRI_stime"ms\n",
+ data->name, xsplice_work.timeout / MILLISECS(1));
+
+ atomic_set(&xsplice_work.semaphore, -1);
+ atomic_set(&xsplice_work.irq_semaphore, -1);
+
+ xsplice_work.ready = 0;
+
+ smp_wmb();
+
+ xsplice_work.do_work = 1;
+ this_cpu(work_to_do) = 1;
+
+ put_cpu_maps();
+
+ return 0;
+}
+
+static void reschedule_fn(void *unused)
+{
+ this_cpu(work_to_do) = 1;
+ raise_softirq(SCHEDULE_SOFTIRQ);
+}
+
+static int xsplice_spin(atomic_t *counter, s_time_t timeout,
+ unsigned int cpus, const char *s)
+{
+ int rc = 0;
+
+ while ( atomic_read(counter) != cpus && NOW() < timeout )
+ cpu_relax();
+
+ /* Log & abort. */
+ if ( atomic_read(counter) != cpus )
+ {
+ printk(XENLOG_ERR XSPLICE "%s: Timed out on %s semaphore %u/%u\n",
+ xsplice_work.data->name, s, atomic_read(counter), cpus);
+ rc = -EBUSY;
+ xsplice_work.data->rc = rc;
+ xsplice_work.do_work = 0;
+ smp_wmb();
+ }
+
+ return rc;
+}
+
+/*
+ * The main function which manages the work of quiescing the system and
+ * patching code.
+ */
+void check_for_xsplice_work(void)
+{
+#define ACTION(x) [XSPLICE_ACTION_##x] = #x
+ static const char *const names[] = {
+ ACTION(APPLY),
+ ACTION(REVERT),
+ ACTION(REPLACE),
+ };
+#undef ACTION
+ unsigned int cpu = smp_processor_id();
+ s_time_t timeout;
+ unsigned long flags;
+
+ /* Fast path: no work to do. */
+ if ( !per_cpu(work_to_do, cpu ) )
+ return;
+
+ smp_rmb();
+ /* In case we aborted, other CPUs can skip right away. */
+ if ( !xsplice_work.do_work )
+ {
+ per_cpu(work_to_do, cpu) = 0;
+ return;
+ }
+
+ ASSERT(local_irq_is_enabled());
+
+ /* Set at -1, so will go up to num_online_cpus - 1. */
+ if ( atomic_inc_and_test(&xsplice_work.semaphore) )
+ {
+ struct payload *p;
+ unsigned int cpus;
+
+ p = xsplice_work.data;
+ if ( !get_cpu_maps() )
+ {
+ printk(XENLOG_ERR XSPLICE "%s: CPU%u - unable to get cpu_maps lock!\n",
+ p->name, cpu);
+ per_cpu(work_to_do, cpu) = 0;
+ xsplice_work.data->rc = -EBUSY;
+ xsplice_work.do_work = 0;
+ /*
+ * Do NOT decrement semaphore down - as that may cause the other
+ * CPU (which may be at this ready to increment it)
+ * to assume the role of master and then needlessly time out
+ * out (as do_work is zero).
+ */
+ smp_wmb();
+ return;
+ }
+ /* "Mask" NMIs. */
+ arch_xsplice_mask();
+
+ barrier(); /* MUST do it after get_cpu_maps. */
+ cpus = num_online_cpus() - 1;
+
+ if ( cpus )
+ {
+ dprintk(XENLOG_DEBUG, XSPLICE "%s: CPU%u - IPIing the other %u CPUs\n",
+ p->name, cpu, cpus);
+ smp_call_function(reschedule_fn, NULL, 0);
+ }
+
+ timeout = xsplice_work.timeout + NOW();
+ if ( xsplice_spin(&xsplice_work.semaphore, timeout, cpus, "CPU") )
+ goto abort;
+
+ /* All CPUs are waiting, now signal to disable IRQs. */
+ xsplice_work.ready = 1;
+ smp_wmb();
+
+ atomic_inc(&xsplice_work.irq_semaphore);
+ if ( !xsplice_spin(&xsplice_work.irq_semaphore, timeout, cpus, "IRQ") )
+ {
+ local_irq_save(flags);
+ /* Do the patching. */
+ xsplice_do_action();
+ /* Flush the CPU i-cache via CPUID instruction (on x86). */
+ arch_xsplice_post_action();
+ local_irq_restore(flags);
+ }
+ arch_xsplice_unmask();
+
+ abort:
+ per_cpu(work_to_do, cpu) = 0;
+ xsplice_work.do_work = 0;
+
+ smp_wmb(); /* MUST complete writes before put_cpu_maps(). */
+
+ put_cpu_maps();
+
+ printk(XENLOG_INFO XSPLICE "%s finished %s with rc=%d\n",
+ p->name, names[xsplice_work.cmd], p->rc);
+ }
+ else
+ {
+ /* Wait for all CPUs to rendezvous. */
+ while ( xsplice_work.do_work && !xsplice_work.ready )
+ cpu_relax();
+
+ /* Disable IRQs and signal. */
+ local_irq_save(flags);
+ atomic_inc(&xsplice_work.irq_semaphore);
+
+ /* Wait for patching to complete. */
+ while ( xsplice_work.do_work )
+ cpu_relax();
+
+ /* To flush out pipeline. */
+ arch_xsplice_post_action();
+ local_irq_restore(flags);
+
+ per_cpu(work_to_do, cpu) = 0;
+ }
+}
+
static int xsplice_action(xen_sysctl_xsplice_action_t *action)
{
struct payload *data;
@@ -502,27 +929,24 @@ static int xsplice_action(xen_sysctl_xsplice_action_t *action)
case XSPLICE_ACTION_REVERT:
if ( data->state == XSPLICE_STATE_APPLIED )
{
- /* No implementation yet. */
- data->state = XSPLICE_STATE_CHECKED;
- data->rc = 0;
+ data->rc = -EAGAIN;
+ rc = schedule_work(data, action->cmd, action->timeout);
}
break;
case XSPLICE_ACTION_APPLY:
if ( data->state == XSPLICE_STATE_CHECKED )
{
- /* No implementation yet. */
- data->state = XSPLICE_STATE_APPLIED;
- data->rc = 0;
+ data->rc = -EAGAIN;
+ rc = schedule_work(data, action->cmd, action->timeout);
}
break;
case XSPLICE_ACTION_REPLACE:
if ( data->state == XSPLICE_STATE_CHECKED )
{
- /* No implementation yet. */
- data->state = XSPLICE_STATE_CHECKED;
- data->rc = 0;
+ data->rc = -EAGAIN;
+ rc = schedule_work(data, action->cmd, action->timeout);
}
break;
@@ -587,6 +1011,7 @@ static const char *state2str(uint32_t state)
static void xsplice_printall(unsigned char key)
{
struct payload *data;
+ unsigned int i;
printk("'%u' pressed - Dumping all xsplice patches\n", key);
@@ -597,15 +1022,43 @@ static void xsplice_printall(unsigned char key)
}
list_for_each_entry ( data, &payload_list, list )
+ {
printk(" name=%s state=%s(%d) %p (.data=%p, .rodata=%p) using %zu pages.\n",
data->name, state2str(data->state), data->state, data->text_addr,
data->rw_addr, data->ro_addr, data->pages);
+ for ( i = 0; i < data->nfuncs; i++ )
+ {
+ struct xsplice_patch_func_internal *f = &(data->funcs[i]);
+ printk(" %s patch %p(%u) with %p (%u)\n",
+ f->name, f->old_addr, f->old_size, f->new_addr, f->new_size);
+
+ if ( i && !(i % 64) )
+ {
+ spin_unlock(&payload_lock);
+ process_pending_softirqs();
+ spin_lock(&payload_lock);
+ }
+ }
+ }
+
spin_unlock(&payload_lock);
}
static int __init xsplice_init(void)
{
+ BUILD_BUG_ON( sizeof(struct xsplice_patch_func) !=
+ sizeof(struct xsplice_patch_func_internal) );
+ BUILD_BUG_ON( sizeof(struct xsplice_patch_func_internal) !=
+ XSPLICE_PATCH_FUNC_INTERNAL_SIZE );
+
+#if BITS_PER_LONG == 64
+ BUILD_BUG_ON( offsetof(struct xsplice_patch_func, new_addr) != 8 );
+ BUILD_BUG_ON( offsetof(struct xsplice_patch_func, new_size) != 24 );
+#else
+ BUILD_BUG_ON( offsetof(struct xsplice_patch_func, new_addr) != 4 );
+ BUILD_BUG_ON( offsetof(struct xsplice_patch_func, new_size) != 12 );
+#endif
register_keyhandler('x', xsplice_printall, "print xsplicing info", 1);
arch_xsplice_init();
diff --git a/xen/include/asm-x86/current.h b/xen/include/asm-x86/current.h
index 4083261..027aa0c 100644
--- a/xen/include/asm-x86/current.h
+++ b/xen/include/asm-x86/current.h
@@ -86,10 +86,18 @@ static inline struct cpu_info *get_cpu_info(void)
unsigned long get_stack_trace_bottom(unsigned long sp);
unsigned long get_stack_dump_bottom (unsigned long sp);
+#ifdef CONFIG_XSPLICE
+# define __CHECK_FOR_XSPLICE_WORK "call check_for_xsplice_work;"
+#else
+# define __CHECK_FOR_XSPLICE_WORK ""
+#endif
+
#define reset_stack_and_jump(__fn) \
({ \
__asm__ __volatile__ ( \
- "mov %0,%%"__OP"sp; jmp %c1" \
+ "mov %0,%%"__OP"sp;" \
+ __CHECK_FOR_XSPLICE_WORK \
+ "jmp %c1" \
: : "r" (guest_cpu_user_regs()), "i" (__fn) : "memory" ); \
unreachable(); \
})
diff --git a/xen/include/public/sysctl.h b/xen/include/public/sysctl.h
index 090fd21..3d47b47 100644
--- a/xen/include/public/sysctl.h
+++ b/xen/include/public/sysctl.h
@@ -833,6 +833,33 @@ DEFINE_XEN_GUEST_HANDLE(xen_sysctl_featureset_t);
* If zero exit with success.
*/
+#define XSPLICE_PAYLOAD_VERSION 1
+/*
+ * .xsplice.funcs structure layout defined in the `Payload format`
+ * section in the xSplice design document.
+ *
+ * The size should be exactly 64 bytes (64) or 52 bytes (32).
+ *
+ * We guard this with __XEN__ as toolstacks do not need to use it.
+ */
+#ifdef __XEN__
+struct xsplice_patch_func {
+ const char *name; /* Name of function to be patched. */
+#if CONFIG_ARM_32
+ uint32_t new_addr;
+ uint32_t old_addr;
+#else
+ uint64_t new_addr;
+ uint64_t old_addr; /* Can be zero and name will be looked up. */
+#endif
+ uint32_t new_size;
+ uint32_t old_size;
+ uint8_t version; /* MUST be XSPLICE_PAYLOAD_VERSION. */
+ uint8_t pad[31]; /* MUST be zero filled. */
+};
+typedef struct xsplice_patch_func xsplice_patch_func_t;
+#endif
+
/*
* Structure describing an ELF payload. Uniquely identifies the
* payload. Should be human readable.
diff --git a/xen/include/xen/xsplice.h b/xen/include/xen/xsplice.h
index 83e4f31..536a9e8 100644
--- a/xen/include/xen/xsplice.h
+++ b/xen/include/xen/xsplice.h
@@ -11,12 +11,43 @@ struct xsplice_elf_sec;
struct xsplice_elf_sym;
struct xen_sysctl_xsplice_op;
+#include <xen/elfstructs.h>
#ifdef CONFIG_XSPLICE
+/*
+ * The structure which defines the patching. This is what the hypervisor
+ * expects in the '.xsplice.func' section of the ELF file.
+ *
+ * This MUST be in sync with what the tools generate. We expose
+ * for the tools the 'struct xsplice_patch_func' which does not have
+ * platform specific entries.
+ */
+#if BITS_PER_LONG == 64
+#define XSPLICE_PATCH_FUNC_INTERNAL_SIZE 64
+#else
+#define XSPLICE_PATCH_FUNC_INTERNAL_SIZE 52
+#endif
+
+struct xsplice_patch_func_internal {
+ const char *name;
+ void *new_addr;
+ void *old_addr;
+ uint32_t new_size;
+ uint32_t old_size;
+ uint8_t version;
+ union {
+#ifndef CONFIG_ARM
+ uint8_t undo[8];
+#endif
+ uint8_t pad[31];
+ } u;
+};
+
/* Convenience define for printk. */
#define XSPLICE "xsplice: "
int xsplice_op(struct xen_sysctl_xsplice_op *);
+void check_for_xsplice_work(void);
/* Arch hooks. */
int arch_xsplice_verify_elf(const struct xsplice_elf *elf);
@@ -44,6 +75,21 @@ int arch_xsplice_secure(void *va, unsigned int pages, enum va_type types);
void arch_xsplice_free_payload(void *va);
void arch_xsplice_init(void);
+
+int arch_xsplice_verify_func(const struct xsplice_patch_func_internal *func);
+/*
+ * These functions are called around the critical region patching live code,
+ * for an architecture to take make appropratie global state adjustments.
+ */
+void arch_xsplice_patching_enter(void);
+void arch_xsplice_patching_leave(void);
+
+void arch_xsplice_apply_jmp(struct xsplice_patch_func_internal *func);
+void arch_xsplice_revert_jmp(const struct xsplice_patch_func_internal *func);
+void arch_xsplice_post_action(void);
+
+void arch_xsplice_mask(void);
+void arch_xsplice_unmask(void);
#else
#include <xen/errno.h> /* For -ENOSYS */
@@ -52,6 +98,7 @@ static inline int xsplice_op(struct xen_sysctl_xsplice_op *op)
return -ENOSYS;
}
+static inline void check_for_xsplice_work(void) { };
#endif /* CONFIG_XSPLICE */
#endif /* __XEN_XSPLICE_H__ */
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 13/27] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version'.
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (11 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 12/27] xsplice: Implement support for applying/reverting/replacing patches Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-19 17:40 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address Konrad Rzeszutek Wilk
` (14 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Julien Grall, Stefano Stabellini, Keir Fraser, Jan Beulich,
Konrad Rzeszutek Wilk
This change demonstrates how to generate an xSplice ELF payload.
The idea here is that we want to patch in the hypervisor
the 'xen_version_extra' function with an function that will
return 'Hello World'. The 'xl info | grep extraversion'
will reflect the new value after the patching.
To generate this ELF payload file we need:
- C code of the new code (xen_hello_world_func.c).
- C code generating the .xsplice.funcs structure
(xen_hello_world.c)
- The address of the old code (xen_extra_version). We
retrieve it by using 'nm --defined' on xen-syms.
- The size of the new and old code for which we use
nm --defined -S on our code and xen-syms respectively.
There are two C files and one header files generated
during build. One could make this one C file if the
size of the newly patched function size was known in
advance (or an random value was choosen).
There is also a strict order of compiling:
1) xen_hello_world_func.c
2) config.h - extract the size of the new function,
the old function and the old function address.
3) xen_hello_world.c - which contains the .xsplice.funcs
structure.
4) Link the object files in an xen_hello_world.xsplice file.
The use-case is simple:
$xen-xsplice load /usr/lib/debug/xen_hello_world.xsplice
$xen-xsplice list
ID | status
----------------------------------------+------------
xen_hello_world APPLIED
$xl info | grep extra
xen_extra : Hello World
$xen-xsplice revert xen_hello_world
Performing revert: completed
$xen-xsplice unload xen_hello_world
Performing unload: completed
$xl info | grep extra
xen_extra : -unstable
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Julien Grall <julien.grall@arm.com> [ARM]
---
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Julien Grall <julien.grall@arm.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
v2: Do it using hypervisor Makefiles
v3: Remove the stale linker file.
Add Copyright and local definition block
s/name/xen_hello_world_name/
v6: Remove the 'install', and 'uninstall' destinations.
Remove xen/config.h from files.
v7: Made the build target be called 'tests'.
Changed the .name to have 'xen_extra_version' to be consistent
with the spec.
Add Julien's Ack and Andrew's Reviewed-by.
---
---
.gitignore | 2 ++
docs/misc/xsplice.markdown | 37 +++++++++++++++++++++++++++
xen/Makefile | 8 ++++--
xen/arch/arm/Makefile | 2 ++
xen/arch/x86/Makefile | 4 +++
xen/arch/x86/test/Makefile | 44 ++++++++++++++++++++++++++++++++
xen/arch/x86/test/xen_hello_world.c | 30 ++++++++++++++++++++++
xen/arch/x86/test/xen_hello_world_func.c | 22 ++++++++++++++++
8 files changed, 147 insertions(+), 2 deletions(-)
create mode 100644 xen/arch/x86/test/Makefile
create mode 100644 xen/arch/x86/test/xen_hello_world.c
create mode 100644 xen/arch/x86/test/xen_hello_world_func.c
diff --git a/.gitignore b/.gitignore
index 39eb779..4a81f43 100644
--- a/.gitignore
+++ b/.gitignore
@@ -246,6 +246,8 @@ xen/arch/x86/efi.lds
xen/arch/x86/efi/check.efi
xen/arch/x86/efi/disabled
xen/arch/x86/efi/mkreloc
+xen/arch/x86/test/config.h
+xen/arch/x86/test/xen_hello_world.xsplice
xen/arch/*/efi/boot.c
xen/arch/*/efi/compat.c
xen/arch/*/efi/efi.h
diff --git a/docs/misc/xsplice.markdown b/docs/misc/xsplice.markdown
index 7a19b60..4b9403e 100644
--- a/docs/misc/xsplice.markdown
+++ b/docs/misc/xsplice.markdown
@@ -336,6 +336,43 @@ When reverting a patch, the hypervisor iterates over each `xsplice_patch_func`
and the core code copies the data from the undo buffer (private internal copy)
to `old_addr`.
+### Example of .xsplice.funcs
+
+A simple example of what a payload file can be:
+
+<pre>
+/* MUST be in sync with hypervisor. */
+struct xsplice_patch_func {
+ const char *name;
+ uint64_t new_addr;
+ uint64_t old_addr;
+ uint32_t new_size;
+ uint32_t old_size;
+ uint8_t version;
+ uint8_t pad[31];
+};
+
+/* Our replacement function for xen_extra_version. */
+const char *xen_hello_world(void)
+{
+ return "Hello World";
+}
+
+static unsigned char patch_this_fnc[] = "xen_extra_version";
+
+struct xsplice_patch_func xsplice_hello_world = {
+ .version = XSPLICE_PAYLOAD_VERSION,
+ .name = patch_this_fnc,
+ .new_addr = (unsigned long)(xen_hello_world),
+ .old_addr = 0xffff82d08013963c, /* Extracted from xen-syms. */
+ .new_size = 13, /* To be be computed by scripts. */
+ .old_size = 13, /* -----------""--------------- */
+} __attribute__((__section__(".xsplice.funcs")));
+
+</pre>
+
+Code must be compiled with -fPIC.
+
## Hypercalls
We will employ the sub operations of the system management hypercall (sysctl).
diff --git a/xen/Makefile b/xen/Makefile
index c908544..eb0482e 100644
--- a/xen/Makefile
+++ b/xen/Makefile
@@ -39,8 +39,8 @@ dist: install
build install:: include/config/auto.conf
-.PHONY: build install uninstall clean distclean cscope TAGS tags MAP gtags
-build install uninstall debug clean distclean cscope TAGS tags MAP gtags::
+.PHONY: build install uninstall clean distclean cscope TAGS tags MAP gtags tests
+build install uninstall debug clean distclean cscope TAGS tags MAP gtags tests::
ifneq ($(XEN_TARGET_ARCH),x86_32)
$(MAKE) -f Rules.mk _$@
else
@@ -76,6 +76,10 @@ _install: $(TARGET)$(CONFIG_XEN_INSTALL_SUFFIX)
fi; \
fi
+.PHONY: _tests
+_tests:
+ $(MAKE) -f $(BASEDIR)/Rules.mk -C arch/$(TARGET_ARCH) tests
+
.PHONY: _uninstall
_uninstall: D=$(DESTDIR)
_uninstall: T=$(notdir $(TARGET))
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index eae5cb3..0afa414 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -57,6 +57,8 @@ ifeq ($(CONFIG_ARM_64),y)
ln -sf $(notdir $@) ../../$(notdir $@).efi
endif
+tests:
+
$(TARGET).axf: $(TARGET)-syms
# XXX: VE model loads by VMA so instead of
# making a proper ELF we link with LMA == VMA and adjust crudely
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 8a6a7d5..6c2d5fa 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -76,6 +76,9 @@ $(TARGET): $(TARGET)-syms $(efi-y) boot/mkelf32
./boot/mkelf32 $(TARGET)-syms $(TARGET) 0x100000 \
`$(NM) -nr $(TARGET)-syms | head -n 1 | sed -e 's/^\([^ ]*\).*/0x\1/'`
+.PHONY: tests
+tests:
+ $(MAKE) -f $(BASEDIR)/Rules.mk -C test xsplice
ALL_OBJS := $(BASEDIR)/arch/x86/boot/built_in.o $(BASEDIR)/arch/x86/efi/built_in.o $(ALL_OBJS)
@@ -179,3 +182,4 @@ clean::
rm -f $(BASEDIR)/.xen-syms.[0-9]* boot/.*.d
rm -f $(BASEDIR)/.xen.efi.[0-9]* efi/*.o efi/.*.d efi/*.efi efi/disabled efi/mkreloc
rm -f boot/reloc.S boot/reloc.lnk boot/reloc.bin
+ $(MAKE) -f $(BASEDIR)/Rules.mk -C test clean
diff --git a/xen/arch/x86/test/Makefile b/xen/arch/x86/test/Makefile
new file mode 100644
index 0000000..b9cf13c
--- /dev/null
+++ b/xen/arch/x86/test/Makefile
@@ -0,0 +1,44 @@
+include $(XEN_ROOT)/Config.mk
+
+CODE_ADDR=$(shell nm --defined $(1) | grep $(2) | awk '{print "0x"$$1}')
+CODE_SZ=$(shell nm --defined -S $(1) | grep $(2) | awk '{ print "0x"$$2}')
+
+.PHONY: default
+
+XSPLICE := xen_hello_world.xsplice
+
+default: xsplice
+
+install: xsplice
+ $(INSTALL_DATA) $(XSPLICE) $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE)
+uninstall:
+ rm -f $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE)
+
+.PHONY: clean
+clean::
+ rm -f *.o .*.o.d $(XSPLICE) config.h
+
+#
+# To compute these values we need the binary files: xen-syms
+# and xen_hello_world_func.o to be already compiled.
+#
+# We can be assured that xen-syms is already built as we are
+# the last entry in the build target.
+#
+.PHONY: config.h
+config.h: OLD_CODE=$(call CODE_ADDR,$(BASEDIR)/xen-syms,xen_extra_version)
+config.h: OLD_CODE_SZ=$(call CODE_SZ,$(BASEDIR)/xen-syms,xen_extra_version)
+config.h: NEW_CODE_SZ=$(call CODE_SZ,$<,xen_hello_world)
+config.h: xen_hello_world_func.o
+ (set -e; \
+ echo "#define NEW_CODE_SZ $(NEW_CODE_SZ)"; \
+ echo "#define OLD_CODE_SZ $(OLD_CODE_SZ)"; \
+ echo "#define OLD_CODE $(OLD_CODE)") > $@
+
+.PHONY: xsplice
+xsplice: config.h
+ # Need to have these done in sequential order
+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_hello_world_func.o
+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_hello_world.o
+ $(LD) $(LDFLAGS) -r -o $(XSPLICE) xen_hello_world_func.o \
+ xen_hello_world.o
diff --git a/xen/arch/x86/test/xen_hello_world.c b/xen/arch/x86/test/xen_hello_world.c
new file mode 100644
index 0000000..21831e9
--- /dev/null
+++ b/xen/arch/x86/test/xen_hello_world.c
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
+ *
+ */
+
+#include "config.h"
+#include <xen/types.h>
+#include <xen/xsplice.h>
+
+static char hello_world_patch_this_fnc[] = "xen_extra_version";
+extern const char *xen_hello_world(void);
+
+struct xsplice_patch_func __section(".xsplice.funcs") xsplice_xen_hello_world = {
+ .version = XSPLICE_PAYLOAD_VERSION,
+ .name = hello_world_patch_this_fnc,
+ .new_addr = (unsigned long)(xen_hello_world),
+ .old_addr = OLD_CODE,
+ .new_size = NEW_CODE_SZ,
+ .old_size = OLD_CODE_SZ,
+};
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/x86/test/xen_hello_world_func.c b/xen/arch/x86/test/xen_hello_world_func.c
new file mode 100644
index 0000000..1ad002a
--- /dev/null
+++ b/xen/arch/x86/test/xen_hello_world_func.c
@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
+ *
+ */
+
+#include <xen/types.h>
+
+/* Our replacement function for xen_extra_version. */
+const char *xen_hello_world(void)
+{
+ return "Hello World";
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (12 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 13/27] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version' Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-19 19:31 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 15/27] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup Konrad Rzeszutek Wilk
` (13 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Keir Fraser, Jan Beulich, Konrad Rzeszutek Wilk
From: Ross Lagerwall <ross.lagerwall@citrix.com>
If in the payload we do not have the old_addr we can resolve
the virtual address based on the UNDEFined symbols.
We also use an boolean flag: new_symbol to track symbols. The usual
case this is used is by:
* A payload may introduce a new symbol
* A payload may override an existing symbol (introduced in Xen or another
payload)
* Overriding symbols must exist in the symtab for backtraces.
* A payload must always link against the object which defines the new symbol.
Considering that payloads may be loaded in any order it would be incorrect to
link against a payload which simply overrides a symbol because you could end
up with a chain of jumps which is inefficient and may result in the expected
function not being executed.
Also we include a local definition block in the symbols.c file.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
v1: Ross original version.
v2: Include test-case and document update.
v2: s/size_t/ssize_t/
Include core_text_size, core_text calculation
v4: Cast on dprintk to uint64_t to make ELF 32bit build.
v6: Rebase where the spinlock is no more recursive. Drop the spinlock
usage in xsplice_symbols_lookup_by_name
v7: Add Andrew's Reviewed-by
Initialize addr and symname to zero as xensyms_read uses it.
v8: Change one XENLOG_DEBUG to XENLOG_ERR.
Change printk to dprintk on symbols and one error case.
---
xen/arch/x86/Makefile | 16 +++-
xen/arch/x86/test/Makefile | 4 +-
xen/arch/x86/test/xen_hello_world.c | 5 +-
xen/common/symbols.c | 34 ++++++++
xen/common/xsplice.c | 156 +++++++++++++++++++++++++++++++++++-
xen/common/xsplice_elf.c | 19 ++++-
xen/include/xen/symbols.h | 2 +
xen/include/xen/xsplice.h | 8 ++
8 files changed, 232 insertions(+), 12 deletions(-)
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 6c2d5fa..57c93e1 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -72,6 +72,12 @@ efi-y := $(shell if [ ! -r $(BASEDIR)/include/xen/compile.h -o \
-O $(BASEDIR)/include/xen/compile.h ]; then \
echo '$(TARGET).efi'; fi)
+ifdef CONFIG_XSPLICE
+all_symbols = --all-symbols
+else
+all_symbols =
+endif
+
$(TARGET): $(TARGET)-syms $(efi-y) boot/mkelf32
./boot/mkelf32 $(TARGET)-syms $(TARGET) 0x100000 \
`$(NM) -nr $(TARGET)-syms | head -n 1 | sed -e 's/^\([^ ]*\).*/0x\1/'`
@@ -111,12 +117,14 @@ $(TARGET)-syms: prelink.o xen.lds $(BASEDIR)/common/symbols-dummy.o
$(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
$(BASEDIR)/common/symbols-dummy.o -o $(@D)/.$(@F).0
$(NM) -pa --format=sysv $(@D)/.$(@F).0 \
- | $(BASEDIR)/tools/symbols --sysv --sort >$(@D)/.$(@F).0.S
+ | $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort \
+ >$(@D)/.$(@F).0.S
$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).0.o
$(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
$(@D)/.$(@F).0.o -o $(@D)/.$(@F).1
$(NM) -pa --format=sysv $(@D)/.$(@F).1 \
- | $(BASEDIR)/tools/symbols --sysv --sort --warn-dup >$(@D)/.$(@F).1.S
+ | $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort --warn-dup \
+ >$(@D)/.$(@F).1.S
$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1.o
$(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
$(@D)/.$(@F).1.o -o $@
@@ -140,14 +148,14 @@ $(TARGET).efi: prelink-efi.o efi.lds efi/relocs-dummy.o $(BASEDIR)/common/symbol
$(BASEDIR)/common/symbols-dummy.o -o $(@D)/.$(@F).$(base).0 &&) :
$(guard) efi/mkreloc $(foreach base,$(VIRT_BASE) $(ALT_BASE),$(@D)/.$(@F).$(base).0) >$(@D)/.$(@F).0r.S
$(guard) $(NM) -pa --format=sysv $(@D)/.$(@F).$(VIRT_BASE).0 \
- | $(guard) $(BASEDIR)/tools/symbols --sysv --sort >$(@D)/.$(@F).0s.S
+ | $(guard) $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort >$(@D)/.$(@F).0s.S
$(guard) $(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).0r.o $(@D)/.$(@F).0s.o
$(foreach base, $(VIRT_BASE) $(ALT_BASE), \
$(guard) $(LD) $(call EFI_LDFLAGS,$(base)) -T efi.lds -N $< \
$(@D)/.$(@F).0r.o $(@D)/.$(@F).0s.o -o $(@D)/.$(@F).$(base).1 &&) :
$(guard) efi/mkreloc $(foreach base,$(VIRT_BASE) $(ALT_BASE),$(@D)/.$(@F).$(base).1) >$(@D)/.$(@F).1r.S
$(guard) $(NM) -pa --format=sysv $(@D)/.$(@F).$(VIRT_BASE).1 \
- | $(guard) $(BASEDIR)/tools/symbols --sysv --sort >$(@D)/.$(@F).1s.S
+ | $(guard) $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort >$(@D)/.$(@F).1s.S
$(guard) $(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1r.o $(@D)/.$(@F).1s.o
$(guard) $(LD) $(call EFI_LDFLAGS,$(VIRT_BASE)) -T efi.lds -N $< \
$(@D)/.$(@F).1r.o $(@D)/.$(@F).1s.o -o $@
diff --git a/xen/arch/x86/test/Makefile b/xen/arch/x86/test/Makefile
index b9cf13c..baa4820 100644
--- a/xen/arch/x86/test/Makefile
+++ b/xen/arch/x86/test/Makefile
@@ -26,14 +26,12 @@ clean::
# the last entry in the build target.
#
.PHONY: config.h
-config.h: OLD_CODE=$(call CODE_ADDR,$(BASEDIR)/xen-syms,xen_extra_version)
config.h: OLD_CODE_SZ=$(call CODE_SZ,$(BASEDIR)/xen-syms,xen_extra_version)
config.h: NEW_CODE_SZ=$(call CODE_SZ,$<,xen_hello_world)
config.h: xen_hello_world_func.o
(set -e; \
echo "#define NEW_CODE_SZ $(NEW_CODE_SZ)"; \
- echo "#define OLD_CODE_SZ $(OLD_CODE_SZ)"; \
- echo "#define OLD_CODE $(OLD_CODE)") > $@
+ echo "#define OLD_CODE_SZ $(OLD_CODE_SZ)") > $@
.PHONY: xsplice
xsplice: config.h
diff --git a/xen/arch/x86/test/xen_hello_world.c b/xen/arch/x86/test/xen_hello_world.c
index 21831e9..22fe2e7 100644
--- a/xen/arch/x86/test/xen_hello_world.c
+++ b/xen/arch/x86/test/xen_hello_world.c
@@ -10,11 +10,14 @@
static char hello_world_patch_this_fnc[] = "xen_extra_version";
extern const char *xen_hello_world(void);
+/* External symbol. */
+extern const char *xen_extra_version(void);
+
struct xsplice_patch_func __section(".xsplice.funcs") xsplice_xen_hello_world = {
.version = XSPLICE_PAYLOAD_VERSION,
.name = hello_world_patch_this_fnc,
.new_addr = (unsigned long)(xen_hello_world),
- .old_addr = OLD_CODE,
+ .old_addr = (unsigned long)(xen_extra_version),
.new_size = NEW_CODE_SZ,
.old_size = OLD_CODE_SZ,
};
diff --git a/xen/common/symbols.c b/xen/common/symbols.c
index b18ddcd1..781765d 100644
--- a/xen/common/symbols.c
+++ b/xen/common/symbols.c
@@ -207,3 +207,37 @@ int xensyms_read(uint32_t *symnum, char *type,
return 0;
}
+
+unsigned long symbols_lookup_by_name(const char *symname)
+{
+ char name[KSYM_NAME_LEN + 1] = { 0 };
+ uint32_t symnum = 0;
+ char type;
+ uint64_t addr = 0;
+ int rc;
+
+ if ( symname == '\0' )
+ return 0;
+
+ do {
+ rc = xensyms_read(&symnum, &type, &addr, name);
+ if ( rc )
+ break;
+
+ if ( !strcmp(name, symname) )
+ return addr;
+
+ } while ( name[0] != '\0' );
+
+ return 0;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c
index 9e6697e..28e7769 100644
--- a/xen/common/xsplice.c
+++ b/xen/common/xsplice.c
@@ -14,6 +14,7 @@
#include <xen/smp.h>
#include <xen/softirq.h>
#include <xen/spinlock.h>
+#include <xen/symbols.h>
#include <xen/vmap.h>
#include <xen/wait.h>
#include <xen/xsplice_elf.h>
@@ -51,6 +52,9 @@ struct payload {
struct list_head applied_list; /* Linked to 'applied_list'. */
struct xsplice_patch_func_internal *funcs; /* The array of functions to patch. */
unsigned int nfuncs; /* Nr of functions to patch. */
+ struct xsplice_symbol *symtab; /* All symbols. */
+ char *strtab; /* Pointer to .strtab. */
+ unsigned int nsyms; /* Nr of entries in .strtab and symbols. */
char name[XEN_XSPLICE_NAME_SIZE]; /* Name of it. */
};
@@ -114,6 +118,28 @@ static int verify_payload(const xen_sysctl_xsplice_upload_t *upload, char *n)
return 0;
}
+unsigned long xsplice_symbols_lookup_by_name(const char *symname)
+{
+ struct payload *data;
+
+ ASSERT(spin_is_locked(&payload_lock));
+ list_for_each_entry ( data, &payload_list, list )
+ {
+ unsigned int i;
+
+ for ( i = 0; i < data->nsyms; i++ )
+ {
+ if ( !data->symtab[i].new_symbol )
+ continue;
+
+ if ( !strcmp(data->symtab[i].name, symname) )
+ return data->symtab[i].value;
+ }
+ }
+
+ return 0;
+}
+
static struct payload *find_payload(const char *name)
{
struct payload *data, *found = NULL;
@@ -379,11 +405,129 @@ static int prepare_payload(struct payload *payload,
for ( j = 0; j < ARRAY_SIZE(f->u.pad); j++ )
if ( f->u.pad[j] )
return -EINVAL;
+
+ /* Lookup function's old address if not already resolved. */
+ if ( !f->old_addr )
+ {
+ f->old_addr = (void *)symbols_lookup_by_name(f->name);
+ if ( !f->old_addr )
+ {
+ f->old_addr = (void *)xsplice_symbols_lookup_by_name(f->name);
+ if ( !f->old_addr )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Could not resolve old address of %s\n",
+ elf->name, f->name);
+ return -ENOENT;
+ }
+ }
+ dprintk(XENLOG_DEBUG, XSPLICE "%s: Resolved old address %s => %p\n",
+ elf->name, f->name, f->old_addr);
+ }
}
return 0;
}
+static bool_t is_payload_symbol(const struct xsplice_elf *elf,
+ const struct xsplice_elf_sym *sym)
+{
+ if ( sym->sym->st_shndx == SHN_UNDEF ||
+ sym->sym->st_shndx >= elf->hdr->e_shnum )
+ return 0;
+
+ return (elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) &&
+ (ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT ||
+ ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
+}
+
+static int build_symbol_table(struct payload *payload,
+ const struct xsplice_elf *elf)
+{
+ unsigned int i, j, nsyms = 0;
+ size_t strtab_len = 0;
+ struct xsplice_symbol *symtab;
+ char *strtab;
+
+ ASSERT(payload->nfuncs);
+
+ /* Recall that section @0 is always NULL. */
+ for ( i = 1; i < elf->nsym; i++ )
+ {
+ if ( is_payload_symbol(elf, elf->sym + i) )
+ {
+ nsyms++;
+ strtab_len += strlen(elf->sym[i].name) + 1;
+ }
+ }
+
+ symtab = xmalloc_array(struct xsplice_symbol, nsyms);
+ strtab = xmalloc_array(char, strtab_len);
+
+ if ( !strtab || !symtab )
+ {
+ xfree(strtab);
+ xfree(symtab);
+ return -ENOMEM;
+ }
+
+ nsyms = 0;
+ strtab_len = 0;
+ for ( i = 1; i < elf->nsym; i++ )
+ {
+ if ( is_payload_symbol(elf, elf->sym + i) )
+ {
+ symtab[nsyms].name = strtab + strtab_len;
+ symtab[nsyms].size = elf->sym[i].sym->st_size;
+ symtab[nsyms].value = elf->sym[i].sym->st_value;
+ symtab[nsyms].new_symbol = 0; /* To be checked below. */
+ strtab_len += strlcpy(strtab + strtab_len, elf->sym[i].name,
+ KSYM_NAME_LEN) + 1;
+ nsyms++;
+ }
+ }
+
+ for ( i = 0; i < nsyms; i++ )
+ {
+ bool_t found = 0;
+
+ for ( j = 0; j < payload->nfuncs; j++ )
+ {
+ if ( symtab[i].value == (unsigned long)payload->funcs[j].new_addr )
+ {
+ found = 1;
+ break;
+ }
+ }
+
+ if ( !found )
+ {
+ if ( xsplice_symbols_lookup_by_name(symtab[i].name) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: duplicate new symbol: %s\n",
+ elf->name, symtab[i].name);
+ xfree(symtab);
+ xfree(strtab);
+ return -EEXIST;
+ }
+ symtab[i].new_symbol = 1;
+ dprintk(XENLOG_DEBUG, XSPLICE "%s: new symbol %s\n",
+ elf->name, symtab[i].name);
+ }
+ else
+ {
+ /* new_symbol is not set. */
+ dprintk(XENLOG_DEBUG, XSPLICE "%s: overriding symbol %s\n",
+ elf->name, symtab[i].name);
+ }
+ }
+
+ payload->symtab = symtab;
+ payload->strtab = strtab;
+ payload->nsyms = nsyms;
+
+ return 0;
+}
+
static void free_payload(struct payload *data)
{
ASSERT(spin_is_locked(&payload_lock));
@@ -391,6 +535,8 @@ static void free_payload(struct payload *data)
payload_cnt--;
payload_version++;
free_payload_data(data);
+ xfree(data->symtab);
+ xfree(data->strtab);
xfree(data);
}
@@ -423,6 +569,10 @@ static int load_payload_data(struct payload *payload, void *raw, size_t len)
if ( rc )
goto out;
+ rc = build_symbol_table(payload, &elf);
+ if ( rc )
+ goto out;
+
rc = secure_payload(payload, &elf);
out:
@@ -494,8 +644,12 @@ static int xsplice_upload(xen_sysctl_xsplice_upload_t *upload)
vfree(raw_data);
- if ( rc )
+ if ( rc && data )
+ {
+ xfree(data->symtab);
+ xfree(data->strtab);
xfree(data);
+ }
return rc;
}
diff --git a/xen/common/xsplice_elf.c b/xen/common/xsplice_elf.c
index f59f011..fbc86eb 100644
--- a/xen/common/xsplice_elf.c
+++ b/xen/common/xsplice_elf.c
@@ -4,6 +4,7 @@
#include <xen/errno.h>
#include <xen/lib.h>
+#include <xen/symbols.h>
#include <xen/xsplice_elf.h>
#include <xen/xsplice.h>
@@ -274,9 +275,21 @@ int xsplice_elf_resolve_symbols(struct xsplice_elf *elf)
break;
case SHN_UNDEF:
- dprintk(XENLOG_ERR, XSPLICE "%s: Unknown symbol: %s\n",
- elf->name, elf->sym[i].name);
- rc = -ENOENT;
+ elf->sym[i].sym->st_value = (unsigned long)symbols_lookup_by_name(elf->sym[i].name);
+ if ( !elf->sym[i].sym->st_value )
+ {
+ elf->sym[i].sym->st_value = (unsigned long)
+ xsplice_symbols_lookup_by_name(elf->sym[i].name);
+ if ( !elf->sym[i].sym->st_value )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Unknown symbol: %s\n",
+ elf->name, elf->sym[i].name);
+ rc = -ENOENT;
+ break;
+ }
+ }
+ dprintk(XENLOG_DEBUG, XSPLICE "%s: Undefined symbol resolved: %s => %#"PRIxElfAddr"\n",
+ elf->name, elf->sym[i].name, elf->sym[i].sym->st_value);
break;
case SHN_ABS:
diff --git a/xen/include/xen/symbols.h b/xen/include/xen/symbols.h
index f58e611..d9bd35f 100644
--- a/xen/include/xen/symbols.h
+++ b/xen/include/xen/symbols.h
@@ -23,4 +23,6 @@ const char *symbols_lookup(unsigned long addr,
int xensyms_read(uint32_t *symnum, char *type,
uint64_t *address, char *name);
+unsigned long symbols_lookup_by_name(const char *symname);
+
#endif /*_XEN_SYMBOLS_H*/
diff --git a/xen/include/xen/xsplice.h b/xen/include/xen/xsplice.h
index 536a9e8..0599476 100644
--- a/xen/include/xen/xsplice.h
+++ b/xen/include/xen/xsplice.h
@@ -46,8 +46,16 @@ struct xsplice_patch_func_internal {
/* Convenience define for printk. */
#define XSPLICE "xsplice: "
+struct xsplice_symbol {
+ const char *name;
+ uint64_t value;
+ size_t size;
+ bool_t new_symbol;
+};
+
int xsplice_op(struct xen_sysctl_xsplice_op *);
void check_for_xsplice_work(void);
+unsigned long xsplice_symbols_lookup_by_name(const char *symname);
/* Arch hooks. */
int arch_xsplice_verify_elf(const struct xsplice_elf *elf);
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 15/27] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (13 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-19 19:52 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 16/27] x86, xsplice: Print payload's symbol name and payload name in backtraces Konrad Rzeszutek Wilk
` (12 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Keir Fraser, Jan Beulich, Konrad Rzeszutek Wilk
The current mechanism is geared towards fast virtual address ->
symbol names lookup. This is fine for the normal use cases
(BUG_ON, WARN_ON, etc), but for xSplice - where we need to find
hypervisor symbols - it is slow.
To understand this patch, a description of the existing
method is explained first. For folks familar go to 'NEW CODE:'.
HOW IT WORKS:
The symbol table lookup mechanism uses a simple encoding mechanism
where it extracts the common ascii characters that the symbol's use.
This saves us space. The lookup mechanism is geared towards looking
up symbols based on address. We have one 0..N (where N is
the number of symbols, so 6849 for example) table:
symbols_addresses[0..N]
And an 1-1 (in a loose fashion) of the symbols (encoded) in a
symbols_names stream of size N.
The N is variable (later on that below)
The symbols_names are sorted based on symbols_addresses, which
means that the decoded entries inside symbols_names are not in
ascending or descending order.
There is also the encoding mechanism - the table of 255 entries
called symbols_token_index[]. And the symbols_token_table which
is an stream of ASCIIZ characters, such as (it really
is not a table as the values are variable):
@0 .asciz "credit"
@6 .asciz "mask"
..
@300 .asciz "S"
And the symbols_token_index:
@0 .short 0
@1 .short 7
@2 .short 12
@4 .short 16
...
@84 .short 300
The relationship between them is that the symbols_token_index
gives us the offset to symbols_token_table.
The symbol_names[] array is a stream of encoded values. Each value
follows the same pattern - <len> followed by <encoding values>.
And the another <len> followed by <encoding values>.
Hence to find the right one you need to read <len>, add <len>
(to skip over), read <len>, add <len>, and so on until one
finds the right tuple offset.
The <encoding values> are the indicies into the symbols_token_index.
Meaning if you have:
0x04, 0x54, 0xda, 0xe2, 0x74
[4, 84, 218, 226, 116 in human numbering]
The 0x04 tells us that the symbol is four bytes past this one (so next
symbol offset starts at 5). If we lookup symbols_token_index[84] we get 300.
symbols_token[300] gets us the "S". And so on, the string eventually
end up being decode to be 'S_stext'. The first character is the type,
then optionally follwed by the filename (and # right after filename)
and then lastly the symbol, such as:
tvpmu_intel.c#core2_vpmu_do_interrupt
Keep in mind that there are two fixed sized tables:
symbols_addresses[0..symbols_num_syms], and
symbols_markers[0..symbols_num_syms/255].
The symbols_markers is used to speed searching for the right address.
It gives us the offsets within symbol_names that start at the <len><encoded value>.
The way to find a symbol based on the address is:
1) Figure out the 'tuple offset' from symbols_address[0..symbols_num_syms].
This table is sorted by virtual addresses so finding the value is simple.
2) Get starting offset of symbol_names by retrieving value of
symbol_markers['tuple offset' / 255].
3). Iterate up to 'tuple_offset & 255' in symbols_markers stream starting
at 'offset'.
4). Decode the <len><encoded value>
This however does not work very well if we want to search the other
way - we have the symbol name and want to find the address.
NEW CODE:
To make that work we add three tables:
1) symbols_addresses_index_sorted[0..symbols_num_syms]. The values are
indicies into symbols_addresses array. This is a 1-1 table:
symbols_addresses_index_sorted:
.long 6315
.long 6097
To get the address of a symbol at offset 0 in symbols_name_sorted
(see below) we look in symbols_addresses_index_sorted[0] to get
6315 and then look in symbols_addresses_index[6315] to find it.
2) The symbols_names_sorted stream - same format as symbols_names but
constructued by sorting the <type>[filename#]<symbol> by <symbol>,
then [filename#] and lastly type. Recall that symbol_names is sorted
based on addresses of the symbols.
3) To make it simpler to search we also add an symbols_markers_sorted
array (of size symbols_num_syms/255).
Searching for symbols is simplified as we can do a binary search
on symbol_names_sorted (and using symbols_markers_sorted). Since the
symbols are sorted it takes on average 13 calls to symbols_expand_symbol.
Doing small tests (search for five different symbols) using the old
and new mechanism show 2ms vs 0ms improvement.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
CC: Keir Fraser <keir@xen.org>
CC: Jan Beulich <jbeulich@suse.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
v8: New
- Remove the debug code
- Return the 'mid' index in symbol_addresses, not the 'low'.
---
---
xen/arch/x86/Makefile | 3 ++
xen/common/Kconfig | 12 ++++++
xen/common/symbols-dummy.c | 6 +++
xen/common/symbols.c | 75 +++++++++++++++++++++++++++++++++----
xen/tools/symbols.c | 93 +++++++++++++++++++++++++++++++++++++++++++---
5 files changed, 176 insertions(+), 13 deletions(-)
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 57c93e1..4ce2346 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -74,6 +74,9 @@ efi-y := $(shell if [ ! -r $(BASEDIR)/include/xen/compile.h -o \
ifdef CONFIG_XSPLICE
all_symbols = --all-symbols
+ifdef CONFIG_FAST_SYMBOL_LOOKUP
+all_symbols = --all-symbols --add-extra-sorted
+endif
else
all_symbols =
endif
diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index fea33d3..639dc4b 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -200,4 +200,16 @@ config XSPLICE
If unsure, say Y.
+config FAST_SYMBOL_LOOKUP
+ bool "Fast symbol lookup (bigger binary)"
+ default y
+ depends on XSPLICE
+ ---help---
+ When searching for symbol addresses we can use the built-in system
+ that is optimized for searching symbols using addresses as the key.
+ However using it for the inverse (find address using the symbol name)
+ it is slow. This extra data (~128kB) speeds up the search.
+ The only user of this is xSplice.
+
+ If unsure, say Y.
endmenu
diff --git a/xen/common/symbols-dummy.c b/xen/common/symbols-dummy.c
index 5090c3b..18d572c 100644
--- a/xen/common/symbols-dummy.c
+++ b/xen/common/symbols-dummy.c
@@ -14,6 +14,12 @@ const unsigned long symbols_addresses[1];
const unsigned int symbols_num_syms;
const u8 symbols_names[1];
+#ifdef CONFIG_FAST_SYMBOL_LOOKUP
+const u8 symbols_names_sorted[1];
+const unsigned int symbols_addresses_index_sorted[1];
+const unsigned int symbols_markers_sorted[1];
+#endif
+
const u8 symbols_token_table[1];
const u16 symbols_token_index[1];
diff --git a/xen/common/symbols.c b/xen/common/symbols.c
index 781765d..cb792cd 100644
--- a/xen/common/symbols.c
+++ b/xen/common/symbols.c
@@ -31,6 +31,12 @@ extern const unsigned long symbols_addresses[];
extern const unsigned int symbols_num_syms;
extern const u8 symbols_names[];
+#ifdef CONFIG_FAST_SYMBOL_LOOKUP
+extern const u8 symbols_names_sorted[];
+extern const unsigned int symbols_addresses_index_sorted[];
+extern const unsigned int symbols_markers_sorted[];
+#endif
+
extern const u8 symbols_token_table[];
extern const u16 symbols_token_index[];
@@ -38,13 +44,13 @@ extern const unsigned int symbols_markers[];
/* expand a compressed symbol data into the resulting uncompressed string,
given the offset to where the symbol is in the compressed stream */
-static unsigned int symbols_expand_symbol(unsigned int off, char *result)
+static unsigned int symbols_expand_symbol(const u8 *array, unsigned int off, char *result)
{
int len, skipped_first = 0;
const u8 *tptr, *data;
/* get the compressed symbol length from the first symbol byte */
- data = &symbols_names[off];
+ data = array + off;
len = *data;
data++;
@@ -77,14 +83,19 @@ static unsigned int symbols_expand_symbol(unsigned int off, char *result)
/* find the offset on the compressed stream given and index in the
* symbols array */
-static unsigned int get_symbol_offset(unsigned long pos)
+static unsigned int get_symbol_offset(unsigned long pos, bool_t sorted)
{
const u8 *name;
int i;
/* use the closest marker we have. We have markers every 256 positions,
* so that should be close enough */
- name = &symbols_names[ symbols_markers[pos>>8] ];
+#ifdef CONFIG_FAST_SYMBOL_LOOKUP
+ if (sorted)
+ name = &symbols_names_sorted[ symbols_markers_sorted[pos>>8] ];
+ else
+#endif
+ name = &symbols_names[ symbols_markers[pos>>8] ];
/* sequentially scan all the symbols up to the point we're searching for.
* Every symbol is stored in a [<len>][<len> bytes of data] format, so we
@@ -93,6 +104,11 @@ static unsigned int get_symbol_offset(unsigned long pos)
for(i = 0; i < (pos&0xFF); i++)
name = name + (*name) + 1;
+#ifdef CONFIG_FAST_SYMBOL_LOOKUP
+ if (sorted)
+ return name - symbols_names_sorted;
+#endif
+
return name - symbols_names;
}
@@ -136,7 +152,7 @@ const char *symbols_lookup(unsigned long addr,
--low;
/* Grab name */
- symbols_expand_symbol(get_symbol_offset(low), namebuf);
+ symbols_expand_symbol(symbols_names, get_symbol_offset(low, 0), namebuf);
/* Search for next non-aliased symbol */
for (i = low + 1; i < symbols_num_syms; i++) {
@@ -195,10 +211,10 @@ int xensyms_read(uint32_t *symnum, char *type,
next_offset = next_symbol = 0;
if ( next_symbol != *symnum )
/* Non-sequential access */
- next_offset = get_symbol_offset(*symnum);
+ next_offset = get_symbol_offset(*symnum, 0);
*type = symbols_get_symbol_type(next_offset);
- next_offset = symbols_expand_symbol(next_offset, name);
+ next_offset = symbols_expand_symbol(symbols_names, next_offset, name);
*address = symbols_address(*symnum);
next_symbol = ++*symnum;
@@ -208,8 +224,51 @@ int xensyms_read(uint32_t *symnum, char *type,
return 0;
}
+#ifdef CONFIG_FAST_SYMBOL_LOOKUP
unsigned long symbols_lookup_by_name(const char *symname)
{
+ char namebuf[KSYM_NAME_LEN + 1] = { 0 };
+ unsigned long low, high;
+ static const char *filename_token = "#";
+
+ if ( symname == '\0' )
+ return 0;
+
+ /* Unsupported search for filename in symbol right now. */
+ if ( strpbrk(symname, filename_token) )
+ return 0;
+
+ low = 0;
+ high = symbols_num_syms;
+ while ( low < high )
+ {
+ unsigned long mid = low + ((high - low) / 2);
+ unsigned long offset;
+ const char *p;
+ int rc;
+
+ offset = get_symbol_offset(mid, 1);
+ (void)symbols_expand_symbol(symbols_names_sorted, offset, namebuf);
+ /* Format is: [filename]#<symbol>. symbols_expand_symbol eats type.*/
+ p = strpbrk((const char *)namebuf, filename_token);
+ if ( !p )
+ p = namebuf;
+ else
+ p++; /* Skip # */
+ rc = strcmp(symname, p);
+ if ( rc < 0 )
+ high = mid;
+ else if ( rc > 0 )
+ low = mid + 1;
+ else
+ return symbols_address(symbols_addresses_index_sorted[mid]);
+ }
+ return 0;
+}
+
+#else
+unsigned long symbols_lookup_by_name(const char *symname)
+ {
char name[KSYM_NAME_LEN + 1] = { 0 };
uint32_t symnum = 0;
char type;
@@ -231,7 +290,7 @@ unsigned long symbols_lookup_by_name(const char *symname)
return 0;
}
-
+#endif
/*
* Local variables:
* mode: C
diff --git a/xen/tools/symbols.c b/xen/tools/symbols.c
index 196db74..0a56c5e 100644
--- a/xen/tools/symbols.c
+++ b/xen/tools/symbols.c
@@ -40,6 +40,10 @@ struct sym_entry {
unsigned long long addr;
unsigned int len;
unsigned char *sym;
+ unsigned char *symbol;
+ unsigned char *filename;
+ unsigned int idx;
+ unsigned char type;
};
#define SYMBOL_NAME(s) ((char *)(s)->sym + 1)
@@ -47,8 +51,10 @@ static struct sym_entry *table;
static unsigned int table_size, table_cnt;
static unsigned long long _stext, _etext, _sinittext, _einittext, _sextratext, _eextratext;
static int all_symbols = 0;
+static int extra_sorted = 0;
static char symbol_prefix_char = '\0';
static enum { fmt_bsd, fmt_sysv } input_format;
+static int compare_name(const void *p1, const void *p2);
int token_profit[0x10000];
@@ -79,6 +85,7 @@ static int read_symbol(FILE *in, struct sym_entry *s)
char *sym, stype;
static enum { symbol, single_source, multi_source } last;
static char *filename;
+ unsigned int len;
int rc = -1;
switch (input_format) {
@@ -165,18 +172,29 @@ static int read_symbol(FILE *in, struct sym_entry *s)
/* include the type field in the symbol name, so that it gets
* compressed together */
- s->len = strlen(str) + 1;
+ s->len = len = strlen(str) + 1;
if (islower(stype) && filename)
s->len += strlen(filename) + 1;
s->sym = malloc(s->len + 1);
+ if (extra_sorted)
+ s->symbol = malloc(len + 1);
sym = SYMBOL_NAME(s);
if (islower(stype) && filename) {
sym = stpcpy(sym, filename);
*sym++ = '#';
- }
+ if (extra_sorted) {
+ s->filename = malloc(strlen(filename) + 1);
+ strcpy((char *)s->filename, filename);
+ }
+ } else
+ s->filename = NULL;
+
strcpy(sym, str);
+ if (extra_sorted) {
+ strcpy((char *)s->symbol, str);
+ s->type = stype; /* As s->sym[0] ends mangled. */
+ }
s->sym[0] = stype;
-
rc = 0;
skip_tail:
@@ -276,6 +294,36 @@ static int expand_symbol(unsigned char *data, int len, char *result)
return total;
}
+/* Sort by symbol names, then filename, and lastly type. */
+static int compare_name_orig(const void *p1, const void *p2)
+{
+ const struct sym_entry *sym1 = p1;
+ const struct sym_entry *sym2 = p2;
+ int rc;
+
+ rc = strcmp((char *)(sym1->symbol), (char *)(sym2->symbol));
+
+ if (!rc) {
+ if (sym1->filename && sym2->filename)
+ rc = strcmp((char *)sym1->filename, (char *)sym2->filename);
+ else if (!sym1->filename && sym2->filename)
+ rc = -1;
+ else if (sym1->filename && !sym2->filename)
+ rc = 1;
+
+ if (!rc) {
+ if (sym1->type < sym2->type)
+ rc = -1;
+ else if (sym1->type > sym2->type)
+ rc = 1;
+ else
+ rc = 0;
+ }
+ }
+
+ return rc;
+}
+
static void write_src(void)
{
unsigned int i, k, off;
@@ -334,7 +382,6 @@ static void write_src(void)
printf("\t.long\t%d\n", markers[i]);
printf("\n");
- free(markers);
output_label("symbols_token_table");
off = 0;
@@ -350,6 +397,40 @@ static void write_src(void)
for (i = 0; i < 256; i++)
printf("\t.short\t%d\n", best_idx[i]);
printf("\n");
+
+ if (!extra_sorted) {
+ free(markers);
+ return;
+ }
+
+ /* Sorted by original symbol names, filename, and lastly type. */
+ qsort(table, table_cnt, sizeof(*table), compare_name_orig);
+
+ /* Lookup table to symbols_addresses (or symbols_offsets).*/
+ output_label("symbols_addresses_index_sorted");
+ for (i = 0; i < table_cnt; i++) {
+ printf("\t.long\t%d\n", table[i].idx);
+ }
+ printf("\n");
+
+ output_label("symbols_names_sorted");
+ off = 0;
+ for (i = 0; i < table_cnt; i++) {
+ if ((i & 0xFF) == 0)
+ markers[i >> 8] = off;
+ printf("\t.byte 0x%02x", table[i].len);
+ for (k = 0; k < table[i].len; k++)
+ printf(", 0x%02x", table[i].sym[k]);
+ printf("\n");
+ off += table[i].len + 1;
+ }
+ printf("\n");
+ output_label("symbols_markers_sorted");
+ for (i = 0; i < ((table_cnt + 255) >> 8); i++)
+ printf("\t.long\t%d\n", markers[i]);
+ printf("\n");
+
+ free(markers);
}
@@ -409,7 +490,7 @@ static void compress_symbols(unsigned char *str, int idx)
len = table[i].len;
p1 = table[i].sym;
-
+ table[i].idx = i;
/* find the token on the symbol */
p2 = memmem_pvt(p1, len, str, 2);
if (!p2) continue;
@@ -561,6 +642,8 @@ int main(int argc, char **argv)
input_format = fmt_sysv;
else if (strcmp(argv[i], "--sort") == 0)
unsorted = true;
+ else if (strcmp(argv[i], "--add-extra-sorted") == 0)
+ extra_sorted = 1;
else if (strcmp(argv[i], "--warn-dup") == 0)
warn_dup = true;
else
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 16/27] x86, xsplice: Print payload's symbol name and payload name in backtraces
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (14 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 15/27] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-19 20:09 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 17/27] xsplice: Add support for bug frames Konrad Rzeszutek Wilk
` (11 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Keir Fraser, Tim Deegan, Ian Jackson, Jan Beulich, Konrad Rzeszutek Wilk
From: Ross Lagerwall <ross.lagerwall@citrix.com>
Naturally the backtrace is presented when an instruction
hits an bug_frame or %p is used.
The payloads do not support bug_frames yet - however the functions
the payloads call could hit an BUG() or WARN().
The traps.c has logic to scan for it this - and eventually it will
find the correct bug_frame and the walk the stack using %p to print
the backtrace. For %p and symbols to print a string - the
'is_active_kernel_text' is consulted which uses an 'struct virtual_region'.
Therefore we register our start->end addresses so that
'is_active_kernel_text' will include our payload address.
We also register our symbol lookup table function so that it can
scan the list of payloads and retrieve the correct name.
Lastly we change vsprintf to take into account s and namebuf.
For core code they are the same, but for payloads they are different.
This gets us:
Xen call trace:
[<ffff82d080a00041>] revert_hook+0x31/0x35 [xen_hello_world]
[<ffff82d0801431bd>] xsplice.c#revert_payload+0x86/0xc6
[<ffff82d080143502>] check_for_xsplice_work+0x233/0x3cd
[<ffff82d08017a0b2>] domain.c#continue_idle_domain+0x9/0x1f
Which is great if payloads have similar or same symbol names.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Tim Deegan <tim@xen.org>
v2: Add missing full stop.
v3: s/module/payload/
v4: Expand comment and include registration of 'virtual_region'
Redo the vsprintf handling of payload name.
Drop the ->skip function
v6: Add comment explaining the purpose behind the strcmp.
Redid per Jan's review.
v7: Add Andrew's Review-by
Drop the strcmp and just do pointer checks.
---
---
xen/common/vsprintf.c | 19 +++++++++++++++--
xen/common/xsplice.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 76 insertions(+), 2 deletions(-)
diff --git a/xen/common/vsprintf.c b/xen/common/vsprintf.c
index 18d2634..acabb3a 100644
--- a/xen/common/vsprintf.c
+++ b/xen/common/vsprintf.c
@@ -20,6 +20,7 @@
#include <xen/symbols.h>
#include <xen/lib.h>
#include <xen/sched.h>
+#include <xen/xsplice.h>
#include <asm/div64.h>
#include <asm/page.h>
@@ -331,16 +332,23 @@ static char *pointer(char *str, char *end, const char **fmt_ptr,
{
unsigned long sym_size, sym_offset;
char namebuf[KSYM_NAME_LEN+1];
+ bool_t payload = 0;
/* Advance parents fmt string, as we have consumed 's' or 'S' */
++*fmt_ptr;
s = symbols_lookup((unsigned long)arg, &sym_size, &sym_offset, namebuf);
-
- /* If the symbol is not found, fall back to printing the address */
+ /* If the symbol is not found, fall back to printing the address. */
if ( !s )
break;
+ /*
+ * namebuf contents and s for core hypervisor are same but for xSplice
+ * payloads they differ (namebuf contains the name of the payload).
+ */
+ if ( namebuf != s )
+ payload = 1;
+
/* Print symbol name */
str = string(str, end, s, -1, -1, 0);
@@ -354,6 +362,13 @@ static char *pointer(char *str, char *end, const char **fmt_ptr,
str = number(str, end, sym_size, 16, -1, -1, SPECIAL);
}
+ if ( payload )
+ {
+ str = string(str, end, " [", -1, -1, 0);
+ str = string(str, end, namebuf, -1, -1, 0);
+ str = string(str, end, "]", -1, -1, 0);
+ }
+
return str;
}
diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c
index 28e7769..12e5a13 100644
--- a/xen/common/xsplice.c
+++ b/xen/common/xsplice.c
@@ -14,7 +14,9 @@
#include <xen/smp.h>
#include <xen/softirq.h>
#include <xen/spinlock.h>
+#include <xen/string.h>
#include <xen/symbols.h>
+#include <xen/virtual_region.h>
#include <xen/vmap.h>
#include <xen/wait.h>
#include <xen/xsplice_elf.h>
@@ -52,6 +54,8 @@ struct payload {
struct list_head applied_list; /* Linked to 'applied_list'. */
struct xsplice_patch_func_internal *funcs; /* The array of functions to patch. */
unsigned int nfuncs; /* Nr of functions to patch. */
+ struct virtual_region region; /* symbol, bug.frame patching and
+ exception table (x86). */
struct xsplice_symbol *symtab; /* All symbols. */
char *strtab; /* Pointer to .strtab. */
unsigned int nsyms; /* Nr of entries in .strtab and symbols. */
@@ -140,6 +144,51 @@ unsigned long xsplice_symbols_lookup_by_name(const char *symname)
return 0;
}
+static const char *xsplice_symbols_lookup(unsigned long addr,
+ unsigned long *symbolsize,
+ unsigned long *offset,
+ char *namebuf)
+{
+ struct payload *data;
+ unsigned int i;
+ int best;
+
+ /*
+ * No locking since this list is only ever changed during apply or revert
+ * context.
+ */
+ list_for_each_entry ( data, &applied_list, applied_list )
+ {
+ if ( (void *)addr < data->text_addr &&
+ (void *)addr >= (data->text_addr + data->pages * PAGE_SIZE) )
+ continue;
+
+ best = -1;
+
+ for ( i = 0; i < data->nsyms; i++ )
+ {
+ if ( data->symtab[i].value <= addr &&
+ (best == -1 ||
+ data->symtab[best].value < data->symtab[i].value) )
+ best = i;
+ }
+
+ if ( best == -1 )
+ return NULL;
+
+ if ( symbolsize )
+ *symbolsize = data->symtab[best].size;
+ if ( offset )
+ *offset = addr - data->symtab[best].value;
+ if ( namebuf )
+ strlcpy(namebuf, data->name, KSYM_NAME_LEN);
+
+ return data->symtab[best].name;
+ }
+
+ return NULL;
+}
+
static struct payload *find_payload(const char *name)
{
struct payload *data, *found = NULL;
@@ -364,6 +413,7 @@ static int prepare_payload(struct payload *payload,
const struct xsplice_elf_sec *sec;
unsigned int i;
struct xsplice_patch_func_internal *f;
+ struct virtual_region *region;
sec = xsplice_elf_sec_by_name(elf, ".xsplice.funcs");
ASSERT(sec);
@@ -425,6 +475,13 @@ static int prepare_payload(struct payload *payload,
}
}
+ /* Setup the virtual region with proper data. */
+ region = &payload->region;
+
+ region->symbols_lookup = xsplice_symbols_lookup;
+ region->start = (unsigned long)payload->text_addr;
+ region->end = (unsigned long)(payload->text_addr + payload->text_size);
+
return 0;
}
@@ -769,6 +826,7 @@ static int apply_payload(struct payload *data)
arch_xsplice_patching_leave();
list_add_tail(&data->applied_list, &applied_list);
+ register_virtual_region(&data->region);
return 0;
}
@@ -787,6 +845,7 @@ static int revert_payload(struct payload *data)
arch_xsplice_patching_leave();
list_del_init(&data->applied_list);
+ unregister_virtual_region(&data->region);
return 0;
}
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 17/27] xsplice: Add support for bug frames.
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (15 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 16/27] x86, xsplice: Print payload's symbol name and payload name in backtraces Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-19 20:17 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 18/27] xsplice: Add support for exception tables Konrad Rzeszutek Wilk
` (10 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Keir Fraser, Jan Beulich, Konrad Rzeszutek Wilk
From: Ross Lagerwall <ross.lagerwall@citrix.com>
Add support for handling bug frames contained with xsplice modules. If a
trap occurs search either the kernel bug table or an applied payload's
bug table depending on the instruction pointer.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
v2:- s/module/payload/
- add build time check in case amount of bug frames expands.
- add define for the number of bug-frames.
v3:
- add missing BUGFRAME_NR, squash s/core_size/core/ in earlier patch.
- Moved code around.
- Changed per Andrew's recommendation.
- Fixed style changes.
- Made it compile under ARM (PRIu32,PRIu64)
v4: Use 'struct virtual_region'
- Rip more of the is_active_text code.
- Use one function for the ->skip
- Include test-case
v5: Rip out the ->skip function.
v7: Add a text check as well.
Add Andrew's Reviewed-by.
v8: Changed dprintk XENLOG_DEBUG to XENLOG_ERR
---
---
xen/arch/x86/traps.c | 5 +++--
xen/common/xsplice.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++
xen/include/xen/xsplice.h | 5 +++++
3 files changed, 58 insertions(+), 2 deletions(-)
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index f73f7f3..8384158 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -50,6 +50,7 @@
#include <xen/paging.h>
#include <xen/virtual_region.h>
#include <xen/watchdog.h>
+#include <xen/xsplice.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/atomic.h>
@@ -1287,7 +1288,7 @@ void do_invalid_op(struct cpu_user_regs *regs)
/* WARN, BUG or ASSERT: decode the filename pointer and line number. */
filename = bug_ptr(bug);
- if ( !is_kernel(filename) )
+ if ( !is_kernel(filename) && !is_patch(filename) )
goto die;
fixup = strlen(filename);
if ( fixup > 50 )
@@ -1314,7 +1315,7 @@ void do_invalid_op(struct cpu_user_regs *regs)
case BUGFRAME_assert:
/* ASSERT: decode the predicate string pointer. */
predicate = bug_msg(bug);
- if ( !is_kernel(predicate) )
+ if ( !is_kernel(predicate) && !is_patch(predicate) )
predicate = "<unknown>";
printk("Assertion '%s' failed at %s%s:%d\n",
diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c
index 12e5a13..97a0555 100644
--- a/xen/common/xsplice.c
+++ b/xen/common/xsplice.c
@@ -122,6 +122,32 @@ static int verify_payload(const xen_sysctl_xsplice_upload_t *upload, char *n)
return 0;
}
+bool_t is_patch(const void *ptr)
+{
+ struct payload *data;
+
+ /*
+ * No locking since this list is only ever changed during apply or revert
+ * context.
+ */
+ list_for_each_entry ( data, &applied_list, applied_list )
+ {
+ if ( ptr >= data->rw_addr &&
+ ptr < (data->rw_addr + data->rw_size) )
+ return 1;
+
+ if ( ptr >= data->ro_addr &&
+ ptr < (data->ro_addr + data->ro_size) )
+ return 1;
+
+ if ( ptr >= data->text_addr &&
+ ptr < (data->text_addr + data->text_size) )
+ return 1;
+ }
+
+ return 0;
+}
+
unsigned long xsplice_symbols_lookup_by_name(const char *symname)
{
struct payload *data;
@@ -482,6 +508,30 @@ static int prepare_payload(struct payload *payload,
region->start = (unsigned long)payload->text_addr;
region->end = (unsigned long)(payload->text_addr + payload->text_size);
+ /* Optional sections. */
+ for ( i = 0; i < BUGFRAME_NR; i++ )
+ {
+ char str[14];
+
+ snprintf(str, sizeof(str), ".bug_frames.%u", i);
+ sec = xsplice_elf_sec_by_name(elf, str);
+ if ( !sec )
+ continue;
+
+ if ( sec->sec->sh_size &&
+ (sec->sec->sh_size % sizeof(*region->frame[i].bugs)) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong size of .bug_frames.%u!\n",
+ elf->name, i);
+ return -EINVAL;
+ }
+
+ region->frame[i].bugs = sec->load_addr;
+ if ( sec->sec->sh_size)
+ region->frame[i].n_bugs = sec->sec->sh_size /
+ sizeof(*region->frame[i].bugs);
+ }
+
return 0;
}
diff --git a/xen/include/xen/xsplice.h b/xen/include/xen/xsplice.h
index 0599476..10e8a30 100644
--- a/xen/include/xen/xsplice.h
+++ b/xen/include/xen/xsplice.h
@@ -55,6 +55,7 @@ struct xsplice_symbol {
int xsplice_op(struct xen_sysctl_xsplice_op *);
void check_for_xsplice_work(void);
+bool_t is_patch(const void *addr);
unsigned long xsplice_symbols_lookup_by_name(const char *symname);
/* Arch hooks. */
@@ -107,6 +108,10 @@ static inline int xsplice_op(struct xen_sysctl_xsplice_op *op)
}
static inline void check_for_xsplice_work(void) { };
+static inline bool_t is_patch(const void *addr)
+{
+ return 0;
+}
#endif /* CONFIG_XSPLICE */
#endif /* __XEN_XSPLICE_H__ */
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 18/27] xsplice: Add support for exception tables.
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (16 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 17/27] xsplice: Add support for bug frames Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
2016-04-19 20:31 ` Jan Beulich
2016-04-13 22:02 ` [PATCH v8.1 19/27] xsplice: Add support for alternatives Konrad Rzeszutek Wilk
` (9 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Keir Fraser, Jan Beulich, Konrad Rzeszutek Wilk
From: Ross Lagerwall <ross.lagerwall@citrix.com>
Add support for exception tables contained within xSplice payloads. If an
exception occurs search either the main exception table or a particular
active payload's exception table depending on the instruction pointer.
Also we add an test-case to make sure we have an exception that
is handled.
To not grow the code-base if xSplice is not compiled in we add
certain #define to help in determining if code needs to be __init
or not.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
v3:
- s/module/payload/
- sanity checks.
- Move code around.
- s/module/payload/
v4: Use 'struct virtual_region'
v5:
- Expand test-case.
- Deal with struct exception_table_entry being const.
v6:
- Make the code have __init if not compiled with xSplice
- Remove not needed declarations.
v7:
- Make the non_canonical_addr be 0xdead000000000000ULL
- Remove casts
- Add Reviewed-by from Andrew
- Change ifdef to be !ARM
v8:
- Change dprintk XENLOG_DEBUG to XENLOG_ERR on dprintk.
---
---
xen/arch/x86/extable.c | 31 ++++++++++++++++++-------------
xen/arch/x86/test/xen_hello_world_func.c | 11 +++++++++++
xen/common/xsplice.c | 25 +++++++++++++++++++++++++
xen/include/asm-x86/uaccess.h | 2 ++
xen/include/xen/xsplice.h | 17 +++++++++++++++++
5 files changed, 73 insertions(+), 13 deletions(-)
diff --git a/xen/arch/x86/extable.c b/xen/arch/x86/extable.c
index 2a06cca..e0ba35f 100644
--- a/xen/arch/x86/extable.c
+++ b/xen/arch/x86/extable.c
@@ -7,6 +7,7 @@
#include <xen/spinlock.h>
#include <asm/uaccess.h>
#include <xen/virtual_region.h>
+#include <xen/xsplice.h>
#define EX_FIELD(ptr, field) ((unsigned long)&(ptr)->field + (ptr)->field)
@@ -20,7 +21,7 @@ static inline unsigned long ex_cont(const struct exception_table_entry *x)
return EX_FIELD(x, cont);
}
-static int __init cmp_ex(const void *a, const void *b)
+static int __INIT cmp_ex(const void *a, const void *b)
{
const struct exception_table_entry *l = a, *r = b;
unsigned long lip = ex_addr(l);
@@ -35,7 +36,7 @@ static int __init cmp_ex(const void *a, const void *b)
}
#ifndef swap_ex
-static void __init swap_ex(void *a, void *b, int size)
+static void __INIT swap_ex(void *a, void *b, int size)
{
struct exception_table_entry *l = a, *r = b, tmp;
long delta = b - a;
@@ -48,19 +49,23 @@ static void __init swap_ex(void *a, void *b, int size)
}
#endif
-void __init sort_exception_tables(void)
+void __INIT sort_exception_table(struct exception_table_entry *start,
+ struct exception_table_entry *stop)
{
- sort(__start___ex_table, __stop___ex_table - __start___ex_table,
- sizeof(struct exception_table_entry), cmp_ex, swap_ex);
- sort(__start___pre_ex_table,
- __stop___pre_ex_table - __start___pre_ex_table,
+ sort(start, stop - start,
sizeof(struct exception_table_entry), cmp_ex, swap_ex);
}
-static inline unsigned long
-search_one_table(const struct exception_table_entry *first,
- const struct exception_table_entry *last,
- unsigned long value)
+void __init sort_exception_tables(void)
+{
+ sort_exception_table(__start___ex_table, __stop___ex_table);
+ sort_exception_table(__start___pre_ex_table, __stop___pre_ex_table);
+}
+
+unsigned long
+search_one_extable(const struct exception_table_entry *first,
+ const struct exception_table_entry *last,
+ unsigned long value)
{
const struct exception_table_entry *mid;
long diff;
@@ -85,7 +90,7 @@ search_exception_table(unsigned long addr)
const struct virtual_region *region = find_text_region(addr);
if ( region && region->ex )
- return search_one_table(region->ex, region->ex_end - 1, addr);
+ return search_one_extable(region->ex, region->ex_end - 1, addr);
return 0;
}
@@ -94,7 +99,7 @@ unsigned long
search_pre_exception_table(struct cpu_user_regs *regs)
{
unsigned long addr = (unsigned long)regs->eip;
- unsigned long fixup = search_one_table(
+ unsigned long fixup = search_one_extable(
__start___pre_ex_table, __stop___pre_ex_table-1, addr);
if ( fixup )
{
diff --git a/xen/arch/x86/test/xen_hello_world_func.c b/xen/arch/x86/test/xen_hello_world_func.c
index 1ad002a..432954f 100644
--- a/xen/arch/x86/test/xen_hello_world_func.c
+++ b/xen/arch/x86/test/xen_hello_world_func.c
@@ -5,9 +5,20 @@
#include <xen/types.h>
+static unsigned long *non_canonical_addr = (unsigned long *)(0xdead000000000000ULL);
+
/* Our replacement function for xen_extra_version. */
const char *xen_hello_world(void)
{
+ unsigned long tmp;
+ int rc;
+ /*
+ * Any BUG, or WARN_ON will contain symbol and payload name. Furthermore
+ * exceptions will be caught and processed properly.
+ */
+ rc = __get_user(tmp, non_canonical_addr);
+ BUG_ON(rc != -EFAULT);
+
return "Hello World";
}
diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c
index 97a0555..089321f 100644
--- a/xen/common/xsplice.c
+++ b/xen/common/xsplice.c
@@ -532,6 +532,31 @@ static int prepare_payload(struct payload *payload,
sizeof(*region->frame[i].bugs);
}
+#ifndef CONFIG_ARM
+ sec = xsplice_elf_sec_by_name(elf, ".ex_table");
+ if ( sec )
+ {
+ struct exception_table_entry *s, *e;
+
+ if ( !sec->sec->sh_size ||
+ (sec->sec->sh_size % sizeof(*region->ex)) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong size of .ex_table (exp:%lu vs %lu)!\n",
+ elf->name, sizeof(*region->ex),
+ sec->sec->sh_size);
+ return -EINVAL;
+ }
+
+ s = sec->load_addr;
+ e = sec->load_addr + sec->sec->sh_size;
+
+ sort_exception_table(s ,e);
+
+ region->ex = s;
+ region->ex_end = e;
+ }
+#endif
+
return 0;
}
diff --git a/xen/include/asm-x86/uaccess.h b/xen/include/asm-x86/uaccess.h
index 947470d..2c839a9 100644
--- a/xen/include/asm-x86/uaccess.h
+++ b/xen/include/asm-x86/uaccess.h
@@ -277,5 +277,7 @@ extern struct exception_table_entry __stop___pre_ex_table[];
extern unsigned long search_exception_table(unsigned long);
extern void sort_exception_tables(void);
+extern void sort_exception_table(struct exception_table_entry *start,
+ struct exception_table_entry *stop);
#endif /* __X86_UACCESS_H__ */
diff --git a/xen/include/xen/xsplice.h b/xen/include/xen/xsplice.h
index 10e8a30..3af5642 100644
--- a/xen/include/xen/xsplice.h
+++ b/xen/include/xen/xsplice.h
@@ -43,6 +43,15 @@ struct xsplice_patch_func_internal {
} u;
};
+/*
+ * We use alternative and exception table code - which by default are __init
+ * only, however we need them during runtime. These macros allows us to build
+ * the image with these functions built-in. (See the #else below).
+ */
+#define __INITCONST
+#define __INITDATA
+#define __INIT
+
/* Convenience define for printk. */
#define XSPLICE "xsplice: "
@@ -101,6 +110,14 @@ void arch_xsplice_mask(void);
void arch_xsplice_unmask(void);
#else
+/*
+ * If not compiling with xSplice certain functionality should stay as
+ * __init.
+ */
+#define __INITCONST __initconst
+#define __INITDATA __initdata
+#define __INIT __init
+
#include <xen/errno.h> /* For -ENOSYS */
static inline int xsplice_op(struct xen_sysctl_xsplice_op *op)
{
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 19/27] xsplice: Add support for alternatives
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (17 preceding siblings ...)
2016-04-13 22:01 ` [PATCH v8.1 18/27] xsplice: Add support for exception tables Konrad Rzeszutek Wilk
@ 2016-04-13 22:02 ` Konrad Rzeszutek Wilk
2016-04-20 6:28 ` Jan Beulich
2016-04-13 22:02 ` [PATCH v8.1 20/27] build_id: Provide ld-embedded build-ids Konrad Rzeszutek Wilk
` (8 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:02 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Keir Fraser, Jan Beulich, Konrad Rzeszutek Wilk
From: Ross Lagerwall <ross.lagerwall@citrix.com>
Add support for applying alternative sections within xsplice payload.
At payload load time, apply an alternative sections that are found.
Also we add an test-case exercising a rather useless alternative
(patching a NOP with a NOP) - but it does exercise the code-path.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
v2: Make a new alternative function that does not ASSERT on IRQs and
don't disable IRQs in the code when loading payload.
v4: Include test-case
Include check for size of alternatives and that it is not a 0 size
section.
v6: Add #define INIT to preserve __initness on alternative code.
Double check that alt_instr are only patching payload code.
v7: Move cr0 manipulation in apply_alternatives.
ifdef around alternative.o in Makefile
Pick X86_FEATURE_LM in test-case
Drop casting from load_addr
It is alternative.init.o, not alternative_init.o (thanks Andrew!)
v8: Change XENLOG_DEBUG to XENLOG_ERR on dprintk.
---
---
xen/arch/x86/Makefile | 4 +++
xen/arch/x86/alternative.c | 42 ++++++++++++++++++++------------
xen/arch/x86/test/xen_hello_world_func.c | 5 ++++
xen/common/xsplice.c | 34 ++++++++++++++++++++++++++
xen/include/asm-x86/alternative.h | 4 +++
5 files changed, 74 insertions(+), 15 deletions(-)
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 4ce2346..da5a135 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -6,7 +6,11 @@ subdir-y += mm
subdir-$(CONFIG_XENOPROF) += oprofile
subdir-y += x86_64
+ifdef CONFIG_XSPLICE
+obj-y += alternative.o
+else
obj-bin-y += alternative.init.o
+endif
obj-y += apic.o
obj-y += bitops.o
obj-bin-y += bzimage.init.o
diff --git a/xen/arch/x86/alternative.c b/xen/arch/x86/alternative.c
index f735ff8..366ad86 100644
--- a/xen/arch/x86/alternative.c
+++ b/xen/arch/x86/alternative.c
@@ -22,13 +22,14 @@
#include <asm/system.h>
#include <asm/traps.h>
#include <asm/nmi.h>
+#include <xen/xsplice.h>
#define MAX_PATCH_LEN (255-1)
extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
#ifdef K8_NOP1
-static const unsigned char k8nops[] __initconst = {
+static const unsigned char k8nops[] __INITCONST = {
K8_NOP1,
K8_NOP2,
K8_NOP3,
@@ -52,7 +53,7 @@ static const unsigned char * const k8_nops[ASM_NOP_MAX+1] __initconstrel = {
#endif
#ifdef P6_NOP1
-static const unsigned char p6nops[] __initconst = {
+static const unsigned char p6nops[] __INITCONST = {
P6_NOP1,
P6_NOP2,
P6_NOP3,
@@ -75,7 +76,7 @@ static const unsigned char * const p6_nops[ASM_NOP_MAX+1] __initconstrel = {
};
#endif
-static const unsigned char * const *ideal_nops __initdata = k8_nops;
+static const unsigned char * const *ideal_nops __INITDATA = k8_nops;
static int __init mask_nmi_callback(const struct cpu_user_regs *regs, int cpu)
{
@@ -100,7 +101,7 @@ static void __init arch_init_ideal_nops(void)
}
/* Use this to add nops to a buffer, then text_poke the whole buffer. */
-static void __init add_nops(void *insns, unsigned int len)
+static void __INIT add_nops(void *insns, unsigned int len)
{
while ( len > 0 )
{
@@ -114,7 +115,7 @@ static void __init add_nops(void *insns, unsigned int len)
}
/*
- * text_poke_early - Update instructions on a live kernel at boot time
+ * text_poke - Update instructions on a live kernel or non-executed code.
* @addr: address to modify
* @opcode: source of the copy
* @len: length to copy
@@ -125,9 +126,10 @@ static void __init add_nops(void *insns, unsigned int len)
* instructions. And on the local CPU you need to be protected again NMI or MCE
* handlers seeing an inconsistent instruction while you patch.
*
- * This routine is called with local interrupt disabled.
+ * You should run this with interrupts disabled or on code that has never
+ * been executed.
*/
-static void *__init text_poke_early(void *addr, const void *opcode, size_t len)
+static void *__INIT text_poke(void *addr, const void *opcode, size_t len)
{
memcpy(addr, opcode, len);
sync_core();
@@ -142,20 +144,14 @@ static void *__init text_poke_early(void *addr, const void *opcode, size_t len)
* APs have less capabilities than the boot processor are not handled.
* Tough. Make sure you disable such features by hand.
*/
-static void __init apply_alternatives(struct alt_instr *start, struct alt_instr *end)
+void __INIT apply_alternatives_nocheck(struct alt_instr *start, struct alt_instr *end)
{
struct alt_instr *a;
u8 *instr, *replacement;
u8 insnbuf[MAX_PATCH_LEN];
- unsigned long cr0 = read_cr0();
-
- ASSERT(!local_irq_is_enabled());
printk(KERN_INFO "alt table %p -> %p\n", start, end);
- /* Disable WP to allow application of alternatives to read-only pages. */
- write_cr0(cr0 & ~X86_CR0_WP);
-
/*
* The scan order should be from start to end. A later scanned
* alternative code can overwrite a previous scanned alternative code.
@@ -183,8 +179,24 @@ static void __init apply_alternatives(struct alt_instr *start, struct alt_instr
add_nops(insnbuf + a->replacementlen,
a->instrlen - a->replacementlen);
- text_poke_early(instr, insnbuf, a->instrlen);
+ text_poke(instr, insnbuf, a->instrlen);
}
+}
+
+/*
+ * This routine is called with local interrupt disabled and used during
+ * bootup.
+ */
+void __init apply_alternatives(struct alt_instr *start, struct alt_instr *end)
+{
+ unsigned long cr0 = read_cr0();
+
+ ASSERT(!local_irq_is_enabled());
+
+ /* Disable WP to allow application of alternatives to read-only pages. */
+ write_cr0(cr0 & ~X86_CR0_WP);
+
+ apply_alternatives_nocheck(start, end);
/* Reinstate WP. */
write_cr0(cr0);
diff --git a/xen/arch/x86/test/xen_hello_world_func.c b/xen/arch/x86/test/xen_hello_world_func.c
index 432954f..b57822a 100644
--- a/xen/arch/x86/test/xen_hello_world_func.c
+++ b/xen/arch/x86/test/xen_hello_world_func.c
@@ -3,6 +3,9 @@
*
*/
+#include <asm/alternative.h>
+#include <asm/nops.h>
+#include <asm/uaccess.h>
#include <xen/types.h>
static unsigned long *non_canonical_addr = (unsigned long *)(0xdead000000000000ULL);
@@ -12,6 +15,8 @@ const char *xen_hello_world(void)
{
unsigned long tmp;
int rc;
+
+ alternative(ASM_NOP1, ASM_NOP1, X86_FEATURE_LM);
/*
* Any BUG, or WARN_ON will contain symbol and payload name. Furthermore
* exceptions will be caught and processed properly.
diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c
index 089321f..a6323e2 100644
--- a/xen/common/xsplice.c
+++ b/xen/common/xsplice.c
@@ -533,6 +533,39 @@ static int prepare_payload(struct payload *payload,
}
#ifndef CONFIG_ARM
+ sec = xsplice_elf_sec_by_name(elf, ".altinstructions");
+ if ( sec )
+ {
+ struct alt_instr *a, *start, *end;
+
+ if ( !sec->sec->sh_size ||
+ (sec->sec->sh_size % sizeof(*a)) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong size of .alt_instr (exp:%lu vs %lu)!\n",
+ elf->name, sizeof(*a),
+ sec->sec->sh_size);
+ return -EINVAL;
+ }
+
+ start = sec->load_addr;
+ end = sec->load_addr + sec->sec->sh_size;
+
+ for ( a = start; a < end; a++ )
+ {
+ unsigned long instr = (unsigned long)(&a->instr_offset + a->instr_offset);
+ unsigned long replacement = (unsigned long)(&a->repl_offset + a->repl_offset);
+
+ if ( (instr < region->start && instr >= region->end) ||
+ (replacement < region->start && replacement >= region->end) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s Alt patching outside payload: 0x%lx!\n",
+ elf->name, instr);
+ return -EINVAL;
+ }
+ }
+ apply_alternatives_nocheck(start, end);
+ }
+
sec = xsplice_elf_sec_by_name(elf, ".ex_table");
if ( sec )
{
@@ -555,6 +588,7 @@ static int prepare_payload(struct payload *payload,
region->ex = s;
region->ex_end = e;
}
+
#endif
return 0;
diff --git a/xen/include/asm-x86/alternative.h b/xen/include/asm-x86/alternative.h
index 1056630..bce959f 100644
--- a/xen/include/asm-x86/alternative.h
+++ b/xen/include/asm-x86/alternative.h
@@ -23,6 +23,10 @@ struct alt_instr {
u8 replacementlen; /* length of new instruction, <= instrlen */
};
+/* Similar to apply_alternatives except it can be run with IRQs enabled. */
+extern void apply_alternatives_nocheck(struct alt_instr *start,
+ struct alt_instr *end);
+extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
extern void alternative_instructions(void);
#define OLDINSTR(oldinstr) "661:\n\t" oldinstr "\n662:\n"
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 20/27] build_id: Provide ld-embedded build-ids
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (18 preceding siblings ...)
2016-04-13 22:02 ` [PATCH v8.1 19/27] xsplice: Add support for alternatives Konrad Rzeszutek Wilk
@ 2016-04-13 22:02 ` Konrad Rzeszutek Wilk
2016-04-20 7:14 ` Jan Beulich
2016-04-13 22:02 ` [PATCH v8.1 21/27] xsplice: Print build_id in keyhandler and on bootup Konrad Rzeszutek Wilk
` (7 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:02 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Stefano Stabellini, Keir Fraser, Konrad Rzeszutek Wilk,
Martin Pohlack, Julien Grall, Jan Beulich
This patch enables the Elf to be built with the build-id
and provide in the Xen hypervisor the code to extract it.
The man-page for ld --build-id says it is:
"Request the creation of a ".note.gnu.build-id" ELF note
section or a ".build-id" COFF section. The contents of the
note are unique bits identifying this linked file. style can be
"uuid" to use 128 random bits, "sha1" to use a 160-bit SHA1 hash
on the normative parts of the output contents, ..."
One can also retrieve the value of the build-id by doing
'readelf -n xen-syms'.
For EFI builds we re-use the same build-id that the xen-syms
was built with.
The version of ld that first implemented --build-id is v2.18.
We check for to see if the linker supports the --build-id
parameter and if so use it.
For x86 we have two binaries - the xen-syms and the xen - an
smaller version with lots of sections removed. To make it possible
for readelf -n xen we also modify mkelf32 and xen.lds.S to include
the PT_NOTE ELF section.
The EFI binary is more complicated. We only build one type of
binary and expanding the amount of sections the EFI binary has to
include an .note one is pointless - as there is no concept of
PT_NOTE. The best we can do is move this .note in the .rodata section.
Further development wise should move it to .buildid section
so that DataDirectory debug data nor CodeView can view it.
(The author has no clue what those are).
Note that in earlier patches the linker script had:
__note_gnu_build_id_start = .;
*(.rodata.note.gnu.build-id)
__note_gnu_build_id_end = .;
*(.note)
*(.note.*)
Which meant you could have different ELF notes _outside_ the
__note_gnu_build_id_end. However for EFI builds we take the whole
.note* section and jam it in the EFI to be between
__note_gnu_build_id_start and __note_gnu_build_id_end.
To not make this happend we make on the ELF build the section
be called .note.gnu.build-id (instead of just .note).
If there is a need for a different type of note other folks
can add it as a different section name.
Note that we do call --binary-id=sha1 on all linker invocations.
We have to do to enforce that the symbol offsets don't changes
(the side effect is that we we would have multiple binary ids -
except that the last one is the final one).
Without this working the symbol table embedded in Xen ends
up incorrect - some of the values it contains would be offset by the
size of the included build id.
This obviously causes problems when resolving symbols.
We also define the NT_GNU_BUILD_ID in the elfstructs.h as we
need to use it in various places.
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Martin Pohlack <mpohlack@amazon.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Julien Grall <julien.grall@arm.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
v1: Rebase it on Martin's initial patch
v2: Move it to XENVER hypercall
v3: Fix EFI building (Ross's fix)
Don't use the third argument for length.
Use new structure for XENVER_build_id with variable buf.
Include Ross's fix.
Include detection of bin-utils for build-id support, add
probing for size, and return -EPERM for XSM denied calls.
Build xen_build_id under ARM, required adding ELFSIZE in proper file.
Rebase on top XSM version class.
v4:
Include the build-id .note in the xen ELF binary.
s/build_id/build_id_linker/
For EFI build, moved the --build-id values in .data section
Rebase on staging.
Split patch in two. Always do --build-id call. Include the .note in
.rodata. USe const void * and ssize_t
Use -S to make build_id.o and objcopy differently (Andrew suggested)
v5: Put back the #ifdef LOCK_PROFILE on ARM. (Bad change). Move the _erodata
around. s/ssize_t/unsigned int/
v6: Redid it per Jan's review.
v7: Move build-id note in .rodata.note for EFI builds only.
Move build-id note in .rodata for EFI builds only. Retain
it in .note. Change name of object file used by EFI builds to notes.o
Make on ELF builds the PT_NOTE section name be .note.gnu.build-id and
ingest that in ELF build.
Define NT_GNU_BUILD_ID in elfstructs.h
v8: s/num_phdrs/notes_phdrs/
Added Andrew's Reviewed-by
---
---
Config.mk | 11 ++++
xen/arch/arm/Makefile | 2 +-
xen/arch/arm/xen.lds.S | 15 ++++-
xen/arch/x86/Makefile | 30 ++++++++--
xen/arch/x86/boot/mkelf32.c | 129 ++++++++++++++++++++++++++++++++++++++-----
xen/arch/x86/xen.lds.S | 28 ++++++++++
xen/common/version.c | 50 +++++++++++++++++
xen/include/xen/elfstructs.h | 3 +
xen/include/xen/version.h | 1 +
9 files changed, 247 insertions(+), 22 deletions(-)
diff --git a/Config.mk b/Config.mk
index 79eb2bd..db70638 100644
--- a/Config.mk
+++ b/Config.mk
@@ -126,6 +126,17 @@ endef
check-$(gcc) = $(call cc-ver-check,CC,0x040100,"Xen requires at least gcc-4.1")
$(eval $(check-y))
+ld-ver-build-id = $(shell $(1) --build-id 2>&1 | \
+ grep -q unrecognized && echo n || echo y)
+
+export XEN_HAS_BUILD_ID ?= n
+ifeq ($(call ld-ver-build-id,$(LD)),n)
+build_id_linker :=
+else
+CFLAGS += -DBUILD_ID
+build_id_linker := --build-id=sha1
+endif
+
# as-insn: Check whether assembler supports an instruction.
# Usage: cflags-y += $(call as-insn "insn",option-yes,option-no)
as-insn = $(if $(shell echo 'void _(void) { asm volatile ( $(2) ); }' \
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 0afa414..fcae290 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -92,7 +92,7 @@ $(TARGET)-syms: prelink.o xen.lds $(BASEDIR)/common/symbols-dummy.o
$(NM) -pa --format=sysv $(@D)/.$(@F).1 \
| $(BASEDIR)/tools/symbols --sysv --sort >$(@D)/.$(@F).1.S
$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1.o
- $(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
+ $(LD) $(LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
$(@D)/.$(@F).1.o -o $@
rm -f $(@D)/.$(@F).[0-9]*
diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
index 9909595..1f010bd 100644
--- a/xen/arch/arm/xen.lds.S
+++ b/xen/arch/arm/xen.lds.S
@@ -22,6 +22,9 @@ OUTPUT_ARCH(FORMAT)
PHDRS
{
text PT_LOAD /* XXX should be AT ( XEN_PHYS_START ) */ ;
+#if defined(BUILD_ID)
+ note PT_NOTE ;
+#endif
}
SECTIONS
{
@@ -57,10 +60,18 @@ SECTIONS
*(.lockprofile.data)
__lock_profile_end = .;
#endif
-
- _erodata = .; /* End of read-only data */
} :text
+#if defined(BUILD_ID)
+ . = ALIGN(4);
+ .note.gnu.build-id : {
+ __note_gnu_build_id_start = .;
+ *(.note.gnu.build-id)
+ __note_gnu_build_id_end = .;
+ } :note :text
+#endif
+ _erodata = .; /* End of read-only data */
+
.data : { /* Data */
. = ALIGN(PAGE_SIZE);
*(.data.page_aligned)
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index da5a135..485f681 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -76,6 +76,12 @@ efi-y := $(shell if [ ! -r $(BASEDIR)/include/xen/compile.h -o \
-O $(BASEDIR)/include/xen/compile.h ]; then \
echo '$(TARGET).efi'; fi)
+ifneq ($(build_id_linker),)
+notes_phdrs = --notes
+else
+notes_phdrs =
+endif
+
ifdef CONFIG_XSPLICE
all_symbols = --all-symbols
ifdef CONFIG_FAST_SYMBOL_LOOKUP
@@ -87,7 +93,8 @@ endif
$(TARGET): $(TARGET)-syms $(efi-y) boot/mkelf32
./boot/mkelf32 $(TARGET)-syms $(TARGET) 0x100000 \
- `$(NM) -nr $(TARGET)-syms | head -n 1 | sed -e 's/^\([^ ]*\).*/0x\1/'`
+ `$(NM) -nr $(TARGET)-syms | head -n 1 | sed -e 's/^\([^ ]*\).*/0x\1/'` \
+ $(notes_phdrs)
.PHONY: tests
tests:
@@ -121,22 +128,28 @@ $(BASEDIR)/common/symbols-dummy.o:
$(MAKE) -f $(BASEDIR)/Rules.mk -C $(BASEDIR)/common symbols-dummy.o
$(TARGET)-syms: prelink.o xen.lds $(BASEDIR)/common/symbols-dummy.o
- $(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
+ $(LD) $(LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
$(BASEDIR)/common/symbols-dummy.o -o $(@D)/.$(@F).0
$(NM) -pa --format=sysv $(@D)/.$(@F).0 \
| $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort \
>$(@D)/.$(@F).0.S
$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).0.o
- $(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
+ $(LD) $(LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
$(@D)/.$(@F).0.o -o $(@D)/.$(@F).1
$(NM) -pa --format=sysv $(@D)/.$(@F).1 \
| $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort --warn-dup \
>$(@D)/.$(@F).1.S
$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1.o
- $(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
+ $(LD) $(LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
$(@D)/.$(@F).1.o -o $@
rm -f $(@D)/.$(@F).[0-9]*
+note.o: $(TARGET)-syms
+ $(OBJCOPY) -O binary --only-section=.note.gnu.build-id $(BASEDIR)/xen-syms $@.bin
+ $(OBJCOPY) -I binary -O elf64-x86-64 -B i386:x86-64 \
+ --rename-section=.data=.note.gnu.build-id -S $@.bin $@
+ rm -f $@.bin
+
EFI_LDFLAGS = $(patsubst -m%,-mi386pep,$(LDFLAGS)) --subsystem=10
EFI_LDFLAGS += --image-base=$(1) --stack=0,0 --heap=0,0 --strip-debug
EFI_LDFLAGS += --section-alignment=0x200000 --file-alignment=0x20
@@ -149,6 +162,13 @@ $(TARGET).efi: VIRT_BASE = 0x$(shell $(NM) efi/relocs-dummy.o | sed -n 's, A VIR
$(TARGET).efi: ALT_BASE = 0x$(shell $(NM) efi/relocs-dummy.o | sed -n 's, A ALT_START$$,,p')
# Don't use $(wildcard ...) here - at least make 3.80 expands this too early!
$(TARGET).efi: guard = $(if $(shell echo efi/dis* | grep disabled),:)
+ifneq ($(build_id_linker),)
+$(TARGET).efi: note.o
+note_file := note.o
+else
+note_file :=
+endif
+
$(TARGET).efi: prelink-efi.o efi.lds efi/relocs-dummy.o $(BASEDIR)/common/symbols-dummy.o efi/mkreloc
$(foreach base, $(VIRT_BASE) $(ALT_BASE), \
$(guard) $(LD) $(call EFI_LDFLAGS,$(base)) -T efi.lds -N $< efi/relocs-dummy.o \
@@ -165,7 +185,7 @@ $(TARGET).efi: prelink-efi.o efi.lds efi/relocs-dummy.o $(BASEDIR)/common/symbol
| $(guard) $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort >$(@D)/.$(@F).1s.S
$(guard) $(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1r.o $(@D)/.$(@F).1s.o
$(guard) $(LD) $(call EFI_LDFLAGS,$(VIRT_BASE)) -T efi.lds -N $< \
- $(@D)/.$(@F).1r.o $(@D)/.$(@F).1s.o -o $@
+ $(@D)/.$(@F).1r.o $(@D)/.$(@F).1s.o $(note_file) -o $@
if $(guard) false; then rm -f $@; echo 'EFI support disabled'; fi
rm -f $(@D)/.$(@F).[0-9]*
diff --git a/xen/arch/x86/boot/mkelf32.c b/xen/arch/x86/boot/mkelf32.c
index 993a7ee..fce1716 100644
--- a/xen/arch/x86/boot/mkelf32.c
+++ b/xen/arch/x86/boot/mkelf32.c
@@ -45,9 +45,9 @@ static Elf32_Ehdr out_ehdr = {
0, /* e_flags */
sizeof(Elf32_Ehdr), /* e_ehsize */
sizeof(Elf32_Phdr), /* e_phentsize */
- 1, /* e_phnum */
+ 1, /* modify based on num_phdrs */ /* e_phnum */
sizeof(Elf32_Shdr), /* e_shentsize */
- 3, /* e_shnum */
+ 3, /* modify based on num_phdrs */ /* e_shnum */
2 /* e_shstrndx */
};
@@ -61,8 +61,20 @@ static Elf32_Phdr out_phdr = {
PF_R|PF_W|PF_X, /* p_flags */
64 /* p_align */
};
+static Elf32_Phdr note_phdr = {
+ PT_NOTE, /* p_type */
+ DYNAMICALLY_FILLED, /* p_offset */
+ DYNAMICALLY_FILLED, /* p_vaddr */
+ DYNAMICALLY_FILLED, /* p_paddr */
+ DYNAMICALLY_FILLED, /* p_filesz */
+ DYNAMICALLY_FILLED, /* p_memsz */
+ PF_R, /* p_flags */
+ 4 /* p_align */
+};
static u8 out_shstrtab[] = "\0.text\0.shstrtab";
+/* If num_phdrs >= 2, we need to tack the .note. */
+static u8 out_shstrtab_extra[] = ".note\0";
static Elf32_Shdr out_shdr[] = {
{ 0 },
@@ -90,6 +102,23 @@ static Elf32_Shdr out_shdr[] = {
}
};
+/*
+ * The 17 points to the '.note' in the out_shstrtab and out_shstrtab_extra
+ * laid out in the file.
+ */
+static Elf32_Shdr out_shdr_note = {
+ 17, /* sh_name */
+ SHT_NOTE, /* sh_type */
+ 0, /* sh_flags */
+ DYNAMICALLY_FILLED, /* sh_addr */
+ DYNAMICALLY_FILLED, /* sh_offset */
+ DYNAMICALLY_FILLED, /* sh_size */
+ 0, /* sh_link */
+ 0, /* sh_info */
+ 4, /* sh_addralign */
+ 0 /* sh_entsize */
+};
+
/* Some system header files define these macros and pollute our namespace. */
#undef swap16
#undef swap32
@@ -228,21 +257,22 @@ static void do_read(int fd, void *data, int len)
int main(int argc, char **argv)
{
u64 final_exec_addr;
- u32 loadbase, dat_siz, mem_siz;
+ u32 loadbase, dat_siz, mem_siz, note_base, note_sz, offset;
char *inimage, *outimage;
int infd, outfd;
char buffer[1024];
int bytes, todo, i;
+ int num_phdrs = 1;
Elf32_Ehdr in32_ehdr;
Elf64_Ehdr in64_ehdr;
Elf64_Phdr in64_phdr;
- if ( argc != 5 )
+ if ( argc < 5 )
{
fprintf(stderr, "Usage: mkelf32 <in-image> <out-image> "
- "<load-base> <final-exec-addr>\n");
+ "<load-base> <final-exec-addr> <number of program headers> [--notes]\n");
return 1;
}
@@ -250,6 +280,8 @@ int main(int argc, char **argv)
outimage = argv[2];
loadbase = strtoul(argv[3], NULL, 16);
final_exec_addr = strtoull(argv[4], NULL, 16);
+ if ( argv[5] && (!strcmp(argv[5], "--notes")) )
+ num_phdrs = 2;
infd = open(inimage, O_RDONLY);
if ( infd == -1 )
@@ -285,11 +317,10 @@ int main(int argc, char **argv)
(int)in64_ehdr.e_phentsize, (int)sizeof(in64_phdr));
return 1;
}
-
- if ( in64_ehdr.e_phnum != 1 )
+ if ( in64_ehdr.e_phnum != num_phdrs )
{
- fprintf(stderr, "Expect precisly 1 program header; found %d.\n",
- (int)in64_ehdr.e_phnum);
+ fprintf(stderr, "Expect precisly %d program header; found %d.\n",
+ num_phdrs, (int)in64_ehdr.e_phnum);
return 1;
}
@@ -304,6 +335,32 @@ int main(int argc, char **argv)
/*mem_siz = (u32)in64_phdr.p_memsz;*/
mem_siz = (u32)(final_exec_addr - in64_phdr.p_vaddr);
+ note_sz = note_base = offset = 0;
+ if ( num_phdrs > 1 )
+ {
+ offset = in64_phdr.p_offset;
+ note_base = in64_phdr.p_vaddr;
+
+ (void)lseek(infd, in64_ehdr.e_phoff+sizeof(in64_phdr), SEEK_SET);
+ do_read(infd, &in64_phdr, sizeof(in64_phdr));
+ endianadjust_phdr64(&in64_phdr);
+
+ (void)lseek(infd, offset, SEEK_SET);
+
+ note_sz = in64_phdr.p_memsz;
+ note_base = in64_phdr.p_vaddr - note_base;
+
+ if ( in64_phdr.p_offset > dat_siz || offset > in64_phdr.p_offset )
+ {
+ fprintf(stderr, "Expected .note section within .text section!\n" \
+ "Offset %ld not within %d!\n",
+ in64_phdr.p_offset, dat_siz);
+ return 1;
+ }
+ /* Gets us the absolute offset within the .text section. */
+ offset = in64_phdr.p_offset - offset;
+ }
+
/*
* End the image on a page boundary. This gets round alignment bugs
* in the boot- or chain-loader (e.g., kexec on the XenoBoot CD).
@@ -322,6 +379,31 @@ int main(int argc, char **argv)
out_shdr[1].sh_size = dat_siz;
out_shdr[2].sh_offset = RAW_OFFSET + dat_siz + sizeof(out_shdr);
+ if ( num_phdrs > 1 )
+ {
+ /* We have two of them! */
+ out_ehdr.e_phnum = num_phdrs;
+ /* Extra .note section. */
+ out_ehdr.e_shnum++;
+
+ /* Fill out the PT_NOTE program header. */
+ note_phdr.p_vaddr = note_base;
+ note_phdr.p_paddr = note_base;
+ note_phdr.p_filesz = note_sz;
+ note_phdr.p_memsz = note_sz;
+ note_phdr.p_offset = offset;
+
+ /* Tack on the .note\0 */
+ out_shdr[2].sh_size += sizeof(out_shstrtab_extra);
+ /* And move it past the .note section. */
+ out_shdr[2].sh_offset += sizeof(out_shdr_note);
+
+ /* Fill out the .note section. */
+ out_shdr_note.sh_size = note_sz;
+ out_shdr_note.sh_addr = note_base;
+ out_shdr_note.sh_offset = RAW_OFFSET + offset;
+ }
+
outfd = open(outimage, O_WRONLY|O_CREAT|O_TRUNC, 0775);
if ( outfd == -1 )
{
@@ -335,8 +417,14 @@ int main(int argc, char **argv)
endianadjust_phdr32(&out_phdr);
do_write(outfd, &out_phdr, sizeof(out_phdr));
-
- if ( (bytes = RAW_OFFSET - sizeof(out_ehdr) - sizeof(out_phdr)) < 0 )
+
+ if ( num_phdrs > 1 )
+ {
+ endianadjust_phdr32(¬e_phdr);
+ do_write(outfd, ¬e_phdr, sizeof(note_phdr));
+ }
+
+ if ( (bytes = RAW_OFFSET - sizeof(out_ehdr) - (num_phdrs * sizeof(out_phdr)) ) < 0 )
{
fprintf(stderr, "Header overflow.\n");
return 1;
@@ -355,9 +443,22 @@ int main(int argc, char **argv)
endianadjust_shdr32(&out_shdr[i]);
do_write(outfd, &out_shdr[0], sizeof(out_shdr));
- do_write(outfd, out_shstrtab, sizeof(out_shstrtab));
- do_write(outfd, buffer, 4-((sizeof(out_shstrtab)+dat_siz)&3));
-
+ if ( num_phdrs > 1 )
+ {
+ endianadjust_shdr32(&out_shdr_note);
+ /* Append the .note section. */
+ do_write(outfd, &out_shdr_note, sizeof(out_shdr_note));
+ /* The normal strings - .text\0.. */
+ do_write(outfd, out_shstrtab, sizeof(out_shstrtab));
+ /* Our .note */
+ do_write(outfd, out_shstrtab_extra, sizeof(out_shstrtab_extra));
+ do_write(outfd, buffer, 4-((sizeof(out_shstrtab)+sizeof(out_shstrtab_extra)+dat_siz)&3));
+ }
+ else
+ {
+ do_write(outfd, out_shstrtab, sizeof(out_shstrtab));
+ do_write(outfd, buffer, 4-((sizeof(out_shstrtab)+dat_siz)&3));
+ }
close(infd);
close(outfd);
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 5eb825e..b3d880f 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -31,6 +31,9 @@ OUTPUT_ARCH(i386:x86-64)
PHDRS
{
text PT_LOAD ;
+#if defined(BUILD_ID) && !defined(EFI)
+ note PT_NOTE ;
+#endif
}
SECTIONS
{
@@ -79,6 +82,16 @@ SECTIONS
*(.rodata)
*(.rodata.*)
+#if defined(BUILD_ID) && defined(EFI)
+/*
+ * No mechanism to put an PT_NOTE in the EFI file - so put
+ * it in .rodata section. (notes.o supplies us with .note.gnu.build-id).
+ */
+ . = ALIGN(4);
+ __note_gnu_build_id_start = .;
+ *(.note.gnu.build-id)
+ __note_gnu_build_id_end = .;
+#endif
. = ALIGN(8);
/* Exception table */
__start___ex_table = .;
@@ -99,6 +112,21 @@ SECTIONS
_erodata = .;
} :text
+#if defined(BUILD_ID) && !defined(EFI)
+/*
+ * What a strange section name. The reason is that on ELF builds this section
+ * is extracted to notes.o (which then is ingested in the EFI file). But the
+ * compiler may want to inject other things in the .note which we don't care
+ * about - hence this unique name.
+ */
+ . = ALIGN(4);
+ .note.gnu.build-id : {
+ __note_gnu_build_id_start = .;
+ *(.note.gnu.build-id)
+ __note_gnu_build_id_end = .;
+ } :note :text
+#endif
+
#ifdef EFI
. = ALIGN(MB(2));
#else
diff --git a/xen/common/version.c b/xen/common/version.c
index fc9bf42..01d9409 100644
--- a/xen/common/version.c
+++ b/xen/common/version.c
@@ -1,4 +1,9 @@
#include <xen/compile.h>
+#include <xen/init.h>
+#include <xen/errno.h>
+#include <xen/string.h>
+#include <xen/types.h>
+#include <xen/elf.h>
#include <xen/version.h>
const char *xen_compile_date(void)
@@ -61,6 +66,51 @@ const char *xen_deny(void)
return "<denied>";
}
+static const void *build_id_p;
+static unsigned int build_id_len;
+
+int xen_build_id(const void **p, unsigned int *len)
+{
+ if ( !build_id_len )
+ return -ENODATA;
+
+ *len = build_id_len;
+ *p = build_id_p;
+
+ return 0;
+}
+
+#ifdef BUILD_ID
+/* Defined in linker script. */
+extern const Elf_Note __note_gnu_build_id_start[], __note_gnu_build_id_end[];
+
+static int __init xen_build_init(void)
+{
+ const Elf_Note *n = __note_gnu_build_id_start;
+
+ /* --build-id invoked with wrong parameters. */
+ if ( __note_gnu_build_id_end <= &n[0] )
+ return -ENODATA;
+
+ /* Check for full Note header. */
+ if ( &n[1] > __note_gnu_build_id_end )
+ return -ENODATA;;
+
+ /* Check if we really have a build-id. */
+ if ( NT_GNU_BUILD_ID != n->type )
+ return -ENODATA;
+
+ /* Sanity check, name should be "GNU" for ld-generated build-id. */
+ if ( strncmp(ELFNOTE_NAME(n), "GNU", n->namesz) != 0 )
+ return -ENODATA;
+
+ build_id_len = n->descsz;
+ build_id_p = ELFNOTE_DESC(n);
+
+ return 0;
+}
+__initcall(xen_build_init);
+#endif
/*
* Local variables:
* mode: C
diff --git a/xen/include/xen/elfstructs.h b/xen/include/xen/elfstructs.h
index be55985..5babac7 100644
--- a/xen/include/xen/elfstructs.h
+++ b/xen/include/xen/elfstructs.h
@@ -40,6 +40,9 @@ typedef uint32_t Elf64_Word;
typedef int64_t Elf64_Sxword;
typedef uint64_t Elf64_Xword;
+/* Unique build id string format when using --build-id. */
+#define NT_GNU_BUILD_ID 3
+
/*
* e_ident[] identification indexes
* See http://www.caldera.com/developers/gabi/2000-07-17/ch4.eheader.html
diff --git a/xen/include/xen/version.h b/xen/include/xen/version.h
index 2015c0b..400160f 100644
--- a/xen/include/xen/version.h
+++ b/xen/include/xen/version.h
@@ -13,5 +13,6 @@ const char *xen_extra_version(void);
const char *xen_changeset(void);
const char *xen_banner(void);
const char *xen_deny(void);
+int xen_build_id(const void **p, unsigned int *len);
#endif /* __XEN_VERSION_H__ */
--
2.5.0
_______________________________________________
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Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 21/27] xsplice: Print build_id in keyhandler and on bootup.
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (19 preceding siblings ...)
2016-04-13 22:02 ` [PATCH v8.1 20/27] build_id: Provide ld-embedded build-ids Konrad Rzeszutek Wilk
@ 2016-04-13 22:02 ` Konrad Rzeszutek Wilk
2016-04-13 22:02 ` [PATCH v8.1 22/27] XENVER_build_id/libxc: Provide ld-embedded build-id Konrad Rzeszutek Wilk
` (6 subsequent siblings)
27 siblings, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:02 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Keir Fraser, Tim Deegan, Ian Jackson, Jan Beulich, Konrad Rzeszutek Wilk
As it should be an useful debug mechanism.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
--
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Tim Deegan <tim@xen.org>
v2: s/char */const void *
v5: s/ssize_t/unsigned int/
v6: Remove pointless initializers, use string literal instead of %s,
add Jan's Ack.
v7: Add Andrew's Reviewed-by
---
---
xen/common/xsplice.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c
index a6323e2..7d3d96d 100644
--- a/xen/common/xsplice.c
+++ b/xen/common/xsplice.c
@@ -16,6 +16,7 @@
#include <xen/spinlock.h>
#include <xen/string.h>
#include <xen/symbols.h>
+#include <xen/version.h>
#include <xen/virtual_region.h>
#include <xen/vmap.h>
#include <xen/wait.h>
@@ -1333,10 +1334,15 @@ static const char *state2str(uint32_t state)
static void xsplice_printall(unsigned char key)
{
struct payload *data;
+ const void *binary_id = NULL;
+ unsigned int len = 0;
unsigned int i;
printk("'%u' pressed - Dumping all xsplice patches\n", key);
+ if ( !xen_build_id(&binary_id, &len) )
+ printk("build-id: %*phN\n", len, binary_id);
+
if ( !spin_trylock(&payload_lock) )
{
printk("Lock held. Try again.\n");
@@ -1369,6 +1375,9 @@ static void xsplice_printall(unsigned char key)
static int __init xsplice_init(void)
{
+ const void *binary_id;
+ unsigned int len;
+
BUILD_BUG_ON( sizeof(struct xsplice_patch_func) !=
sizeof(struct xsplice_patch_func_internal) );
BUILD_BUG_ON( sizeof(struct xsplice_patch_func_internal) !=
@@ -1381,6 +1390,9 @@ static int __init xsplice_init(void)
BUILD_BUG_ON( offsetof(struct xsplice_patch_func, new_addr) != 4 );
BUILD_BUG_ON( offsetof(struct xsplice_patch_func, new_size) != 12 );
#endif
+ if ( !xen_build_id(&binary_id, &len) )
+ printk(XENLOG_INFO XSPLICE ": build-id: %*phN\n", len, binary_id);
+
register_keyhandler('x', xsplice_printall, "print xsplicing info", 1);
arch_xsplice_init();
--
2.5.0
_______________________________________________
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Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 22/27] XENVER_build_id/libxc: Provide ld-embedded build-id
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (20 preceding siblings ...)
2016-04-13 22:02 ` [PATCH v8.1 21/27] xsplice: Print build_id in keyhandler and on bootup Konrad Rzeszutek Wilk
@ 2016-04-13 22:02 ` Konrad Rzeszutek Wilk
2016-04-14 15:03 ` Wei Liu
` (2 more replies)
2016-04-13 22:02 ` [PATCH v8.1 23/27] libxl: info: Display build_id of the hypervisor Konrad Rzeszutek Wilk
` (5 subsequent siblings)
27 siblings, 3 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:02 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Wei Liu, Daniel De Graaf, Ian Jackson, Konrad Rzeszutek Wilk
If the hypervisor was built with build-ids we can expose the
build-id value to the toolstack (if it is not built with
it will just return -ENODATA). This is a priviligied operation
so only the controlling stack is able to request this.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
CC: Daniel De Graaf <dgdegra@tycho.nsa.gov>
CC: Ian Jackson <ian.jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
v1: Rebase it on Martin's initial patch
v2: Move it to XENVER hypercall
v3: Don't use the third argument for length.
- Use new structure for XENVER_build_id with variable buf.
v8: Resurrected from v3!
---
---
tools/flask/policy/policy/modules/xen/xen.te | 1 +
tools/libxc/xc_private.c | 7 ++++++
tools/libxc/xc_private.h | 11 +++++++++
xen/common/kernel.c | 36 ++++++++++++++++++++++++++++
xen/include/public/version.h | 18 +++++++++++++-
xen/xsm/flask/hooks.c | 3 +++
xen/xsm/flask/policy/access_vectors | 2 ++
7 files changed, 77 insertions(+), 1 deletion(-)
diff --git a/tools/flask/policy/policy/modules/xen/xen.te b/tools/flask/policy/policy/modules/xen/xen.te
index daa1315..bef33b0 100644
--- a/tools/flask/policy/policy/modules/xen/xen.te
+++ b/tools/flask/policy/policy/modules/xen/xen.te
@@ -82,6 +82,7 @@ allow dom0_t xen_t:xen2 {
allow dom0_t xen_t:version {
xen_extraversion xen_compile_info xen_capabilities
xen_changeset xen_pagesize xen_guest_handle xen_commandline
+ xen_build_id
};
allow dom0_t xen_t:mmu memorymap;
diff --git a/tools/libxc/xc_private.c b/tools/libxc/xc_private.c
index c41e433..d57c39a 100644
--- a/tools/libxc/xc_private.c
+++ b/tools/libxc/xc_private.c
@@ -495,6 +495,13 @@ int xc_version(xc_interface *xch, int cmd, void *arg)
case XENVER_commandline:
sz = sizeof(xen_commandline_t);
break;
+ case XENVER_build_id:
+ {
+ xen_build_id_t *build_id = (xen_build_id_t *)arg;
+ sz = sizeof(*build_id) + build_id->len;
+ HYPERCALL_BOUNCE_SET_DIR(arg, XC_HYPERCALL_BUFFER_BOUNCE_BOTH);
+ break;
+ }
default:
ERROR("xc_version: unknown command %d\n", cmd);
return -EINVAL;
diff --git a/tools/libxc/xc_private.h b/tools/libxc/xc_private.h
index aa8daf1..75b761c 100644
--- a/tools/libxc/xc_private.h
+++ b/tools/libxc/xc_private.h
@@ -197,6 +197,17 @@ enum {
#define HYPERCALL_BOUNCE_SET_SIZE(_buf, _sz) do { (HYPERCALL_BUFFER(_buf))->sz = _sz; } while (0)
/*
+ * Change the direction.
+ *
+ * Can only be used if the bounce_pre/bounce_post commands have
+ * not been used.
+ */
+#define HYPERCALL_BOUNCE_SET_DIR(_buf, _dir) do { if ((HYPERCALL_BUFFER(_buf))->hbuf) \
+ assert(1); \
+ (HYPERCALL_BUFFER(_buf))->dir = _dir; \
+ } while (0)
+
+/*
* Initialise and free hypercall safe memory. Takes care of any required
* copying.
*/
diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index a4a3c36..f912257 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -376,6 +376,42 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
return -EFAULT;
return 0;
}
+
+ case XENVER_build_id:
+ {
+ xen_build_id_t build_id;
+ unsigned int sz = 0;
+ int rc = 0;
+ const void *p = NULL;
+
+ if ( deny )
+ return -EPERM;
+
+ /* Only return size. */
+ if ( !guest_handle_is_null(arg) )
+ {
+ if ( copy_from_guest(&build_id, arg, 1) )
+ return -EFAULT;
+
+ if ( build_id.len == 0 )
+ return -EINVAL;
+ }
+
+ rc = xen_build_id(&p, &sz);
+ if ( rc )
+ return rc;
+
+ if ( guest_handle_is_null(arg) )
+ return sz;
+
+ if ( sz > build_id.len )
+ return -ENOBUFS;
+
+ if ( copy_to_guest_offset(arg, offsetof(xen_build_id_t, buf), p, sz) )
+ return -EFAULT;
+
+ return sz;
+ }
}
return -ENOSYS;
diff --git a/xen/include/public/version.h b/xen/include/public/version.h
index 24a582f..cb84565 100644
--- a/xen/include/public/version.h
+++ b/xen/include/public/version.h
@@ -30,7 +30,8 @@
#include "xen.h"
-/* NB. All ops return zero on success, except XENVER_{version,pagesize} */
+/* NB. All ops return zero on success, except XENVER_{version,pagesize}
+ * XENVER_{version,pagesize,build_id} */
/* arg == NULL; returns major:minor (16:16). */
#define XENVER_version 0
@@ -87,6 +88,21 @@ typedef struct xen_feature_info xen_feature_info_t;
#define XENVER_commandline 9
typedef char xen_commandline_t[1024];
+/*
+ * Return value is the number of bytes written, or XEN_Exx on error.
+ * Calling with empty parameter returns the size of build_id.
+ */
+#define XENVER_build_id 10
+struct xen_build_id {
+ uint32_t len; /* IN: size of buf[]. */
+#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
+ unsigned char buf[];
+#elif defined(__GNUC__)
+ unsigned char buf[1]; /* OUT: Variable length buffer with build_id. */
+#endif
+};
+typedef struct xen_build_id xen_build_id_t;
+
#endif /* __XEN_PUBLIC_VERSION_H__ */
/*
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index c2df48f..7477dbe 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -1663,6 +1663,9 @@ static int flask_xen_version (uint32_t op)
case XENVER_commandline:
return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
VERSION__XEN_COMMANDLINE, NULL);
+ case XENVER_build_id:
+ return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
+ VERSION__XEN_BUILD_ID, NULL);
default:
return -EPERM;
}
diff --git a/xen/xsm/flask/policy/access_vectors b/xen/xsm/flask/policy/access_vectors
index e9ab149..4d1b548 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -525,4 +525,6 @@ class version
xen_guest_handle
# Xen command line.
xen_commandline
+# Xen build id
+ xen_build_id
}
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 23/27] libxl: info: Display build_id of the hypervisor.
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (21 preceding siblings ...)
2016-04-13 22:02 ` [PATCH v8.1 22/27] XENVER_build_id/libxc: Provide ld-embedded build-id Konrad Rzeszutek Wilk
@ 2016-04-13 22:02 ` Konrad Rzeszutek Wilk
2016-04-14 15:06 ` Wei Liu
2016-04-13 22:02 ` [PATCH v8.1 24/27] xsplice: Stacking build-id dependency checking Konrad Rzeszutek Wilk
` (4 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:02 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Wei Liu, Ian Jackson, Konrad Rzeszutek Wilk
If the hypervisor is built with we will display it.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
CC: Ian Jackson <ian.jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
v2: Include HAVE_*, use libxl_zalloc, s/rc/ret/
v3: Retry with different size if 1020 is not enough.
v4: Use VERSION_OP subops instead of the XENVER_ subops
v5: Change it per Wei's review. s/VERSION_OP/VERSION/
And actually use the proper Style!
v8: VERSION_OP was reverted, resurrect v3 version.
---
tools/libxl/libxl.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
tools/libxl/libxl.h | 6 ++++++
tools/libxl/libxl_types.idl | 1 +
tools/libxl/xl_cmdimpl.c | 1 +
4 files changed, 53 insertions(+)
diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index eec899d..4ba45a4 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -5353,6 +5353,38 @@ libxl_numainfo *libxl_get_numainfo(libxl_ctx *ctx, int *nr)
return ret;
}
+static const int libxl__xc_version_wrap(libxl__gc *gc, libxl_version_info *info,
+ xen_build_id_t *build)
+{
+ int r;
+
+ r = xc_version(CTX->xch, XENVER_build_id, build);
+ switch (r) {
+ case -EPERM:
+ case -ENODATA:
+ case 0:
+ info->build_id = libxl__strdup(NOGC, "");
+ break;
+
+ case -ENOBUFS:
+ break;
+
+ default:
+ if (r > 0) {
+ unsigned int i;
+
+ info->build_id = libxl__zalloc(NOGC, (r * 2) + 1);
+
+ for (i = 0; i < r ; i++)
+ snprintf(&info->build_id[i * 2], 3, "%02hhx", build->buf[i]);
+
+ r = 0;
+ }
+ break;
+ }
+ return r;
+}
+
const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx)
{
GC_INIT(ctx);
@@ -5363,8 +5395,10 @@ const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx)
xen_capabilities_info_t xen_caps;
xen_platform_parameters_t p_parms;
xen_commandline_t xen_commandline;
+ xen_build_id_t build_id;
} u;
long xen_version;
+ int r;
libxl_version_info *info = &ctx->version_info;
if (info->xen_version_extra != NULL)
@@ -5397,6 +5431,17 @@ const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx)
xc_version(ctx->xch, XENVER_commandline, &u.xen_commandline);
info->commandline = libxl__strdup(NOGC, u.xen_commandline);
+ u.build_id.len = sizeof(u) - sizeof(u.build_id);
+ r = libxl__xc_version_wrap(gc, info, &u.build_id);
+ if (r == -ENOBUFS) {
+ xen_build_id_t *build_id;
+
+ build_id = libxl__zalloc(gc, info->pagesize);
+ build_id->len = info->pagesize - sizeof(*build_id);
+ r = libxl__xc_version_wrap(gc, info, build_id);
+ if (r)
+ LOGEV(ERROR, r, "getting build_id");
+ }
out:
GC_FREE;
return info;
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 3fc5c48..a68f698 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -247,6 +247,12 @@
#define LIBXL_HAVE_APIC_ASSIST 1
/*
+ * LIBXL_HAVE_BUILD_ID means that libxl_version_info has the extra
+ * field for the hypervisor build_id.
+ */
+#define LIBXL_HAVE_BUILD_ID 1
+
+/*
* libxl ABI compatibility
*
* The only guarantee which libxl makes regarding ABI compatibility
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index c3161f3..9840f3b 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -365,6 +365,7 @@ libxl_version_info = Struct("version_info", [
("virt_start", uint64),
("pagesize", integer),
("commandline", string),
+ ("build_id", string),
], dir=DIR_OUT)
libxl_domain_create_info = Struct("domain_create_info",[
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 6346017..ac7d759 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -5920,6 +5920,7 @@ static void output_xeninfo(void)
printf("cc_compile_by : %s\n", info->compile_by);
printf("cc_compile_domain : %s\n", info->compile_domain);
printf("cc_compile_date : %s\n", info->compile_date);
+ printf("build_id : %s\n", info->build_id);
return;
}
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 24/27] xsplice: Stacking build-id dependency checking.
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (22 preceding siblings ...)
2016-04-13 22:02 ` [PATCH v8.1 23/27] libxl: info: Display build_id of the hypervisor Konrad Rzeszutek Wilk
@ 2016-04-13 22:02 ` Konrad Rzeszutek Wilk
2016-04-20 7:49 ` Jan Beulich
2016-04-13 22:02 ` [PATCH v8.1 25/27] xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE Konrad Rzeszutek Wilk
` (3 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:02 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Keir Fraser, Jan Beulich, Konrad Rzeszutek Wilk
We now expect that the ELF payloads be built with the
--build-id.
Also the .xsplice.deps section has to have the contents
of the hypervisor (or a preceding payload) build-id.
We already have the code to verify the Elf_Note build-id
so export parts of it.
This dependency means the hypervisor MUST be compiled with
--build-id - so we gate the build of xSplice on the availability
of said functionality.
This does not impact the ordering of how the payloads can
be loaded, but it does enforce an STRICT ordering when the
payloads are applied. Also the REPLACE is special - we need
to check that its dependency against the hypervisor - not
the last applied patch.
To make this easier to test we also add an extra test-case
to be used - which can only be applied on top of the
xen_hello_world payload.
As in, one can apply xen_hello_world and then xen_bye_world
on top of that. Not the other way.
We also print the dependency and payloads build_in the keyhandler.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
v3: First time included.
v4: Andrew fix against the build_id.o mutilations.
Andrew fix to not include extra symbols in binary.id
v5: s/ssize_t/unsigned int/
v6: s/an NT_GNU../a NT_GNU/
- Squash "xsplice: Print dependency and payloads build_id in the keyhandler"
in this patch.
- Add in xen_build_id_check size of section for better checking.
v7: Added Andrew's reviewed-by.
Change the .name in test-case to adhere to spec.
Dropped NT_GNU_BUILD_ID and moved that to earlier patch
(build_id: Provide ld-embedded build-ids)
Amended spec and code to only have one of .xsplice.depends and
.note.gnu.build-id
Expanded comment about note.o and why we don't use arch/x86/note.o.bin
Moved xen_build_id_check definition to xsplice.h from version.h
(and dropping the #include's in version.h)
Sort header files in tests.
v8:
- Change two of the dprinkt from XENLOG_DEBUG to XENLOG_ERR
---
---
.gitignore | 1 +
Config.mk | 1 +
docs/misc/xsplice.markdown | 99 +++++++++++++++++----------
xen/arch/x86/test/Makefile | 45 +++++++++++--
xen/arch/x86/test/xen_bye_world.c | 34 ++++++++++
xen/arch/x86/test/xen_bye_world_func.c | 24 +++++++
xen/common/Kconfig | 6 +-
xen/common/version.c | 42 +++++++++---
xen/common/xsplice.c | 118 ++++++++++++++++++++++++++++++++-
xen/include/xen/xsplice.h | 2 +
10 files changed, 318 insertions(+), 54 deletions(-)
create mode 100644 xen/arch/x86/test/xen_bye_world.c
create mode 100644 xen/arch/x86/test/xen_bye_world_func.c
diff --git a/.gitignore b/.gitignore
index 4a81f43..88cec1d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -248,6 +248,7 @@ xen/arch/x86/efi/disabled
xen/arch/x86/efi/mkreloc
xen/arch/x86/test/config.h
xen/arch/x86/test/xen_hello_world.xsplice
+xen/arch/x86/test/xen_bye_world.xsplice
xen/arch/*/efi/boot.c
xen/arch/*/efi/compat.c
xen/arch/*/efi/efi.h
diff --git a/Config.mk b/Config.mk
index db70638..4b6f3f5 100644
--- a/Config.mk
+++ b/Config.mk
@@ -134,6 +134,7 @@ ifeq ($(call ld-ver-build-id,$(LD)),n)
build_id_linker :=
else
CFLAGS += -DBUILD_ID
+export XEN_HAS_BUILD_ID=y
build_id_linker := --build-id=sha1
endif
diff --git a/docs/misc/xsplice.markdown b/docs/misc/xsplice.markdown
index 4b9403e..fb13a7d 100644
--- a/docs/misc/xsplice.markdown
+++ b/docs/misc/xsplice.markdown
@@ -283,8 +283,17 @@ The xSplice core code loads the payload as a standard ELF binary, relocates it
and handles the architecture-specifc sections as needed. This process is much
like what the Linux kernel module loader does.
-The payload contains a section (xsplice_patch_func) with an array of structures
-describing the functions to be patched:
+The payload contains at least three sections:
+
+ * `.xsplice.funcs` - which is an array of xsplice_patch_func structures.
+ * `.xsplice.depends` - which is an ELF Note that describes what the payload
+ depends on. **MUST** have one.
+ * `.note.gnu.build-id` - the build-id of this payload. **MUST** have one.
+
+### .xsplice.funcs
+
+The `.xsplice.funcs` contains an array of xsplice_patch_func structures
+which describe the functions to be patched:
<pre>
struct xsplice_patch_func {
@@ -373,6 +382,23 @@ struct xsplice_patch_func xsplice_hello_world = {
Code must be compiled with -fPIC.
+### .xsplice.depends and .note.gnu.build-id
+
+To support dependencies checking and safe loading (to load the
+appropiate payload against the right hypervisor) there is a need
+to embbed an build-id dependency.
+
+This is done by the payload containing an section `.xsplice.depends`
+which follows the format of an ELF Note. The contents of this
+(name, and description) are specific to the linker utilized to
+build the hypevisor and payload.
+
+If GNU linker is used then the name is `GNU` and the description
+is a NT_GNU_BUILD_ID type ID. The description can be an SHA1
+checksum, MD5 checksum or any unique value.
+
+The size of these structures varies with the --build-id linker option.
+
## Hypercalls
We will employ the sub operations of the system management hypercall (sysctl).
@@ -868,6 +894,42 @@ This is implemented in the Xen Project hypervisor.
Only the privileged domain should be allowed to do this operation.
+### xSplice interdependencies
+
+xSplice patches interdependencies are tricky.
+
+There are the ways this can be addressed:
+ * A single large patch that subsumes and replaces all previous ones.
+ Over the life-time of patching the hypervisor this large patch
+ grows to accumulate all the code changes.
+ * Hotpatch stack - where an mechanism exists that loads the hotpatches
+ in the same order they were built in. We would need an build-id
+ of the hypevisor to make sure the hot-patches are build against the
+ correct build.
+ * Payload containing the old code to check against that. That allows
+ the hotpatches to be loaded indepedently (if they don't overlap) - or
+ if the old code also containst previously patched code - even if they
+ overlap.
+
+The disadvantage of the first large patch is that it can grow over
+time and not provide an bisection mechanism to identify faulty patches.
+
+The hot-patch stack puts stricts requirements on the order of the patches
+being loaded and requires an hypervisor build-id to match against.
+
+The old code allows much more flexibility and an additional guard,
+but is more complex to implement.
+
+The second option which requires an build-id of the hypervisor
+is implemented in the Xen Project hypervisor.
+
+Specifically each payload has two build-id ELF notes:
+ * The build-id of the payload itself (generated via --build-id).
+ * The build-id of the payload it depends on (extracted from the
+ the previous payload or hypervisor during build time).
+
+This means that the very first payload depends on the hypervisor
+build-id.
# Not Yet Done
@@ -885,13 +947,6 @@ The implementation must also have a mechanism for (in no particular order):
Specifically we want to make sure that xSplice codepaths cannot be patched.
* NOP out the code sequence if `new_size` is zero.
* Deal with other relocation types: R_X86_64_[8,16,32,32S], R_X86_64_PC[8,16,64] in payload file.
- * An dependency mechanism for the payloads. To use that information to load:
- - The appropiate payload. To verify that payload is built against the
- hypervisor. This can be done via the `build-id`
- or via providing an copy of the old code - so that the hypervisor can
- verify it against the code in memory.
- - To construct an appropiate order of payloads to load in case they
- depend on each other.
### Handle inlined __LINE__
@@ -956,32 +1011,6 @@ the function itself.
Similar considerations are true to a lesser extent for __FILE__, but it
could be argued that file renaming should be done outside of hotpatches.
-### xSplice interdependencies
-
-xSplice patches interdependencies are tricky.
-
-There are the ways this can be addressed:
- * A single large patch that subsumes and replaces all previous ones.
- Over the life-time of patching the hypervisor this large patch
- grows to accumulate all the code changes.
- * Hotpatch stack - where an mechanism exists that loads the hotpatches
- in the same order they were built in. We would need an build-id
- of the hypevisor to make sure the hot-patches are build against the
- correct build.
- * Payload containing the old code to check against that. That allows
- the hotpatches to be loaded indepedently (if they don't overlap) - or
- if the old code also containst previously patched code - even if they
- overlap.
-
-The disadvantage of the first large patch is that it can grow over
-time and not provide an bisection mechanism to identify faulty patches.
-
-The hot-patch stack puts stricts requirements on the order of the patches
-being loaded and requires an hypervisor build-id to match against.
-
-The old code allows much more flexibility and an additional guard,
-but is more complex to implement.
-
## Signature checking requirements.
The signature checking requires that the layout of the data in memory
diff --git a/xen/arch/x86/test/Makefile b/xen/arch/x86/test/Makefile
index baa4820..7d73184 100644
--- a/xen/arch/x86/test/Makefile
+++ b/xen/arch/x86/test/Makefile
@@ -6,17 +6,20 @@ CODE_SZ=$(shell nm --defined -S $(1) | grep $(2) | awk '{ print "0x"$$2}')
.PHONY: default
XSPLICE := xen_hello_world.xsplice
+XSPLICE_BYE := xen_bye_world.xsplice
default: xsplice
install: xsplice
$(INSTALL_DATA) $(XSPLICE) $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE)
+ $(INSTALL_DATA) $(XSPLICE_BYE) $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE_BYE)
uninstall:
rm -f $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE)
+ rm -f $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE_BYE)
.PHONY: clean
clean::
- rm -f *.o .*.o.d $(XSPLICE) config.h
+ rm -f *.o .*.o.d $(XSPLICE) config.h note.o
#
# To compute these values we need the binary files: xen-syms
@@ -28,15 +31,47 @@ clean::
.PHONY: config.h
config.h: OLD_CODE_SZ=$(call CODE_SZ,$(BASEDIR)/xen-syms,xen_extra_version)
config.h: NEW_CODE_SZ=$(call CODE_SZ,$<,xen_hello_world)
-config.h: xen_hello_world_func.o
+config.h: xen_hello_world_func.o xen_bye_world_func.o
(set -e; \
echo "#define NEW_CODE_SZ $(NEW_CODE_SZ)"; \
echo "#define OLD_CODE_SZ $(OLD_CODE_SZ)") > $@
+#
+# This target is only accessible if CONFIG_XSPLICE is defined, which
+# depends on $(build_id_linker) being available. Hence we do not
+# need any checks.
+#
+# N.B. The reason we don't use arch/x86/note.o is that it may
+# not be built (it is for EFI builds), and that we do not have
+# the note.o.bin to muck with (as it gets deleted)
+#
+.PHONY: note.o
+note.o:
+ $(OBJCOPY) -O binary --only-section=.note.gnu.build-id $(BASEDIR)/xen-syms $@.bin
+ $(OBJCOPY) -I binary -O elf64-x86-64 -B i386:x86-64 \
+ --rename-section=.data=.xsplice.depends -S $@.bin $@
+ rm -f $@.bin
+
+#
+# Extract the build-id of the xen_hello_world.xsplice
+# (which xen_bye_world will depend on).
+#
+.PHONY: hello_world_note.o
+hello_world_note.o:
+ $(OBJCOPY) -O binary --only-section=.note.gnu.build-id $(XSPLICE) $@.bin
+ $(OBJCOPY) -I binary -O elf64-x86-64 -B i386:x86-64 \
+ --rename-section=.data=.xsplice.depends -S $@.bin $@
+ rm -f $@.bin
+
.PHONY: xsplice
-xsplice: config.h
+xsplice: config.h note.o
# Need to have these done in sequential order
$(MAKE) -f $(BASEDIR)/Rules.mk xen_hello_world_func.o
$(MAKE) -f $(BASEDIR)/Rules.mk xen_hello_world.o
- $(LD) $(LDFLAGS) -r -o $(XSPLICE) xen_hello_world_func.o \
- xen_hello_world.o
+ $(LD) $(LDFLAGS) $(build_id_linker) -r -o $(XSPLICE) \
+ xen_hello_world_func.o xen_hello_world.o note.o
+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_bye_world_func.o
+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_bye_world.o
+ $(MAKE) -f $(BASEDIR)/Rules.mk hello_world_note.o
+ $(LD) $(LDFLAGS) $(build_id_linker) -r -o $(XSPLICE_BYE) \
+ xen_bye_world_func.o xen_bye_world.o hello_world_note.o
diff --git a/xen/arch/x86/test/xen_bye_world.c b/xen/arch/x86/test/xen_bye_world.c
new file mode 100644
index 0000000..b2f25bd
--- /dev/null
+++ b/xen/arch/x86/test/xen_bye_world.c
@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
+ *
+ */
+
+#include "config.h"
+#include <xen/lib.h>
+#include <xen/types.h>
+#include <xen/xsplice.h>
+
+static char bye_world_patch_this_fnc[] = "xen_extra_version";
+extern const char *xen_bye_world(void);
+
+/* External symbol. */
+extern const char *xen_extra_version(void);
+
+struct xsplice_patch_func __section(".xsplice.funcs") xsplice_xen_bye_world = {
+ .version = XSPLICE_PAYLOAD_VERSION,
+ .name = bye_world_patch_this_fnc,
+ .new_addr = (unsigned long)(xen_bye_world),
+ .old_addr = (unsigned long)(xen_extra_version),
+ .new_size = NEW_CODE_SZ,
+ .old_size = OLD_CODE_SZ,
+};
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/x86/test/xen_bye_world_func.c b/xen/arch/x86/test/xen_bye_world_func.c
new file mode 100644
index 0000000..66c582f
--- /dev/null
+++ b/xen/arch/x86/test/xen_bye_world_func.c
@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
+ *
+ */
+
+#include <xen/types.h>
+#include <asm/nops.h>
+#include <asm/alternative.h>
+
+/* Our replacement function for xen_hello_world. */
+const char *xen_bye_world(void)
+{
+ return "Bye World!";
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index 639dc4b..e9735a6 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -60,6 +60,10 @@ config HAS_GDBSX
config HAS_IOPORTS
bool
+config HAS_BUILD_ID
+ string
+ option env="XEN_HAS_BUILD_ID"
+
# Enable/Disable kexec support
config KEXEC
bool "kexec support"
@@ -192,7 +196,7 @@ endmenu
config XSPLICE
bool "xSplice live patching support"
default n
- depends on X86
+ depends on X86 && HAS_BUILD_ID = "y"
---help---
Allows a running Xen hypervisor to be dynamically patched using
binary patches without rebooting. This is primarily used to binarily
diff --git a/xen/common/version.c b/xen/common/version.c
index 01d9409..9b9ae48 100644
--- a/xen/common/version.c
+++ b/xen/common/version.c
@@ -84,9 +84,38 @@ int xen_build_id(const void **p, unsigned int *len)
/* Defined in linker script. */
extern const Elf_Note __note_gnu_build_id_start[], __note_gnu_build_id_end[];
+int xen_build_id_check(const Elf_Note *n, unsigned int n_sz,
+ const void **p, unsigned int *len)
+{
+ /* Check if we really have a build-id. */
+ if ( NT_GNU_BUILD_ID != n->type )
+ return -ENODATA;
+
+ if ( n->namesz >= n_sz )
+ return -EINVAL;
+
+ if ( n->descsz >= n_sz )
+ return -EINVAL;
+
+ if ( n->namesz + n->descsz >= n_sz )
+ return -EINVAL;
+
+ /* Sanity check, name should be "GNU" for ld-generated build-id. */
+ if ( strncmp(ELFNOTE_NAME(n), "GNU", n->namesz) != 0 )
+ return -ENODATA;
+
+ if ( len )
+ *len = n->descsz;
+ if ( p )
+ *p = ELFNOTE_DESC(n);
+
+ return 0;
+}
+
static int __init xen_build_init(void)
{
const Elf_Note *n = __note_gnu_build_id_start;
+ size_t sz;
/* --build-id invoked with wrong parameters. */
if ( __note_gnu_build_id_end <= &n[0] )
@@ -96,18 +125,9 @@ static int __init xen_build_init(void)
if ( &n[1] > __note_gnu_build_id_end )
return -ENODATA;;
- /* Check if we really have a build-id. */
- if ( NT_GNU_BUILD_ID != n->type )
- return -ENODATA;
-
- /* Sanity check, name should be "GNU" for ld-generated build-id. */
- if ( strncmp(ELFNOTE_NAME(n), "GNU", n->namesz) != 0 )
- return -ENODATA;
-
- build_id_len = n->descsz;
- build_id_p = ELFNOTE_DESC(n);
+ sz = (size_t)__note_gnu_build_id_end - (size_t)&n[0];
- return 0;
+ return xen_build_id_check(n, sz, &build_id_p, &build_id_len);
}
__initcall(xen_build_init);
#endif
diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c
index 7d3d96d..2f4aec8 100644
--- a/xen/common/xsplice.c
+++ b/xen/common/xsplice.c
@@ -4,6 +4,7 @@
*/
#include <xen/cpu.h>
+#include <xen/elf.h>
#include <xen/err.h>
#include <xen/guest_access.h>
#include <xen/keyhandler.h>
@@ -41,6 +42,12 @@ static LIST_HEAD(applied_list);
static unsigned int payload_cnt;
static unsigned int payload_version = 1;
+/* To contain the ELF Note header. */
+struct xsplice_build_id {
+ const void *p;
+ unsigned int len;
+};
+
struct payload {
uint32_t state; /* One of the XSPLICE_STATE_*. */
int32_t rc; /* 0 or -XEN_EXX. */
@@ -60,6 +67,8 @@ struct payload {
struct xsplice_symbol *symtab; /* All symbols. */
char *strtab; /* Pointer to .strtab. */
unsigned int nsyms; /* Nr of entries in .strtab and symbols. */
+ struct xsplice_build_id id; /* ELFNOTE_DESC(.note.gnu.build-id) of the payload. */
+ struct xsplice_build_id dep; /* ELFNOTE_DESC(.xsplice.depends). */
char name[XEN_XSPLICE_NAME_SIZE]; /* Name of it. */
};
@@ -397,8 +406,10 @@ static int secure_payload(struct payload *payload, struct xsplice_elf *elf)
static int check_special_sections(const struct xsplice_elf *elf)
{
unsigned int i;
- static const char *const names[] = { ".xsplice.funcs" };
- unsigned int count[ARRAY_SIZE(names)] = { 0 };
+ static const char *const names[] = { ".xsplice.funcs" ,
+ ".xsplice.depends",
+ ".note.gnu.build-id"};
+ unsigned int count[ARRAY_SIZE(names)] = { 0, 0, 0 };
for ( i = 0; i < ARRAY_SIZE(names); i++ )
{
@@ -441,6 +452,7 @@ static int prepare_payload(struct payload *payload,
unsigned int i;
struct xsplice_patch_func_internal *f;
struct virtual_region *region;
+ Elf_Note *n;
sec = xsplice_elf_sec_by_name(elf, ".xsplice.funcs");
ASSERT(sec);
@@ -502,6 +514,37 @@ static int prepare_payload(struct payload *payload,
}
}
+ sec = xsplice_elf_sec_by_name(elf, ".note.gnu.build-id");
+ if ( sec )
+ {
+ n = sec->load_addr;
+
+ if ( sec->sec->sh_size <= sizeof(*n) )
+ return -EINVAL;
+
+ if ( xen_build_id_check(n, sec->sec->sh_size,
+ &payload->id.p, &payload->id.len) )
+ return -EINVAL;
+
+ if ( !payload->id.len || !payload->id.p )
+ return -EINVAL;
+ }
+
+ sec = xsplice_elf_sec_by_name(elf, ".xsplice.depends");
+ {
+ n = sec->load_addr;
+
+ if ( sec->sec->sh_size <= sizeof(*n) )
+ return -EINVAL;
+
+ if ( xen_build_id_check(n, sec->sec->sh_size,
+ &payload->dep.p, &payload->dep.len) )
+ return -EINVAL;
+
+ if ( !payload->dep.len || !payload->dep.p )
+ return -EINVAL;
+ }
+
/* Setup the virtual region with proper data. */
region = &payload->region;
@@ -1206,6 +1249,54 @@ void check_for_xsplice_work(void)
}
}
+/*
+ * Only allow dependent payload is applied on top of the correct
+ * build-id.
+ *
+ * This enforces an stacking order - the first payload MUST be against the
+ * hypervisor. The second against the first payload, and so on.
+ *
+ * Unless the 'internal' parameter is used - in which case we only
+ * check against the hypervisor.
+ */
+static int build_id_dep(struct payload *payload, bool_t internal)
+{
+ const void *id = NULL;
+ unsigned int len = 0;
+ int rc;
+ const char *name = "hypervisor";
+
+ ASSERT(payload->dep.len && payload->dep.p);
+
+ /* First time user is against hypervisor. */
+ if ( internal )
+ {
+ rc = xen_build_id(&id, &len);
+ if ( rc )
+ return rc;
+ }
+ else
+ {
+ /* We should be against the last applied one. */
+ struct payload *data = list_last_entry(&applied_list, struct payload,
+ applied_list);
+
+ id = data->id.p;
+ len = data->id.len;
+ name = data->name;
+ }
+
+ if ( payload->dep.len != len ||
+ memcmp(id, payload->dep.p, len) )
+ {
+ dprintk(XENLOG_ERR, "%s%s: check against %s build-id failed!\n",
+ XSPLICE, payload->name, name);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static int xsplice_action(xen_sysctl_xsplice_action_t *action)
{
struct payload *data;
@@ -1252,6 +1343,18 @@ static int xsplice_action(xen_sysctl_xsplice_action_t *action)
case XSPLICE_ACTION_REVERT:
if ( data->state == XSPLICE_STATE_APPLIED )
{
+ struct payload *p = list_last_entry(&applied_list, struct payload,
+ applied_list);
+
+ ASSERT(p);
+ /* We should be the last applied one. */
+ if ( p != data )
+ {
+ dprintk(XENLOG_ERR, "%s%s: can't unload. Top is %s!\n",
+ XSPLICE, data->name, p->name);
+ rc = -EBUSY;
+ break;
+ }
data->rc = -EAGAIN;
rc = schedule_work(data, action->cmd, action->timeout);
}
@@ -1260,6 +1363,9 @@ static int xsplice_action(xen_sysctl_xsplice_action_t *action)
case XSPLICE_ACTION_APPLY:
if ( data->state == XSPLICE_STATE_CHECKED )
{
+ rc = build_id_dep(data, list_empty(&applied_list));
+ if ( rc )
+ break;
data->rc = -EAGAIN;
rc = schedule_work(data, action->cmd, action->timeout);
}
@@ -1268,6 +1374,9 @@ static int xsplice_action(xen_sysctl_xsplice_action_t *action)
case XSPLICE_ACTION_REPLACE:
if ( data->state == XSPLICE_STATE_CHECKED )
{
+ rc = build_id_dep(data, 1 /* against hypervisor. */);
+ if ( rc )
+ break;
data->rc = -EAGAIN;
rc = schedule_work(data, action->cmd, action->timeout);
}
@@ -1368,6 +1477,11 @@ static void xsplice_printall(unsigned char key)
spin_lock(&payload_lock);
}
}
+ if ( data->id.len )
+ printk("build-id=%*phN\n", data->id.len, data->id.p);
+
+ if ( data->dep.len )
+ printk("depend-on=%*phN\n", data->dep.len, data->dep.p);
}
spin_unlock(&payload_lock);
diff --git a/xen/include/xen/xsplice.h b/xen/include/xen/xsplice.h
index 3af5642..38f3cea 100644
--- a/xen/include/xen/xsplice.h
+++ b/xen/include/xen/xsplice.h
@@ -66,6 +66,8 @@ int xsplice_op(struct xen_sysctl_xsplice_op *);
void check_for_xsplice_work(void);
bool_t is_patch(const void *addr);
unsigned long xsplice_symbols_lookup_by_name(const char *symname);
+int xen_build_id_check(const Elf_Note *n, unsigned int n_sz,
+ const void **p, unsigned int *len);
/* Arch hooks. */
int arch_xsplice_verify_elf(const struct xsplice_elf *elf);
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 25/27] xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (23 preceding siblings ...)
2016-04-13 22:02 ` [PATCH v8.1 24/27] xsplice: Stacking build-id dependency checking Konrad Rzeszutek Wilk
@ 2016-04-13 22:02 ` Konrad Rzeszutek Wilk
2016-04-20 11:12 ` Jan Beulich
2016-04-13 22:02 ` [PATCH v8.1 26/27] xsplice: Prevent duplicate payloads from being loaded Konrad Rzeszutek Wilk
` (2 subsequent siblings)
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:02 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Keir Fraser, Jan Beulich, Konrad Rzeszutek Wilk
With this third payload one can do:
-bash-4.1# xen-xsplice load xen_hello_world.xsplice
Uploading xen_hello_world.xsplice (10148 bytes)
Performing check: completed
Performing apply:. completed
[xen_hello_world depends on hypervisor build-id]
-bash-4.1# xen-xsplice load xen_bye_world.xsplice
Uploading xen_bye_world.xsplice (7076 bytes)
Performing check: completed
Performing apply:. completed
[xen_bye_world depends on xen_hello_world build-id]
-bash-4.1# xen-xsplice upload xen_replace_world xen_replace_world.xsplice
Uploading xen_replace_world.xsplice (7148 bytes)
-bash-4.1# xen-xsplice list
ID | status
----------------------------------------+------------
xen_hello_world | APPLIED
xen_bye_world | APPLIED
xen_replace_world | CHECKED
-bash-4.1# xen-xsplice replace xen_replace_world
Performing replace:. completed
-bash-4.1# xl info | grep extra
xen_extra : Hello Again World!
-bash-4.1# xen-xsplice list
ID | status
----------------------------------------+------------
xen_hello_world | CHECKED
xen_bye_world | CHECKED
xen_replace_world | APPLIED
and revert both of the previous payloads and apply
the xen_replace_world.
All the magic of this is in the Makefile - we extract
the build-id from the hypervisor (xen-syms) and jam it
in the xen_replace_world as .xsplice.depends.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
v4: New. Make the objcopy use -S to strip the name.
v7: Added Andrew's Reviewed-by
---
---
.gitignore | 1 +
xen/arch/x86/test/Makefile | 8 +++++++
xen/arch/x86/test/xen_replace_world.c | 34 ++++++++++++++++++++++++++++++
xen/arch/x86/test/xen_replace_world_func.c | 24 +++++++++++++++++++++
4 files changed, 67 insertions(+)
create mode 100644 xen/arch/x86/test/xen_replace_world.c
create mode 100644 xen/arch/x86/test/xen_replace_world_func.c
diff --git a/.gitignore b/.gitignore
index 88cec1d..1b73293 100644
--- a/.gitignore
+++ b/.gitignore
@@ -249,6 +249,7 @@ xen/arch/x86/efi/mkreloc
xen/arch/x86/test/config.h
xen/arch/x86/test/xen_hello_world.xsplice
xen/arch/x86/test/xen_bye_world.xsplice
+xen/arch/x86/test/xen_replace_world.xsplice
xen/arch/*/efi/boot.c
xen/arch/*/efi/compat.c
xen/arch/*/efi/efi.h
diff --git a/xen/arch/x86/test/Makefile b/xen/arch/x86/test/Makefile
index 7d73184..5310b94 100644
--- a/xen/arch/x86/test/Makefile
+++ b/xen/arch/x86/test/Makefile
@@ -7,15 +7,18 @@ CODE_SZ=$(shell nm --defined -S $(1) | grep $(2) | awk '{ print "0x"$$2}')
XSPLICE := xen_hello_world.xsplice
XSPLICE_BYE := xen_bye_world.xsplice
+XSPLICE_REPLACE := xen_replace_world.xsplice
default: xsplice
install: xsplice
$(INSTALL_DATA) $(XSPLICE) $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE)
$(INSTALL_DATA) $(XSPLICE_BYE) $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE_BYE)
+ $(INSTALL_DATA) $(XSPLICE_REPLACE) $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE_REPLACE)
uninstall:
rm -f $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE)
rm -f $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE_BYE)
+ rm -f $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE_REPLACE)
.PHONY: clean
clean::
@@ -75,3 +78,8 @@ xsplice: config.h note.o
$(MAKE) -f $(BASEDIR)/Rules.mk hello_world_note.o
$(LD) $(LDFLAGS) $(build_id_linker) -r -o $(XSPLICE_BYE) \
xen_bye_world_func.o xen_bye_world.o hello_world_note.o
+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_replace_world_func.o
+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_replace_world.o
+ $(LD) $(LDFLAGS) $(build_id_linker) -r -o $(XSPLICE_REPLACE) \
+ xen_replace_world_func.o \
+ xen_replace_world.o note.o
diff --git a/xen/arch/x86/test/xen_replace_world.c b/xen/arch/x86/test/xen_replace_world.c
new file mode 100644
index 0000000..70516bc
--- /dev/null
+++ b/xen/arch/x86/test/xen_replace_world.c
@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
+ *
+ */
+
+#include "config.h"
+#include <xen/lib.h>
+#include <xen/types.h>
+#include <xen/xsplice.h>
+
+static char xen_replace_world_name[] = "xen_extra_version";
+extern const char *xen_replace_world(void);
+
+/* External symbol. */
+extern const char *xen_extra_version(void);
+
+struct xsplice_patch_func __section(".xsplice.funcs") xsplice_xen_replace_world = {
+ .version = XSPLICE_PAYLOAD_VERSION,
+ .name = xen_replace_world_name,
+ .new_addr = (unsigned long)(xen_replace_world),
+ .old_addr = (unsigned long)(xen_extra_version),
+ .new_size = NEW_CODE_SZ,
+ .old_size = OLD_CODE_SZ,
+};
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/x86/test/xen_replace_world_func.c b/xen/arch/x86/test/xen_replace_world_func.c
new file mode 100644
index 0000000..e37da85
--- /dev/null
+++ b/xen/arch/x86/test/xen_replace_world_func.c
@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
+ *
+ */
+
+#include <xen/types.h>
+#include <asm/nops.h>
+#include <asm/alternative.h>
+
+/* Our replacement function for xen_hello_world. */
+const char *xen_replace_world(void)
+{
+ return "Hello Again World!";
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
--
2.5.0
_______________________________________________
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Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 26/27] xsplice: Prevent duplicate payloads from being loaded.
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (24 preceding siblings ...)
2016-04-13 22:02 ` [PATCH v8.1 25/27] xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE Konrad Rzeszutek Wilk
@ 2016-04-13 22:02 ` Konrad Rzeszutek Wilk
2016-04-20 11:16 ` Jan Beulich
2016-04-13 22:02 ` [PATCH v8.1 27/27] MAINTAINERS/xsplice: Add myself and Ross as the maintainers Konrad Rzeszutek Wilk
2016-04-14 14:26 ` [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
27 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:02 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Keir Fraser, Tim Deegan, Ian Jackson, Jan Beulich, Konrad Rzeszutek Wilk
From: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Tim Deegan <tim@xen.org>
v6: Drop recursive lock - also now the caller is holding the lock
Move the code up in the code above.
v7: Add Andrew's Reviewed-by
---
---
xen/common/xsplice.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c
index 2f4aec8..dd8b6cc 100644
--- a/xen/common/xsplice.c
+++ b/xen/common/xsplice.c
@@ -517,6 +517,8 @@ static int prepare_payload(struct payload *payload,
sec = xsplice_elf_sec_by_name(elf, ".note.gnu.build-id");
if ( sec )
{
+ struct payload *data;
+
n = sec->load_addr;
if ( sec->sec->sh_size <= sizeof(*n) )
@@ -528,6 +530,20 @@ static int prepare_payload(struct payload *payload,
if ( !payload->id.len || !payload->id.p )
return -EINVAL;
+
+ /* Make sure it is not a duplicate. */
+ list_for_each_entry ( data, &payload_list, list )
+ {
+ /* No way _this_ payload is on the list. */
+ ASSERT(data != payload);
+ if ( data->id.len &&
+ !memcmp(data->id.p, payload->id.p, data->id.len) )
+ {
+ dprintk(XENLOG_DEBUG, XSPLICE "%s: Already loaded as %s!\n",
+ elf->name, data->name);
+ return -EEXIST;
+ }
+ }
}
sec = xsplice_elf_sec_by_name(elf, ".xsplice.depends");
--
2.5.0
_______________________________________________
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Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* [PATCH v8.1 27/27] MAINTAINERS/xsplice: Add myself and Ross as the maintainers.
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (25 preceding siblings ...)
2016-04-13 22:02 ` [PATCH v8.1 26/27] xsplice: Prevent duplicate payloads from being loaded Konrad Rzeszutek Wilk
@ 2016-04-13 22:02 ` Konrad Rzeszutek Wilk
2016-04-14 14:26 ` [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
27 siblings, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:02 UTC (permalink / raw)
To: xen-devel, konrad, ross.lagerwall, mpohlack, andrew.cooper3, sasha.levin
Cc: Keir Fraser, Tim Deegan, Ian Jackson, Jan Beulich, Konrad Rzeszutek Wilk
If you have a patch for xSplice send it our way!
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Tim Deegan <tim@xen.org>
v5: Sort them F: fields (Jan)
v7: Added Andrew's Reviewed-by
---
---
MAINTAINERS | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index a34685d..2182c24 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -436,6 +436,16 @@ F: xen/include/xsm/
F: xen/xsm/
F: docs/misc/xsm-flask.txt
+XSPLICE
+M: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+M: Ross Lagerwall <ross.lagerwall@citrix.com>
+S: Supported
+F: docs/misc/xsplice.markdown
+F: tools/misc/xen-xsplice.c
+F: xen/arch/*/xsplice*
+F: xen/common/xsplice*
+F: xen/include/xen/xsplice*
+
THE REST
M: Ian Jackson <ian.jackson@eu.citrix.com>
M: Jan Beulich <jbeulich@suse.com>
--
2.5.0
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 09/27] x86/mm: Introduce modify_xen_mappings()
2016-04-13 22:01 ` [PATCH v8.1 09/27] x86/mm: Introduce modify_xen_mappings() Konrad Rzeszutek Wilk
@ 2016-04-14 4:07 ` Jan Beulich
2016-04-14 13:34 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-14 4:07 UTC (permalink / raw)
To: konrad
Cc: george.dunlap, andrew.cooper3, mpohlack, ross.lagerwall,
sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
>- /* If we are done with the L2E, check if it is now empty. */
>- if ( (v != e) && (l1_table_offset(v) != 0) )
>+ /*
>+ * If we not destroying mappings, or are not done with the L2E,
>+ * skip the empty&free check.
It would have been really nice if you had added the missing "are" ...
>- /* If we are done with the L3E, check if it is now empty. */
>- if ( (v != e) && (l2_table_offset(v) + l1_table_offset(v) != 0) )
>+ /*
>+ * If we are not destroying mappings, or not done with the L3E,
>+ * skip the empty&free check.
... just like you did here.
Jan
_______________________________________________
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http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 09/27] x86/mm: Introduce modify_xen_mappings()
2016-04-14 4:07 ` Jan Beulich
@ 2016-04-14 13:34 ` Konrad Rzeszutek Wilk
0 siblings, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-14 13:34 UTC (permalink / raw)
To: Jan Beulich
Cc: ross.lagerwall, george.dunlap, andrew.cooper3, mpohlack,
sasha.levin, xen-devel
On Wed, Apr 13, 2016 at 10:07:18PM -0600, Jan Beulich wrote:
> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
> >- /* If we are done with the L2E, check if it is now empty. */
> >- if ( (v != e) && (l1_table_offset(v) != 0) )
> >+ /*
> >+ * If we not destroying mappings, or are not done with the L2E,
> >+ * skip the empty&free check.
>
> It would have been really nice if you had added the missing "are" ...
>
> >- /* If we are done with the L3E, check if it is now empty. */
> >- if ( (v != e) && (l2_table_offset(v) + l1_table_offset(v) != 0) )
> >+ /*
> >+ * If we are not destroying mappings, or not done with the L3E,
> >+ * skip the empty&free check.
>
> ... just like you did here.
<smack his head>
Yes. Fixed!
>
> Jan
>
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1] xSplice v1 design and implementation.
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (26 preceding siblings ...)
2016-04-13 22:02 ` [PATCH v8.1 27/27] MAINTAINERS/xsplice: Add myself and Ross as the maintainers Konrad Rzeszutek Wilk
@ 2016-04-14 14:26 ` Konrad Rzeszutek Wilk
2016-04-14 14:29 ` Julien Grall
2016-04-14 15:12 ` Andrew Cooper
27 siblings, 2 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-14 14:26 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk, Julien Grall, Stefano Stabellini
Cc: xen-devel, andrew.cooper3, mpohlack, sasha.levin, ross.lagerwall
> Julien, Stefano, I dropped Julien's Ack on
>
> [PATCH v8.1 11/27] xsplice: Implement payload loading
>
> as Jan's expressed a desire not to have BITS_PER_LONG exposed
> in the public headers. I've put CONFIG_ARM_32 in there. On IRC
> Stefano was OK (relucantly) with it.
>
> Patchset has been tested on ARM (tweaking the Kconfig to build xSplice and then
> booting and using it under ARM CubieTruck - granted there is no patching
> yet but the hypercalls work), ARM64 (only built it), and x86 (legacy and EFI)
>
.. snip..
>
> *Are there any TODOs left from v5,v6,v7 reviews?*
>
> Just how the sysctl.h definition for 'struct xsplice_patch_func' should be:
>
> #define XSPLICE_PAYLOAD_VERSION 1
> /*
> * .xsplice.funcs structure layout defined in the `Payload format`
> * section in the xSplice design document.
> *
> * The size should be exactly 64 bytes (64) or 52 bytes (32).
> *
> * We guard this with __XEN__ as toolstacks do not need to use it.
> */
> #ifdef __XEN__
> struct xsplice_patch_func {
> const char *name; /* Name of function to be patched. */
> #if CONFIG_ARM_32
> uint32_t new_addr;
> uint32_t old_addr;
> #else
> uint64_t new_addr;
> uint64_t old_addr; /* Can be zero and name will be looked up. */
> #endif
> uint32_t new_size;
> uint32_t old_size;
> uint8_t version; /* MUST be XSPLICE_PAYLOAD_VERSION. */
> uint8_t pad[31]; /* MUST be zero filled. */
> };
> typedef struct xsplice_patch_func xsplice_patch_func_t;
> #endif
>
> Please note the __XEN__ so even if toolstack does include the public/sysctl.h
> it won't find it the structure.
>
> With this I am able to compile early-test-cases-prototype-work xSplice on ARM32.
Jan suggested to just drop the uint32_t and uint64_t business and use
a void pointer. It is nicer so I've put a new version up with this.
The interdiff between this (v8.1) and (v9) is:
Julien, Stefano,
Are you guys OK with this? It does compile under ARM/ARM64 without
trouble. If you are OK I will re-instate Julien's Ack on the
patch that uses and introduces this:
(xsplice: Implement support for applying/reverting/replacing patches.)
diff --git a/docs/misc/xsplice.markdown b/docs/misc/xsplice.markdown
index fb13a7d..d5abab0 100644
--- a/docs/misc/xsplice.markdown
+++ b/docs/misc/xsplice.markdown
@@ -298,13 +298,8 @@ which describe the functions to be patched:
<pre>
struct xsplice_patch_func {
const char *name;
-#if BITS_PER_LONG == 32
- uint32_t new_addr;
- uint32_t old_addr;
-#else
- uint64_t new_addr;
- uint64_t old_addr;
-#endif
+ void *new_addr;
+ void *old_addr;
uint32_t new_size;
uint32_t old_size;
uint8_t version;
@@ -312,8 +307,8 @@ struct xsplice_patch_func {
};
</pre>
-The size of the structure is 64 bytes or 52 bytes if compiled under 32-bit
-hypervisors.
+The size of the structure is 64 bytes on 64-bit hypervisors. It will be
+52 on 32-bit hypervisors.
* `name` is the symbol name of the old function. Only used if `old_addr` is
zero, otherwise will be used during dynamic linking (when hypervisor loads
@@ -353,8 +348,8 @@ A simple example of what a payload file can be:
/* MUST be in sync with hypervisor. */
struct xsplice_patch_func {
const char *name;
- uint64_t new_addr;
- uint64_t old_addr;
+ void *new_addr;
+ void *old_addr;
uint32_t new_size;
uint32_t old_size;
uint8_t version;
@@ -372,8 +367,8 @@ static unsigned char patch_this_fnc[] = "xen_extra_version";
struct xsplice_patch_func xsplice_hello_world = {
.version = XSPLICE_PAYLOAD_VERSION,
.name = patch_this_fnc,
- .new_addr = (unsigned long)(xen_hello_world),
- .old_addr = 0xffff82d08013963c, /* Extracted from xen-syms. */
+ .new_addr = xen_hello_world,
+ .old_addr = (void *)0xffff82d08013963c, /* Extracted from xen-syms. */
.new_size = 13, /* To be be computed by scripts. */
.old_size = 13, /* -----------""--------------- */
} __attribute__((__section__(".xsplice.funcs")));
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 73798c3..3a76f55 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -6102,7 +6102,7 @@ void modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf)
v += PAGE_SIZE;
/*
- * If we not destroying mappings, or are not done with the L2E,
+ * If we are not destroying mappings, or not done with the L2E,
* skip the empty&free check.
*/
if ( (nf & _PAGE_PRESENT) || ((v != e) && (l1_table_offset(v) != 0)) )
diff --git a/xen/arch/x86/test/xen_bye_world.c b/xen/arch/x86/test/xen_bye_world.c
index b2f25bd..be83b5a 100644
--- a/xen/arch/x86/test/xen_bye_world.c
+++ b/xen/arch/x86/test/xen_bye_world.c
@@ -17,8 +17,8 @@ extern const char *xen_extra_version(void);
struct xsplice_patch_func __section(".xsplice.funcs") xsplice_xen_bye_world = {
.version = XSPLICE_PAYLOAD_VERSION,
.name = bye_world_patch_this_fnc,
- .new_addr = (unsigned long)(xen_bye_world),
- .old_addr = (unsigned long)(xen_extra_version),
+ .new_addr = xen_bye_world,
+ .old_addr = (xen_extra_version,
.new_size = NEW_CODE_SZ,
.old_size = OLD_CODE_SZ,
};
diff --git a/xen/arch/x86/test/xen_hello_world.c b/xen/arch/x86/test/xen_hello_world.c
index 22fe2e7..a67b798 100644
--- a/xen/arch/x86/test/xen_hello_world.c
+++ b/xen/arch/x86/test/xen_hello_world.c
@@ -16,8 +16,8 @@ extern const char *xen_extra_version(void);
struct xsplice_patch_func __section(".xsplice.funcs") xsplice_xen_hello_world = {
.version = XSPLICE_PAYLOAD_VERSION,
.name = hello_world_patch_this_fnc,
- .new_addr = (unsigned long)(xen_hello_world),
- .old_addr = (unsigned long)(xen_extra_version),
+ .new_addr = xen_hello_world,
+ .old_addr = xen_extra_version,
.new_size = NEW_CODE_SZ,
.old_size = OLD_CODE_SZ,
};
diff --git a/xen/arch/x86/test/xen_replace_world.c b/xen/arch/x86/test/xen_replace_world.c
index 70516bc..6030139 100644
--- a/xen/arch/x86/test/xen_replace_world.c
+++ b/xen/arch/x86/test/xen_replace_world.c
@@ -17,8 +17,8 @@ extern const char *xen_extra_version(void);
struct xsplice_patch_func __section(".xsplice.funcs") xsplice_xen_replace_world = {
.version = XSPLICE_PAYLOAD_VERSION,
.name = xen_replace_world_name,
- .new_addr = (unsigned long)(xen_replace_world),
- .old_addr = (unsigned long)(xen_extra_version),
+ .new_addr = xen_replace_world,
+ .old_addr = xen_extra_version,
.new_size = NEW_CODE_SZ,
.old_size = OLD_CODE_SZ,
};
diff --git a/xen/include/public/sysctl.h b/xen/include/public/sysctl.h
index 3d47b47..3876b04 100644
--- a/xen/include/public/sysctl.h
+++ b/xen/include/public/sysctl.h
@@ -845,13 +845,8 @@ DEFINE_XEN_GUEST_HANDLE(xen_sysctl_featureset_t);
#ifdef __XEN__
struct xsplice_patch_func {
const char *name; /* Name of function to be patched. */
-#if CONFIG_ARM_32
- uint32_t new_addr;
- uint32_t old_addr;
-#else
- uint64_t new_addr;
- uint64_t old_addr; /* Can be zero and name will be looked up. */
-#endif
+ void *new_addr;
+ void *old_addr;
uint32_t new_size;
uint32_t old_size;
uint8_t version; /* MUST be XSPLICE_PAYLOAD_VERSION. */
_______________________________________________
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http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1] xSplice v1 design and implementation.
2016-04-14 14:26 ` [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
@ 2016-04-14 14:29 ` Julien Grall
2016-04-14 15:12 ` Andrew Cooper
1 sibling, 0 replies; 126+ messages in thread
From: Julien Grall @ 2016-04-14 14:29 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk, Konrad Rzeszutek Wilk, Stefano Stabellini
Cc: xen-devel, andrew.cooper3, mpohlack, sasha.levin, ross.lagerwall
On 14/04/16 15:26, Konrad Rzeszutek Wilk wrote:
> Julien, Stefano,
Hi Konrad,
> Are you guys OK with this? It does compile under ARM/ARM64 without
> trouble. If you are OK I will re-instate Julien's Ack on the
> patch that uses and introduces this:
> (xsplice: Implement support for applying/reverting/replacing patches.)
I'm fine with this solution.
Regards,
--
Julien Grall
_______________________________________________
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 22/27] XENVER_build_id/libxc: Provide ld-embedded build-id
2016-04-13 22:02 ` [PATCH v8.1 22/27] XENVER_build_id/libxc: Provide ld-embedded build-id Konrad Rzeszutek Wilk
@ 2016-04-14 15:03 ` Wei Liu
2016-04-14 15:04 ` Daniel De Graaf
2016-04-20 7:19 ` Jan Beulich
2 siblings, 0 replies; 126+ messages in thread
From: Wei Liu @ 2016-04-14 15:03 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: Wei Liu, andrew.cooper3, Ian Jackson, mpohlack, ross.lagerwall,
sasha.levin, xen-devel, Daniel De Graaf
On Wed, Apr 13, 2016 at 06:02:03PM -0400, Konrad Rzeszutek Wilk wrote:
> If the hypervisor was built with build-ids we can expose the
> build-id value to the toolstack (if it is not built with
> it will just return -ENODATA). This is a priviligied operation
> so only the controlling stack is able to request this.
>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
> CC: Daniel De Graaf <dgdegra@tycho.nsa.gov>
> CC: Ian Jackson <ian.jackson@eu.citrix.com>
> CC: Wei Liu <wei.liu2@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 22/27] XENVER_build_id/libxc: Provide ld-embedded build-id
2016-04-13 22:02 ` [PATCH v8.1 22/27] XENVER_build_id/libxc: Provide ld-embedded build-id Konrad Rzeszutek Wilk
2016-04-14 15:03 ` Wei Liu
@ 2016-04-14 15:04 ` Daniel De Graaf
2016-04-20 7:19 ` Jan Beulich
2 siblings, 0 replies; 126+ messages in thread
From: Daniel De Graaf @ 2016-04-14 15:04 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk, xen-devel, konrad, ross.lagerwall,
mpohlack, andrew.cooper3, sasha.levin
Cc: Wei Liu, Ian Jackson
On 04/13/2016 06:02 PM, Konrad Rzeszutek Wilk wrote:
> If the hypervisor was built with build-ids we can expose the
> build-id value to the toolstack (if it is not built with
> it will just return -ENODATA). This is a priviligied operation
> so only the controlling stack is able to request this.
>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 23/27] libxl: info: Display build_id of the hypervisor.
2016-04-13 22:02 ` [PATCH v8.1 23/27] libxl: info: Display build_id of the hypervisor Konrad Rzeszutek Wilk
@ 2016-04-14 15:06 ` Wei Liu
0 siblings, 0 replies; 126+ messages in thread
From: Wei Liu @ 2016-04-14 15:06 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: Wei Liu, andrew.cooper3, Ian Jackson, mpohlack, ross.lagerwall,
sasha.levin, xen-devel
On Wed, Apr 13, 2016 at 06:02:04PM -0400, Konrad Rzeszutek Wilk wrote:
> If the hypervisor is built with we will display it.
>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
> CC: Ian Jackson <ian.jackson@eu.citrix.com>
> CC: Wei Liu <wei.liu2@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
One nit below.
> const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx)
> {
> GC_INIT(ctx);
> @@ -5363,8 +5395,10 @@ const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx)
> xen_capabilities_info_t xen_caps;
> xen_platform_parameters_t p_parms;
> xen_commandline_t xen_commandline;
> + xen_build_id_t build_id;
> } u;
> long xen_version;
> + int r;
> libxl_version_info *info = &ctx->version_info;
>
> if (info->xen_version_extra != NULL)
> @@ -5397,6 +5431,17 @@ const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx)
> xc_version(ctx->xch, XENVER_commandline, &u.xen_commandline);
> info->commandline = libxl__strdup(NOGC, u.xen_commandline);
>
> + u.build_id.len = sizeof(u) - sizeof(u.build_id);
> + r = libxl__xc_version_wrap(gc, info, &u.build_id);
> + if (r == -ENOBUFS) {
> + xen_build_id_t *build_id;
> +
> + build_id = libxl__zalloc(gc, info->pagesize);
> + build_id->len = info->pagesize - sizeof(*build_id);
> + r = libxl__xc_version_wrap(gc, info, build_id);
> + if (r)
> + LOGEV(ERROR, r, "getting build_id");
Indentation of this block is wrong.
Wei.
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1] xSplice v1 design and implementation.
2016-04-14 14:26 ` [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
2016-04-14 14:29 ` Julien Grall
@ 2016-04-14 15:12 ` Andrew Cooper
2016-04-14 15:17 ` Jan Beulich
1 sibling, 1 reply; 126+ messages in thread
From: Andrew Cooper @ 2016-04-14 15:12 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk, Konrad Rzeszutek Wilk, Julien Grall,
Stefano Stabellini
Cc: xen-devel, mpohlack, sasha.levin, ross.lagerwall
On 14/04/16 15:26, Konrad Rzeszutek Wilk wrote:
> @@ -312,8 +307,8 @@ struct xsplice_patch_func {
> };
> </pre>
>
> -The size of the structure is 64 bytes or 52 bytes if compiled under 32-bit
> -hypervisors.
> +The size of the structure is 64 bytes on 64-bit hypervisors. It will be
> +52 on 32-bit hypervisors.
I would go further an explicitly declare this API unstable, as patches
must be built against an exact hypervisor source. This also gives us
leaway in the future.
~Andrew
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1] xSplice v1 design and implementation.
2016-04-14 15:12 ` Andrew Cooper
@ 2016-04-14 15:17 ` Jan Beulich
2016-04-15 0:55 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-14 15:17 UTC (permalink / raw)
To: andrew.cooper3, konrad, konrad.wilk
Cc: sstabellini, mpohlack, ross.lagerwall, julien.grall, xen-devel,
sasha.levin
>>> Andrew Cooper <andrew.cooper3@citrix.com> 04/14/16 5:14 PM >>>
>On 14/04/16 15:26, Konrad Rzeszutek Wilk wrote:
>> @@ -312,8 +307,8 @@ struct xsplice_patch_func {
>> };
>> </pre>
>>
>> -The size of the structure is 64 bytes or 52 bytes if compiled under 32-bit
>> -hypervisors.
>> +The size of the structure is 64 bytes on 64-bit hypervisors. It will be
>> +52 on 32-bit hypervisors.
>
>I would go further an explicitly declare this API unstable, as patches
>must be built against an exact hypervisor source. This also gives us
>leaway in the future.
Which it effectively is, now being (iirc) inside a __XEN__ conditional.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 02/27] Revert "HYPERCALL_version_op. New hypercall mirroring XENVER_ but sane."
2016-04-13 22:01 ` [PATCH v8.1 02/27] Revert "HYPERCALL_version_op. New hypercall mirroring XENVER_ but sane." Konrad Rzeszutek Wilk
@ 2016-04-14 16:14 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-14 16:14 UTC (permalink / raw)
To: konrad, konrad.wilk
Cc: andrew.cooper3, xen-devel, mpohlack, sasha.levin, ross.lagerwall
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:04 AM >>>
>This reverts commit 2716d875379d538c1dfccad78a99ca7db2e09f90.
>
>As it was decided that the existing XENVER hypercall - while having
>grown organically over the years can still be expanded.
>
>Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Requested-and-acked-by: Jan Beulich <jbeulich@suse.com>
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 04/27] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op
2016-04-13 22:01 ` [PATCH v8.1 04/27] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op Konrad Rzeszutek Wilk
@ 2016-04-14 16:36 ` Jan Beulich
2016-04-15 2:28 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-14 16:36 UTC (permalink / raw)
To: konrad, konrad.wilk
Cc: sstabellini, wei.liu2, andrew.cooper3, ian.jackson, mpohlack,
ross.lagerwall, sasha.levin, xen-devel, dgdegra
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:05 AM >>>
> @@ -460,6 +461,11 @@ long do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
> ret = tmem_control(&op->u.tmem_op);
> break;
>
> + case XEN_SYSCTL_xsplice_op:
> + ret = xsplice_op(&op->u.xsplice);
> + copyback = (ret == -ENOSYS || ret == -EOPNOTSUPP) ? 0 : 1;
Why use a conditional expression here when its condition already is a boolean one
just needing negating?
> +static int verify_name(const xen_xsplice_name_t *name, char *n)
> +{
> + if ( !name->size || name->size > XEN_XSPLICE_NAME_SIZE )
> + return -EINVAL;
> +
> + if ( name->pad[0] || name->pad[1] || name->pad[2] )
> + return -EINVAL;
> +
> + if ( !guest_handle_okay(name->name, name->size) )
> + return -EINVAL;
> +
> + if ( __copy_from_guest(n, name->name, name->size) )
> + return -EFAULT;
Is there a particular reason why you open code copy_from_guest() here? And
considering that you now also read the string here, isn't the function name
somewhat off?
> +static int xsplice_upload(xen_sysctl_xsplice_upload_t *upload)
> +{
> + struct payload *data = NULL, *found;
> + char n[XEN_XSPLICE_NAME_SIZE];
> + int rc;
> +
> + rc = verify_payload(upload, n);
> + if ( rc )
> + return rc;
> +
> + spin_lock(&payload_lock);
> +
> + found = find_payload(n);
> + if ( IS_ERR(found) )
> + {
> + rc = PTR_ERR(found);
> + goto out;
> + }
> + else if ( found )
> + {
> + rc = -EEXIST;
> + goto out;
> + }
> +
> + data = xzalloc(struct payload);
I generally advocate for not doing allocations with locks held, and I don't think
it would severely complicate the code here doing so.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 07/27] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables lookup.
2016-04-13 22:01 ` [PATCH v8.1 07/27] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables lookup Konrad Rzeszutek Wilk
@ 2016-04-14 16:50 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-14 16:50 UTC (permalink / raw)
To: konrad, konrad.wilk
Cc: sstabellini, keir, andrew.cooper3, mpohlack, ross.lagerwall,
julien.grall, sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:04 AM >>>
>+/*
>+ * RCU locking. Additions are done either at startup (when there is only
>+ * one CPU) or when all CPUs are running without IRQs.
>+ *
>+ * Deletions are big tricky. We do it when xSplicing (all CPUs running
"big tricky"?
>+ * without IRQs) or during bootup (when clearing the init).
>+ *
>+ * Hence we use list_del_rcu (which sports an memory fence) and a spinlock
>+ * on deletion.
>+ *
>+ * All readers of virtual_region_list MUST use list list_for_each_entry_rcu.
>+ *
>+ */
Stray empty comment line.
>--- /dev/null
>+++ b/xen/include/xen/virtual_region.h
>@@ -0,0 +1,47 @@
>+/*
>+ * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
>+ *
>+ */
>+
>+#ifndef __XEN_VIRTUAL_REGION__
__XEN_VIRTUAL_REGION_H__
With those minor aspects taken care of,
Acked-by: Jan Beulich <jbeulich@suse.com>
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1] xSplice v1 design and implementation.
2016-04-14 15:17 ` Jan Beulich
@ 2016-04-15 0:55 ` Konrad Rzeszutek Wilk
2016-04-17 8:00 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-15 0:55 UTC (permalink / raw)
To: Jan Beulich
Cc: sstabellini, andrew.cooper3, mpohlack, ross.lagerwall,
julien.grall, xen-devel, sasha.levin
On Thu, Apr 14, 2016 at 09:17:14AM -0600, Jan Beulich wrote:
> >>> Andrew Cooper <andrew.cooper3@citrix.com> 04/14/16 5:14 PM >>>
> >On 14/04/16 15:26, Konrad Rzeszutek Wilk wrote:
> >> @@ -312,8 +307,8 @@ struct xsplice_patch_func {
> >> };
> >> </pre>
> >>
> >> -The size of the structure is 64 bytes or 52 bytes if compiled under 32-bit
> >> -hypervisors.
> >> +The size of the structure is 64 bytes on 64-bit hypervisors. It will be
> >> +52 on 32-bit hypervisors.
> >
> >I would go further an explicitly declare this API unstable, as patches
> >must be built against an exact hypervisor source. This also gives us
> >leaway in the future.
It will present a problem to the xsplice-tools.git which are outside
the tree. Right now they have their own header file (which mirrors this
one). But if we make it unstable and start mucking around then folks
using the tool would need to pass parameters for 'what version' is
this.
I would rather not have this happen - and now that we do not need
the #ifdef BITS_PER_LONG we can also remove the __XEN__ conditional.
Either way, this is something that can be done later.
>
> Which it effectively is, now being (iirc) inside a __XEN__ conditional.
>
> Jan
>
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 04/27] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op
2016-04-14 16:36 ` Jan Beulich
@ 2016-04-15 2:28 ` Konrad Rzeszutek Wilk
2016-04-17 8:05 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-15 2:28 UTC (permalink / raw)
To: Jan Beulich
Cc: sstabellini, wei.liu2, andrew.cooper3, ian.jackson, mpohlack,
ross.lagerwall, sasha.levin, xen-devel, dgdegra
On Thu, Apr 14, 2016 at 10:36:46AM -0600, Jan Beulich wrote:
> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:05 AM >>>
> > @@ -460,6 +461,11 @@ long do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
> > ret = tmem_control(&op->u.tmem_op);
> > break;
> >
> > + case XEN_SYSCTL_xsplice_op:
> > + ret = xsplice_op(&op->u.xsplice);
> > + copyback = (ret == -ENOSYS || ret == -EOPNOTSUPP) ? 0 : 1;
>
> Why use a conditional expression here when its condition already is a boolean one
> just needing negating?
B/c I thought you would want it this way.
I changed it to
466 if ( ret != -ENOSYS && ret != -EOPNOTSUPP )
467 copyback = 1;
But I don't think this what you meant by 'negating'? As in:
copyback = !rc ?
But one of the subops returns the number of items and we definitly
want copyback=1 for that.
>
> > +static int verify_name(const xen_xsplice_name_t *name, char *n)
> > +{
> > + if ( !name->size || name->size > XEN_XSPLICE_NAME_SIZE )
> > + return -EINVAL;
> > +
> > + if ( name->pad[0] || name->pad[1] || name->pad[2] )
> > + return -EINVAL;
> > +
> > + if ( !guest_handle_okay(name->name, name->size) )
> > + return -EINVAL;
> > +
> > + if ( __copy_from_guest(n, name->name, name->size) )
> > + return -EFAULT;
>
> Is there a particular reason why you open code copy_from_guest() here? And
> considering that you now also read the string here, isn't the function name
> somewhat off?
Yes. In the earlier versions I only verified the name->name and
then later on made the copy. You pointed out that in effect I had
invalidated the earlier checks. Also you asked to make the
name have a NUL padding - so I put that together - the verification
here checks the name for this. And since to verify I need to copy it in first..
I will change the name of the function to 'get_name'
>
> > +static int xsplice_upload(xen_sysctl_xsplice_upload_t *upload)
> > +{
> > + struct payload *data = NULL, *found;
> > + char n[XEN_XSPLICE_NAME_SIZE];
> > + int rc;
> > +
> > + rc = verify_payload(upload, n);
> > + if ( rc )
> > + return rc;
> > +
> > + spin_lock(&payload_lock);
> > +
> > + found = find_payload(n);
> > + if ( IS_ERR(found) )
> > + {
> > + rc = PTR_ERR(found);
> > + goto out;
> > + }
> > + else if ( found )
> > + {
> > + rc = -EEXIST;
> > + goto out;
> > + }
> > +
> > + data = xzalloc(struct payload);
>
> I generally advocate for not doing allocations with locks held, and I don't think
> it would severely complicate the code here doing so.
I can certainly unlock and then lock again (when adding
it to the list).
That has the positive aspect that in the later patches when
we do vzalloc for the payload we can do it without holding locks.
>
> Jan
>
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1] xSplice v1 design and implementation.
2016-04-15 0:55 ` Konrad Rzeszutek Wilk
@ 2016-04-17 8:00 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-17 8:00 UTC (permalink / raw)
To: konrad
Cc: sstabellini, ross.lagerwall, andrew.cooper3, mpohlack,
julien.grall, sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad@darnok.org> 04/15/16 2:55 AM >>>
>On Thu, Apr 14, 2016 at 09:17:14AM -0600, Jan Beulich wrote:
>> >>> Andrew Cooper <andrew.cooper3@citrix.com> 04/14/16 5:14 PM >>>
>> >On 14/04/16 15:26, Konrad Rzeszutek Wilk wrote:
>> >> @@ -312,8 +307,8 @@ struct xsplice_patch_func {
>> >> };
>> >> </pre>
>> >>
>> >> -The size of the structure is 64 bytes or 52 bytes if compiled under 32-bit
>> >> -hypervisors.
>> >> +The size of the structure is 64 bytes on 64-bit hypervisors. It will be
>> >> +52 on 32-bit hypervisors.
>> >
>> >I would go further an explicitly declare this API unstable, as patches
>> >must be built against an exact hypervisor source. This also gives us
>> >leaway in the future.
>
>It will present a problem to the xsplice-tools.git which are outside
>the tree. Right now they have their own header file (which mirrors this
>one). But if we make it unstable and start mucking around then folks
>using the tool would need to pass parameters for 'what version' is
>this.
>
>I would rather not have this happen - and now that we do not need
>the #ifdef BITS_PER_LONG we can also remove the __XEN__ conditional.
I don't think that's the case: The mere use of pointer types in there makes it
so the type shouldn't be exposed to entities executing outside of hypervisor
context.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 04/27] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op
2016-04-15 2:28 ` Konrad Rzeszutek Wilk
@ 2016-04-17 8:05 ` Jan Beulich
2016-04-18 7:48 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-17 8:05 UTC (permalink / raw)
To: konrad
Cc: sstabellini, wei.liu2, andrew.cooper3, ian.jackson, mpohlack,
ross.lagerwall, sasha.levin, xen-devel, dgdegra
>>> Konrad Rzeszutek Wilk <konrad@kernel.org> 04/15/16 4:29 AM >>>
>On Thu, Apr 14, 2016 at 10:36:46AM -0600, Jan Beulich wrote:
>> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:05 AM >>>
>> > @@ -460,6 +461,11 @@ long do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
>> > ret = tmem_control(&op->u.tmem_op);
>> > break;
>> >
>> > + case XEN_SYSCTL_xsplice_op:
>> > + ret = xsplice_op(&op->u.xsplice);
>> > + copyback = (ret == -ENOSYS || ret == -EOPNOTSUPP) ? 0 : 1;
>>
>> Why use a conditional expression here when its condition already is a boolean one
>> just needing negating?
>
>B/c I thought you would want it this way.
>
>I changed it to
>
>466 if ( ret != -ENOSYS && ret != -EOPNOTSUPP )
>467 copyback = 1;
That's fine too.
>But I don't think this what you meant by 'negating'? As in:
>
>copyback = !rc ?
>
>But one of the subops returns the number of items and we definitly
>want copyback=1 for that.
What I mean with "negating" was
copyback = (ret != -ENOSYS && ret != -EOPNOTSUPP);
>> > + spin_lock(&payload_lock);
>> > +
>> > + found = find_payload(n);
>> > + if ( IS_ERR(found) )
>> > + {
>> > + rc = PTR_ERR(found);
>> > + goto out;
>> > + }
>> > + else if ( found )
>> > + {
>> > + rc = -EEXIST;
>> > + goto out;
>> > + }
>> > +
>> > + data = xzalloc(struct payload);
>>
>> I generally advocate for not doing allocations with locks held, and I don't think
>> it would severely complicate the code here doing so.
>
>I can certainly unlock and then lock again (when adding
>it to the list).
That would create a race again afaict. Instead what I have been trying to hint
at is that the allocation should be done before taking the lock, freeing the object
again if in the end it turned out it's not going to be needed. Hence the referral to
possibly complicating the code.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 08/27] arm/x86/vmap: Add vmalloc_xen, vfree_xen and vm_init_type
2016-04-13 22:01 ` [PATCH v8.1 08/27] arm/x86/vmap: Add vmalloc_xen, vfree_xen and vm_init_type Konrad Rzeszutek Wilk
@ 2016-04-17 20:17 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-17 20:17 UTC (permalink / raw)
To: andrew.cooper3, konrad, konrad.wilk
Cc: sstabellini, keir, tim, ian.jackson, mpohlack, ross.lagerwall,
julien.grall, sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
>Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>Suggested-by: Jan Beulich <jbeulich@suse.com>
>Acked-by: Julien Grall <julien.grall@arm.com> [ARM]
>Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Is that really the case? I think it was Andrew who suggested to not expose a
second variant of vfree(), as the address type can be inferred from the address.
>@@ -52,27 +55,30 @@ void *vm_alloc(unsigned int nr, unsigned int align)
>else if ( align & (align - 1) )
>align &= -align;
>
>+ if ( !vm_base[t] )
>+ return NULL;
How about ASSERT()ing that t is in range before using it as an array index?
With the address/type parameter redundancy dropped at the very least from
the non-internal functions, I think everything else here is fine.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 10/27] xsplice: Add helper elf routines
2016-04-13 22:01 ` [PATCH v8.1 10/27] xsplice: Add helper elf routines Konrad Rzeszutek Wilk
@ 2016-04-17 20:55 ` Jan Beulich
2016-04-18 5:53 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-17 20:55 UTC (permalink / raw)
To: ross.lagerwall, konrad, konrad.wilk
Cc: keir, andrew.cooper3, ian.jackson, mpohlack, tim, xen-devel, sasha.levin
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
>+static int elf_verify_strtab(const struct xsplice_elf_sec *sec)
>+{
>+ const Elf_Shdr *s;
>+ const uint8_t *contents;
Considering it's a string table, perhaps better const char *?
>+ s = sec->sec;
>+
>+ if ( s->sh_type != SHT_STRTAB )
>+ return -EINVAL;
>+
>+ if ( !s->sh_size )
>+ return -EOPNOTSUPP;
Why not also -EINVAL? I don't think the standard permits empty string table
sections.
>+ contents = (const uint8_t *)sec->data;
Pointless cast.
>+static int elf_resolve_sections(struct xsplice_elf *elf, const void *data)
>+{
>+ struct xsplice_elf_sec *sec;
>+ unsigned int i;
>+ Elf_Off delta;
>+ int rc;
>+
>+ /* xsplice_elf_load sanity checked e_shnum. */
>+ sec = xmalloc_array(struct xsplice_elf_sec, elf->hdr->e_shnum);
>+ if ( !sec )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE"%s: Could not allocate memory for section table!\n",
>+ elf->name);
>+ return -ENOMEM;
>+ }
>+
>+ elf->sec = sec;
>+
>+ delta = elf->hdr->e_shoff + elf->hdr->e_shnum * elf->hdr->e_shentsize;
I think Andrew had asked this before - are we not worried of overflow here?
>+ if ( delta > elf->len )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Section table is past end of payload!\n",
>+ elf->name);
>+ return -EINVAL;
>+ }
>+
>+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
>+ {
>+ delta = elf->hdr->e_shoff + i * elf->hdr->e_shentsize;
>+
>+ sec[i].sec = (void *)data + delta;
Casting away constness is one of the main reasons I complain about casts in
general. If you really need to modify some fields in the section header, you should
imo cast away constness just there. But even better would be if you left the
section header alone.
>+ delta = sec[i].sec->sh_offset;
>+
>+ /*
>+ * N.B. elf_resolve_section_names, elf_get_sym skip this check as
>+ * we do it here.
>+ */
>+ if ( delta && (delta + sec[i].sec->sh_size > elf->len) )
Allowing delta to be zero here seems suspicious: Are you doing that because
some sections come without data (and hence without offset)? In that case you'd
better skip the check on those section types (e.g. SHT_NOBITS) only. In fact
the offset being below the end of the ELF header would likely indicate a broken
image.
>+ /* Name is populated in xsplice_elf_sections_name. */
Stale function name afaict.
>+ /*
>+ * elf->symtab->sec->sh_link would point to the right section
>+ * but we hadn't finished parsing all the sections.
>+ */
>+ if ( elf->symtab->sec->sh_link > elf->hdr->e_shnum )
>= (and I know I had asked before to check all these bounds checks for off
by one errors)
>+ if ( !elf->symtab->sec->sh_size ||
>+ elf->symtab->sec->sh_entsize < sizeof(Elf_Sym) )
|| sh_size % sh_entsize
>+ /*
>+ * There can be multiple SHT_STRTAB (.shstrtab, .strtab) so pick one
>+ * associated with the symbol table.
>+ */
... pick the one ...
>+static int elf_resolve_section_names(struct xsplice_elf *elf, const void *data)
>+{
>+ const char *shstrtab;
>+ unsigned int i;
>+ Elf_Off offset, delta;
>+ struct xsplice_elf_sec *sec;
>+ int rc;
>+
>+ /*
>+ * The elf->sec[0 -> e_shnum] structures have been verified by
>+ * elf_resolve_sections. Find file offset for section string table
>+ * (normally called .shstrtab)
>+ */
>+ sec = &elf->sec[elf->hdr->e_shstrndx];
>+
>+ rc = elf_verify_strtab(sec);
>+ if ( rc )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Section string table is corrupted\n",
>+ elf->name);
>+ return rc;
>+ }
>+
>+ /* Verified in elf_resolve_sections but just in case. */
>+ offset = sec->sec->sh_offset;
>+ ASSERT(offset < elf->len && (offset + sec->sec->sh_size <= elf->len));
>+
>+ shstrtab = data + offset;
>+
>+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
>+ {
>+ delta = elf->sec[i].sec->sh_name;
>+
>+ if ( delta && delta >= sec->sec->sh_size )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: shstrtab [%u] data is past end of payload!\n",
>+ elf->name, i);
Isn't this redundant with the check in elf_resolve_sections()? Or is this needed
because the one here runs before that other one?
>+static int elf_get_sym(struct xsplice_elf *elf, const void *data)
>+{
>+ const struct xsplice_elf_sec *symtab_sec, *strtab_sec;
>+ struct xsplice_elf_sym *sym;
>+ unsigned int i, delta, offset, nsym;
>+
>+ symtab_sec = elf->symtab;
>+ strtab_sec = elf->strtab;
>+
>+ /* Pointers arithmetic to get file offset. */
>+ offset = strtab_sec->data - data;
>+
>+ /* Checked already in elf_resolve_sections, but just in case. */
>+ ASSERT(offset == strtab_sec->sec->sh_offset);
>+ ASSERT(offset < elf->len && (offset + strtab_sec->sec->sh_size <= elf->len));
>+
>+ /* symtab_sec->data was computed in elf_resolve_sections. */
>+ ASSERT((symtab_sec->sec->sh_offset + data) == symtab_sec->data);
>+
>+ /* No need to check values as elf_resolve_sections did it. */
>+ nsym = symtab_sec->sec->sh_size / symtab_sec->sec->sh_entsize;
>+
>+ sym = xmalloc_array(struct xsplice_elf_sym, nsym);
>+ if ( !sym )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Could not allocate memory for symbols\n",
>+ elf->name);
>+ return -ENOMEM;
>+ }
>+
>+ /* So we don't leak memory. */
>+ elf->sym = sym;
>+
>+ for ( i = 1; i < nsym; i++ )
>+ {
>+ Elf_Sym *s = &((Elf_Sym *)symtab_sec->data)[i];
>+
>+ /* If st->name is STN_UNDEF zero, the check will always be true. */
>+ delta = s->st_name;
>+
>+ if ( delta && (delta > strtab_sec->sec->sh_size) )
Now here I don't see why you special case delta being zero, the more with the
comment right above.
>+static int xsplice_header_check(const struct xsplice_elf *elf)
>+{
>+ const Elf_Ehdr *hdr = elf->hdr;
>+
>+ if ( sizeof(*elf->hdr) > elf->len )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Section header is bigger than payload!\n",
>+ elf->name);
>+ return -EINVAL;
>+ }
>+
>+ if ( !IS_ELF(*hdr) )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Not an ELF payload!\n", elf->name);
>+ return -EINVAL;
>+ }
>+
>+ if ( hdr->e_ident[EI_CLASS] != ELFCLASS64 ||
>+ hdr->e_ident[EI_DATA] != ELFDATA2LSB ||
>+ hdr->e_ident[EI_OSABI] != ELFOSABI_SYSV ||
>+ hdr->e_type != ET_REL ||
>+ hdr->e_phnum != 0 )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Invalid ELF payload!\n", elf->name);
>+ return -EOPNOTSUPP;
>+ }
>+
>+ if ( elf->hdr->e_shstrndx == SHN_UNDEF )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Section name idx is undefined!?\n",
>+ elf->name);
>+ return -EINVAL;
>+ }
>+
>+ /* Check that section name index is within the sections. */
>+ if ( elf->hdr->e_shstrndx >= elf->hdr->e_shnum )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Section name idx (%u) is past end of sections (%u)!\n",
>+ elf->name, elf->hdr->e_shstrndx, elf->hdr->e_shnum);
>+ return -EINVAL;
>+ }
>+
>+ if ( elf->hdr->e_shnum > 64 )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Too many (%u) sections!\n",
>+ elf->name, elf->hdr->e_shnum);
>+ return -EINVAL;
This isn't invalid, but unsupported.
>+ if ( elf->hdr->e_shoff > elf->len )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Bogus e_shoff!\n", elf->name);
>+ return -EINVAL;
>+ }
If this check is needed, then >=. But I think it should be redundant with the more
complete one in elf_resolve_sections().
>+struct xsplice_elf_sec {
>+ Elf_Shdr *sec; /* Hooked up in elf_resolve_sections.*/
const
>+struct xsplice_elf_sym {
>+ Elf_Sym *sym;
const
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 10/27] xsplice: Add helper elf routines
2016-04-17 20:55 ` Jan Beulich
@ 2016-04-18 5:53 ` Konrad Rzeszutek Wilk
2016-04-18 6:23 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-18 5:53 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, andrew.cooper3, ian.jackson, mpohlack, tim, ross.lagerwall,
sasha.levin, xen-devel
. snip..
> >+static int elf_resolve_sections(struct xsplice_elf *elf, const void *data)
> >+{
> >+ struct xsplice_elf_sec *sec;
> >+ unsigned int i;
> >+ Elf_Off delta;
> >+ int rc;
> >+
> >+ /* xsplice_elf_load sanity checked e_shnum. */
> >+ sec = xmalloc_array(struct xsplice_elf_sec, elf->hdr->e_shnum);
> >+ if ( !sec )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE"%s: Could not allocate memory for section table!\n",
> >+ elf->name);
> >+ return -ENOMEM;
> >+ }
> >+
> >+ elf->sec = sec;
> >+
> >+ delta = elf->hdr->e_shoff + elf->hdr->e_shnum * elf->hdr->e_shentsize;
>
> I think Andrew had asked this before - are we not worried of overflow here?
Yes. That ends up being checked in xsplice_header_check. Added comment
here.
>
> >+ if ( delta > elf->len )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Section table is past end of payload!\n",
> >+ elf->name);
> >+ return -EINVAL;
> >+ }
> >+
> >+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
> >+ {
> >+ delta = elf->hdr->e_shoff + i * elf->hdr->e_shentsize;
> >+
> >+ sec[i].sec = (void *)data + delta;
>
> Casting away constness is one of the main reasons I complain about casts in
> general. If you really need to modify some fields in the section header, you should
> imo cast away constness just there. But even better would be if you left the
In earlier reviews you said that casting away constness in
function would be a big no no.
> section header alone.
I modify sec[i].sec->sh_entsize in calc_section
>
> >+ delta = sec[i].sec->sh_offset;
> >+
> >+ /*
> >+ * N.B. elf_resolve_section_names, elf_get_sym skip this check as
> >+ * we do it here.
> >+ */
> >+ if ( delta && (delta + sec[i].sec->sh_size > elf->len) )
>
> Allowing delta to be zero here seems suspicious: Are you doing that because
> some sections come without data (and hence without offset)? In that case you'd
> better skip the check on those section types (e.g. SHT_NOBITS) only. In fact
> the offset being below the end of the ELF header would likely indicate a broken
> image.
The loop (earlier) had started at 0 so the delta could have been zero.
Anyhow that not being the case anymore I will just do:
if ( !delta )
return -EINVAL;
>
> >+ /* Name is populated in xsplice_elf_sections_name. */
>
> Stale function name afaict.
>
> >+ /*
> >+ * elf->symtab->sec->sh_link would point to the right section
> >+ * but we hadn't finished parsing all the sections.
> >+ */
> >+ if ( elf->symtab->sec->sh_link > elf->hdr->e_shnum )
>
> >= (and I know I had asked before to check all these bounds checks for off
> by one errors)
>
> >+ if ( !elf->symtab->sec->sh_size ||
> >+ elf->symtab->sec->sh_entsize < sizeof(Elf_Sym) )
>
> || sh_size % sh_entsize
>
> >+ /*
> >+ * There can be multiple SHT_STRTAB (.shstrtab, .strtab) so pick one
> >+ * associated with the symbol table.
> >+ */
>
> ... pick the one ...
>
> >+static int elf_resolve_section_names(struct xsplice_elf *elf, const void *data)
> >+{
> >+ const char *shstrtab;
> >+ unsigned int i;
> >+ Elf_Off offset, delta;
> >+ struct xsplice_elf_sec *sec;
> >+ int rc;
> >+
> >+ /*
> >+ * The elf->sec[0 -> e_shnum] structures have been verified by
> >+ * elf_resolve_sections. Find file offset for section string table
> >+ * (normally called .shstrtab)
> >+ */
> >+ sec = &elf->sec[elf->hdr->e_shstrndx];
> >+
> >+ rc = elf_verify_strtab(sec);
> >+ if ( rc )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Section string table is corrupted\n",
> >+ elf->name);
> >+ return rc;
> >+ }
> >+
> >+ /* Verified in elf_resolve_sections but just in case. */
> >+ offset = sec->sec->sh_offset;
> >+ ASSERT(offset < elf->len && (offset + sec->sec->sh_size <= elf->len));
> >+
> >+ shstrtab = data + offset;
> >+
> >+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
> >+ {
> >+ delta = elf->sec[i].sec->sh_name;
> >+
> >+ if ( delta && delta >= sec->sec->sh_size )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: shstrtab [%u] data is past end of payload!\n",
> >+ elf->name, i);
>
> Isn't this redundant with the check in elf_resolve_sections()? Or is this needed
> because the one here runs before that other one?
We don't verify sh_name in elf_resolve_sections.
This is where we check that sh_name is within the shstrtab.
>
> >+static int elf_get_sym(struct xsplice_elf *elf, const void *data)
> >+{
> >+ const struct xsplice_elf_sec *symtab_sec, *strtab_sec;
> >+ struct xsplice_elf_sym *sym;
> >+ unsigned int i, delta, offset, nsym;
> >+
> >+ symtab_sec = elf->symtab;
> >+ strtab_sec = elf->strtab;
> >+
> >+ /* Pointers arithmetic to get file offset. */
> >+ offset = strtab_sec->data - data;
> >+
> >+ /* Checked already in elf_resolve_sections, but just in case. */
> >+ ASSERT(offset == strtab_sec->sec->sh_offset);
> >+ ASSERT(offset < elf->len && (offset + strtab_sec->sec->sh_size <= elf->len));
> >+
> >+ /* symtab_sec->data was computed in elf_resolve_sections. */
> >+ ASSERT((symtab_sec->sec->sh_offset + data) == symtab_sec->data);
> >+
> >+ /* No need to check values as elf_resolve_sections did it. */
> >+ nsym = symtab_sec->sec->sh_size / symtab_sec->sec->sh_entsize;
> >+
> >+ sym = xmalloc_array(struct xsplice_elf_sym, nsym);
> >+ if ( !sym )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Could not allocate memory for symbols\n",
> >+ elf->name);
> >+ return -ENOMEM;
> >+ }
> >+
> >+ /* So we don't leak memory. */
> >+ elf->sym = sym;
> >+
> >+ for ( i = 1; i < nsym; i++ )
> >+ {
> >+ Elf_Sym *s = &((Elf_Sym *)symtab_sec->data)[i];
> >+
> >+ /* If st->name is STN_UNDEF zero, the check will always be true. */
> >+ delta = s->st_name;
> >+
> >+ if ( delta && (delta > strtab_sec->sec->sh_size) )
>
> Now here I don't see why you special case delta being zero, the more with the
> comment right above.
That one is stale. Removed the 'if ( delta)' part and the comment.
>
> >+static int xsplice_header_check(const struct xsplice_elf *elf)
> >+{
> >+ const Elf_Ehdr *hdr = elf->hdr;
> >+
> >+ if ( sizeof(*elf->hdr) > elf->len )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Section header is bigger than payload!\n",
> >+ elf->name);
> >+ return -EINVAL;
> >+ }
> >+
> >+ if ( !IS_ELF(*hdr) )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Not an ELF payload!\n", elf->name);
> >+ return -EINVAL;
> >+ }
> >+
> >+ if ( hdr->e_ident[EI_CLASS] != ELFCLASS64 ||
> >+ hdr->e_ident[EI_DATA] != ELFDATA2LSB ||
> >+ hdr->e_ident[EI_OSABI] != ELFOSABI_SYSV ||
> >+ hdr->e_type != ET_REL ||
> >+ hdr->e_phnum != 0 )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Invalid ELF payload!\n", elf->name);
> >+ return -EOPNOTSUPP;
> >+ }
> >+
> >+ if ( elf->hdr->e_shstrndx == SHN_UNDEF )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Section name idx is undefined!?\n",
> >+ elf->name);
> >+ return -EINVAL;
> >+ }
> >+
> >+ /* Check that section name index is within the sections. */
> >+ if ( elf->hdr->e_shstrndx >= elf->hdr->e_shnum )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Section name idx (%u) is past end of sections (%u)!\n",
> >+ elf->name, elf->hdr->e_shstrndx, elf->hdr->e_shnum);
> >+ return -EINVAL;
> >+ }
> >+
> >+ if ( elf->hdr->e_shnum > 64 )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Too many (%u) sections!\n",
> >+ elf->name, elf->hdr->e_shnum);
> >+ return -EINVAL;
>
> This isn't invalid, but unsupported.
>
> >+ if ( elf->hdr->e_shoff > elf->len )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Bogus e_shoff!\n", elf->name);
> >+ return -EINVAL;
> >+ }
>
> If this check is needed, then >=. But I think it should be redundant with the more
> complete one in elf_resolve_sections().
This is the overflow check Andrew asked for.
>
> >+struct xsplice_elf_sec {
> >+ Elf_Shdr *sec; /* Hooked up in elf_resolve_sections.*/
>
> const
>
> >+struct xsplice_elf_sym {
> >+ Elf_Sym *sym;
>
> const
That will make 'xsplice_elf_resolve_symbols' unhappy:
elf->sym[i].sym->st_value = (unsigned
long)symbols_lookup_by_name(elf->sym[i].name);
Unless I cast away constness.
>
> Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 11/27] xsplice: Implement payload loading
2016-04-13 22:01 ` [PATCH v8.1 11/27] xsplice: Implement payload loading Konrad Rzeszutek Wilk
@ 2016-04-18 6:16 ` Jan Beulich
2016-04-20 15:59 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-18 6:16 UTC (permalink / raw)
To: ross.lagerwall, konrad, konrad.wilk
Cc: sstabellini, keir, andrew.cooper3, mpohlack, julien.grall,
xen-devel, sasha.levin
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:04 AM >>>
>--- a/xen/arch/x86/Makefile
>+++ b/xen/arch/x86/Makefile
>@@ -64,6 +64,7 @@ obj-y += vm_event.o
>obj-y += xstate.o
>
>obj-$(crash_debug) += gdbstub.o
>+obj-$(CONFIG_XSPLICE) += xsplice.o
This should be added in the main section, somewhere ahead of the xstate.o
still visible in context.
>+int arch_xsplice_perform_rela(struct xsplice_elf *elf,
>+ const struct xsplice_elf_sec *base,
>+ const struct xsplice_elf_sec *rela)
>+{
>+ const Elf_RelA *r;
>+ unsigned int symndx, i;
>+ uint64_t val;
>+ uint8_t *dest;
>+
>+ if ( !rela->sec->sh_entsize || !rela->sec->sh_size ||
>+ rela->sec->sh_entsize != sizeof(Elf_RelA) )
< and again missing the sh_size % sh_entsize check. Plus an empty relocation
section is in no way invalid.
>+ for ( i = 0; i < (rela->sec->sh_size / rela->sec->sh_entsize); i++ )
>+ {
>+ r = rela->data + i * rela->sec->sh_entsize;
>+ if ( (unsigned long)r > (unsigned long)(elf->hdr + elf->len) )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Relative entry %u in %s is past end!\n",
>+ elf->name, i, rela->name);
With sections having got verified already, I don't see the point of this check.
>+ symndx = ELF64_R_SYM(r->r_info);
>+ if ( symndx > elf->nsym )
>=
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Relative symbol wants symbol@%u which is past end!\n",
"Relative relocation wants ..."
>+ dest = base->load_addr + r->r_offset;
I'm sure I've commented on this before: What if r_offset points outside the
section being relocated?
>+ val = r->r_addend + elf->sym[symndx].sym->st_value;
>+
>+ switch ( ELF64_R_TYPE(r->r_info) )
>+ {
>+ case R_X86_64_NONE:
>+ break;
>+
>+ case R_X86_64_64:
>+ *(uint64_t *)dest = val;
>+ break;
>+
>+ case R_X86_64_PLT32:
>+ /*
>+ * Xen uses -fpic which normally uses PLT relocations
>+ * except that it sets visibility to hidden which means
>+ * that they are not used. However, when gcc cannot
>+ * inline memcpy it emits memcpy with default visibility
>+ * which then creates a PLT relocation. It can just be
>+ * treated the same as R_X86_64_PC32.
>+ */
>+ /* Fall through */
Same here, just to repeat an earlier review comment: This second comment isn't
really useful.
>+ case R_X86_64_PC32:
>+ val -= (uint64_t)dest;
>+ *(uint32_t *)dest = val;
int32_t
>+ if ( (s64)val != *(s32 *)dest )
int64_t and int32_t please (for consistency); I actually doubt the cast on the left
side is really needed at all.
>+void *arch_xsplice_alloc_payload(unsigned int pages)
>+{
>+ unsigned int i;
>+ void *p;
>+
>+ ASSERT(pages);
>+
>+ p = vmalloc_xen(pages * PAGE_SIZE);
>+ WARN_ON(!p);
Why? If at all, a dprintk() in the else to ...
>+ if ( p )
>+ {
>+ /* By default they are PAGE_HYPERVISOR aka PAGE_HYPERVISOR_RWX.*/
>+ for ( i = 0; i < pages; i++ )
>+ clear_page(p + (i * PAGE_SIZE) );
>+ }
... this.
>+int arch_xsplice_secure(void *va, unsigned int pages, enum va_type type)
const void *va
>+{
>+ unsigned long start = (unsigned long)va;
>+ int flag;
unsigned int flags;
>+
>+ ASSERT(va);
>+ ASSERT(pages);
>+
>+ if ( type == XSPLICE_VA_RX ) /* PAGE_HYPERVISOR_RX */
>+ flag = _PAGE_PRESENT;
>+ else if ( type == XSPLICE_VA_RW ) /* PAGE_HYPERVISOR_RW */
>+ flag = _PAGE_RW | _PAGE_NX | _PAGE_PRESENT;
>+ else /* PAGE_HYPERVISOR_RO */
>+ flag = _PAGE_NX | _PAGE_PRESENT;
According to the most recent version of that patch, shouldn't you use the values in
the comments here instead of the open coded variants?
>+void arch_xsplice_free_payload(void *va)
>+{
>+ vfree_xen(va);
>+}
What is the idea behind having this hook (instead of generic code just calling
vfree_xen() [or really just vfree()])?
>@@ -29,6 +30,13 @@ struct payload {
>uint32_t state; /* One of the XSPLICE_STATE_*. */
>int32_t rc; /* 0 or -XEN_EXX. */
>struct list_head list; /* Linked to 'payload_list'. */
>+ void *text_addr; /* Virtual address of .text. */
>+ size_t text_size; /* .. and its size. */
>+ void *rw_addr; /* Virtual address of .data. */
>+ size_t rw_size; /* .. and its size (if any). */
>+ void *ro_addr; /* Virtual address of .rodata. */
>+ size_t ro_size; /* .. and its size (if any). */
And again the question: Do these pointers really need to be non-const?
>+ size_t pages; /* Total pages for [text,rw,ro]_addr */
Why size_t and not just unsigned int?
>+static void calc_section(struct xsplice_elf_sec *sec, size_t *size)
>+{
>+ Elf_Shdr *s = sec->sec;
>+ size_t align_size;
>+
>+ align_size = ROUNDUP(*size, s->sh_addralign);
>+ s->sh_entsize = align_size;
So this is one of the places (the only one?) where the section header gets
altered. Are you not expecting problems down the road resulting from
overwriting this field? After all it's used not just in control sections...
>+static int move_payload(struct payload *payload, struct xsplice_elf *elf)
>+{
>+ uint8_t *buf;
>+ unsigned int i;
>+ size_t size = 0;
>+
>+ /* Compute text regions. */
>+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
>+ {
>+ if ( (elf->sec[i].sec->sh_flags & (SHF_ALLOC|SHF_EXECINSTR)) ==
>+ (SHF_ALLOC|SHF_EXECINSTR) )
>+ calc_section(&elf->sec[i], &payload->text_size);
>+ }
>+
>+ /* Compute rw data. */
>+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
>+ {
>+ if ( (elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
>+ !(elf->sec[i].sec->sh_flags & SHF_EXECINSTR) &&
>+ (elf->sec[i].sec->sh_flags & SHF_WRITE) )
>+ calc_section(&elf->sec[i], &payload->rw_size);
>+ }
>+
>+ /* Compute ro data. */
>+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
>+ {
>+ if ( (elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
>+ !(elf->sec[i].sec->sh_flags & SHF_EXECINSTR) &&
>+ !(elf->sec[i].sec->sh_flags & SHF_WRITE) )
>+ calc_section(&elf->sec[i], &payload->ro_size);
>+ }
>+
>+ /* Do not accept wx. */
>+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
>+ {
>+ if ( !(elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
>+ (elf->sec[i].sec->sh_flags & SHF_EXECINSTR) &&
>+ (elf->sec[i].sec->sh_flags & SHF_WRITE) )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: No WX sections!\n", elf->name);
>+ return -EINVAL;
>+ }
Is there any reason to have four loops here, with quite a bit of redundancy in
the if()s, instead of just one loop with a if/else sequence?
Also it's not really clear whether you really mean to honor non-progbits, non-
nobits sections with SHF_ALLOC set. Perhaps such would better be refused
for the now at least.
>+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
>+ {
>+ if ( elf->sec[i].sec->sh_flags & SHF_ALLOC )
>+ {
>+ if ( (elf->sec[i].sec->sh_flags & SHF_EXECINSTR) )
>+ buf = payload->text_addr;
>+ else if ( (elf->sec[i].sec->sh_flags & SHF_WRITE) )
>+ buf = payload->rw_addr;
>+ else
Something's wrong with indentation here (not visible above anymore due to
the limitations of this web frontend of our mail system).
>+ /* Don't copy NOBITS - such as BSS. */
>+ if ( elf->sec[i].sec->sh_type != SHT_NOBITS )
>+ {
>+ memcpy(elf->sec[i].load_addr, elf->sec[i].data,
>+ elf->sec[i].sec->sh_size);
>+ dprintk(XENLOG_DEBUG, XSPLICE "%s: Loaded %s at 0x%p\n",
>+ elf->name, elf->sec[i].name, elf->sec[i].load_addr);
>+ }
"else memset();" is what I would have expected here. Now I see that the
allocation function clears the pages (in a bogusly open coded way, instead
of using vzalloc()), but why is that so?
>+int xsplice_elf_resolve_symbols(struct xsplice_elf *elf)
>+{
>+ unsigned int i;
>+ int rc = 0;
>+
>+ /*
>+ * The first entry of an ELF symbol table is the "undefined symbol index".
>+ * aka reserved so we skip it.
>+ */
>+ ASSERT(elf->sym);
>+
>+ for ( i = 1; i < elf->nsym; i++ )
>+ {
>+ uint16_t idx = elf->sym[i].sym->st_shndx;
Any reason not to use unsigned int here?
>+ rc = 0;
rc is already zero whenever you get here afaict.
>+ default:
>+ /* SHN_COMMON and SHN_ABS are above. */
>+ if ( idx > SHN_LORESERVE )
>=
>+ rc = -EOPNOTSUPP;
>+ /* SHN_UNDEF (0) above. */
>+ else if ( idx > elf->hdr->e_shnum && idx < SHN_LORESERVE )
>= and the right side of the && seems pointless due to the preceding if().
>+ if ( !(elf->sec[idx].sec->sh_flags & SHF_ALLOC) )
>+ break;
If you really mean to check this, shouldn't this be done earlier, avoiding needless
errors on unsupported symbol kinds above?
>+int xsplice_elf_perform_relocs(struct xsplice_elf *elf)
>+{
>+ struct xsplice_elf_sec *rela, *base;
>+ unsigned int i;
>+ int rc = 0;
>+
>+ /*
>+ * The first entry of an ELF symbol table is the "undefined symbol index".
>+ * aka reserved so we skip it.
>+ */
This comment seems at least misplaced, if not pointless.
>+ ASSERT(elf->sym);
>+
>+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
>+ {
>+ rela = &elf->sec[i];
>+
>+ if ( (rela->sec->sh_type != SHT_RELA) &&
>+ (rela->sec->sh_type != SHT_REL) )
>+ continue;
With this the variable name "rela" is bogus (as it suggests RELA only).
>@@ -497,6 +499,8 @@ typedef struct {
>
>#define AuxInfo Aux32Info
>#elif defined(ELFSIZE) && (ELFSIZE == 64)
>+#define PRIxElfAddr "lx"
PRIx64?
>--- a/xen/include/xen/xsplice.h
>+++ b/xen/include/xen/xsplice.h
>@@ -6,6 +6,9 @@
>#ifndef __XEN_XSPLICE_H__
>#define __XEN_XSPLICE_H__
>
>+struct xsplice_elf;
>+struct xsplice_elf_sec;
>+struct xsplice_elf_sym;
>struct xen_sysctl_xsplice_op;
>
>#ifdef CONFIG_XSPLICE
>@@ -15,6 +18,32 @@ struct xen_sysctl_xsplice_op;
>
>int xsplice_op(struct xen_sysctl_xsplice_op *);
>
>+/* Arch hooks. */
>+int arch_xsplice_verify_elf(const struct xsplice_elf *elf);
>+int arch_xsplice_perform_rel(struct xsplice_elf *elf,
>+ const struct xsplice_elf_sec *base,
>+ const struct xsplice_elf_sec *rela);
>+int arch_xsplice_perform_rela(struct xsplice_elf *elf,
>+ const struct xsplice_elf_sec *base,
>+ const struct xsplice_elf_sec *rela);
>+enum va_type {
>+ XSPLICE_VA_RX, /* .text */
>+ XSPLICE_VA_RW, /* .data */
>+ XSPLICE_VA_RO, /* .rodata */
>+};
>+
>+#include <xen/mm.h>
Why at all? And if needed, why placed in the middle?
>@@ -29,8 +31,10 @@ struct xsplice_elf {
>struct xsplice_elf_sec *sec; /* Array of sections, allocated by us. */
>struct xsplice_elf_sym *sym; /* Array of symbols , allocated by us. */
>unsigned int nsym;
>- const struct xsplice_elf_sec *symtab;/* Pointer to .symtab section - aka to sec[x]. */
>+ const struct xsplice_elf_sec *symtab;/* Pointer to .symtab section - aka to
>+ sec[symtab_idx]. */
>const struct xsplice_elf_sec *strtab;/* Pointer to .strtab section - aka to sec[y]. */
With the adjustment above - who is y? (But perhaps this needs taking care of in
an earlier patch.)
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 10/27] xsplice: Add helper elf routines
2016-04-18 5:53 ` Konrad Rzeszutek Wilk
@ 2016-04-18 6:23 ` Jan Beulich
2016-04-20 16:07 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-18 6:23 UTC (permalink / raw)
To: konrad.wilk
Cc: keir, ross.lagerwall, andrew.cooper3, ian.jackson, mpohlack, tim,
sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/18/16 7:55 AM >>>
>> >+ if ( delta > elf->len )
>> >+ {
>> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Section table is past end of payload!\n",
>> >+ elf->name);
>> >+ return -EINVAL;
>> >+ }
>> >+
>> >+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
>> >+ {
>> >+ delta = elf->hdr->e_shoff + i * elf->hdr->e_shentsize;
>> >+
>> >+ sec[i].sec = (void *)data + delta;
>>
>> Casting away constness is one of the main reasons I complain about casts in
>> general. If you really need to modify some fields in the section header, you should
>> imo cast away constness just there. But even better would be if you left the
>
>In earlier reviews you said that casting away constness in
>function would be a big no no.
Exactly. Yet what do you do above?
>> section header alone.
>
>I modify sec[i].sec->sh_entsize in calc_section
See the comment there (in the next patch it was, I think).
>>
>> >+ delta = sec[i].sec->sh_offset;
>> >+
>> >+ /*
>> >+ * N.B. elf_resolve_section_names, elf_get_sym skip this check as
>> >+ * we do it here.
>> >+ */
>> >+ if ( delta && (delta + sec[i].sec->sh_size > elf->len) )
>>
>> Allowing delta to be zero here seems suspicious: Are you doing that because
>> some sections come without data (and hence without offset)? In that case you'd
>> better skip the check on those section types (e.g. SHT_NOBITS) only. In fact
>> the offset being below the end of the ELF header would likely indicate a broken
>> image.
>
>The loop (earlier) had started at 0 so the delta could have been zero.
>Anyhow that not being the case anymore I will just do:
>
>if ( !delta )
>return -EINVAL;
As said, I'd suggest making this even more strict by checking at least against
the ELF header size.
>> >+ if ( elf->hdr->e_shoff > elf->len )
>> >+ {
>> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Bogus e_shoff!\n", elf->name);
>> >+ return -EINVAL;
>> >+ }
>>
>> If this check is needed, then >=. But I think it should be redundant with the more
>> complete one in elf_resolve_sections().
>
>This is the overflow check Andrew asked for.
I don't think so - there's no overflow being checked for here at all, this is
just a within bounds check. Just compare with the other one.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 04/27] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op
2016-04-17 8:05 ` Jan Beulich
@ 2016-04-18 7:48 ` Konrad Rzeszutek Wilk
2016-04-18 16:33 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-18 7:48 UTC (permalink / raw)
To: Jan Beulich
Cc: sstabellini, wei.liu2, ross.lagerwall, andrew.cooper3,
ian.jackson, mpohlack, sasha.levin, xen-devel, dgdegra
On Sun, Apr 17, 2016 at 02:05:10AM -0600, Jan Beulich wrote:
> >>> Konrad Rzeszutek Wilk <konrad@kernel.org> 04/15/16 4:29 AM >>>
> >On Thu, Apr 14, 2016 at 10:36:46AM -0600, Jan Beulich wrote:
> >> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:05 AM >>>
> >> > @@ -460,6 +461,11 @@ long do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
> >> > ret = tmem_control(&op->u.tmem_op);
> >> > break;
> >> >
> >> > + case XEN_SYSCTL_xsplice_op:
> >> > + ret = xsplice_op(&op->u.xsplice);
> >> > + copyback = (ret == -ENOSYS || ret == -EOPNOTSUPP) ? 0 : 1;
> >>
> >> Why use a conditional expression here when its condition already is a boolean one
> >> just needing negating?
> >
> >B/c I thought you would want it this way.
> >
> >I changed it to
> >
> >466 if ( ret != -ENOSYS && ret != -EOPNOTSUPP )
> >467 copyback = 1;
>
> That's fine too.
>
> >But I don't think this what you meant by 'negating'? As in:
> >
> >copyback = !rc ?
> >
> >But one of the subops returns the number of items and we definitly
> >want copyback=1 for that.
>
> What I mean with "negating" was
>
> copyback = (ret != -ENOSYS && ret != -EOPNOTSUPP);
>
> >> > + spin_lock(&payload_lock);
> >> > +
> >> > + found = find_payload(n);
> >> > + if ( IS_ERR(found) )
> >> > + {
> >> > + rc = PTR_ERR(found);
> >> > + goto out;
> >> > + }
> >> > + else if ( found )
> >> > + {
> >> > + rc = -EEXIST;
> >> > + goto out;
> >> > + }
> >> > +
> >> > + data = xzalloc(struct payload);
> >>
> >> I generally advocate for not doing allocations with locks held, and I don't think
> >> it would severely complicate the code here doing so.
> >
> >I can certainly unlock and then lock again (when adding
> >it to the list).
>
> That would create a race again afaict. Instead what I have been trying to hint
> at is that the allocation should be done before taking the lock, freeing the object
> again if in the end it turned out it's not going to be needed. Hence the referral to
What if I get -ENOMEM and that the user supplied an payload we already
have? In that case I would return -ENOMEM while I would expect us to
return -EEXIST.
Unless I add some extra checks to continue on?
Also one could do a bit of memory DoS (perhaps by mistake) by continously
uploading the same and same payload and us first allocating the memory,
and then doing the check for the payload existence (which would then
free the memory). Since the allocation is outside the lock we can
eat a bit of memory.
> possibly complicating the code.
>
> Jan
>
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 04/27] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op
2016-04-18 7:48 ` Konrad Rzeszutek Wilk
@ 2016-04-18 16:33 ` Jan Beulich
2016-04-19 10:14 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-18 16:33 UTC (permalink / raw)
To: konrad.wilk
Cc: sstabellini, wei.liu2, ross.lagerwall, andrew.cooper3,
ian.jackson, mpohlack, sasha.levin, xen-devel, dgdegra
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/18/16 9:50 AM >>>
>On Sun, Apr 17, 2016 at 02:05:10AM -0600, Jan Beulich wrote:
>> >>> Konrad Rzeszutek Wilk <konrad@kernel.org> 04/15/16 4:29 AM >>>
>> >On Thu, Apr 14, 2016 at 10:36:46AM -0600, Jan Beulich wrote:
>> >> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:05 AM >>>
>> >> > + spin_lock(&payload_lock);
>> >> > +
>> >> > + found = find_payload(n);
>> >> > + if ( IS_ERR(found) )
>> >> > + {
>> >> > + rc = PTR_ERR(found);
>> >> > + goto out;
>> >> > + }
>> >> > + else if ( found )
>> >> > + {
>> >> > + rc = -EEXIST;
>> >> > + goto out;
>> >> > + }
>> >> > +
>> >> > + data = xzalloc(struct payload);
>> >>
>> >> I generally advocate for not doing allocations with locks held, and I don't think
>> >> it would severely complicate the code here doing so.
>> >
>> >I can certainly unlock and then lock again (when adding
>> >it to the list).
>>
>> That would create a race again afaict. Instead what I have been trying to hint
>> at is that the allocation should be done before taking the lock, freeing the object
>> again if in the end it turned out it's not going to be needed. Hence the referral to
>
>What if I get -ENOMEM and that the user supplied an payload we already
>have? In that case I would return -ENOMEM while I would expect us to
>return -EEXIST.
>
>Unless I add some extra checks to continue on?
Or unless you didn't check the allocation result right after the allocation call,
but only where you check it now.
>Also one could do a bit of memory DoS (perhaps by mistake) by continously
>uploading the same and same payload and us first allocating the memory,
>and then doing the check for the payload existence (which would then
>free the memory). Since the allocation is outside the lock we can
>eat a bit of memory.
Why that? You'd free the memory right away on the error path.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 12/27] xsplice: Implement support for applying/reverting/replacing patches.
2016-04-13 22:01 ` [PATCH v8.1 12/27] xsplice: Implement support for applying/reverting/replacing patches Konrad Rzeszutek Wilk
@ 2016-04-19 6:27 ` Jan Beulich
2016-04-21 0:28 ` Konrad Rzeszutek Wilk
2016-04-22 17:26 ` Konrad Rzeszutek Wilk
0 siblings, 2 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-19 6:27 UTC (permalink / raw)
To: ross.lagerwall, konrad, konrad.wilk
Cc: kevin.tian, sstabellini, keir, suravee.suthikulpanit,
andrew.cooper3, mpohlack, julien.grall, jun.nakajima,
sasha.levin, xen-devel, boris.ostrovsky
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
>--- a/docs/misc/xsplice.markdown
>+++ b/docs/misc/xsplice.markdown
>@@ -289,8 +289,13 @@ describing the functions to be patched:
><pre>
>struct xsplice_patch_func {
>const char *name;
>+#if BITS_PER_LONG == 32
>+ uint32_t new_addr;
>+ uint32_t old_addr;
>+#else
>uint64_t new_addr;
>uint64_t old_addr;
>+#endif
I don't think this belongs here (instead it should go wherever the structure gets
introduced).
>@@ -298,7 +303,8 @@ struct xsplice_patch_func {
>};
></pre>
>
>-The size of the structure is 64 bytes.
>+The size of the structure is 64 bytes or 52 bytes if compiled under 32-bit
>+hypervisors.
And I'm uncertain this sentence is of much value.
>@@ -120,6 +121,7 @@ static void idle_loop(void)
>(*pm_idle)();
>do_tasklet();
>do_softirq();
>+ check_for_xsplice_work(); /* Must be last. */
Without also saying why, the comment isn't very useful imo.
>+void arch_xsplice_apply_jmp(struct xsplice_patch_func_internal *func)
>+{
>+ int32_t val;
>+ uint8_t *old_ptr;
>+
>+ BUILD_BUG_ON(PATCH_INSN_SIZE > sizeof(func->u.undo));
>+ BUILD_BUG_ON(PATCH_INSN_SIZE != (1 + sizeof val));
Standard sizeof() please.
>+ old_ptr = func->old_addr;
>+ memcpy(func->u.undo, old_ptr, PATCH_INSN_SIZE);
>+
>+ *old_ptr++ = 0xe9; /* Relative jump */
>+ val = func->new_addr - func->old_addr - PATCH_INSN_SIZE;
>+ memcpy(old_ptr, &val, sizeof val);
Again (and I won't make further comments to that effect, the more that this was
requested in a previous round already anyway).
>+/*
>+ * Note that because of this NOP code the do_nmi is not safely patchable.
>+ * Also if we do receive 'real' NMIs we have lost them. Ditto for MCE.
>+ */
The reference to MCE is misleading here: You don't redirect the latter here, so its
handling is not the same as NMI.
>@@ -148,12 +224,12 @@ int arch_xsplice_secure(void *va, unsigned int pages, enum va_type type)
>ASSERT(va);
>ASSERT(pages);
>
>- if ( type == XSPLICE_VA_RX ) /* PAGE_HYPERVISOR_RX */
>- flag = _PAGE_PRESENT;
>- else if ( type == XSPLICE_VA_RW ) /* PAGE_HYPERVISOR_RW */
>- flag = _PAGE_RW | _PAGE_NX | _PAGE_PRESENT;
>- else /* PAGE_HYPERVISOR_RO */
>- flag = _PAGE_NX | _PAGE_PRESENT;
>+ if ( type == XSPLICE_VA_RX )
>+ flag = PAGE_HYPERVISOR_RX;
>+ else if ( type == XSPLICE_VA_RW )
>+ flag = PAGE_HYPERVISOR_RW;
>+ else
>+ flag = PAGE_HYPERVISOR_RO;
Misplaced hunk (belongs in an earlier patch, and matches exactly what I had asked
for there).
>@@ -11,18 +12,28 @@
>#include <xen/mm.h>
>#include <xen/sched.h>
>#include <xen/smp.h>
>+#include <xen/softirq.h>
>#include <xen/spinlock.h>
>#include <xen/vmap.h>
>+#include <xen/wait.h>
>#include <xen/xsplice_elf.h>
>#include <xen/xsplice.h>
>
>#include <asm/event.h>
>#include <public/sysctl.h>
>
>-/* Protects against payload_list operations. */
>+/*
>+ * Protects against payload_list operations and also allows only one
>+ * caller in schedule_work.
>+ */
>static DEFINE_SPINLOCK(payload_lock);
>static LIST_HEAD(payload_list);
>
>+/*
>+ * Patches which have been applied.
>+ */
Ehem - comment style (still).
>+/* Defines an outstanding patching action. */
>+struct xsplice_work
>+{
>+ atomic_t semaphore; /* Used for rendezvous. */
>+ atomic_t irq_semaphore; /* Used to signal all IRQs disabled. */
Why do you, btw, need two of them? I would seem to me that having just one
for both purposes should be fine.
>+static int check_special_sections(const struct xsplice_elf *elf)
>+{
>+ unsigned int i;
>+ static const char *const names[] = { ".xsplice.funcs" };
>+ unsigned int count[ARRAY_SIZE(names)] = { 0 };
>+
>+ for ( i = 0; i < ARRAY_SIZE(names); i++ )
>+ {
>+ const struct xsplice_elf_sec *sec;
>+
>+ sec = xsplice_elf_sec_by_name(elf, names[i]);
>+ if ( !sec )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: %s is missing!\n",
>+ elf->name, names[i]);
>+ return -EINVAL;
>+ }
>+
>+ if ( !sec->sec->sh_size )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: %s is empty!\n",
>+ elf->name, names[i]);
>+ return -EINVAL;
>+ }
>+ count[i]++;
To conserve stack space, use a bool_t array instead and do the check-and-exit
here instead of in a second loop.
>+static int prepare_payload(struct payload *payload,
>+ struct xsplice_elf *elf)
>+{
>+ const struct xsplice_elf_sec *sec;
>+ unsigned int i;
>+ struct xsplice_patch_func_internal *f;
Why is there a second ("internal") variant of this structure now? What
guarantees it to remain in sync with the non-"internal" one?
>+ sec = xsplice_elf_sec_by_name(elf, ".xsplice.funcs");
Since the string literal occurs at least twice, I'd suggest having a #define for it.
>+ ASSERT(sec);
>+ if ( sec->sec->sh_size % sizeof(*payload->funcs) )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong size of .xsplice.funcs!\n",
>+ elf->name);
>+ return -EINVAL;
>+ }
>+
>+ payload->funcs = sec->load_addr;
>+ payload->nfuncs = sec->sec->sh_size / sizeof(*payload->funcs);
Following to our discussion yesterday - can't we (ab)use the section merge
flag here to report the structure size, along the lines of what relocation
sections do for their elements?
>+ for ( i = 0; i < payload->nfuncs; i++ )
>+ {
>+ int rc;
>+ unsigned int j;
>+
>+ f = &(payload->funcs[i]);
>+
>+ if ( f->version != XSPLICE_PAYLOAD_VERSION )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong version (%u). Expected %d!\n",
>+ elf->name, f->version, XSPLICE_PAYLOAD_VERSION);
>+ return -EOPNOTSUPP;
>+ }
>+
>+ if ( !f->new_addr || !f->new_size )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Address or size fields are zero!\n",
>+ elf->name);
>+ return -EINVAL;
>+ }
>+
>+ rc = arch_xsplice_verify_func(f);
>+ if ( rc )
>+ return rc;
>+
>+ for ( j = 0; j < ARRAY_SIZE(f->u.pad); j++ )
>+ if ( f->u.pad[j] )
>+ return -EINVAL;
>+ }
Is that actually useful? It doesn't really matter what's in that space.
>+static int apply_payload(struct payload *data)
>+{
>+ unsigned int i;
>+
>+ printk(XENLOG_INFO XSPLICE "%s: Applying %u functions.\n",
No full stops in log messages please.
>+/*
>+ * This function is executed having all other CPUs with no stack (we may
>+ * have cpu_idle on it) and IRQs disabled. We guard against NMI by temporarily
>+ * installing our NOP NMI handler.
>+ */
The recurring (from the design doc) use of the wording "with no stack" has been
puzzling me from the beginning. Nothing really executes with no stack. How
about "without deep call stack" or some such?
Also - aren't we in common code here? If so, a reference to NMI doesn't belong
here (and a reference to MCE should really be added if the comment got moved
elsewhere).
>+static void xsplice_do_action(void)
>+{
>+ int rc;
>+ struct payload *data, *other, *tmp;
>+
>+ data = xsplice_work.data;
>+ /*
>+ * Now this function should be the only one on any stack.
>+ * No need to lock the payload list or applied list.
>+ */
Is "the only one" really a precise, architecture independent statement? Aren't
we getting here perhaps with at least one more return address on the stack
(the transition back from C to assembly code)?
>+static int xsplice_spin(atomic_t *counter, s_time_t timeout,
>+ unsigned int cpus, const char *s)
>+{
>+ int rc = 0;
>+
>+ while ( atomic_read(counter) != cpus && NOW() < timeout )
>+ cpu_relax();
>+
>+ /* Log & abort. */
>+ if ( atomic_read(counter) != cpus )
>+ {
>+ printk(XENLOG_ERR XSPLICE "%s: Timed out on %s semaphore %u/%u\n",
>+ xsplice_work.data->name, s, atomic_read(counter), cpus);
>+ rc = -EBUSY;
>+ xsplice_work.data->rc = rc;
>+ xsplice_work.do_work = 0;
>+ smp_wmb();
Doesn't this need to move one line up? There's no further write following here,
so there's nothing this barrier separates right now.
>+ /*
>+ * Do NOT decrement semaphore down - as that may cause the other
>+ * CPU (which may be at this ready to increment it)
Odd wording?
>+ * to assume the role of master and then needlessly time out
>+ * out (as do_work is zero).
>+ */
>+ smp_wmb();
Same comment as above regarding placement.
>+ /* Flush the CPU i-cache via CPUID instruction (on x86). */
>+ arch_xsplice_post_action();
CPUID, as mentioned before, does not do any i-cache flushing.
>+ abort:
>+ per_cpu(work_to_do, cpu) = 0;
>+ xsplice_work.do_work = 0;
>+
>+ smp_wmb(); /* MUST complete writes before put_cpu_maps(). */
>+
>+ put_cpu_maps();
put_cpu_maps() is a spin unlock, i.e. a write barrier anyway.
>@@ -597,15 +1022,43 @@ static void xsplice_printall(unsigned char key)
>}
>
>list_for_each_entry ( data, &payload_list, list )
>+ {
>printk(" name=%s state=%s(%d) %p (.data=%p, .rodata=%p) using %zu pages.\n",
>data->name, state2str(data->state), data->state, data->text_addr,
>data->rw_addr, data->ro_addr, data->pages);
>
>+ for ( i = 0; i < data->nfuncs; i++ )
>+ {
>+ struct xsplice_patch_func_internal *f = &(data->funcs[i]);
>+ printk(" %s patch %p(%u) with %p (%u)\n",
>+ f->name, f->old_addr, f->old_size, f->new_addr, f->new_size);
>+
>+ if ( i && !(i % 64) )
>+ {
>+ spin_unlock(&payload_lock);
>+ process_pending_softirqs();
>+ spin_lock(&payload_lock);
Iirc the initial acquire now intentionally is a try-lock. Hence it's quite clear
that this one can't be anything else either.
>static int __init xsplice_init(void)
>{
>+ BUILD_BUG_ON( sizeof(struct xsplice_patch_func) !=
>+ sizeof(struct xsplice_patch_func_internal) );
>+ BUILD_BUG_ON( sizeof(struct xsplice_patch_func_internal) !=
>+ XSPLICE_PATCH_FUNC_INTERNAL_SIZE );
>+
>+#if BITS_PER_LONG == 64
>+ BUILD_BUG_ON( offsetof(struct xsplice_patch_func, new_addr) != 8 );
>+ BUILD_BUG_ON( offsetof(struct xsplice_patch_func, new_size) != 24 );
>+#else
>+ BUILD_BUG_ON( offsetof(struct xsplice_patch_func, new_addr) != 4 );
>+ BUILD_BUG_ON( offsetof(struct xsplice_patch_func, new_size) != 12 );
>+#endif
I don't see the point of these: If anything, you want to make sure "internal" and
normal structure offsets don't disagree.
>--- a/xen/include/asm-x86/current.h
>+++ b/xen/include/asm-x86/current.h
>@@ -86,10 +86,18 @@ static inline struct cpu_info *get_cpu_info(void)
>unsigned long get_stack_trace_bottom(unsigned long sp);
>unsigned long get_stack_dump_bottom (unsigned long sp);
>
>+#ifdef CONFIG_XSPLICE
>+# define __CHECK_FOR_XSPLICE_WORK "call check_for_xsplice_work;"
>+#else
>+# define __CHECK_FOR_XSPLICE_WORK ""
>+#endif
No leading underscores please.
>--- a/xen/include/public/sysctl.h
>+++ b/xen/include/public/sysctl.h
>@@ -833,6 +833,33 @@ DEFINE_XEN_GUEST_HANDLE(xen_sysctl_featureset_t);
>* If zero exit with success.
>*/
>
>+#define XSPLICE_PAYLOAD_VERSION 1
>+/*
>+ * .xsplice.funcs structure layout defined in the `Payload format`
>+ * section in the xSplice design document.
>+ *
>+ * The size should be exactly 64 bytes (64) or 52 bytes (32).
Putting aside the usefulness of this comment, the items in parentheses aren't
really clear - DYM 64-bit and 32-bit respectively?
>+ * We guard this with __XEN__ as toolstacks do not need to use it.
I'd make this even more strict, if you want such a comment at all.
>+/*
>+ * The structure which defines the patching. This is what the hypervisor
>+ * expects in the '.xsplice.func' section of the ELF file.
>+ *
>+ * This MUST be in sync with what the tools generate. We expose
>+ * for the tools the 'struct xsplice_patch_func' which does not have
>+ * platform specific entries.
>+ */
>+#if BITS_PER_LONG == 64
>+#define XSPLICE_PATCH_FUNC_INTERNAL_SIZE 64
>+#else
>+#define XSPLICE_PATCH_FUNC_INTERNAL_SIZE 52
>+#endif
This is getting really odd. I can only hope all this goes away with ...
>+struct xsplice_patch_func_internal {
... this getting folded back into the public header version.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 04/27] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op
2016-04-18 16:33 ` Jan Beulich
@ 2016-04-19 10:14 ` Konrad Rzeszutek Wilk
0 siblings, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-19 10:14 UTC (permalink / raw)
To: Jan Beulich
Cc: sstabellini, wei.liu2, ross.lagerwall, andrew.cooper3,
ian.jackson, mpohlack, sasha.levin, xen-devel, dgdegra
On Mon, Apr 18, 2016 at 10:33:46AM -0600, Jan Beulich wrote:
> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/18/16 9:50 AM >>>
> >On Sun, Apr 17, 2016 at 02:05:10AM -0600, Jan Beulich wrote:
> >> >>> Konrad Rzeszutek Wilk <konrad@kernel.org> 04/15/16 4:29 AM >>>
> >> >On Thu, Apr 14, 2016 at 10:36:46AM -0600, Jan Beulich wrote:
> >> >> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:05 AM >>>
> >> >> > + spin_lock(&payload_lock);
> >> >> > +
> >> >> > + found = find_payload(n);
> >> >> > + if ( IS_ERR(found) )
> >> >> > + {
> >> >> > + rc = PTR_ERR(found);
> >> >> > + goto out;
> >> >> > + }
> >> >> > + else if ( found )
> >> >> > + {
> >> >> > + rc = -EEXIST;
> >> >> > + goto out;
> >> >> > + }
> >> >> > +
> >> >> > + data = xzalloc(struct payload);
> >> >>
> >> >> I generally advocate for not doing allocations with locks held, and I don't think
> >> >> it would severely complicate the code here doing so.
> >> >
> >> >I can certainly unlock and then lock again (when adding
> >> >it to the list).
> >>
> >> That would create a race again afaict. Instead what I have been trying to hint
> >> at is that the allocation should be done before taking the lock, freeing the object
> >> again if in the end it turned out it's not going to be needed. Hence the referral to
> >
> >What if I get -ENOMEM and that the user supplied an payload we already
> >have? In that case I would return -ENOMEM while I would expect us to
> >return -EEXIST.
> >
> >Unless I add some extra checks to continue on?
>
> Or unless you didn't check the allocation result right after the allocation call,
> but only where you check it now.
Which is OK for data = xzalloc(struct payload);
That is not much data.
The issue is later (the 'Implement payload loading') is the allocation
of the raw_data which wants memory of size by ELF file.
This can be say 100kB or such.
>
> >Also one could do a bit of memory DoS (perhaps by mistake) by continously
> >uploading the same and same payload and us first allocating the memory,
> >and then doing the check for the payload existence (which would then
> >free the memory). Since the allocation is outside the lock we can
> >eat a bit of memory.
>
> Why that? You'd free the memory right away on the error path.
>
> Jan
>
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 13/27] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version'.
2016-04-13 22:01 ` [PATCH v8.1 13/27] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version' Konrad Rzeszutek Wilk
@ 2016-04-19 17:40 ` Jan Beulich
2016-04-20 16:10 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-19 17:40 UTC (permalink / raw)
To: ross.lagerwall, konrad, konrad.wilk
Cc: sstabellini, keir, andrew.cooper3, mpohlack, julien.grall,
xen-devel, sasha.levin
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
>--- a/xen/arch/arm/Makefile
>+++ b/xen/arch/arm/Makefile
>@@ -57,6 +57,8 @@ ifeq ($(CONFIG_ARM_64),y)
>ln -sf $(notdir $@) ../../$(notdir $@).efi
>endif
>
>+tests:
I think this should be phony just like ...
>--- a/xen/arch/x86/Makefile
>+++ b/xen/arch/x86/Makefile
>@@ -76,6 +76,9 @@ $(TARGET): $(TARGET)-syms $(efi-y) boot/mkelf32
>./boot/mkelf32 $(TARGET)-syms $(TARGET) 0x100000 \
>`$(NM) -nr $(TARGET)-syms | head -n 1 | sed -e 's/^\([^ ]*\).*/0x\1/'`
>
>+.PHONY: tests
>+tests:
>+ $(MAKE) -f $(BASEDIR)/Rules.mk -C test xsplice
... this one.
>--- /dev/null
>+++ b/xen/arch/x86/test/Makefile
>@@ -0,0 +1,44 @@
>+include $(XEN_ROOT)/Config.mk
>+
>+CODE_ADDR=$(shell nm --defined $(1) | grep $(2) | awk '{print "0x"$$1}')
>+CODE_SZ=$(shell nm --defined -S $(1) | grep $(2) | awk '{ print "0x"$$2}')
>+
>+.PHONY: default
>+
>+XSPLICE := xen_hello_world.xsplice
>+
>+default: xsplice
>+
>+install: xsplice
>+ $(INSTALL_DATA) $(XSPLICE) $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE)
>+uninstall:
>+ rm -f $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE)
>+
>+.PHONY: clean
>+clean::
>+ rm -f *.o .*.o.d $(XSPLICE) config.h
>+
>+#
>+# To compute these values we need the binary files: xen-syms
>+# and xen_hello_world_func.o to be already compiled.
>+#
>+# We can be assured that xen-syms is already built as we are
>+# the last entry in the build target.
Stale comment afaict.
>+.PHONY: xsplice
>+xsplice: config.h
>+ # Need to have these done in sequential order
>+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_hello_world_func.o
>+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_hello_world.o
Why do these two need doing in order? And why can't $(XSPLICE) not just depend
on its to object files, without needing explict make invocation to generate them?
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-13 22:01 ` [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address Konrad Rzeszutek Wilk
@ 2016-04-19 19:31 ` Jan Beulich
2016-04-20 12:55 ` Ross Lagerwall
2016-04-21 0:26 ` Konrad Rzeszutek Wilk
0 siblings, 2 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-19 19:31 UTC (permalink / raw)
To: ross.lagerwall, konrad, konrad.wilk
Cc: andrew.cooper3, keir, mpohlack, sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:02 AM >>>
>--- a/xen/arch/x86/test/xen_hello_world.c
>+++ b/xen/arch/x86/test/xen_hello_world.c
>@@ -10,11 +10,14 @@
>static char hello_world_patch_this_fnc[] = "xen_extra_version";
>extern const char *xen_hello_world(void);
>
>+/* External symbol. */
>+extern const char *xen_extra_version(void);
To give a good example, I think this would better include the respective
header.
>struct xsplice_patch_func __section(".xsplice.funcs") xsplice_xen_hello_world = {
>.version = XSPLICE_PAYLOAD_VERSION,
>.name = hello_world_patch_this_fnc,
>.new_addr = (unsigned long)(xen_hello_world),
>- .old_addr = OLD_CODE,
>+ .old_addr = (unsigned long)(xen_extra_version),
Pointless parentheses (also btw on the new_addr initializer, which would be
nice to get fixed in the earlier patch).
>+unsigned long symbols_lookup_by_name(const char *symname)
>+{
>+ char name[KSYM_NAME_LEN + 1] = { 0 };
I continue to think that this initializer is pointless. And if this or a variant filling
just the first byte was needed, then please be consistent with the rest of the
function and either use '\0' here or plain 0 in the other two relevant places.
>+ uint32_t symnum = 0;
>+ char type;
>+ uint64_t addr = 0;
Same here.
>+ int rc;
>+
>+ if ( symname == '\0' )
DYM *symname?
>@@ -51,6 +52,9 @@ struct payload {
>struct list_head applied_list; /* Linked to 'applied_list'. */
>struct xsplice_patch_func_internal *funcs; /* The array of functions to patch. */
>unsigned int nfuncs; /* Nr of functions to patch. */
>+ struct xsplice_symbol *symtab; /* All symbols. */
>+ char *strtab; /* Pointer to .strtab. */
At least the latter of the two I'm convinced can be const.
>+unsigned long xsplice_symbols_lookup_by_name(const char *symname)
>+{
>+ struct payload *data;
const
>+ ASSERT(spin_is_locked(&payload_lock));
>+ list_for_each_entry ( data, &payload_list, list )
>+ {
>+ unsigned int i;
>+
>+ for ( i = 0; i < data->nsyms; i++ )
>+ {
>+ if ( !data->symtab[i].new_symbol )
>+ continue;
Do you need symbols other than those marked "new_symbol" past the loading
of the module? If not, wouldn't it be worthwhile to shrink the symbol table to just
those, likely speeding up the lookup?
>@@ -379,11 +405,129 @@ static int prepare_payload(struct payload *payload,
>for ( j = 0; j < ARRAY_SIZE(f->u.pad); j++ )
>if ( f->u.pad[j] )
>return -EINVAL;
>+
>+ /* Lookup function's old address if not already resolved. */
>+ if ( !f->old_addr )
>+ {
>+ f->old_addr = (void *)symbols_lookup_by_name(f->name);
>+ if ( !f->old_addr )
>+ {
>+ f->old_addr = (void *)xsplice_symbols_lookup_by_name(f->name);
The two casts make me wonder whether the two functions shouldn't return
void *, and then whether struct xsplice_symbol's value field shouldn't then
perhaps be void * too.
>+ if ( !f->old_addr )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Could not resolve old address of %s\n",
>+ elf->name, f->name);
>+ return -ENOENT;
>+ }
>+ }
>+ dprintk(XENLOG_DEBUG, XSPLICE "%s: Resolved old address %s => %p\n",
>+ elf->name, f->name, f->old_addr);
>+ }
>}
>
>return 0;
>}
So one thing I'm realizing only now: Is there no support for using <symbol>+<offset>
to fill ->old_addr?
>+static bool_t is_payload_symbol(const struct xsplice_elf *elf,
>+ const struct xsplice_elf_sym *sym)
>+{
>+ if ( sym->sym->st_shndx == SHN_UNDEF ||
>+ sym->sym->st_shndx >= elf->hdr->e_shnum )
>+ return 0;
>+
>+ return (elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) &&
>+ (ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT ||
>+ ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
I don't recall having seen a reply to the question on not allowing STT_NOTYPE here.
>+static int build_symbol_table(struct payload *payload,
>+ const struct xsplice_elf *elf)
>+{
>+ unsigned int i, j, nsyms = 0;
>+ size_t strtab_len = 0;
>+ struct xsplice_symbol *symtab;
>+ char *strtab;
>+
>+ ASSERT(payload->nfuncs);
>+
>+ /* Recall that section @0 is always NULL. */
>+ for ( i = 1; i < elf->nsym; i++ )
>+ {
>+ if ( is_payload_symbol(elf, elf->sym + i) )
>+ {
>+ nsyms++;
>+ strtab_len += strlen(elf->sym[i].name) + 1;
>+ }
>+ }
>+
>+ symtab = xmalloc_array(struct xsplice_symbol, nsyms);
>+ strtab = xmalloc_array(char, strtab_len);
>+
>+ if ( !strtab || !symtab )
>+ {
>+ xfree(strtab);
>+ xfree(symtab);
>+ return -ENOMEM;
>+ }
>+
>+ nsyms = 0;
>+ strtab_len = 0;
>+ for ( i = 1; i < elf->nsym; i++ )
>+ {
>+ if ( is_payload_symbol(elf, elf->sym + i) )
>+ {
>+ symtab[nsyms].name = strtab + strtab_len;
>+ symtab[nsyms].size = elf->sym[i].sym->st_size;
>+ symtab[nsyms].value = elf->sym[i].sym->st_value;
>+ symtab[nsyms].new_symbol = 0; /* To be checked below. */
Why "checked"? The only thing happening further down is this possibly
getting overwritten with 1.
>@@ -274,9 +275,21 @@ int xsplice_elf_resolve_symbols(struct xsplice_elf *elf)
>break;
>
>case SHN_UNDEF:
>- dprintk(XENLOG_ERR, XSPLICE "%s: Unknown symbol: %s\n",
>- elf->name, elf->sym[i].name);
>- rc = -ENOENT;
>+ elf->sym[i].sym->st_value = (unsigned long)symbols_lookup_by_name(elf->sym[i].name);
With its current return value, the cast is pointless. But this makes clear that either
here or above a cast is going to be needed. So perhaps just keep it as is, except
for this unnecessary cast.
>+ if ( !elf->sym[i].sym->st_value )
>+ {
>+ elf->sym[i].sym->st_value = (unsigned long)xsplice_symbols_lookup_by_name(elf->sym[i].name);
And this one then, obviously.
>--- a/xen/include/xen/xsplice.h
>+++ b/xen/include/xen/xsplice.h
>@@ -46,8 +46,16 @@ struct xsplice_patch_func_internal {
>/* Convenience define for printk. */
>#define XSPLICE "xsplice: "
>
>+struct xsplice_symbol {
>+ const char *name;
>+ uint64_t value;
Either void * (see above) or unsigned long. No point in being 64-bit for e.g. ARM32.
>+ size_t size;
I don't see this field being used for anything, it seems to only ever get written to.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 15/27] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup
2016-04-13 22:01 ` [PATCH v8.1 15/27] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup Konrad Rzeszutek Wilk
@ 2016-04-19 19:52 ` Jan Beulich
2016-04-22 15:21 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-19 19:52 UTC (permalink / raw)
To: mpohlack, andrew.cooper3, ross.lagerwall, konrad, xen-devel,
konrad.wilk, sasha.levin
Cc: keir
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:02 AM >>>
>NEW CODE:
>
>To make that work we add three tables:
Why three? Two (or a single one with element pairs) ought to be sufficient:
Afaict you could just have (symbol-address,symbol-offset) pairs which you
then sort and search by name (using symbols_expand_symbol() on
symbol-offset, which in turn you store using the result of get_symbol_offset()
during setup of the table).
>1) symbols_addresses_index_sorted[0..symbols_num_syms]. The values are
>indicies into symbols_addresses array. This is a 1-1 table:
>
>symbols_addresses_index_sorted:
>.long 6315
>.long 6097
>
>To get the address of a symbol at offset 0 in symbols_name_sorted
>(see below) we look in symbols_addresses_index_sorted[0] to get
>6315 and then look in symbols_addresses_index[6315] to find it.
>
>2) The symbols_names_sorted stream - same format as symbols_names but
>constructued by sorting the <type>[filename#]<symbol> by <symbol>,
>then [filename#] and lastly type. Recall that symbol_names is sorted
>based on addresses of the symbols.
Why would you treat the <filename># prefix specially? The full thing is the
symbol you should care about imo.
>3) To make it simpler to search we also add an symbols_markers_sorted
>array (of size symbols_num_syms/255).
>Searching for symbols is simplified as we can do a binary search
>on symbol_names_sorted (and using symbols_markers_sorted). Since the
>symbols are sorted it takes on average 13 calls to symbols_expand_symbol.
>
>Doing small tests (search for five different symbols) using the old
>and new mechanism show 2ms vs 0ms improvement.
What does "2m vs 0ms" improvement mean here? If you mean to say that on
some symbols there's no gain at all, then I'd question whether millisecond
granularity is enough to see an improvement.
With the basic data question above I'm not going to look at the actual code
for now; I'll leave this until either I understand why the suggested variant
can't work, or until a future version implementing that one.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 16/27] x86, xsplice: Print payload's symbol name and payload name in backtraces
2016-04-13 22:01 ` [PATCH v8.1 16/27] x86, xsplice: Print payload's symbol name and payload name in backtraces Konrad Rzeszutek Wilk
@ 2016-04-19 20:09 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-19 20:09 UTC (permalink / raw)
To: ross.lagerwall, konrad, konrad.wilk
Cc: keir, andrew.cooper3, ian.jackson, mpohlack, tim, xen-devel, sasha.levin
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
>@@ -331,16 +332,23 @@ static char *pointer(char *str, char *end, const char **fmt_ptr,
>{
>unsigned long sym_size, sym_offset;
>char namebuf[KSYM_NAME_LEN+1];
>+ bool_t payload = 0;
I don't see the point of this variable. You can simply do ...
>/* Advance parents fmt string, as we have consumed 's' or 'S' */
>++*fmt_ptr;
>
>s = symbols_lookup((unsigned long)arg, &sym_size, &sym_offset, namebuf);
>-
>- /* If the symbol is not found, fall back to printing the address */
>+ /* If the symbol is not found, fall back to printing the address. */
... (perhaps omitting this unrelated style correction) ...
>if ( !s )
>break;
>
>+ /*
>+ * namebuf contents and s for core hypervisor are same but for xSplice
>+ * payloads they differ (namebuf contains the name of the payload).
>+ */
>+ if ( namebuf != s )
... this comparison ...
>@@ -354,6 +362,13 @@ static char *pointer(char *str, char *end, const char **fmt_ptr,
>str = number(str, end, sym_size, 16, -1, -1, SPECIAL);
>}
>
>+ if ( payload )
... here.
>+static const char *xsplice_symbols_lookup(unsigned long addr,
>+ unsigned long *symbolsize,
>+ unsigned long *offset,
>+ char *namebuf)
>+{
>+ struct payload *data;
const
>+ unsigned int i;
>+ int best;
>+
>+ /*
>+ * No locking since this list is only ever changed during apply or revert
>+ * context.
>+ */
>+ list_for_each_entry ( data, &applied_list, applied_list )
>+ {
>+ if ( (void *)addr < data->text_addr &&
>+ (void *)addr >= (data->text_addr + data->pages * PAGE_SIZE) )
>+ continue;
>+
>+ best = -1;
>+
>+ for ( i = 0; i < data->nsyms; i++ )
>+ {
>+ if ( data->symtab[i].value <= addr &&
>+ (best == -1 ||
>+ data->symtab[best].value < data->symtab[i].value) )
>+ best = i;
Considering this, "best" would probably also better be unsigned int, and
you could then set and compare it to data->nsyms or UINT_MAX.
>+ }
>+
>+ if ( best == -1 )
>+ return NULL;
>+
>+ if ( symbolsize )
>+ *symbolsize = data->symtab[best].size;
Ah, here is where you need the size.
>@@ -425,6 +475,13 @@ static int prepare_payload(struct payload *payload,
>}
>}
>
>+ /* Setup the virtual region with proper data. */
>+ region = &payload->region;
>+
>+ region->symbols_lookup = xsplice_symbols_lookup;
>+ region->start = (unsigned long)payload->text_addr;
>+ region->end = (unsigned long)(payload->text_addr + payload->text_size);
Again makes questionable whether region's start and end fields wouldn't better be
const void *.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 17/27] xsplice: Add support for bug frames.
2016-04-13 22:01 ` [PATCH v8.1 17/27] xsplice: Add support for bug frames Konrad Rzeszutek Wilk
@ 2016-04-19 20:17 ` Jan Beulich
2016-04-21 0:29 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-19 20:17 UTC (permalink / raw)
To: ross.lagerwall, konrad, konrad.wilk
Cc: andrew.cooper3, keir, mpohlack, sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:02 AM >>>
>+bool_t is_patch(const void *ptr)
>+{
>+ struct payload *data;
You guess it: const.
>+ /*
>+ * No locking since this list is only ever changed during apply or revert
>+ * context.
>+ */
What if you crash while applying or reverting a patch? Is the list update at
least done such that the (then nested) traversal remains safe?
>@@ -482,6 +508,30 @@ static int prepare_payload(struct payload *payload,
>region->start = (unsigned long)payload->text_addr;
>region->end = (unsigned long)(payload->text_addr + payload->text_size);
>
>+ /* Optional sections. */
>+ for ( i = 0; i < BUGFRAME_NR; i++ )
>+ {
>+ char str[14];
>+
>+ snprintf(str, sizeof(str), ".bug_frames.%u", i);
>+ sec = xsplice_elf_sec_by_name(elf, str);
>+ if ( !sec )
>+ continue;
>+
>+ if ( sec->sec->sh_size &&
>+ (sec->sec->sh_size % sizeof(*region->frame[i].bugs)) )
The left side of the && seems pointless.
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong size of .bug_frames.%u!\n",
>+ elf->name, i);
>+ return -EINVAL;
>+ }
>+
>+ region->frame[i].bugs = sec->load_addr;
>+ if ( sec->sec->sh_size)
>+ region->frame[i].n_bugs = sec->sec->sh_size /
>+ sizeof(*region->frame[i].bugs);
As does the conditional here.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 18/27] xsplice: Add support for exception tables.
2016-04-13 22:01 ` [PATCH v8.1 18/27] xsplice: Add support for exception tables Konrad Rzeszutek Wilk
@ 2016-04-19 20:31 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-19 20:31 UTC (permalink / raw)
To: ross.lagerwall, konrad, konrad.wilk
Cc: andrew.cooper3, keir, mpohlack, sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
>@@ -48,19 +49,23 @@ static void __init swap_ex(void *a, void *b, int size)
>}
>#endif
>
>-void __init sort_exception_tables(void)
>+void __INIT sort_exception_table(struct exception_table_entry *start,
>+ struct exception_table_entry *stop)
The latter can (and hence should) be const.
>--- a/xen/arch/x86/test/xen_hello_world_func.c
>+++ b/xen/arch/x86/test/xen_hello_world_func.c
>@@ -5,9 +5,20 @@
>
>#include <xen/types.h>
>
>+static unsigned long *non_canonical_addr = (unsigned long *)(0xdead000000000000ULL);
Stray parentheses.
>--- a/xen/include/xen/xsplice.h
>+++ b/xen/include/xen/xsplice.h
>@@ -43,6 +43,15 @@ struct xsplice_patch_func_internal {
>} u;
>};
>
>+/*
>+ * We use alternative and exception table code - which by default are __init
>+ * only, however we need them during runtime. These macros allows us to build
>+ * the image with these functions built-in. (See the #else below).
>+ */
>+#define __INITCONST
>+#define __INITDATA
>+#define __INIT
I'm generally opposed to new symbols with double underscores in front of
them. Maybe (considering the non-xSplice case) in this case they're warranted,
but I'd prefer something along the lines of Linux'es __init_or_module (without
the double underscores then of course).
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 19/27] xsplice: Add support for alternatives
2016-04-13 22:02 ` [PATCH v8.1 19/27] xsplice: Add support for alternatives Konrad Rzeszutek Wilk
@ 2016-04-20 6:28 ` Jan Beulich
2016-04-21 0:30 ` Konrad Rzeszutek Wilk
` (2 more replies)
0 siblings, 3 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-20 6:28 UTC (permalink / raw)
To: ross.lagerwall, konrad, konrad.wilk
Cc: andrew.cooper3, keir, mpohlack, sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:02 AM >>>
>--- a/xen/arch/x86/Makefile
>+++ b/xen/arch/x86/Makefile
>@@ -6,7 +6,11 @@ subdir-y += mm
>subdir-$(CONFIG_XENOPROF) += oprofile
>subdir-y += x86_64
>
>+ifdef CONFIG_XSPLICE
>+obj-y += alternative.o
>+else
>obj-bin-y += alternative.init.o
>+endif
For now this is okay, but please try to use the list model in favor of ifdef-s in
the future, whenever possible.
>#ifdef K8_NOP1
>-static const unsigned char k8nops[] __initconst = {
>+static const unsigned char k8nops[] __INITCONST = {
>K8_NOP1,
>K8_NOP2,
>K8_NOP3,
>@@ -52,7 +53,7 @@ static const unsigned char * const k8_nops[ASM_NOP_MAX+1] __initconstrel = {
The context here suggests you didn't complete your conversion work: The
__initconstrel hardly can remain unchanged if the objects are now being
referenced by objects in non-init sections.
>@@ -125,9 +126,10 @@ static void __init add_nops(void *insns, unsigned int len)
>* instructions. And on the local CPU you need to be protected again NMI or MCE
>* handlers seeing an inconsistent instruction while you patch.
>*
>- * This routine is called with local interrupt disabled.
>+ * You should run this with interrupts disabled or on code that has never
>+ * been executed.
The second half is misleading - there's no such requirement for early boot
patching. The requirement is that the code must not currently be executing
(which at that time is guaranteed by there only being a single CPU, which
is in a well defined region of code).
>@@ -12,6 +15,8 @@ const char *xen_hello_world(void)
>{
>unsigned long tmp;
>int rc;
>+
>+ alternative(ASM_NOP1, ASM_NOP1, X86_FEATURE_LM);
So to cover the issue pointed out above you should be patching a longer
instruction with a shorter one here.
>--- a/xen/common/xsplice.c
>+++ b/xen/common/xsplice.c
>@@ -533,6 +533,39 @@ static int prepare_payload(struct payload *payload,
>}
>
>#ifndef CONFIG_ARM
>+ sec = xsplice_elf_sec_by_name(elf, ".altinstructions");
>+ if ( sec )
>+ {
>+ struct alt_instr *a, *start, *end;
>+
>+ if ( !sec->sec->sh_size ||
Once again I don't see what harm a zero size section would do.
>+ (sec->sec->sh_size % sizeof(*a)) )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong size of .alt_instr (exp:%lu vs %lu)!\n",
>+ elf->name, sizeof(*a),
sizeof() wants to be formatted with %zu and ...
>+ sec->sec->sh_size);
... didn't you add an ELF-specific format macro for cases like this?
Also if you printed the message outside of the conditional, expected and actual
values would likely disagree anyway (as soon as there are multiple entries), so
some editing of the text would be nice too.
>+ return -EINVAL;
>+ }
>+
>+ start = sec->load_addr;
>+ end = sec->load_addr + sec->sec->sh_size;
>+
>+ for ( a = start; a < end; a++ )
>+ {
>+ unsigned long instr = (unsigned long)(&a->instr_offset + a->instr_offset);
>+ unsigned long replacement = (unsigned long)(&a->repl_offset + a->repl_offset);
>+
>+ if ( (instr < region->start && instr >= region->end) ||
>+ (replacement < region->start && replacement >= region->end) )
>+ {
>+ dprintk(XENLOG_ERR, XSPLICE "%s Alt patching outside payload: 0x%lx!\n",
%#lx please
>@@ -555,6 +588,7 @@ static int prepare_payload(struct payload *payload,
>region->ex = s;
>region->ex_end = e;
>}
>+
>#endif
Stray addition of a blank line.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 20/27] build_id: Provide ld-embedded build-ids
2016-04-13 22:02 ` [PATCH v8.1 20/27] build_id: Provide ld-embedded build-ids Konrad Rzeszutek Wilk
@ 2016-04-20 7:14 ` Jan Beulich
2016-04-21 0:33 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-20 7:14 UTC (permalink / raw)
To: ross.lagerwall, konrad, konrad.wilk
Cc: sstabellini, keir, andrew.cooper3, mpohlack, mpohlack,
julien.grall, sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
>--- a/Config.mk
>+++ b/Config.mk
>@@ -126,6 +126,17 @@ endef
>check-$(gcc) = $(call cc-ver-check,CC,0x040100,"Xen requires at least gcc-4.1")
>$(eval $(check-y))
>
>+ld-ver-build-id = $(shell $(1) --build-id 2>&1 | \
>+ grep -q unrecognized && echo n || echo y)
What about localized binutils?
>@@ -87,7 +93,8 @@ endif
>
>$(TARGET): $(TARGET)-syms $(efi-y) boot/mkelf32
>./boot/mkelf32 $(TARGET)-syms $(TARGET) 0x100000 \
>- `$(NM) -nr $(TARGET)-syms | head -n 1 | sed -e 's/^\([^ ]*\).*/0x\1/'`
>+ `$(NM) -nr $(TARGET)-syms | head -n 1 | sed -e 's/^\([^ ]*\).*/0x\1/'` \
>+ $(notes_phdrs)
The placement makes it somewhat non-obvious that this is an option passed
to mkelf32 - it'd probably better go on the first line.
>+note.o: $(TARGET)-syms
>+ $(OBJCOPY) -O binary --only-section=.note.gnu.build-id $(BASEDIR)/xen-syms $@.bin
>+ $(OBJCOPY) -I binary -O elf64-x86-64 -B i386:x86-64 \
>+ --rename-section=.data=.note.gnu.build-id -S $@.bin $@
>+ rm -f $@.bin
This, btw, should be accompanied by an adjustment to the clean target, for the
case where a build gets interrupted before the rule above manages to delete the
intermediate file.
>@@ -99,6 +112,21 @@ SECTIONS
>_erodata = .;
>} :text
>
>+#if defined(BUILD_ID) && !defined(EFI)
>+/*
>+ * What a strange section name. The reason is that on ELF builds this section
>+ * is extracted to notes.o (which then is ingested in the EFI file). But the
>+ * compiler may want to inject other things in the .note which we don't care
>+ * about - hence this unique name.
>+ */
>+ . = ALIGN(4);
>+ .note.gnu.build-id : {
>+ __note_gnu_build_id_start = .;
>+ *(.note.gnu.build-id)
>+ __note_gnu_build_id_end = .;
>+ } :note :text
>+#endif
Am I misremembering that we had agreed for this to live ahead of _erodata?
>@@ -61,6 +66,51 @@ const char *xen_deny(void)
>return "<denied>";
>}
>
>+static const void *build_id_p;
>+static unsigned int build_id_len;
__read_mostly? Also these variables are kind of pointless to have in a build-id-
less build. But I guess that's going to be rare anyway.
Anyway,
Acked-by: Jan Beulich <jbeulich@suse.com>
with or without any of the above suggestions taken care of.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 22/27] XENVER_build_id/libxc: Provide ld-embedded build-id
2016-04-13 22:02 ` [PATCH v8.1 22/27] XENVER_build_id/libxc: Provide ld-embedded build-id Konrad Rzeszutek Wilk
2016-04-14 15:03 ` Wei Liu
2016-04-14 15:04 ` Daniel De Graaf
@ 2016-04-20 7:19 ` Jan Beulich
2 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-20 7:19 UTC (permalink / raw)
To: ross.lagerwall, konrad, konrad.wilk
Cc: wei.liu2, andrew.cooper3, ian.jackson, mpohlack, xen-devel,
sasha.levin, dgdegra
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:04 AM >>>
>--- a/xen/common/kernel.c
>+++ b/xen/common/kernel.c
>@@ -376,6 +376,42 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
>return -EFAULT;
>return 0;
>}
>+
>+ case XENVER_build_id:
>+ {
>+ xen_build_id_t build_id;
>+ unsigned int sz = 0;
>+ int rc = 0;
>+ const void *p = NULL;
All three initializers seem to be pointless.
With that taken care of,
Acked-by: Jan Beulich <jbeulich@suse.com>
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 24/27] xsplice: Stacking build-id dependency checking.
2016-04-13 22:02 ` [PATCH v8.1 24/27] xsplice: Stacking build-id dependency checking Konrad Rzeszutek Wilk
@ 2016-04-20 7:49 ` Jan Beulich
2016-04-22 10:46 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-20 7:49 UTC (permalink / raw)
To: ross.lagerwall, konrad, konrad.wilk
Cc: andrew.cooper3, keir, mpohlack, sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
>+.PHONY: note.o
>+note.o:
>+ $(OBJCOPY) -O binary --only-section=.note.gnu.build-id $(BASEDIR)/xen-syms $@.bin
>+ $(OBJCOPY) -I binary -O elf64-x86-64 -B i386:x86-64 \
>+ --rename-section=.data=.xsplice.depends -S $@.bin $@
>+ rm -f $@.bin
Same note as on the earlier patch regarding an interrupted build here ...
>+.PHONY: hello_world_note.o
>+hello_world_note.o:
>+ $(OBJCOPY) -O binary --only-section=.note.gnu.build-id $(XSPLICE) $@.bin
>+ $(OBJCOPY) -I binary -O elf64-x86-64 -B i386:x86-64 \
>+ --rename-section=.data=.xsplice.depends -S $@.bin $@
>+ rm -f $@.bin
... and here. Thinking about it a second time, wouldn't that then also require
entries in .gitignore?
>$(MAKE) -f $(BASEDIR)/Rules.mk xen_hello_world_func.o
>$(MAKE) -f $(BASEDIR)/Rules.mk xen_hello_world.o
>- $(LD) $(LDFLAGS) -r -o $(XSPLICE) xen_hello_world_func.o \
>- xen_hello_world.o
>+ $(LD) $(LDFLAGS) $(build_id_linker) -r -o $(XSPLICE) \
>+ xen_hello_world_func.o xen_hello_world.o note.o
>+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_bye_world_func.o
>+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_bye_world.o
>+ $(MAKE) -f $(BASEDIR)/Rules.mk hello_world_note.o
>+ $(LD) $(LDFLAGS) $(build_id_linker) -r -o $(XSPLICE_BYE) \
>+ xen_bye_world_func.o xen_bye_world.o hello_world_note.o
Coming back to the remark on the much earlier patch: The latest here it should
become pretty clear that this explicit invocation of make is getting unwieldy.
>--- /dev/null
>+++ b/xen/arch/x86/test/xen_bye_world.c
Any comments previously given on its "hello" sibling would likely apply here too.
>--- a/xen/common/version.c
>+++ b/xen/common/version.c
>@@ -84,9 +84,38 @@ int xen_build_id(const void **p, unsigned int *len)
>/* Defined in linker script. */
>extern const Elf_Note __note_gnu_build_id_start[], __note_gnu_build_id_end[];
>
>+int xen_build_id_check(const Elf_Note *n, unsigned int n_sz,
>+ const void **p, unsigned int *len)
>+{
>+ /* Check if we really have a build-id. */
>+ if ( NT_GNU_BUILD_ID != n->type )
>+ return -ENODATA;
>+
>+ if ( n->namesz >= n_sz )
>+ return -EINVAL;
>+
>+ if ( n->descsz >= n_sz )
>+ return -EINVAL;
>+
>+ if ( n->namesz + n->descsz >= n_sz )
>+ return -EINVAL;
These three checks could be done by two ones, and for one more correctly:
First check that the addition doesn't overflow, and then do the latter check.
But then it looks like the addition should also include sizeof(*n) (and then
use > instead of >=)?
>+ /* Sanity check, name should be "GNU" for ld-generated build-id. */
>+ if ( strncmp(ELFNOTE_NAME(n), "GNU", n->namesz) != 0 )
>+ return -ENODATA;
So if namesz is 3, this will (I think wrongly) pass as it seems.
>@@ -96,18 +125,9 @@ static int __init xen_build_init(void)
>if ( &n[1] > __note_gnu_build_id_end )
>return -ENODATA;;
>
>- /* Check if we really have a build-id. */
>- if ( NT_GNU_BUILD_ID != n->type )
>- return -ENODATA;
>-
>- /* Sanity check, name should be "GNU" for ld-generated build-id. */
>- if ( strncmp(ELFNOTE_NAME(n), "GNU", n->namesz) != 0 )
>- return -ENODATA;
>-
>- build_id_len = n->descsz;
>- build_id_p = ELFNOTE_DESC(n);
>+ sz = (size_t)__note_gnu_build_id_end - (size_t)&n[0];
Why &n[0] instead of just n?
>@@ -441,6 +452,7 @@ static int prepare_payload(struct payload *payload,
>unsigned int i;
>struct xsplice_patch_func_internal *f;
>struct virtual_region *region;
>+ Elf_Note *n;
const
>@@ -1252,6 +1343,18 @@ static int xsplice_action(xen_sysctl_xsplice_action_t *action)
>case XSPLICE_ACTION_REVERT:
>if ( data->state == XSPLICE_STATE_APPLIED )
>{
>+ struct payload *p = list_last_entry(&applied_list, struct payload,
>+ applied_list);
const
>@@ -1260,6 +1363,9 @@ static int xsplice_action(xen_sysctl_xsplice_action_t *action)
>case XSPLICE_ACTION_APPLY:
>if ( data->state == XSPLICE_STATE_CHECKED )
>{
>+ rc = build_id_dep(data, list_empty(&applied_list));
!!list_empty()
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 25/27] xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE
2016-04-13 22:02 ` [PATCH v8.1 25/27] xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE Konrad Rzeszutek Wilk
@ 2016-04-20 11:12 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-20 11:12 UTC (permalink / raw)
To: ross.lagerwall, konrad, konrad.wilk
Cc: andrew.cooper3, keir, mpohlack, sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:02 AM >>>
Same comments here as for previous test cases.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 26/27] xsplice: Prevent duplicate payloads from being loaded.
2016-04-13 22:02 ` [PATCH v8.1 26/27] xsplice: Prevent duplicate payloads from being loaded Konrad Rzeszutek Wilk
@ 2016-04-20 11:16 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-20 11:16 UTC (permalink / raw)
To: ross.lagerwall, konrad, konrad.wilk
Cc: keir, andrew.cooper3, ian.jackson, mpohlack, tim, xen-devel, sasha.levin
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
>--- a/xen/common/xsplice.c
>+++ b/xen/common/xsplice.c
>@@ -517,6 +517,8 @@ static int prepare_payload(struct payload *payload,
>sec = xsplice_elf_sec_by_name(elf, ".note.gnu.build-id");
>if ( sec )
>{
>+ struct payload *data;
And I guess you can guess it: const.
>@@ -528,6 +530,20 @@ static int prepare_payload(struct payload *payload,
>
>if ( !payload->id.len || !payload->id.p )
>return -EINVAL;
>+
>+ /* Make sure it is not a duplicate. */
>+ list_for_each_entry ( data, &payload_list, list )
>+ {
>+ /* No way _this_ payload is on the list. */
>+ ASSERT(data != payload);
>+ if ( data->id.len &&
Checking for zero on a _loaded_ module seems pointless now that you
require build IDs. Independent of that you anyway need
data->id.len != payload->id.len ||
>+ !memcmp(data->id.p, payload->id.p, data->id.len) )
Or else this is possibly accessing out of bounds data.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-19 19:31 ` Jan Beulich
@ 2016-04-20 12:55 ` Ross Lagerwall
2016-04-21 0:26 ` Konrad Rzeszutek Wilk
1 sibling, 0 replies; 126+ messages in thread
From: Ross Lagerwall @ 2016-04-20 12:55 UTC (permalink / raw)
To: Jan Beulich, konrad, konrad.wilk
Cc: andrew.cooper3, keir, mpohlack, sasha.levin, xen-devel
On 04/19/2016 08:31 PM, Jan Beulich wrote:
snip
>> + ASSERT(spin_is_locked(&payload_lock));
>> + list_for_each_entry ( data, &payload_list, list )
>> + {
>> + unsigned int i;
>> +
>> + for ( i = 0; i < data->nsyms; i++ )
>> + {
>> + if ( !data->symtab[i].new_symbol )
>> + continue;
>
> Do you need symbols other than those marked "new_symbol" past the loading
> of the module? If not, wouldn't it be worthwhile to shrink the symbol table to just
> those, likely speeding up the lookup?
new_symbol indicates whether it is newly introduced in this binary patch
or whether it overrides a symbol in a previous binary patch (or the core
binary). Either way, the symbol will be used when resolving a backtrace.
--
Ross Lagerwall
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 11/27] xsplice: Implement payload loading
2016-04-18 6:16 ` Jan Beulich
@ 2016-04-20 15:59 ` Konrad Rzeszutek Wilk
2016-04-20 17:05 ` Jan Beulich
2016-04-21 15:15 ` Konrad Rzeszutek Wilk
0 siblings, 2 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-20 15:59 UTC (permalink / raw)
To: Jan Beulich
Cc: sstabellini, keir, andrew.cooper3, mpohlack, ross.lagerwall,
julien.grall, sasha.levin, xen-devel
> >+void arch_xsplice_free_payload(void *va)
> >+{
> >+ vfree_xen(va);
> >+}
>
> What is the idea behind having this hook (instead of generic code just calling
> vfree_xen() [or really just vfree()])?
To have an symmetry with the allocation one. I don't know enough about
ARM to know whether this logic above can be hoisted in the common code
and hence called (or compiled) on ARM.
Let me try.
>
> >@@ -29,6 +30,13 @@ struct payload {
> >uint32_t state; /* One of the XSPLICE_STATE_*. */
> >int32_t rc; /* 0 or -XEN_EXX. */
> >struct list_head list; /* Linked to 'payload_list'. */
> >+ void *text_addr; /* Virtual address of .text. */
> >+ size_t text_size; /* .. and its size. */
> >+ void *rw_addr; /* Virtual address of .data. */
> >+ size_t rw_size; /* .. and its size (if any). */
> >+ void *ro_addr; /* Virtual address of .rodata. */
> >+ size_t ro_size; /* .. and its size (if any). */
>
> And again the question: Do these pointers really need to be non-const?
I know I tried making them const and the compiler was not happy. I will
follow up with the reasoning.
>
> >+ size_t pages; /* Total pages for [text,rw,ro]_addr */
>
> Why size_t and not just unsigned int?
Oh. I was somehow under the impression you liked size_t more than
unsignged int! I will change it over.
>
> >+static void calc_section(struct xsplice_elf_sec *sec, size_t *size)
> >+{
> >+ Elf_Shdr *s = sec->sec;
> >+ size_t align_size;
> >+
> >+ align_size = ROUNDUP(*size, s->sh_addralign);
> >+ s->sh_entsize = align_size;
>
> So this is one of the places (the only one?) where the section header gets
> altered. Are you not expecting problems down the road resulting from
> overwriting this field? After all it's used not just in control sections...
The 'man elf' tells me :
"Some sections hold a table of fixed-sized entries, such as a symbol
table. For such a section, this member gives the size in bytes for each entry.
This member contains zero if the section does not hold a table of
fixed-size entries."
We may have an value for an payload with one symbol but we don't depend
on this value having any value and just re-use.
We could change the logic to save the aligned size (which would then alter
the amount of pages to allocate along with the amount of bytes to copy)
in some 'per-section' temporary variable (so adding an extra field in
'struct xsplice_elf_sec').
Let me prototype that.
>
> >+static int move_payload(struct payload *payload, struct xsplice_elf *elf)
> >+{
..snip..
> >+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
> >+ {
> >+ if ( !(elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
> >+ (elf->sec[i].sec->sh_flags & SHF_EXECINSTR) &&
> >+ (elf->sec[i].sec->sh_flags & SHF_WRITE) )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: No WX sections!\n", elf->name);
> >+ return -EINVAL;
> >+ }
>
> Is there any reason to have four loops here, with quite a bit of redundancy in
> the if()s, instead of just one loop with a if/else sequence?
There was a historical reason - we wre re-using 'size' but that is no
longer the case.
>
> Also it's not really clear whether you really mean to honor non-progbits, non-
> nobits sections with SHF_ALLOC set. Perhaps such would better be refused
> for the now at least.
OK.
>
> >+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
> >+ {
> >+ if ( elf->sec[i].sec->sh_flags & SHF_ALLOC )
> >+ {
> >+ if ( (elf->sec[i].sec->sh_flags & SHF_EXECINSTR) )
> >+ buf = payload->text_addr;
> >+ else if ( (elf->sec[i].sec->sh_flags & SHF_WRITE) )
> >+ buf = payload->rw_addr;
> >+ else
>
> Something's wrong with indentation here (not visible above anymore due to
> the limitations of this web frontend of our mail system).
>
> >+ /* Don't copy NOBITS - such as BSS. */
> >+ if ( elf->sec[i].sec->sh_type != SHT_NOBITS )
> >+ {
> >+ memcpy(elf->sec[i].load_addr, elf->sec[i].data,
> >+ elf->sec[i].sec->sh_size);
> >+ dprintk(XENLOG_DEBUG, XSPLICE "%s: Loaded %s at 0x%p\n",
> >+ elf->name, elf->sec[i].name, elf->sec[i].load_addr);
> >+ }
>
> "else memset();" is what I would have expected here. Now I see that the
> allocation function clears the pages (in a bogusly open coded way, instead
> of using vzalloc()), but why is that so?
B/c we end up having vzalloc_xen (oh wait, we made that go away). Yes
we do need an memset or introduce vzalloc_xen (and keep vmalloc_xen?).
Your call - memset or introduce vzalloc_xen ?
>
> >+int xsplice_elf_resolve_symbols(struct xsplice_elf *elf)
.. snip..
> >+ default:
> >+ /* SHN_COMMON and SHN_ABS are above. */
> >+ if ( idx > SHN_LORESERVE )
>
> >=
>
> >+ rc = -EOPNOTSUPP;
> >+ /* SHN_UNDEF (0) above. */
> >+ else if ( idx > elf->hdr->e_shnum && idx < SHN_LORESERVE )
>
> >= and the right side of the && seems pointless due to the preceding if().
>
> >+ if ( !(elf->sec[idx].sec->sh_flags & SHF_ALLOC) )
> >+ break;
>
> If you really mean to check this, shouldn't this be done earlier, avoiding needless
> errors on unsupported symbol kinds above?
Right! Will move those checks right above the switch statement.
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 10/27] xsplice: Add helper elf routines
2016-04-18 6:23 ` Jan Beulich
@ 2016-04-20 16:07 ` Konrad Rzeszutek Wilk
2016-04-20 16:59 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-20 16:07 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, ross.lagerwall, andrew.cooper3, ian.jackson, mpohlack, tim,
sasha.levin, xen-devel
On Mon, Apr 18, 2016 at 12:23:26AM -0600, Jan Beulich wrote:
> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/18/16 7:55 AM >>>
> >> >+ if ( delta > elf->len )
> >> >+ {
> >> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Section table is past end of payload!\n",
> >> >+ elf->name);
> >> >+ return -EINVAL;
> >> >+ }
> >> >+
> >> >+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
> >> >+ {
> >> >+ delta = elf->hdr->e_shoff + i * elf->hdr->e_shentsize;
> >> >+
> >> >+ sec[i].sec = (void *)data + delta;
> >>
> >> Casting away constness is one of the main reasons I complain about casts in
> >> general. If you really need to modify some fields in the section header, you should
> >> imo cast away constness just there. But even better would be if you left the
> >
> >In earlier reviews you said that casting away constness in
> >function would be a big no no.
>
> Exactly. Yet what do you do above?
>
> >> section header alone.
> >
> >I modify sec[i].sec->sh_entsize in calc_section
>
> See the comment there (in the next patch it was, I think).
OK, and re-reading above you say "imo cast away constness just there."
so you are OK then with functions casting away constness if they
need to modify the structure.
>
> >>
> >> >+ delta = sec[i].sec->sh_offset;
> >> >+
> >> >+ /*
> >> >+ * N.B. elf_resolve_section_names, elf_get_sym skip this check as
> >> >+ * we do it here.
> >> >+ */
> >> >+ if ( delta && (delta + sec[i].sec->sh_size > elf->len) )
> >>
> >> Allowing delta to be zero here seems suspicious: Are you doing that because
> >> some sections come without data (and hence without offset)? In that case you'd
> >> better skip the check on those section types (e.g. SHT_NOBITS) only. In fact
> >> the offset being below the end of the ELF header would likely indicate a broken
> >> image.
> >
> >The loop (earlier) had started at 0 so the delta could have been zero.
> >Anyhow that not being the case anymore I will just do:
> >
> >if ( !delta )
> >return -EINVAL;
>
> As said, I'd suggest making this even more strict by checking at least against
> the ELF header size.
I am not sure I understand you. Initially I thought you mean the
p_filesz (which is the program header) - but this ELF file is not a
program - it is an relocatable object so there are no program header.
Ah, I think I mislead you! (with the 'if (!delta)..')The code will have:
if ( !delta )
return -EINVAL;
if ( delta + sec[i].sec->sh_size > elf->len )
return -EINVAL;
(Or rather a combination of these and make the printk print the right warning).
>
> >> >+ if ( elf->hdr->e_shoff > elf->len )
> >> >+ {
> >> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Bogus e_shoff!\n", elf->name);
> >> >+ return -EINVAL;
> >> >+ }
> >>
> >> If this check is needed, then >=. But I think it should be redundant with the more
> >> complete one in elf_resolve_sections().
> >
> >This is the overflow check Andrew asked for.
>
> I don't think so - there's no overflow being checked for here at all, this is
> just a within bounds check. Just compare with the other one.
>
So earlier (in common/xsplice, verify_payload) there was a check on the
size of the payload (up to 2MB), hence my check here would catch the
overflow violation ((-1U) > 2(MB), but it is not very clear.
I modified this above to be:
303 if ( elf->hdr->e_shoff > ULONG_MAX - elf->hdr->e_shoff )
304 {
305 dprintk(XENLOG_ERR, XSPLICE "%s: Bogus e_shoff!\n", elf->name);
306 return -EINVAL;
307 }
308
I can also add back the elf->hdr->e_shoff > elf->len in this
conditional if you would like (along with the comment about 2(MB))
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 13/27] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version'.
2016-04-19 17:40 ` Jan Beulich
@ 2016-04-20 16:10 ` Konrad Rzeszutek Wilk
2016-04-20 17:06 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-20 16:10 UTC (permalink / raw)
To: Jan Beulich
Cc: sstabellini, keir, andrew.cooper3, mpohlack, ross.lagerwall,
julien.grall, sasha.levin, xen-devel
> >+.PHONY: xsplice
> >+xsplice: config.h
> >+ # Need to have these done in sequential order
> >+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_hello_world_func.o
> >+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_hello_world.o
>
> Why do these two need doing in order? And why can't $(XSPLICE) not just depend
> on its to object files, without needing explict make invocation to generate them?
That is b/c the the xen_hello_world.c depends on the generation of
config.h.
I _think_ I can do:
xsplice: config.h xen_hello_world_func.o
As the xen_hello_world_func.c should be able to be built without any
dependencies.
Or maybe I can do:
xen_hello_world.o: config.h
$(CC) $(CFLAGS) -c $< -o $@
^^^ - copy-n-paste from Rules.mk
xsplice: config.h xen_hello_world.o xen_hello_world_func.o
But I recall having issues with the $(CC).. I recall that
I tried the same thing as what Rules.mk has for %.o build (as in
copy-n-paste) but it had issues. But it may have been an earlier
bug in my code that I tripped over.
Let me play with this a bit.
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 10/27] xsplice: Add helper elf routines
2016-04-20 16:07 ` Konrad Rzeszutek Wilk
@ 2016-04-20 16:59 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-20 16:59 UTC (permalink / raw)
To: konrad.wilk
Cc: keir, ross.lagerwall, andrew.cooper3, ian.jackson, mpohlack, tim,
sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/20/16 6:09 PM >>>
>On Mon, Apr 18, 2016 at 12:23:26AM -0600, Jan Beulich wrote:
>> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/18/16 7:55 AM >>>
>> >> >+ if ( delta > elf->len )
>> >> >+ {
>> >> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Section table is past end of payload!\n",
>> >> >+ elf->name);
>> >> >+ return -EINVAL;
>> >> >+ }
>> >> >+
>> >> >+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
>> >> >+ {
>> >> >+ delta = elf->hdr->e_shoff + i * elf->hdr->e_shentsize;
>> >> >+
>> >> >+ sec[i].sec = (void *)data + delta;
>> >>
>> >> Casting away constness is one of the main reasons I complain about casts in
>> >> general. If you really need to modify some fields in the section header, you should
>> >> imo cast away constness just there. But even better would be if you left the
>> >
>> >In earlier reviews you said that casting away constness in
>> >function would be a big no no.
>>
>> Exactly. Yet what do you do above?
>>
>> >> section header alone.
>> >
>> >I modify sec[i].sec->sh_entsize in calc_section
>>
>> See the comment there (in the next patch it was, I think).
>
>OK, and re-reading above you say "imo cast away constness just there."
>so you are OK then with functions casting away constness if they
>need to modify the structure.
If it's really just one exceptional place where this happens, I guess it's okay as,
well, an exception. Otherwise the const would need to be dropped wherever
necessary to avoid having to cast it away in certain places.
>> >> >+ delta = sec[i].sec->sh_offset;
>> >> >+
>> >> >+ /*
>> >> >+ * N.B. elf_resolve_section_names, elf_get_sym skip this check as
>> >> >+ * we do it here.
>> >> >+ */
>> >> >+ if ( delta && (delta + sec[i].sec->sh_size > elf->len) )
>> >>
>> >> Allowing delta to be zero here seems suspicious: Are you doing that because
>> >> some sections come without data (and hence without offset)? In that case you'd
>> >> better skip the check on those section types (e.g. SHT_NOBITS) only. In fact
>> >> the offset being below the end of the ELF header would likely indicate a broken
>> >> image.
>> >
>> >The loop (earlier) had started at 0 so the delta could have been zero.
>> >Anyhow that not being the case anymore I will just do:
>> >
>> >if ( !delta )
>> >return -EINVAL;
>>
>> As said, I'd suggest making this even more strict by checking at least against
>> the ELF header size.
>
>I am not sure I understand you. Initially I thought you mean the
>p_filesz (which is the program header) - but this ELF file is not a
>program - it is an relocatable object so there are no program header.
Right, and I indeed mean the ELF header: The section headers clearly can't
start inside it.
>Ah, I think I mislead you! (with the 'if (!delta)..')The code will have:
>if ( !delta )
>return -EINVAL;
>if ( delta + sec[i].sec->sh_size > elf->len )
>return -EINVAL;
That's what I had understood, and the first if() is which I'd like to see made
slightly more strict.
>> >> >+ if ( elf->hdr->e_shoff > elf->len )
>> >> >+ {
>> >> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Bogus e_shoff!\n", elf->name);
>> >> >+ return -EINVAL;
>> >> >+ }
>> >>
>> >> If this check is needed, then >=. But I think it should be redundant with the more
>> >> complete one in elf_resolve_sections().
>> >
>> >This is the overflow check Andrew asked for.
>>
>> I don't think so - there's no overflow being checked for here at all, this is
>> just a within bounds check. Just compare with the other one.
>
>So earlier (in common/xsplice, verify_payload) there was a check on the
>size of the payload (up to 2MB), hence my check here would catch the
>overflow violation ((-1U) > 2(MB), but it is not very clear.
>
>I modified this above to be:
>
>303 if ( elf->hdr->e_shoff > ULONG_MAX - elf->hdr->e_shoff )
Something's clearly wrong here, with e_shoff used on both sides.
>304 {
>305 dprintk(XENLOG_ERR, XSPLICE "%s: Bogus e_shoff!\n", elf->name);
>306 return -EINVAL;
>307 }
>308
>
>I can also add back the elf->hdr->e_shoff > elf->len in this
>conditional if you would like (along with the comment about 2(MB))
It's not because I like it, but for consistency with all the other elf->len checks.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 11/27] xsplice: Implement payload loading
2016-04-20 15:59 ` Konrad Rzeszutek Wilk
@ 2016-04-20 17:05 ` Jan Beulich
2016-04-20 17:36 ` Konrad Rzeszutek Wilk
2016-04-21 15:15 ` Konrad Rzeszutek Wilk
1 sibling, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-20 17:05 UTC (permalink / raw)
To: konrad.wilk
Cc: sstabellini, keir, ross.lagerwall, andrew.cooper3, mpohlack,
julien.grall, sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/20/16 6:00 PM >>>
>> >+ size_t pages; /* Total pages for [text,rw,ro]_addr */
>>
>> Why size_t and not just unsigned int?
>
>Oh. I was somehow under the impression you liked size_t more than
>unsignged int! I will change it over.
When used where actually talking about sizes, I indeed prefer size_t. But
here we have a count which we know will be much lower than UINT_MAX.
>> >+static void calc_section(struct xsplice_elf_sec *sec, size_t *size)
>> >+{
>> >+ Elf_Shdr *s = sec->sec;
>> >+ size_t align_size;
>> >+
>> >+ align_size = ROUNDUP(*size, s->sh_addralign);
>> >+ s->sh_entsize = align_size;
>>
>> So this is one of the places (the only one?) where the section header gets
>> altered. Are you not expecting problems down the road resulting from
>> overwriting this field? After all it's used not just in control sections...
>
>The 'man elf' tells me :
>"Some sections hold a table of fixed-sized entries, such as a symbol
>table. For such a section, this member gives the size in bytes for each entry.
>This member contains zero if the section does not hold a table of
>fixed-size entries."
My main concern is that SHF_MERGE sections (i.e. ordinary data ones) also
already use this field.
>> >+ /* Don't copy NOBITS - such as BSS. */
>> >+ if ( elf->sec[i].sec->sh_type != SHT_NOBITS )
>> >+ {
>> >+ memcpy(elf->sec[i].load_addr, elf->sec[i].data,
>> >+ elf->sec[i].sec->sh_size);
>> >+ dprintk(XENLOG_DEBUG, XSPLICE "%s: Loaded %s at 0x%p\n",
>> >+ elf->name, elf->sec[i].name, elf->sec[i].load_addr);
>> >+ }
>>
>> "else memset();" is what I would have expected here. Now I see that the
>> allocation function clears the pages (in a bogusly open coded way, instead
>> of using vzalloc()), but why is that so?
>
>B/c we end up having vzalloc_xen (oh wait, we made that go away). Yes
>we do need an memset or introduce vzalloc_xen (and keep vmalloc_xen?).
>
>Your call - memset or introduce vzalloc_xen ?
The latter would be my preference.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 13/27] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version'.
2016-04-20 16:10 ` Konrad Rzeszutek Wilk
@ 2016-04-20 17:06 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-20 17:06 UTC (permalink / raw)
To: konrad
Cc: sstabellini, keir, andrew.cooper3, mpohlack, ross.lagerwall,
julien.grall, sasha.levin, xen-devel
>>> Konrad Rzeszutek Wilk <konrad@kernel.org> 04/20/16 6:10 PM >>>
>> >+.PHONY: xsplice
>> >+xsplice: config.h
>> >+ # Need to have these done in sequential order
>> >+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_hello_world_func.o
>> >+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_hello_world.o
>>
>> Why do these two need doing in order? And why can't $(XSPLICE) not just depend
>> on its to object files, without needing explict make invocation to generate them?
>
>That is b/c the the xen_hello_world.c depends on the generation of
>config.h.
>
>I _think_ I can do:
>xsplice: config.h xen_hello_world_func.o
>
>As the xen_hello_world_func.c should be able to be built without any
>dependencies.
>
>Or maybe I can do:
>
>xen_hello_world.o: config.h
>$(CC) $(CFLAGS) -c $< -o $@
>^^^ - copy-n-paste from Rules.mk
But why would you want to duplicate the rule? All you need is representation
of the dependency.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 11/27] xsplice: Implement payload loading
2016-04-20 17:05 ` Jan Beulich
@ 2016-04-20 17:36 ` Konrad Rzeszutek Wilk
2016-04-21 6:41 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-20 17:36 UTC (permalink / raw)
To: Jan Beulich
Cc: sstabellini, Keir Fraser, andrew.cooper3, mpohlack,
ross.lagerwall, julien.grall, xen-devel, sasha.levin
[-- Attachment #1.1: Type: text/plain, Size: 2613 bytes --]
On Apr 20, 2016 6:05 PM, "Jan Beulich" <jbeulich@suse.com> wrote:
>
> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/20/16 6:00 PM >>>
> >> >+ size_t pages; /* Total pages for [text,rw,ro]_addr */
> >>
> >> Why size_t and not just unsigned int?
> >
> >Oh. I was somehow under the impression you liked size_t more than
> >unsignged int! I will change it over.
>
> When used where actually talking about sizes, I indeed prefer size_t. But
> here we have a count which we know will be much lower than UINT_MAX.
>
> >> >+static void calc_section(struct xsplice_elf_sec *sec, size_t *size)
> >> >+{
> >> >+ Elf_Shdr *s = sec->sec;
> >> >+ size_t align_size;
> >> >+
> >> >+ align_size = ROUNDUP(*size, s->sh_addralign);
> >> >+ s->sh_entsize = align_size;
> >>
> >> So this is one of the places (the only one?) where the section header
gets
> >> altered. Are you not expecting problems down the road resulting from
> >> overwriting this field? After all it's used not just in control
sections...
> >
> >The 'man elf' tells me :
> >"Some sections hold a table of fixed-sized entries, such as a symbol
> >table. For such a section, this member gives the size in bytes for each
entry.
> >This member contains zero if the section does not hold a table of
> >fixed-size entries."
>
> My main concern is that SHF_MERGE sections (i.e. ordinary data ones) also
> already use this field.
OK. Let me add the 'offset' member (in xsplice_elf_sec) to store the value.
Albeit it only gets used during move_payload. And later that offset value
can easily computed using ->load_addr minus ->data.
Perhaps I should introduce an temporary array to hold this value instead?
>
> >> >+ /* Don't copy NOBITS - such as BSS. */
> >> >+ if ( elf->sec[i].sec->sh_type != SHT_NOBITS )
> >> >+ {
> >> >+ memcpy(elf->sec[i].load_addr, elf->sec[i].data,
> >> >+ elf->sec[i].sec->sh_size);
> >> >+ dprintk(XENLOG_DEBUG, XSPLICE "%s: Loaded %s at
0x%p\n",
> >> >+ elf->name, elf->sec[i].name,
elf->sec[i].load_addr);
> >> >+ }
> >>
> >> "else memset();" is what I would have expected here. Now I see that the
> >> allocation function clears the pages (in a bogusly open coded way,
instead
> >> of using vzalloc()), but why is that so?
> >
> >B/c we end up having vzalloc_xen (oh wait, we made that go away). Yes
> >we do need an memset or introduce vzalloc_xen (and keep vmalloc_xen?).
> >
> >Your call - memset or introduce vzalloc_xen ?
>
> The latter would be my preference.
OK, will do.
>
> Jan
>
[-- Attachment #1.2: Type: text/html, Size: 3714 bytes --]
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-19 19:31 ` Jan Beulich
2016-04-20 12:55 ` Ross Lagerwall
@ 2016-04-21 0:26 ` Konrad Rzeszutek Wilk
2016-04-21 6:46 ` Jan Beulich
2016-04-22 7:17 ` Ross Lagerwall
1 sibling, 2 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-21 0:26 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, andrew.cooper3, mpohlack, ross.lagerwall, sasha.levin, xen-devel
> >+unsigned long xsplice_symbols_lookup_by_name(const char *symname)
> >+{
> >+ struct payload *data;
>
> Do you need symbols other than those marked "new_symbol" past the loading
> of the module? If not, wouldn't it be worthwhile to shrink the symbol table to just
> those, likely speeding up the lookup?
Ross hopefully answered that to your satisfaction?
>
> >@@ -379,11 +405,129 @@ static int prepare_payload(struct payload *payload,
> >for ( j = 0; j < ARRAY_SIZE(f->u.pad); j++ )
> >if ( f->u.pad[j] )
> >return -EINVAL;
> >+
> >+ /* Lookup function's old address if not already resolved. */
> >+ if ( !f->old_addr )
> >+ {
> >+ f->old_addr = (void *)symbols_lookup_by_name(f->name);
> >+ if ( !f->old_addr )
> >+ {
> >+ f->old_addr = (void *)xsplice_symbols_lookup_by_name(f->name);
>
> The two casts make me wonder whether the two functions shouldn't return
> void *, and then whether struct xsplice_symbol's value field shouldn't then
> perhaps be void * too.
So I did try that and it all worked nicely on x86. However on ARM32:
arm <konrad@localhost:~/xen/xen> make -j8 1>1
symbols.c: In function 'symbols_lookup_by_name':
symbols.c:287:20: error: cast to pointer from integer of different size
[-Werror=int-to-pointer-cast]
275 uint64_t addr = 0; /* MUST be initialized. */
286 if ( !strcmp(name, symname) )
287 return (void *)addr;
Which is rather unfortunate. I think I will have to make it unsigned
long.
>
> >+ if ( !f->old_addr )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Could not resolve old address of %s\n",
> >+ elf->name, f->name);
> >+ return -ENOENT;
> >+ }
> >+ }
> >+ dprintk(XENLOG_DEBUG, XSPLICE "%s: Resolved old address %s => %p\n",
> >+ elf->name, f->name, f->old_addr);
> >+ }
> >}
> >
> >return 0;
> >}
>
> So one thing I'm realizing only now: Is there no support for using <symbol>+<offset>
> to fill ->old_addr?
No. Just <symbol>. I updated the design document to outline this missing
functionality in the Todo section.
>
> >+static bool_t is_payload_symbol(const struct xsplice_elf *elf,
> >+ const struct xsplice_elf_sym *sym)
> >+{
> >+ if ( sym->sym->st_shndx == SHN_UNDEF ||
> >+ sym->sym->st_shndx >= elf->hdr->e_shnum )
> >+ return 0;
> >+
> >+ return (elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) &&
> >+ (ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT ||
> >+ ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
>
> I don't recall having seen a reply to the question on not allowing STT_NOTYPE here.
Ross, could you elaborate a bit please on this?
>
> >+static int build_symbol_table(struct payload *payload,
> >+ const struct xsplice_elf *elf)
> >+{
..snip..
> >+
> >+ /* Recall that section @0 is always NULL. */
> >+ for ( i = 1; i < elf->nsym; i++ )
> >+ {
> >+ symtab[nsyms].new_symbol = 0; /* To be checked below. */
>
> Why "checked"? The only thing happening further down is this possibly
> getting overwritten with 1.
I changed it to say "May be overwritten below."
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 12/27] xsplice: Implement support for applying/reverting/replacing patches.
2016-04-19 6:27 ` Jan Beulich
@ 2016-04-21 0:28 ` Konrad Rzeszutek Wilk
2016-04-21 6:44 ` Jan Beulich
2016-04-22 17:26 ` Konrad Rzeszutek Wilk
1 sibling, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-21 0:28 UTC (permalink / raw)
To: Jan Beulich
Cc: kevin.tian, sstabellini, keir, jun.nakajima, andrew.cooper3,
mpohlack, ross.lagerwall, julien.grall, suravee.suthikulpanit,
sasha.levin, xen-devel, boris.ostrovsky
> >+static int prepare_payload(struct payload *payload,
> >+ struct xsplice_elf *elf)
> >+{
> >+ const struct xsplice_elf_sec *sec;
> >+ unsigned int i;
> >+ struct xsplice_patch_func_internal *f;
>
> Why is there a second ("internal") variant of this structure now? What
> guarantees it to remain in sync with the non-"internal" one?
The internal is gone now.
>
> >+ sec = xsplice_elf_sec_by_name(elf, ".xsplice.funcs");
>
> Since the string literal occurs at least twice, I'd suggest having a #define for it.
OK, I also did it (in the later patches) for the .xsplice.depends
and .gnu....
>
> >+ ASSERT(sec);
> >+ if ( sec->sec->sh_size % sizeof(*payload->funcs) )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong size of .xsplice.funcs!\n",
> >+ elf->name);
> >+ return -EINVAL;
> >+ }
> >+
> >+ payload->funcs = sec->load_addr;
> >+ payload->nfuncs = sec->sec->sh_size / sizeof(*payload->funcs);
>
> Following to our discussion yesterday - can't we (ab)use the section merge
> flag here to report the structure size, along the lines of what relocation
> sections do for their elements?
In other words - the xsplice-tools.git and the test-cases (in
arch/x86/xen/test) would modify the sec->sh_entsize to have the
sizeof(xsplice_patch_func) aka 64 (0x40) ?
[Note this could also extend to .xsplice.hooks.load and
.xsplice.hooks.unload]
The xsplice-tools.git could surely do it, but the built-in test-cases -
not so much. I would need to do some in-place binary handrolling - unless you
know of some tool or some __section modifiers?
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 17/27] xsplice: Add support for bug frames.
2016-04-19 20:17 ` Jan Beulich
@ 2016-04-21 0:29 ` Konrad Rzeszutek Wilk
2016-04-21 6:49 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-21 0:29 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, andrew.cooper3, mpohlack, ross.lagerwall, sasha.levin, xen-devel
On Tue, Apr 19, 2016 at 02:17:35PM -0600, Jan Beulich wrote:
> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:02 AM >>>
> >+bool_t is_patch(const void *ptr)
> >+{
> >+ struct payload *data;
>
> You guess it: const.
>
> >+ /*
> >+ * No locking since this list is only ever changed during apply or revert
> >+ * context.
> >+ */
>
> What if you crash while applying or reverting a patch? Is the list update at
> least done such that the (then nested) traversal remains safe?
Yes! We only add the struct payload to this applied_list _after_ the
patching has been done.` Hence if we crashed the list would not contain the
struct payload that was patching - but would be safe to traverse.
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 19/27] xsplice: Add support for alternatives
2016-04-20 6:28 ` Jan Beulich
@ 2016-04-21 0:30 ` Konrad Rzeszutek Wilk
2016-04-21 6:55 ` Jan Beulich
2016-04-21 0:31 ` Konrad Rzeszutek Wilk
2016-04-22 16:06 ` Konrad Rzeszutek Wilk
2 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-21 0:30 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, andrew.cooper3, mpohlack, ross.lagerwall, sasha.levin, xen-devel
On Wed, Apr 20, 2016 at 12:28:02AM -0600, Jan Beulich wrote:
> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:02 AM >>>
> >--- a/xen/arch/x86/Makefile
> >+++ b/xen/arch/x86/Makefile
> >@@ -6,7 +6,11 @@ subdir-y += mm
> >subdir-$(CONFIG_XENOPROF) += oprofile
> >subdir-y += x86_64
> >
> >+ifdef CONFIG_XSPLICE
> >+obj-y += alternative.o
> >+else
> >obj-bin-y += alternative.init.o
> >+endif
>
> For now this is okay, but please try to use the list model in favor of ifdef-s in
> the future, whenever possible.
As in:
obj-$(CONFIG_XSPLICE) += alternative.o xsplice.o
.. but then how do I define an build for alternative.init.o?
ifndef CONFIG_XSPLICE
obj-bin-$(CONFIG_XSPLICE) += alternative.init.o
endif
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 19/27] xsplice: Add support for alternatives
2016-04-20 6:28 ` Jan Beulich
2016-04-21 0:30 ` Konrad Rzeszutek Wilk
@ 2016-04-21 0:31 ` Konrad Rzeszutek Wilk
2016-04-21 6:56 ` Jan Beulich
2016-04-22 16:06 ` Konrad Rzeszutek Wilk
2 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-21 0:31 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, andrew.cooper3, mpohlack, ross.lagerwall, sasha.levin, xen-devel
> >--- a/xen/common/xsplice.c
> >+++ b/xen/common/xsplice.c
> >@@ -533,6 +533,39 @@ static int prepare_payload(struct payload *payload,
> >}
> >
> >#ifndef CONFIG_ARM
> >+ sec = xsplice_elf_sec_by_name(elf, ".altinstructions");
> >+ if ( sec )
> >+ {
> >+ struct alt_instr *a, *start, *end;
> >+
.. snip..
> >+ (sec->sec->sh_size % sizeof(*a)) )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong size of .alt_instr (exp:%lu vs %lu)!\n",
> >+ elf->name, sizeof(*a),
>
> sizeof() wants to be formatted with %zu and ...
>
> >+ sec->sec->sh_size);
>
> ... didn't you add an ELF-specific format macro for cases like this?
>
> Also if you printed the message outside of the conditional, expected and actual
> values would likely disagree anyway (as soon as there are multiple entries), so
> some editing of the text would be nice too.
Why would I want to print the message outside the conditional?
Or did you mean:
dprintk(XENLOG_ERR, XSPLICE "%s: Size of .alt_instr is not multiple of %zu!\n",
elf->name, sizeof(*a));
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 20/27] build_id: Provide ld-embedded build-ids
2016-04-20 7:14 ` Jan Beulich
@ 2016-04-21 0:33 ` Konrad Rzeszutek Wilk
2016-04-21 6:59 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-21 0:33 UTC (permalink / raw)
To: Jan Beulich
Cc: sstabellini, keir, andrew.cooper3, mpohlack, mpohlack,
ross.lagerwall, julien.grall, sasha.levin, xen-devel
On Wed, Apr 20, 2016 at 01:14:17AM -0600, Jan Beulich wrote:
> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
> >--- a/Config.mk
> >+++ b/Config.mk
> >@@ -126,6 +126,17 @@ endef
> >check-$(gcc) = $(call cc-ver-check,CC,0x040100,"Xen requires at least gcc-4.1")
> >$(eval $(check-y))
> >
> >+ld-ver-build-id = $(shell $(1) --build-id 2>&1 | \
> >+ grep -q unrecognized && echo n || echo y)
>
> What about localized binutils?
I couldn't find the localized entries for binutils, but that may change
in the future.
Do you think it would be better to go back to the version check?
Or look at this at some pointer later - since you mentioned you were
OK with giving an Ack even as is?
>
> >@@ -87,7 +93,8 @@ endif
> >
> >$(TARGET): $(TARGET)-syms $(efi-y) boot/mkelf32
> >./boot/mkelf32 $(TARGET)-syms $(TARGET) 0x100000 \
> >- `$(NM) -nr $(TARGET)-syms | head -n 1 | sed -e 's/^\([^ ]*\).*/0x\1/'`
> >+ `$(NM) -nr $(TARGET)-syms | head -n 1 | sed -e 's/^\([^ ]*\).*/0x\1/'` \
> >+ $(notes_phdrs)
>
> The placement makes it somewhat non-obvious that this is an option passed
> to mkelf32 - it'd probably better go on the first line.
Sure thing.
..s nip..
> >+#if defined(BUILD_ID) && !defined(EFI)
> >+/*
> >+ * What a strange section name. The reason is that on ELF builds this section
> >+ * is extracted to notes.o (which then is ingested in the EFI file). But the
> >+ * compiler may want to inject other things in the .note which we don't care
> >+ * about - hence this unique name.
> >+ */
> >+ . = ALIGN(4);
> >+ .note.gnu.build-id : {
> >+ __note_gnu_build_id_start = .;
> >+ *(.note.gnu.build-id)
> >+ __note_gnu_build_id_end = .;
> >+ } :note :text
> >+#endif
>
> Am I misremembering that we had agreed for this to live ahead of _erodata?
No, I misremebered! Back in.
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 11/27] xsplice: Implement payload loading
2016-04-20 17:36 ` Konrad Rzeszutek Wilk
@ 2016-04-21 6:41 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-21 6:41 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: sstabellini, Keir Fraser, andrew.cooper3, mpohlack,
ross.lagerwall, julien.grall, sasha.levin, xen-devel
>>> On 20.04.16 at 19:36, <konrad@kernel.org> wrote:
> On Apr 20, 2016 6:05 PM, "Jan Beulich" <jbeulich@suse.com> wrote:
>>
>> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/20/16 6:00 PM >>>
>> >> >+ size_t pages; /* Total pages for [text,rw,ro]_addr */
>> >>
>> >> Why size_t and not just unsigned int?
>> >
>> >Oh. I was somehow under the impression you liked size_t more than
>> >unsignged int! I will change it over.
>>
>> When used where actually talking about sizes, I indeed prefer size_t. But
>> here we have a count which we know will be much lower than UINT_MAX.
>>
>> >> >+static void calc_section(struct xsplice_elf_sec *sec, size_t *size)
>> >> >+{
>> >> >+ Elf_Shdr *s = sec->sec;
>> >> >+ size_t align_size;
>> >> >+
>> >> >+ align_size = ROUNDUP(*size, s->sh_addralign);
>> >> >+ s->sh_entsize = align_size;
>> >>
>> >> So this is one of the places (the only one?) where the section header gets
>> >> altered. Are you not expecting problems down the road resulting from
>> >> overwriting this field? After all it's used not just in control sections...
>> >
>> >The 'man elf' tells me :
>> >"Some sections hold a table of fixed-sized entries, such as a symbol
>> >table. For such a section, this member gives the size in bytes for each entry.
>> >This member contains zero if the section does not hold a table of
>> >fixed-size entries."
>>
>> My main concern is that SHF_MERGE sections (i.e. ordinary data ones) also
>> already use this field.
>
> OK. Let me add the 'offset' member (in xsplice_elf_sec) to store the value.
>
> Albeit it only gets used during move_payload. And later that offset value
> can easily computed using ->load_addr minus ->data.
>
> Perhaps I should introduce an temporary array to hold this value instead?
Whichever is more feasible / less convoluted, I would say.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 12/27] xsplice: Implement support for applying/reverting/replacing patches.
2016-04-21 0:28 ` Konrad Rzeszutek Wilk
@ 2016-04-21 6:44 ` Jan Beulich
2016-04-21 20:27 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-21 6:44 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: kevin.tian, sstabellini, keir, suravee.suthikulpanit,
andrew.cooper3, mpohlack, ross.lagerwall, julien.grall,
jun.nakajima, sasha.levin, xen-devel, boris.ostrovsky
>>> On 21.04.16 at 02:28, <konrad.wilk@oracle.com> wrote:
>> >+ ASSERT(sec);
>> >+ if ( sec->sec->sh_size % sizeof(*payload->funcs) )
>> >+ {
>> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong size of .xsplice.funcs!\n",
>> >+ elf->name);
>> >+ return -EINVAL;
>> >+ }
>> >+
>> >+ payload->funcs = sec->load_addr;
>> >+ payload->nfuncs = sec->sec->sh_size / sizeof(*payload->funcs);
>>
>> Following to our discussion yesterday - can't we (ab)use the section merge
>> flag here to report the structure size, along the lines of what relocation
>> sections do for their elements?
>
>
> In other words - the xsplice-tools.git and the test-cases (in
> arch/x86/xen/test) would modify the sec->sh_entsize to have the
> sizeof(xsplice_patch_func) aka 64 (0x40) ?
>
> [Note this could also extend to .xsplice.hooks.load and
> .xsplice.hooks.unload]
>
> The xsplice-tools.git could surely do it, but the built-in test-cases -
> not so much. I would need to do some in-place binary handrolling - unless you
> know of some tool or some __section modifiers?
Well, that's why I suggest (ab) using the SHF_MERGE flag, i.e. to
see whether we can make gas do what we want. Fiddling with the
binary I would not recommend, i.e. if we can't get gas to do what
we want we should rather stay with what there is.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-21 0:26 ` Konrad Rzeszutek Wilk
@ 2016-04-21 6:46 ` Jan Beulich
[not found] ` <CACJDEmrucgYZpCDv3EAkDJUOtdcP9P2T=Vine1o2pzUmwJDY1w@mail.gmail.com>
2016-04-22 7:17 ` Ross Lagerwall
1 sibling, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-21 6:46 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: keir, ross.lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
>>> On 21.04.16 at 02:26, <konrad.wilk@oracle.com> wrote:
>> >+unsigned long xsplice_symbols_lookup_by_name(const char *symname)
>> >+{
>> >+ struct payload *data;
>>
>> Do you need symbols other than those marked "new_symbol" past the loading
>> of the module? If not, wouldn't it be worthwhile to shrink the symbol table to just
>> those, likely speeding up the lookup?
>
> Ross hopefully answered that to your satisfaction?
Yes. Thinko of mine.
>> >@@ -379,11 +405,129 @@ static int prepare_payload(struct payload *payload,
>> >for ( j = 0; j < ARRAY_SIZE(f->u.pad); j++ )
>> >if ( f->u.pad[j] )
>> >return -EINVAL;
>> >+
>> >+ /* Lookup function's old address if not already resolved. */
>> >+ if ( !f->old_addr )
>> >+ {
>> >+ f->old_addr = (void *)symbols_lookup_by_name(f->name);
>> >+ if ( !f->old_addr )
>> >+ {
>> >+ f->old_addr = (void *)xsplice_symbols_lookup_by_name(f->name);
>>
>> The two casts make me wonder whether the two functions shouldn't return
>> void *, and then whether struct xsplice_symbol's value field shouldn't then
>> perhaps be void * too.
>
> So I did try that and it all worked nicely on x86. However on ARM32:
>
> arm <konrad@localhost:~/xen/xen> make -j8 1>1
> symbols.c: In function 'symbols_lookup_by_name':
> symbols.c:287:20: error: cast to pointer from integer of different size
> [-Werror=int-to-pointer-cast]
>
> 275 uint64_t addr = 0; /* MUST be initialized. */
>
>
> 286 if ( !strcmp(name, symname) )
>
> 287 return (void *)addr;
>
> Which is rather unfortunate. I think I will have to make it unsigned
> long.
Well, why would any kind of address be uint64_t on ARM32?
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 17/27] xsplice: Add support for bug frames.
2016-04-21 0:29 ` Konrad Rzeszutek Wilk
@ 2016-04-21 6:49 ` Jan Beulich
2016-04-22 10:10 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-21 6:49 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: keir, ross.lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
>>> On 21.04.16 at 02:29, <konrad.wilk@oracle.com> wrote:
> On Tue, Apr 19, 2016 at 02:17:35PM -0600, Jan Beulich wrote:
>> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:02 AM >>>
>> >+bool_t is_patch(const void *ptr)
>> >+{
>> >+ struct payload *data;
>>
>> You guess it: const.
>>
>> >+ /*
>> >+ * No locking since this list is only ever changed during apply or revert
>> >+ * context.
>> >+ */
>>
>> What if you crash while applying or reverting a patch? Is the list update at
>> least done such that the (then nested) traversal remains safe?
>
> Yes! We only add the struct payload to this applied_list _after_ the
> patching has been done.` Hence if we crashed the list would not contain the
> struct payload that was patching - but would be safe to traverse.
Well, that only partly answers the question. Patch application to me
means the entire process, i.e. up to and including adding the new
patch to the list (read: the crash could also happen there). Hence
I'd still like it to be made sure that even if the addition has got done
only partially, the list remains traversable. Or IOW, I'm not sure the
standard list macros make any guarantees like that.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 19/27] xsplice: Add support for alternatives
2016-04-21 0:30 ` Konrad Rzeszutek Wilk
@ 2016-04-21 6:55 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-21 6:55 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: keir, ross.lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
>>> On 21.04.16 at 02:30, <konrad.wilk@oracle.com> wrote:
> On Wed, Apr 20, 2016 at 12:28:02AM -0600, Jan Beulich wrote:
>> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:02 AM >>>
>> >--- a/xen/arch/x86/Makefile
>> >+++ b/xen/arch/x86/Makefile
>> >@@ -6,7 +6,11 @@ subdir-y += mm
>> >subdir-$(CONFIG_XENOPROF) += oprofile
>> >subdir-y += x86_64
>> >
>> >+ifdef CONFIG_XSPLICE
>> >+obj-y += alternative.o
>> >+else
>> >obj-bin-y += alternative.init.o
>> >+endif
>>
>> For now this is okay, but please try to use the list model in favor of ifdef-s in
>> the future, whenever possible.
>
>
> As in:
> obj-$(CONFIG_XSPLICE) += alternative.o xsplice.o
>
> .. but then how do I define an build for alternative.init.o?
>
> ifndef CONFIG_XSPLICE
> obj-bin-$(CONFIG_XSPLICE) += alternative.init.o
> endif
alternative-y := alternative.init.o
alternative-$(CONFIG_XSPLICE) :=
obj-$(CONFIG_XSPLICE) += alternative.o xsplice.o
obj-bin-y += $(alternative-y)
The main goal with this purely list based approach being that this
way it doesn't matter whether CONFIG_XSPLICE is undefined,
defined but empty, or CONFIG_XSPLICE=n.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 19/27] xsplice: Add support for alternatives
2016-04-21 0:31 ` Konrad Rzeszutek Wilk
@ 2016-04-21 6:56 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-21 6:56 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: keir, ross.lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
>>> On 21.04.16 at 02:31, <konrad.wilk@oracle.com> wrote:
>> >--- a/xen/common/xsplice.c
>> >+++ b/xen/common/xsplice.c
>> >@@ -533,6 +533,39 @@ static int prepare_payload(struct payload *payload,
>> >}
>> >
>> >#ifndef CONFIG_ARM
>> >+ sec = xsplice_elf_sec_by_name(elf, ".altinstructions");
>> >+ if ( sec )
>> >+ {
>> >+ struct alt_instr *a, *start, *end;
>> >+
> .. snip..
>> >+ (sec->sec->sh_size % sizeof(*a)) )
>> >+ {
>> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong size of .alt_instr
> (exp:%lu vs %lu)!\n",
>> >+ elf->name, sizeof(*a),
>>
>> sizeof() wants to be formatted with %zu and ...
>>
>> >+ sec->sec->sh_size);
>>
>> ... didn't you add an ELF-specific format macro for cases like this?
>>
>> Also if you printed the message outside of the conditional, expected and
> actual
>> values would likely disagree anyway (as soon as there are multiple entries),
> so
>> some editing of the text would be nice too.
>
>
> Why would I want to print the message outside the conditional?
You wouldn't want to. This was just mentioned to help explain
the issue. But maybe I managed to confuse you.
> Or did you mean:
>
> dprintk(XENLOG_ERR, XSPLICE "%s: Size of .alt_instr is not
> multiple of %zu!\n",
> elf->name, sizeof(*a));
Indeed that's what I meant to get at.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 20/27] build_id: Provide ld-embedded build-ids
2016-04-21 0:33 ` Konrad Rzeszutek Wilk
@ 2016-04-21 6:59 ` Jan Beulich
2016-04-21 20:30 ` Konrad Rzeszutek Wilk
2016-04-22 16:16 ` Konrad Rzeszutek Wilk
0 siblings, 2 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-21 6:59 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: sstabellini, keir, ross.lagerwall, andrew.cooper3, mpohlack,
mpohlack, julien.grall, sasha.levin, xen-devel
>>> On 21.04.16 at 02:33, <konrad.wilk@oracle.com> wrote:
> On Wed, Apr 20, 2016 at 01:14:17AM -0600, Jan Beulich wrote:
>> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
>> >--- a/Config.mk
>> >+++ b/Config.mk
>> >@@ -126,6 +126,17 @@ endef
>> >check-$(gcc) = $(call cc-ver-check,CC,0x040100,"Xen requires at least gcc-4.1")
>> >$(eval $(check-y))
>> >
>> >+ld-ver-build-id = $(shell $(1) --build-id 2>&1 | \
>> >+ grep -q unrecognized && echo n || echo y)
>>
>> What about localized binutils?
>
> I couldn't find the localized entries for binutils, but that may change
> in the future.
>
> Do you think it would be better to go back to the version check?
No, definitely not. Just that you shouldn't look at textual output
imo, but at the linker actually groking the option.
> Or look at this at some pointer later - since you mentioned you were
> OK with giving an Ack even as is?
Yes, looking at this later is fine, as long as it doesn't get forgotten.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
[not found] ` <CACJDEmrQ6onv-xqYOi3nekioCSASb4c1eZHJ-rzMxU3Wa7SXTQ@mail.gmail.com>
@ 2016-04-21 13:56 ` Konrad Rzeszutek Wilk
2016-04-21 14:25 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-21 13:56 UTC (permalink / raw)
To: Jan Beulich
Cc: Keir Fraser, andrew.cooper3, mpohlack, ross.lagerwall, xen-devel,
sasha.levin
[-- Attachment #1.1: Type: text/plain, Size: 847 bytes --]
> > So I did try that and it all worked nicely on x86. However on ARM32:
> >
> > arm <konrad@localhost:~/xen/xen> make -j8 1>1
> > symbols.c: In function 'symbols_lookup_by_name':
> > symbols.c:287:20: error: cast to pointer from integer of different size
> > [-Werror=int-to-pointer-cast]
> >
> > 275 uint64_t addr = 0; /* MUST be initialized. */
> >
> >
> > 286 if ( !strcmp(name, symname) )
> >
> > 287 return (void *)addr;
> >
> > Which is rather unfortunate. I think I will have to make it unsigned
> > long.
>
> Well, why would any kind of address be uint64_t on ARM32?
>
Oh, the xensyms_read - which is used in a hypercalls (for reading the
symbols) as well - requires an pointer to an uint64_t as an argument. Hence
the need for using that type.
I can certainly muck with it so that it can do xen_pfn_t.
> Jan
>
[-- Attachment #1.2: Type: text/html, Size: 1170 bytes --]
[-- Attachment #2: Type: text/plain, Size: 126 bytes --]
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-21 13:56 ` Konrad Rzeszutek Wilk
@ 2016-04-21 14:25 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-21 14:25 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: Keir Fraser, andrew.cooper3, mpohlack, ross.lagerwall, xen-devel,
sasha.levin
>>> On 21.04.16 at 15:56, <konrad@kernel.org> wrote:
>> > So I did try that and it all worked nicely on x86. However on ARM32:
>> >
>> > arm <konrad@localhost:~/xen/xen> make -j8 1>1
>> > symbols.c: In function 'symbols_lookup_by_name':
>> > symbols.c:287:20: error: cast to pointer from integer of different size
>> > [-Werror=int-to-pointer-cast]
>> >
>> > 275 uint64_t addr = 0; /* MUST be initialized. */
>> >
>> >
>> > 286 if ( !strcmp(name, symname) )
>> >
>> > 287 return (void *)addr;
>> >
>> > Which is rather unfortunate. I think I will have to make it unsigned
>> > long.
>>
>> Well, why would any kind of address be uint64_t on ARM32?
>>
>
> Oh, the xensyms_read - which is used in a hypercalls (for reading the
> symbols) as well - requires an pointer to an uint64_t as an argument. Hence
> the need for using that type.
>
> I can certainly muck with it so that it can do xen_pfn_t.
Which also is a 64-bit type on ARM, and which would be really wrong
to use here. There's really no point in xensyms_read() taking other
than an unsigned long *, and if the sysctl wants a uint64_t, then it
should use a temporary variable to do the conversion.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 11/27] xsplice: Implement payload loading
2016-04-20 15:59 ` Konrad Rzeszutek Wilk
2016-04-20 17:05 ` Jan Beulich
@ 2016-04-21 15:15 ` Konrad Rzeszutek Wilk
2016-04-21 15:36 ` Jan Beulich
1 sibling, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-21 15:15 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: sstabellini, keir, andrew.cooper3, mpohlack, ross.lagerwall,
julien.grall, Jan Beulich, sasha.levin, xen-devel
On Wed, Apr 20, 2016 at 11:59:34AM -0400, Konrad Rzeszutek Wilk wrote:
> > >+void arch_xsplice_free_payload(void *va)
> > >+{
> > >+ vfree_xen(va);
> > >+}
> >
> > What is the idea behind having this hook (instead of generic code just calling
> > vfree_xen() [or really just vfree()])?
>
> To have an symmetry with the allocation one. I don't know enough about
> ARM to know whether this logic above can be hoisted in the common code
> and hence called (or compiled) on ARM.
>
> Let me try.
That worked out nicely. vzalloc_xen and vfree and the
arch_xsplice_alloc_payload and arch_xsplice_free_payload are gone.
> >
> > >@@ -29,6 +30,13 @@ struct payload {
> > >uint32_t state; /* One of the XSPLICE_STATE_*. */
> > >int32_t rc; /* 0 or -XEN_EXX. */
> > >struct list_head list; /* Linked to 'payload_list'. */
> > >+ void *text_addr; /* Virtual address of .text. */
> > >+ size_t text_size; /* .. and its size. */
> > >+ void *rw_addr; /* Virtual address of .data. */
> > >+ size_t rw_size; /* .. and its size (if any). */
> > >+ void *ro_addr; /* Virtual address of .rodata. */
> > >+ size_t ro_size; /* .. and its size (if any). */
> >
> > And again the question: Do these pointers really need to be non-const?
>
> I know I tried making them const and the compiler was not happy. I will
> follow up with the reasoning.
The big problem I ran in was that I had to do casting in
'modify_payload'. To lower the amount of casting I ended making
load_addr be void * (if it was const void * I would have to cast away
the constness in xsplice_elf.c):
elf->sec[i].load_addr = (void *)buf + offset[i];
where 'buf' is:
buf = payload->text_addr;
(and buf it also a const void *).
> >
> > >+static void calc_section(struct xsplice_elf_sec *sec, size_t *size)
> > >+{
> > >+ Elf_Shdr *s = sec->sec;
> > >+ size_t align_size;
> > >+
> > >+ align_size = ROUNDUP(*size, s->sh_addralign);
> > >+ s->sh_entsize = align_size;
> >
> > So this is one of the places (the only one?) where the section header gets
> > altered. Are you not expecting problems down the road resulting from
> > overwriting this field? After all it's used not just in control sections...
>
> The 'man elf' tells me :
> "Some sections hold a table of fixed-sized entries, such as a symbol
> table. For such a section, this member gives the size in bytes for each entry.
> This member contains zero if the section does not hold a table of
> fixed-size entries."
>
> We may have an value for an payload with one symbol but we don't depend
> on this value having any value and just re-use.
>
> We could change the logic to save the aligned size (which would then alter
> the amount of pages to allocate along with the amount of bytes to copy)
> in some 'per-section' temporary variable (so adding an extra field in
> 'struct xsplice_elf_sec').
>
> Let me prototype that.
And it worked out nicely.
.. snip..
> > >+int xsplice_elf_resolve_symbols(struct xsplice_elf *elf)
> .. snip..
> > >+ default:
.. snip..
> > >+ if ( !(elf->sec[idx].sec->sh_flags & SHF_ALLOC) )
> > >+ break;
> >
> > If you really mean to check this, shouldn't this be done earlier, avoiding needless
> > errors on unsupported symbol kinds above?
>
So I am coming back to this. The ones that this hits are:
Symbol's section .note.GNU-stack is !SHF_ALLOC
Symbol's section .comment is !SHF_ALLOC
Symbol's section .debug_aranges is !SHF_ALLOC
Symbol's section .debug_pubnames is !SHF_ALLOC
Symbol's section .debug_info is !SHF_ALLOC
Symbol's section .debug_abbrev is !SHF_ALLOC
Symbol's section .debug_line is !SHF_ALLOC
Symbol's section .debug_frame is !SHF_ALLOC
Symbol's section .debug_str is !SHF_ALLOC
Symbol's section .debug_loc is !SHF_ALLOC
Symbol's section .debug_pubtypes is !SHF_ALLOC
I am not sure what to make out of it. As in the code ignores
these sections. I tried to ake the test code strip these out:
strip -d
But that stripped out the relocation entries out to!
Doing just:
strip -R .comment
Did the same exact thing (ripped out .rela*).
Keep in mind that this code above does not set 'rc' at all - so
the rc is 0 by default and we just ignore this specific section.
I would rather keep it this way - otherwise I have to make the
test code go through an hand-rolled linker script - I can't use
Xen's (xen.lds.S) as it has the ASSERTS that get triggered:
#ifdef CONFIG_KEXEC
ASSERT(kexec_reloc_size - kexec_reloc <= PAGE_SIZE, "kexec_reloc is too
large")
#endif
As the object file has none of these entries in it.
What's your preference? Leave it as is (so skip over those
sections), or be pedantic on them and require no !SHF_ALLOC sections?
And also bail out if any of the sections don't have an st_type that we
implement, such as .comment:
[28] .comment PROGBITS 0000000000000000 000002a4
000000000000005a 0000000000000001 MS 0 0 1
Or let them be but not do anything to them (whcih is what we currently
do).
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 11/27] xsplice: Implement payload loading
2016-04-21 15:15 ` Konrad Rzeszutek Wilk
@ 2016-04-21 15:36 ` Jan Beulich
2016-04-21 16:47 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-21 15:36 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk, Konrad Rzeszutek Wilk
Cc: sstabellini, keir, andrew.cooper3, mpohlack, ross.lagerwall,
julien.grall, sasha.levin, xen-devel
>>> On 21.04.16 at 17:15, <konrad@kernel.org> wrote:
> On Wed, Apr 20, 2016 at 11:59:34AM -0400, Konrad Rzeszutek Wilk wrote:
>> > >@@ -29,6 +30,13 @@ struct payload {
>> > >uint32_t state; /* One of the XSPLICE_STATE_*. */
>> > >int32_t rc; /* 0 or -XEN_EXX. */
>> > >struct list_head list; /* Linked to 'payload_list'. */
>> > >+ void *text_addr; /* Virtual address of .text. */
>> > >+ size_t text_size; /* .. and its size. */
>> > >+ void *rw_addr; /* Virtual address of .data. */
>> > >+ size_t rw_size; /* .. and its size (if any). */
>> > >+ void *ro_addr; /* Virtual address of .rodata. */
>> > >+ size_t ro_size; /* .. and its size (if any). */
>> >
>> > And again the question: Do these pointers really need to be non-const?
>>
>> I know I tried making them const and the compiler was not happy. I will
>> follow up with the reasoning.
>
> The big problem I ran in was that I had to do casting in
> 'modify_payload'. To lower the amount of casting I ended making
>
> load_addr be void * (if it was const void * I would have to cast away
> the constness in xsplice_elf.c):
>
> elf->sec[i].load_addr = (void *)buf + offset[i];
>
> where 'buf' is:
> buf = payload->text_addr;
>
> (and buf it also a const void *).
Hence (taking all of the above) without any cast and with load_addr
being const void *, text_addr could be so, too. Or else the picture
above isn't the complete one.
>> > >+int xsplice_elf_resolve_symbols(struct xsplice_elf *elf)
>> .. snip..
>> > >+ default:
> .. snip..
>> > >+ if ( !(elf->sec[idx].sec->sh_flags & SHF_ALLOC) )
>> > >+ break;
>> >
>> > If you really mean to check this, shouldn't this be done earlier, avoiding
> needless
>> > errors on unsupported symbol kinds above?
With all of the ..snip..-s above, it's now really hard to answer this:
> So I am coming back to this. The ones that this hits are:
> Symbol's section .note.GNU-stack is !SHF_ALLOC
> Symbol's section .comment is !SHF_ALLOC
> Symbol's section .debug_aranges is !SHF_ALLOC
> Symbol's section .debug_pubnames is !SHF_ALLOC
> Symbol's section .debug_info is !SHF_ALLOC
> Symbol's section .debug_abbrev is !SHF_ALLOC
> Symbol's section .debug_line is !SHF_ALLOC
> Symbol's section .debug_frame is !SHF_ALLOC
> Symbol's section .debug_str is !SHF_ALLOC
> Symbol's section .debug_loc is !SHF_ALLOC
> Symbol's section .debug_pubtypes is !SHF_ALLOC
>
> I am not sure what to make out of it. As in the code ignores
> these sections.
Right, because these sections are of no interest to the loading
process. And hence none of the symbols (if there really are any)
in those sections should be of any interest either.
> I tried to ake the test code strip these out:
>
> strip -d
>
> But that stripped out the relocation entries out to!
Was that all relocations, or just those referencing the sections
above?
> Doing just:
>
> strip -R .comment
>
> Did the same exact thing (ripped out .rela*).
That sounds wrong.
> Keep in mind that this code above does not set 'rc' at all - so
> the rc is 0 by default and we just ignore this specific section.
>
> I would rather keep it this way - otherwise I have to make the
> test code go through an hand-rolled linker script - I can't use
> Xen's (xen.lds.S) as it has the ASSERTS that get triggered:
>
> #ifdef CONFIG_KEXEC
> ASSERT(kexec_reloc_size - kexec_reloc <= PAGE_SIZE, "kexec_reloc is too
> large")
> #endif
>
> As the object file has none of these entries in it.
>
> What's your preference? Leave it as is (so skip over those
> sections), or be pedantic on them and require no !SHF_ALLOC sections?
I'm not sure I'm with you here: I didn't ask for anything to be removed
or added, all I had asked is whether that check shouldn't be moved up.
> And also bail out if any of the sections don't have an st_type that we
> implement, such as .comment:
>
> [28] .comment PROGBITS 0000000000000000 000002a4
> 000000000000005a 0000000000000001 MS 0 0 1
>
> Or let them be but not do anything to them (whcih is what we currently
> do).
I don't think I can follow you here either.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 11/27] xsplice: Implement payload loading
2016-04-21 15:36 ` Jan Beulich
@ 2016-04-21 16:47 ` Konrad Rzeszutek Wilk
2016-04-22 7:40 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-21 16:47 UTC (permalink / raw)
To: Jan Beulich, Konrad Rzeszutek Wilk
Cc: sstabellini, keir, andrew.cooper3, mpohlack, ross.lagerwall,
julien.grall, sasha.levin, xen-devel
On April 21, 2016 11:36:24 AM EDT, Jan Beulich <JBeulich@suse.com> wrote:
>>>> On 21.04.16 at 17:15, <konrad@kernel.org> wrote:
>> On Wed, Apr 20, 2016 at 11:59:34AM -0400, Konrad Rzeszutek Wilk
>wrote:
>>> > >@@ -29,6 +30,13 @@ struct payload {
>>> > >uint32_t state; /* One of the
>XSPLICE_STATE_*. */
>>> > >int32_t rc; /* 0 or -XEN_EXX. */
>>> > >struct list_head list; /* Linked to
>'payload_list'. */
>>> > >+ void *text_addr; /* Virtual address of
>.text. */
>>> > >+ size_t text_size; /* .. and its size. */
>>> > >+ void *rw_addr; /* Virtual address of
>.data. */
>>> > >+ size_t rw_size; /* .. and its size (if
>any). */
>>> > >+ void *ro_addr; /* Virtual address of
>.rodata. */
>>> > >+ size_t ro_size; /* .. and its size (if
>any). */
>>> >
>>> > And again the question: Do these pointers really need to be
>non-const?
>>>
>>> I know I tried making them const and the compiler was not happy. I
>will
>>> follow up with the reasoning.
>>
>> The big problem I ran in was that I had to do casting in
>> 'modify_payload'. To lower the amount of casting I ended making
>>
>> load_addr be void * (if it was const void * I would have to cast away
>> the constness in xsplice_elf.c):
>>
>> elf->sec[i].load_addr = (void *)buf + offset[i];
>>
>> where 'buf' is:
>> buf = payload->text_addr;
>>
>> (and buf it also a const void *).
>
>Hence (taking all of the above) without any cast and with load_addr
>being const void *, text_addr could be so, too. Or else the picture
>above isn't the complete one.
>
If I did that I will need to uncast constness when memcpy data in (a couple of lines below in move_payload). And also when doing relocation.
>>> > >+int xsplice_elf_resolve_symbols(struct xsplice_elf *elf)
>>> .. snip..
>>> > >+ default:
>> .. snip..
>>> > >+ if ( !(elf->sec[idx].sec->sh_flags & SHF_ALLOC) )
>>> > >+ break;
>>> >
>>> > If you really mean to check this, shouldn't this be done earlier,
>avoiding
>> needless
>>> > errors on unsupported symbol kinds above?
>
>With all of the ..snip..-s above, it's now really hard to answer this:
Sorry.
>
>> So I am coming back to this. The ones that this hits are:
>> Symbol's section .note.GNU-stack is !SHF_ALLOC
>> Symbol's section .comment is !SHF_ALLOC
>> Symbol's section .debug_aranges is !SHF_ALLOC
>> Symbol's section .debug_pubnames is !SHF_ALLOC
>> Symbol's section .debug_info is !SHF_ALLOC
>> Symbol's section .debug_abbrev is !SHF_ALLOC
>> Symbol's section .debug_line is !SHF_ALLOC
>> Symbol's section .debug_frame is !SHF_ALLOC
>> Symbol's section .debug_str is !SHF_ALLOC
>> Symbol's section .debug_loc is !SHF_ALLOC
>> Symbol's section .debug_pubtypes is !SHF_ALLOC
>>
>> I am not sure what to make out of it. As in the code ignores
>> these sections.
>
>Right, because these sections are of no interest to the loading
>process. And hence none of the symbols (if there really are any)
>in those sections should be of any interest either.
>
OK, so we are in agreement.
>> I tried to ake the test code strip these out:
>>
>> strip -d
>>
>> But that stripped out the relocation entries out to!
>
>Was that all relocations, or just those referencing the sections
>above?
>
All. For .text as well.
>> Doing just:
>>
>> strip -R .comment
>>
>> Did the same exact thing (ripped out .rela*).
>
>That sounds wrong.
Yes. Maybe the version I have is buggy.
>
>> Keep in mind that this code above does not set 'rc' at all - so
>> the rc is 0 by default and we just ignore this specific section.
>>
>> I would rather keep it this way - otherwise I have to make the
>> test code go through an hand-rolled linker script - I can't use
>> Xen's (xen.lds.S) as it has the ASSERTS that get triggered:
>>
>> #ifdef CONFIG_KEXEC
>> ASSERT(kexec_reloc_size - kexec_reloc <= PAGE_SIZE, "kexec_reloc is
>too
>> large")
>> #endif
>>
>> As the object file has none of these entries in it.
>>
>> What's your preference? Leave it as is (so skip over those
>> sections), or be pedantic on them and require no !SHF_ALLOC sections?
>
>I'm not sure I'm with you here: I didn't ask for anything to be removed
>or added, all I had asked is whether that check shouldn't be moved up.
Oh. Yes, I can do that!
>
>> And also bail out if any of the sections don't have an st_type that
>we
>> implement, such as .comment:
>>
>> [28] .comment PROGBITS 0000000000000000 000002a4
>> 000000000000005a 0000000000000001 MS 0 0 1
>>
>> Or let them be but not do anything to them (whcih is what we
>currently
>> do).
>
>I don't think I can follow you here either.
This is a bit of tangent on this above .Let me reply on proper thread.
>
>Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 12/27] xsplice: Implement support for applying/reverting/replacing patches.
2016-04-21 6:44 ` Jan Beulich
@ 2016-04-21 20:27 ` Konrad Rzeszutek Wilk
2016-04-22 7:44 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-21 20:27 UTC (permalink / raw)
To: Jan Beulich
Cc: kevin.tian, sstabellini, keir, jun.nakajima, andrew.cooper3,
mpohlack, ross.lagerwall, julien.grall, suravee.suthikulpanit,
sasha.levin, xen-devel, boris.ostrovsky
On Thu, Apr 21, 2016 at 12:44:41AM -0600, Jan Beulich wrote:
> >>> On 21.04.16 at 02:28, <konrad.wilk@oracle.com> wrote:
> >> >+ ASSERT(sec);
> >> >+ if ( sec->sec->sh_size % sizeof(*payload->funcs) )
> >> >+ {
> >> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong size of .xsplice.funcs!\n",
> >> >+ elf->name);
> >> >+ return -EINVAL;
> >> >+ }
> >> >+
> >> >+ payload->funcs = sec->load_addr;
> >> >+ payload->nfuncs = sec->sec->sh_size / sizeof(*payload->funcs);
> >>
> >> Following to our discussion yesterday - can't we (ab)use the section merge
> >> flag here to report the structure size, along the lines of what relocation
> >> sections do for their elements?
> >
> >
> > In other words - the xsplice-tools.git and the test-cases (in
> > arch/x86/xen/test) would modify the sec->sh_entsize to have the
> > sizeof(xsplice_patch_func) aka 64 (0x40) ?
> >
> > [Note this could also extend to .xsplice.hooks.load and
> > .xsplice.hooks.unload]
> >
> > The xsplice-tools.git could surely do it, but the built-in test-cases -
> > not so much. I would need to do some in-place binary handrolling - unless you
> > know of some tool or some __section modifiers?
>
> Well, that's why I suggest (ab) using the SHF_MERGE flag, i.e. to
> see whether we can make gas do what we want. Fiddling with the
> binary I would not recommend, i.e. if we can't get gas to do what
> we want we should rather stay with what there is.
This:
diff --git a/xen/arch/x86/test/xen_hello_world.c b/xen/arch/x86/test/xen_hello_world.c
index a3da85d..92f2e97 100644
--- a/xen/arch/x86/test/xen_hello_world.c
+++ b/xen/arch/x86/test/xen_hello_world.c
@@ -47,6 +47,13 @@ XSPLICE_UNLOAD_HOOK(hi_func);
XSPLICE_UNLOAD_HOOK(Z_check_fnc);
+#define XSPLICE_FUNC() \
+ asm ( \
+ ".pushsection .xsplice.funcs, \"awM\", @progbits, 64\n " \
+ ".popsection")
+
+XSPLICE_FUNC();
+
struct xsplice_patch_func __section(".xsplice.funcs") xsplice_xen_hello_world = {
.version = XSPLICE_PAYLOAD_VERSION,
.name = hello_world_patch_this_fnc,
Makes the .xsplice.funcs have sh_entsize have the size of 64 bytes:
[ 6] .xsplice.funcs PROGBITS 0000000000000000 000000a0
0000000000000040 0000000000000000 WA 0 0 32
vs
[ 6] .xsplice.funcs PROGBITS 0000000000000000 000000a0
0000000000000040 0000000000000040 WAM 0 0 32
Unfortunatly the compilation throws this:
FC-64 <konrad@build-external:~/xtt-x86_64/xen/xen> make -j4 tests 1>1
dnsdomainname: Name or service not known
{standard input}: Assembler messages:
{standard input}:184: Warning: ignoring changed section attributes for .xsplice.funcs
This is with:
binutils-2.20.51.0.2-15.fc13.x86_64
and with:
binutils-2.25-9.fc22.x86_64
Ideas?
I could try to wrap the definition of these
struct xsplice_patch_func __section(".xsplice.funcs") xsplice_xen_hello_world
using an macro - but that did not work very well (I couldn't manage it
to take the value of say XSPLICE_PAYLOAD_VERSION).
Perhaps skip this?
>
> Jan
>
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^ permalink raw reply related [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 20/27] build_id: Provide ld-embedded build-ids
2016-04-21 6:59 ` Jan Beulich
@ 2016-04-21 20:30 ` Konrad Rzeszutek Wilk
2016-04-22 16:16 ` Konrad Rzeszutek Wilk
1 sibling, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-21 20:30 UTC (permalink / raw)
To: Jan Beulich
Cc: sstabellini, keir, andrew.cooper3, mpohlack, mpohlack,
ross.lagerwall, julien.grall, sasha.levin, xen-devel
On Thu, Apr 21, 2016 at 12:59:00AM -0600, Jan Beulich wrote:
> >>> On 21.04.16 at 02:33, <konrad.wilk@oracle.com> wrote:
> > On Wed, Apr 20, 2016 at 01:14:17AM -0600, Jan Beulich wrote:
> >> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
> >> >--- a/Config.mk
> >> >+++ b/Config.mk
> >> >@@ -126,6 +126,17 @@ endef
> >> >check-$(gcc) = $(call cc-ver-check,CC,0x040100,"Xen requires at least gcc-4.1")
> >> >$(eval $(check-y))
> >> >
> >> >+ld-ver-build-id = $(shell $(1) --build-id 2>&1 | \
> >> >+ grep -q unrecognized && echo n || echo y)
> >>
> >> What about localized binutils?
> >
> > I couldn't find the localized entries for binutils, but that may change
> > in the future.
> >
> > Do you think it would be better to go back to the version check?
>
> No, definitely not. Just that you shouldn't look at textual output
> imo, but at the linker actually groking the option.
>
> > Or look at this at some pointer later - since you mentioned you were
> > OK with giving an Ack even as is?
>
> Yes, looking at this later is fine, as long as it doesn't get forgotten.
Added it on http://wiki.xen.org/wiki/XSplice#Hypervisor so I will not
forget.
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-21 0:26 ` Konrad Rzeszutek Wilk
2016-04-21 6:46 ` Jan Beulich
@ 2016-04-22 7:17 ` Ross Lagerwall
2016-04-22 7:51 ` Jan Beulich
1 sibling, 1 reply; 126+ messages in thread
From: Ross Lagerwall @ 2016-04-22 7:17 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk, Jan Beulich
Cc: keir, andrew.cooper3, mpohlack, sasha.levin, xen-devel
On 04/21/2016 01:26 AM, Konrad Rzeszutek Wilk wrote:
snip
>>
>>> +static bool_t is_payload_symbol(const struct xsplice_elf *elf,
>>> + const struct xsplice_elf_sym *sym)
>>> +{
>>> + if ( sym->sym->st_shndx == SHN_UNDEF ||
>>> + sym->sym->st_shndx >= elf->hdr->e_shnum )
>>> + return 0;
>>> +
>>> + return (elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) &&
>>> + (ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT ||
>>> + ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
>>
>> I don't recall having seen a reply to the question on not allowing STT_NOTYPE here.
>
> Ross, could you elaborate a bit please on this?
The payload will typically have many entries like:
9: 0000000000000000 0 NOTYPE LOCAL DEFAULT 5 .LC1
10: 0000000000000006 0 NOTYPE LOCAL DEFAULT 5 .LC2
11: 000000000000000d 0 NOTYPE LOCAL DEFAULT 5 .LC3
12: 0000000000000028 0 NOTYPE LOCAL DEFAULT 4 .LC4
13: 0000000000000058 0 NOTYPE LOCAL DEFAULT 4 .LC5
used when referencing strings (due to the use of -fPIC). While it is not
a problem for them to go into the symbol table, if more than one payload
is loaded, there will be duplicate conflicting symbols. So, to prevent
these symbols from going into the symbol table, I disallowed STT_NOTYPE.
Perhaps not the best solution but...
--
Ross Lagerwall
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 11/27] xsplice: Implement payload loading
2016-04-21 16:47 ` Konrad Rzeszutek Wilk
@ 2016-04-22 7:40 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-22 7:40 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk, Konrad Rzeszutek Wilk
Cc: sstabellini, keir, andrew.cooper3, mpohlack, ross.lagerwall,
julien.grall, sasha.levin, xen-devel
>>> On 21.04.16 at 18:47, <konrad.wilk@oracle.com> wrote:
> On April 21, 2016 11:36:24 AM EDT, Jan Beulich <JBeulich@suse.com> wrote:
>>>>> On 21.04.16 at 17:15, <konrad@kernel.org> wrote:
>>> On Wed, Apr 20, 2016 at 11:59:34AM -0400, Konrad Rzeszutek Wilk
>>wrote:
>>>> > >@@ -29,6 +30,13 @@ struct payload {
>>>> > >uint32_t state; /* One of the
>>XSPLICE_STATE_*. */
>>>> > >int32_t rc; /* 0 or -XEN_EXX. */
>>>> > >struct list_head list; /* Linked to
>>'payload_list'. */
>>>> > >+ void *text_addr; /* Virtual address of
>>.text. */
>>>> > >+ size_t text_size; /* .. and its size. */
>>>> > >+ void *rw_addr; /* Virtual address of
>>.data. */
>>>> > >+ size_t rw_size; /* .. and its size (if
>>any). */
>>>> > >+ void *ro_addr; /* Virtual address of
>>.rodata. */
>>>> > >+ size_t ro_size; /* .. and its size (if
>>any). */
>>>> >
>>>> > And again the question: Do these pointers really need to be
>>non-const?
>>>>
>>>> I know I tried making them const and the compiler was not happy. I
>>will
>>>> follow up with the reasoning.
>>>
>>> The big problem I ran in was that I had to do casting in
>>> 'modify_payload'. To lower the amount of casting I ended making
>>>
>>> load_addr be void * (if it was const void * I would have to cast away
>>> the constness in xsplice_elf.c):
>>>
>>> elf->sec[i].load_addr = (void *)buf + offset[i];
>>>
>>> where 'buf' is:
>>> buf = payload->text_addr;
>>>
>>> (and buf it also a const void *).
>>
>>Hence (taking all of the above) without any cast and with load_addr
>>being const void *, text_addr could be so, too. Or else the picture
>>above isn't the complete one.
>>
>
> If I did that I will need to uncast constness when memcpy data in (a couple
> of lines below in move_payload).
Ehem - no, not really. This is what the patch has:
uint8_t *buf;
...
buf = arch_xsplice_alloc_payload(size);
...
elf->sec[i].load_addr = buf + elf->sec[i].sec->sh_entsize;
...
memcpy(elf->sec[i].load_addr, elf->sec[i].data,
elf->sec[i].sec->sh_size);
So all it would take is to substitute the first argument to memcpy()
by an expression involving buf (i.e. the right side of the earlier
assignment, or some intermediate variable used to avoid having
the same expression twice).
> And also when doing relocation.
There it would then be really unavoidable. That's a place where I
would say casting away constness could be considered acceptable,
but I'd like to come back to your earlier reply first: You refer to
modify_payload() and an expression involving "buf + offset[i]",
neither of which I can spot anywhere in this patch. Oh, looks like
you mean this
if ( (elf->sec[i].sec->sh_flags & SHF_EXECINSTR) )
buf = payload->text_addr;
else if ( (elf->sec[i].sec->sh_flags & SHF_WRITE) )
buf = payload->rw_addr;
else
buf = payload->ro_addr;
elf->sec[i].load_addr = buf + elf->sec[i].sec->sh_entsize;
in move_payload(). But that's the same as above then - by using
suitable intermediate variables you can deal with the structure
fields pointing to const quite easily, since the loop the above is in
is preceded by
payload->text_addr = buf;
payload->rw_addr = payload->text_addr + PAGE_ALIGN(payload->text_size);
payload->ro_addr = payload->rw_addr + PAGE_ALIGN(payload->rw_size);
and buf points to non-const.
Bottom line: While doing the loading it is clear that some of the
image needs to be modified, and hence you need pointers to
non-const, or cast away constness under rare circumstances.
But since for the whole rest of the lifetime of the module you
do want to express that the image pieces are not supposed to
change, the goal ought to be to have as many as possible
pointers to const in the control structure.
And I'm really sorry for being this picky, you simply suffer from
me having written more than one image loader as well as a linker
and object file analysis/massaging tools in the past.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 12/27] xsplice: Implement support for applying/reverting/replacing patches.
2016-04-21 20:27 ` Konrad Rzeszutek Wilk
@ 2016-04-22 7:44 ` Jan Beulich
2016-04-22 10:51 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-22 7:44 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: kevin.tian, sstabellini, keir, suravee.suthikulpanit,
andrew.cooper3, mpohlack, ross.lagerwall, julien.grall,
jun.nakajima, sasha.levin, xen-devel, boris.ostrovsky
>>> On 21.04.16 at 22:27, <konrad@kernel.org> wrote:
> On Thu, Apr 21, 2016 at 12:44:41AM -0600, Jan Beulich wrote:
>> >>> On 21.04.16 at 02:28, <konrad.wilk@oracle.com> wrote:
>> >> >+ ASSERT(sec);
>> >> >+ if ( sec->sec->sh_size % sizeof(*payload->funcs) )
>> >> >+ {
>> >> >+ dprintk(XENLOG_ERR, XSPLICE "%s: Wrong size of .xsplice.funcs!\n",
>> >> >+ elf->name);
>> >> >+ return -EINVAL;
>> >> >+ }
>> >> >+
>> >> >+ payload->funcs = sec->load_addr;
>> >> >+ payload->nfuncs = sec->sec->sh_size / sizeof(*payload->funcs);
>> >>
>> >> Following to our discussion yesterday - can't we (ab)use the section merge
>> >> flag here to report the structure size, along the lines of what relocation
>> >> sections do for their elements?
>> >
>> >
>> > In other words - the xsplice-tools.git and the test-cases (in
>> > arch/x86/xen/test) would modify the sec->sh_entsize to have the
>> > sizeof(xsplice_patch_func) aka 64 (0x40) ?
>> >
>> > [Note this could also extend to .xsplice.hooks.load and
>> > .xsplice.hooks.unload]
>> >
>> > The xsplice-tools.git could surely do it, but the built-in test-cases -
>> > not so much. I would need to do some in-place binary handrolling - unless you
>> > know of some tool or some __section modifiers?
>>
>> Well, that's why I suggest (ab) using the SHF_MERGE flag, i.e. to
>> see whether we can make gas do what we want. Fiddling with the
>> binary I would not recommend, i.e. if we can't get gas to do what
>> we want we should rather stay with what there is.
>
> This:
>
> diff --git a/xen/arch/x86/test/xen_hello_world.c
> b/xen/arch/x86/test/xen_hello_world.c
> index a3da85d..92f2e97 100644
> --- a/xen/arch/x86/test/xen_hello_world.c
> +++ b/xen/arch/x86/test/xen_hello_world.c
> @@ -47,6 +47,13 @@ XSPLICE_UNLOAD_HOOK(hi_func);
>
> XSPLICE_UNLOAD_HOOK(Z_check_fnc);
>
> +#define XSPLICE_FUNC() \
> + asm ( \
> + ".pushsection .xsplice.funcs, \"awM\", @progbits, 64\n " \
> + ".popsection")
> +
> +XSPLICE_FUNC();
> +
> struct xsplice_patch_func __section(".xsplice.funcs")
> xsplice_xen_hello_world = {
> .version = XSPLICE_PAYLOAD_VERSION,
> .name = hello_world_patch_this_fnc,
>
> Makes the .xsplice.funcs have sh_entsize have the size of 64 bytes:
>
>
> [ 6] .xsplice.funcs PROGBITS 0000000000000000 000000a0
> 0000000000000040 0000000000000000 WA 0 0 32
> vs
>
> [ 6] .xsplice.funcs PROGBITS 0000000000000000 000000a0
> 0000000000000040 0000000000000040 WAM 0 0 32
>
> Unfortunatly the compilation throws this:
>
> FC-64 <konrad@build-external:~/xtt-x86_64/xen/xen> make -j4 tests 1>1
> dnsdomainname: Name or service not known
> {standard input}: Assembler messages:
> {standard input}:184: Warning: ignoring changed section attributes for
> .xsplice.funcs
>
>
> This is with:
> binutils-2.20.51.0.2-15.fc13.x86_64
> and with:
> binutils-2.25-9.fc22.x86_64
>
> Ideas?
Well, this presumably being a redundant .section directive
somewhere it would require seeing the full .c together with the
intermediate .s in order to tell. But I guess to avoid you spending
more time on this secondary aspect, let's just drop this for now
and just put it on the todo list (as long as the thing is tech preview
we can still alter requirements we place on the actual payloads).
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-22 7:17 ` Ross Lagerwall
@ 2016-04-22 7:51 ` Jan Beulich
2016-04-22 8:45 ` Ross Lagerwall
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-22 7:51 UTC (permalink / raw)
To: Ross Lagerwall, Konrad Rzeszutek Wilk
Cc: keir, andrew.cooper3, mpohlack, sasha.levin, xen-devel
>>> On 22.04.16 at 09:17, <ross.lagerwall@citrix.com> wrote:
> On 04/21/2016 01:26 AM, Konrad Rzeszutek Wilk wrote:
> snip
>>>
>>>> +static bool_t is_payload_symbol(const struct xsplice_elf *elf,
>>>> + const struct xsplice_elf_sym *sym)
>>>> +{
>>>> + if ( sym->sym->st_shndx == SHN_UNDEF ||
>>>> + sym->sym->st_shndx >= elf->hdr->e_shnum )
>>>> + return 0;
>>>> +
>>>> + return (elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) &&
>>>> + (ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT ||
>>>> + ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
>>>
>>> I don't recall having seen a reply to the question on not allowing
> STT_NOTYPE here.
>>
>> Ross, could you elaborate a bit please on this?
>
>
> The payload will typically have many entries like:
>
> 9: 0000000000000000 0 NOTYPE LOCAL DEFAULT 5 .LC1
> 10: 0000000000000006 0 NOTYPE LOCAL DEFAULT 5 .LC2
> 11: 000000000000000d 0 NOTYPE LOCAL DEFAULT 5 .LC3
> 12: 0000000000000028 0 NOTYPE LOCAL DEFAULT 4 .LC4
> 13: 0000000000000058 0 NOTYPE LOCAL DEFAULT 4 .LC5
>
> used when referencing strings (due to the use of -fPIC). While it is not
> a problem for them to go into the symbol table, if more than one payload
> is loaded, there will be duplicate conflicting symbols. So, to prevent
> these symbols from going into the symbol table, I disallowed STT_NOTYPE.
> Perhaps not the best solution but...
First of all symbols starting with .L aren't meant to and up in the
symbol table at all (i.e. even that of any intermediate .o file). So
there's likely (but not necessarily) something wrong with the tool
chain used (i.e. normally such symbols wouldn't be needed for e.g.
relocations, as those should get converted to section relative ones).
Yet _if_ such symbols make it into the symbol table of a .o, then
there is no reason for them to not also make it into the runtime
symbol table. Of course similar ones from different modules then
shouldn't conflict with one another, and as these are local symbols
perhaps the reason for them conflicting is that in the process of
creating the runtime symbol table entries you neglect to prefix
them with their source or object file names, as is done by
xen/tools/symbols.c for the core symbol table? Quite obviously
the symbol name generation should match between core and
modules...
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-22 7:51 ` Jan Beulich
@ 2016-04-22 8:45 ` Ross Lagerwall
2016-04-22 10:08 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Ross Lagerwall @ 2016-04-22 8:45 UTC (permalink / raw)
To: Jan Beulich, Konrad Rzeszutek Wilk
Cc: keir, andrew.cooper3, mpohlack, sasha.levin, xen-devel
On 04/22/2016 08:51 AM, Jan Beulich wrote:
>>>> On 22.04.16 at 09:17, <ross.lagerwall@citrix.com> wrote:
>> On 04/21/2016 01:26 AM, Konrad Rzeszutek Wilk wrote: snip
>>>>
>>>>> +static bool_t is_payload_symbol(const struct xsplice_elf
>>>>> *elf, + const struct
>>>>> xsplice_elf_sym *sym) +{ + if ( sym->sym->st_shndx ==
>>>>> SHN_UNDEF || + sym->sym->st_shndx >=
>>>>> elf->hdr->e_shnum ) + return 0; + + return
>>>>> (elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) && +
>>>>> (ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT || +
>>>>> ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
>>>>
>>>> I don't recall having seen a reply to the question on not
>>>> allowing
>> STT_NOTYPE here.
>>>
>>> Ross, could you elaborate a bit please on this?
>>
>>
>> The payload will typically have many entries like:
>>
>> 9: 0000000000000000 0 NOTYPE LOCAL DEFAULT 5 .LC1 10:
>> 0000000000000006 0 NOTYPE LOCAL DEFAULT 5 .LC2 11:
>> 000000000000000d 0 NOTYPE LOCAL DEFAULT 5 .LC3 12:
>> 0000000000000028 0 NOTYPE LOCAL DEFAULT 4 .LC4 13:
>> 0000000000000058 0 NOTYPE LOCAL DEFAULT 4 .LC5
>>
>> used when referencing strings (due to the use of -fPIC). While it
>> is not a problem for them to go into the symbol table, if more than
>> one payload is loaded, there will be duplicate conflicting symbols.
>> So, to prevent these symbols from going into the symbol table, I
>> disallowed STT_NOTYPE. Perhaps not the best solution but...
>
> First of all symbols starting with .L aren't meant to and up in the
> symbol table at all (i.e. even that of any intermediate .o file). So
> there's likely (but not necessarily) something wrong with the tool
> chain used (i.e. normally such symbols wouldn't be needed for e.g.
> relocations, as those should get converted to section relative
> ones).
This is not particular to the xsplice build process. Any version of
GCC+binutils that I've tested with will generate .LC
symbols for strings into the .o file. Clang generates similar .L.str*
symbols, in addition to other useless ones like 'NOTYPE LOCAL DEFAULT
ABS X86_FEATURE_FFXSR'...
Maybe it uses these .LC symbols rather than section relative ones
because they point to a mergeable string section, and merging string
sections would be harder with section relative references?
>
> Yet _if_ such symbols make it into the symbol table of a .o, then
> there is no reason for them to not also make it into the runtime
> symbol table. Of course similar ones from different modules then
> shouldn't conflict with one another, and as these are local symbols
> perhaps the reason for them conflicting is that in the process of
> creating the runtime symbol table entries you neglect to prefix them
> with their source or object file names, as is done by
> xen/tools/symbols.c for the core symbol table? Quite obviously the
> symbol name generation should match between core and modules...
>
The build tool does prefix the required functions and objects with their
source/object file names. The problem is that these are generated
symbols, so even if you had e.g. keyhandler.c#.LC0, keyhandler.c#.LC1,
in the symbol table, they might be completed unrelated if you change the
source even slightly. Having these entries in the symbol table would not
make any sense.
Rather than ignoring STT_NOTYPE, an alternative would be to ignore
symbols starting with ".L".
--
Ross Lagerwall
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-22 8:45 ` Ross Lagerwall
@ 2016-04-22 10:08 ` Jan Beulich
2016-04-22 10:28 ` Konrad Rzeszutek Wilk
2016-04-22 11:13 ` Ross Lagerwall
0 siblings, 2 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-22 10:08 UTC (permalink / raw)
To: Ross Lagerwall; +Cc: keir, andrew.cooper3, mpohlack, xen-devel, sasha.levin
>>> On 22.04.16 at 10:45, <ross.lagerwall@citrix.com> wrote:
> On 04/22/2016 08:51 AM, Jan Beulich wrote:
>>>>> On 22.04.16 at 09:17, <ross.lagerwall@citrix.com> wrote:
>>> On 04/21/2016 01:26 AM, Konrad Rzeszutek Wilk wrote: snip
>>>>>
>>>>>> +static bool_t is_payload_symbol(const struct xsplice_elf
>>>>>> *elf, + const struct
>>>>>> xsplice_elf_sym *sym) +{ + if ( sym->sym->st_shndx ==
>>>>>> SHN_UNDEF || + sym->sym->st_shndx >=
>>>>>> elf->hdr->e_shnum ) + return 0; + + return
>>>>>> (elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) && +
>>>>>> (ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT || +
>>>>>> ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
>>>>>
>>>>> I don't recall having seen a reply to the question on not
>>>>> allowing
>>> STT_NOTYPE here.
>>>>
>>>> Ross, could you elaborate a bit please on this?
>>>
>>>
>>> The payload will typically have many entries like:
>>>
>>> 9: 0000000000000000 0 NOTYPE LOCAL DEFAULT 5 .LC1 10:
>>> 0000000000000006 0 NOTYPE LOCAL DEFAULT 5 .LC2 11:
>>> 000000000000000d 0 NOTYPE LOCAL DEFAULT 5 .LC3 12:
>>> 0000000000000028 0 NOTYPE LOCAL DEFAULT 4 .LC4 13:
>>> 0000000000000058 0 NOTYPE LOCAL DEFAULT 4 .LC5
>>>
>>> used when referencing strings (due to the use of -fPIC). While it
>>> is not a problem for them to go into the symbol table, if more than
>>> one payload is loaded, there will be duplicate conflicting symbols.
>>> So, to prevent these symbols from going into the symbol table, I
>>> disallowed STT_NOTYPE. Perhaps not the best solution but...
>>
>> First of all symbols starting with .L aren't meant to and up in the
>> symbol table at all (i.e. even that of any intermediate .o file). So
>> there's likely (but not necessarily) something wrong with the tool
>> chain used (i.e. normally such symbols wouldn't be needed for e.g.
>> relocations, as those should get converted to section relative
>> ones).
>
> This is not particular to the xsplice build process. Any version of
> GCC+binutils that I've tested with will generate .LC
> symbols for strings into the .o file. Clang generates similar .L.str*
> symbols, in addition to other useless ones like 'NOTYPE LOCAL DEFAULT
> ABS X86_FEATURE_FFXSR'...
I can confirm the symbols getting generated in the .s file, ...
> Maybe it uses these .LC symbols rather than section relative ones
> because they point to a mergeable string section, and merging string
> sections would be harder with section relative references?
... but I can't confirm them making it into the .o file, not to speak
of being used for relocations. I've tried gcc 4.3.4 as well as 5.3.0
(with and without -fPIC).
>> Yet _if_ such symbols make it into the symbol table of a .o, then
>> there is no reason for them to not also make it into the runtime
>> symbol table. Of course similar ones from different modules then
>> shouldn't conflict with one another, and as these are local symbols
>> perhaps the reason for them conflicting is that in the process of
>> creating the runtime symbol table entries you neglect to prefix them
>> with their source or object file names, as is done by
>> xen/tools/symbols.c for the core symbol table? Quite obviously the
>> symbol name generation should match between core and modules...
>>
>
> The build tool does prefix the required functions and objects with their
> source/object file names. The problem is that these are generated
> symbols, so even if you had e.g. keyhandler.c#.LC0, keyhandler.c#.LC1,
> in the symbol table, they might be completed unrelated if you change the
> source even slightly. Having these entries in the symbol table would not
> make any sense.
Why not? They could still serve as anchor for subsequent patches.
> Rather than ignoring STT_NOTYPE, an alternative would be to ignore
> symbols starting with ".L".
That's an option, but as said before, the rules for which symbols to
enter into the symbol table should be consistent for core and modules.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 17/27] xsplice: Add support for bug frames.
2016-04-21 6:49 ` Jan Beulich
@ 2016-04-22 10:10 ` Konrad Rzeszutek Wilk
2016-04-22 10:28 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-22 10:10 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, ross.lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
On Thu, Apr 21, 2016 at 12:49:09AM -0600, Jan Beulich wrote:
> >>> On 21.04.16 at 02:29, <konrad.wilk@oracle.com> wrote:
> > On Tue, Apr 19, 2016 at 02:17:35PM -0600, Jan Beulich wrote:
> >> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:02 AM >>>
> >> >+bool_t is_patch(const void *ptr)
> >> >+{
> >> >+ struct payload *data;
> >>
> >> You guess it: const.
> >>
> >> >+ /*
> >> >+ * No locking since this list is only ever changed during apply or revert
> >> >+ * context.
> >> >+ */
> >>
> >> What if you crash while applying or reverting a patch? Is the list update at
> >> least done such that the (then nested) traversal remains safe?
> >
> > Yes! We only add the struct payload to this applied_list _after_ the
> > patching has been done.` Hence if we crashed the list would not contain the
> > struct payload that was patching - but would be safe to traverse.
>
> Well, that only partly answers the question. Patch application to me
> means the entire process, i.e. up to and including adding the new
> patch to the list (read: the crash could also happen there). Hence
> I'd still like it to be made sure that even if the addition has got done
> only partially, the list remains traversable. Or IOW, I'm not sure the
> standard list macros make any guarantees like that.
It does. I've copied-n-pasted the list_add_tail hacking it have an
BUG_ON(1):
+static inline void __list_add_crash(struct list_head *new,
+ struct list_head *prev, /* applied list */
+ struct list_head *next /* applied_list */)
+{
+ next->prev = new; /* applied_list->prev = new */
+ new->next = next; /* new->next = applied_list */
+ new->prev = prev; /* new->prev = applied_list */
+ BUG_ON(1);
+ prev->next = new; /* applied_list->next=new */
+}
+static inline void list_add_tail_crash(struct list_head *new, struct
list_head *head)
+{
+ __list_add_crash(new, head->prev /* applied_list */, head /* applied_list */);
+}
static int apply_payload(struct payload *data)
{
unsigned int i;
@@ -967,7 +981,7 @@ static int apply_payload(struct payload *data)
arch_xsplice_patching_leave();
- list_add_tail(&data->applied_list, &applied_list);
+ list_add_tail_crash(&data->applied_list, &applied_list);
register_virtual_region(&data->region);
return 0;
And we get:
(XEN) xsplice: xen_hello_world: Applying 1 functions
(XEN) Xen BUG at xsplice.c:963
(XEN) *** DOUBLE FAULT ***
A bit more debugging shows that "is_patch" does not iterate over
the list - (which is inline with what I expected!) - so the insertion
is safe when crashing.
Now why I get a double fault.. will have to investigate that at some
point.
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-22 10:08 ` Jan Beulich
@ 2016-04-22 10:28 ` Konrad Rzeszutek Wilk
2016-04-22 10:50 ` Jan Beulich
2016-04-22 11:13 ` Ross Lagerwall
1 sibling, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-22 10:28 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, andrew.cooper3, mpohlack, Ross Lagerwall, sasha.levin, xen-devel
On Fri, Apr 22, 2016 at 04:08:10AM -0600, Jan Beulich wrote:
> >>> On 22.04.16 at 10:45, <ross.lagerwall@citrix.com> wrote:
> > On 04/22/2016 08:51 AM, Jan Beulich wrote:
> >>>>> On 22.04.16 at 09:17, <ross.lagerwall@citrix.com> wrote:
> >>> On 04/21/2016 01:26 AM, Konrad Rzeszutek Wilk wrote: snip
> >>>>>
> >>>>>> +static bool_t is_payload_symbol(const struct xsplice_elf
> >>>>>> *elf, + const struct
> >>>>>> xsplice_elf_sym *sym) +{ + if ( sym->sym->st_shndx ==
> >>>>>> SHN_UNDEF || + sym->sym->st_shndx >=
> >>>>>> elf->hdr->e_shnum ) + return 0; + + return
> >>>>>> (elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) && +
> >>>>>> (ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT || +
> >>>>>> ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
> >>>>>
> >>>>> I don't recall having seen a reply to the question on not
> >>>>> allowing
> >>> STT_NOTYPE here.
> >>>>
> >>>> Ross, could you elaborate a bit please on this?
> >>>
> >>>
> >>> The payload will typically have many entries like:
> >>>
> >>> 9: 0000000000000000 0 NOTYPE LOCAL DEFAULT 5 .LC1 10:
> >>> 0000000000000006 0 NOTYPE LOCAL DEFAULT 5 .LC2 11:
> >>> 000000000000000d 0 NOTYPE LOCAL DEFAULT 5 .LC3 12:
> >>> 0000000000000028 0 NOTYPE LOCAL DEFAULT 4 .LC4 13:
> >>> 0000000000000058 0 NOTYPE LOCAL DEFAULT 4 .LC5
> >>>
> >>> used when referencing strings (due to the use of -fPIC). While it
> >>> is not a problem for them to go into the symbol table, if more than
> >>> one payload is loaded, there will be duplicate conflicting symbols.
> >>> So, to prevent these symbols from going into the symbol table, I
> >>> disallowed STT_NOTYPE. Perhaps not the best solution but...
> >>
> >> First of all symbols starting with .L aren't meant to and up in the
> >> symbol table at all (i.e. even that of any intermediate .o file). So
> >> there's likely (but not necessarily) something wrong with the tool
> >> chain used (i.e. normally such symbols wouldn't be needed for e.g.
> >> relocations, as those should get converted to section relative
> >> ones).
> >
> > This is not particular to the xsplice build process. Any version of
> > GCC+binutils that I've tested with will generate .LC
> > symbols for strings into the .o file. Clang generates similar .L.str*
> > symbols, in addition to other useless ones like 'NOTYPE LOCAL DEFAULT
> > ABS X86_FEATURE_FFXSR'...
>
> I can confirm the symbols getting generated in the .s file, ...
>
> > Maybe it uses these .LC symbols rather than section relative ones
> > because they point to a mergeable string section, and merging string
> > sections would be harder with section relative references?
>
> ... but I can't confirm them making it into the .o file, not to speak
> of being used for relocations. I've tried gcc 4.3.4 as well as 5.3.0
> (with and without -fPIC).
/home/konrad/xen/xen/arch/x86
[konrad@build-external x86]$ readelf --symbols microcode.o | grep \.LC
50: 0000000000000000 0 NOTYPE LOCAL DEFAULT 12 .LC0
51: 00000000000000e8 0 NOTYPE LOCAL DEFAULT 13 .LC5
52: 0000000000000110 0 NOTYPE LOCAL DEFAULT 13 .LC6
?
(GCC) 4.4.4 20100503 (Red Hat 4.4.4-2)
>
> >> Yet _if_ such symbols make it into the symbol table of a .o, then
> >> there is no reason for them to not also make it into the runtime
> >> symbol table. Of course similar ones from different modules then
> >> shouldn't conflict with one another, and as these are local symbols
> >> perhaps the reason for them conflicting is that in the process of
> >> creating the runtime symbol table entries you neglect to prefix them
> >> with their source or object file names, as is done by
> >> xen/tools/symbols.c for the core symbol table? Quite obviously the
> >> symbol name generation should match between core and modules...
> >>
> >
> > The build tool does prefix the required functions and objects with their
> > source/object file names. The problem is that these are generated
> > symbols, so even if you had e.g. keyhandler.c#.LC0, keyhandler.c#.LC1,
> > in the symbol table, they might be completed unrelated if you change the
> > source even slightly. Having these entries in the symbol table would not
> > make any sense.
>
> Why not? They could still serve as anchor for subsequent patches.
>
> > Rather than ignoring STT_NOTYPE, an alternative would be to ignore
> > symbols starting with ".L".
>
> That's an option, but as said before, the rules for which symbols to
> enter into the symbol table should be consistent for core and modules.
And they seem to - see above on the .o file.
>
> Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 17/27] xsplice: Add support for bug frames.
2016-04-22 10:10 ` Konrad Rzeszutek Wilk
@ 2016-04-22 10:28 ` Jan Beulich
2016-04-22 10:54 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-22 10:28 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: keir, ross.lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
>>> On 22.04.16 at 12:10, <konrad.wilk@oracle.com> wrote:
> On Thu, Apr 21, 2016 at 12:49:09AM -0600, Jan Beulich wrote:
>> >>> On 21.04.16 at 02:29, <konrad.wilk@oracle.com> wrote:
>> > On Tue, Apr 19, 2016 at 02:17:35PM -0600, Jan Beulich wrote:
>> >> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:02 AM >>>
>> >> >+bool_t is_patch(const void *ptr)
>> >> >+{
>> >> >+ struct payload *data;
>> >>
>> >> You guess it: const.
>> >>
>> >> >+ /*
>> >> >+ * No locking since this list is only ever changed during apply or revert
>> >> >+ * context.
>> >> >+ */
>> >>
>> >> What if you crash while applying or reverting a patch? Is the list update at
>> >> least done such that the (then nested) traversal remains safe?
>> >
>> > Yes! We only add the struct payload to this applied_list _after_ the
>> > patching has been done.` Hence if we crashed the list would not contain the
>> > struct payload that was patching - but would be safe to traverse.
>>
>> Well, that only partly answers the question. Patch application to me
>> means the entire process, i.e. up to and including adding the new
>> patch to the list (read: the crash could also happen there). Hence
>> I'd still like it to be made sure that even if the addition has got done
>> only partially, the list remains traversable. Or IOW, I'm not sure the
>> standard list macros make any guarantees like that.
>
> It does. I've copied-n-pasted the list_add_tail hacking it have an
> BUG_ON(1):
>
> +static inline void __list_add_crash(struct list_head *new,
> + struct list_head *prev, /* applied list */
> + struct list_head *next /* applied_list */)
> +{
> + next->prev = new; /* applied_list->prev = new */
> + new->next = next; /* new->next = applied_list */
> + new->prev = prev; /* new->prev = applied_list */
> + BUG_ON(1);
> + prev->next = new; /* applied_list->next=new */
> +}
This doesn't mean anything - in the absence of the BUG_ON() the
compiler is free to re-order all four assignments.
> A bit more debugging shows that "is_patch" does not iterate over
> the list - (which is inline with what I expected!) - so the insertion
> is safe when crashing.
How does that match up with
bool_t is_patch(const void *ptr)
{
struct payload *data;
/*
* No locking since this list is only ever changed during apply or revert
* context.
*/
list_for_each_entry ( data, &applied_list, applied_list )
...
i.e. where we started from here? I really think you want to at least
consider using list_add_rcu() at the insertion site, as your main
concern is that prev->next shouldn't get updated before new->next.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 24/27] xsplice: Stacking build-id dependency checking.
2016-04-20 7:49 ` Jan Beulich
@ 2016-04-22 10:46 ` Konrad Rzeszutek Wilk
2016-04-22 10:55 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-22 10:46 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, andrew.cooper3, mpohlack, ross.lagerwall, sasha.levin, xen-devel
On Wed, Apr 20, 2016 at 01:49:41AM -0600, Jan Beulich wrote:
> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
> >+.PHONY: note.o
> >+note.o:
> >+ $(OBJCOPY) -O binary --only-section=.note.gnu.build-id $(BASEDIR)/xen-syms $@.bin
> >+ $(OBJCOPY) -I binary -O elf64-x86-64 -B i386:x86-64 \
> >+ --rename-section=.data=.xsplice.depends -S $@.bin $@
> >+ rm -f $@.bin
>
> Same note as on the earlier patch regarding an interrupted build here ...
>
> >+.PHONY: hello_world_note.o
> >+hello_world_note.o:
> >+ $(OBJCOPY) -O binary --only-section=.note.gnu.build-id $(XSPLICE) $@.bin
> >+ $(OBJCOPY) -I binary -O elf64-x86-64 -B i386:x86-64 \
> >+ --rename-section=.data=.xsplice.depends -S $@.bin $@
> >+ rm -f $@.bin
>
> ... and here. Thinking about it a second time, wouldn't that then also require
> entries in .gitignore?
Oddly enough - no. The 11th rune in .gitignore may be doing it:
11 *.bin
But then we also have other:
120 tools/firmware/*.bin
200 tools/tests/x86_emulator/blowfish.bin
243 xen/arch/x86/boot/reloc.bin
Which seem to be pointless - I removed them (and had the files) and
'git status' still didn't register the *.bin files.
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-22 10:28 ` Konrad Rzeszutek Wilk
@ 2016-04-22 10:50 ` Jan Beulich
2016-04-22 11:08 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-22 10:50 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: keir, Ross Lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
>>> On 22.04.16 at 12:28, <konrad.wilk@oracle.com> wrote:
> On Fri, Apr 22, 2016 at 04:08:10AM -0600, Jan Beulich wrote:
>> >>> On 22.04.16 at 10:45, <ross.lagerwall@citrix.com> wrote:
>> > On 04/22/2016 08:51 AM, Jan Beulich wrote:
>> >>>>> On 22.04.16 at 09:17, <ross.lagerwall@citrix.com> wrote:
>> >>> On 04/21/2016 01:26 AM, Konrad Rzeszutek Wilk wrote: snip
>> >>>>>
>> >>>>>> +static bool_t is_payload_symbol(const struct xsplice_elf
>> >>>>>> *elf, + const struct
>> >>>>>> xsplice_elf_sym *sym) +{ + if ( sym->sym->st_shndx ==
>> >>>>>> SHN_UNDEF || + sym->sym->st_shndx >=
>> >>>>>> elf->hdr->e_shnum ) + return 0; + + return
>> >>>>>> (elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) && +
>> >>>>>> (ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT || +
>> >>>>>> ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
>> >>>>>
>> >>>>> I don't recall having seen a reply to the question on not
>> >>>>> allowing
>> >>> STT_NOTYPE here.
>> >>>>
>> >>>> Ross, could you elaborate a bit please on this?
>> >>>
>> >>>
>> >>> The payload will typically have many entries like:
>> >>>
>> >>> 9: 0000000000000000 0 NOTYPE LOCAL DEFAULT 5 .LC1 10:
>> >>> 0000000000000006 0 NOTYPE LOCAL DEFAULT 5 .LC2 11:
>> >>> 000000000000000d 0 NOTYPE LOCAL DEFAULT 5 .LC3 12:
>> >>> 0000000000000028 0 NOTYPE LOCAL DEFAULT 4 .LC4 13:
>> >>> 0000000000000058 0 NOTYPE LOCAL DEFAULT 4 .LC5
>> >>>
>> >>> used when referencing strings (due to the use of -fPIC). While it
>> >>> is not a problem for them to go into the symbol table, if more than
>> >>> one payload is loaded, there will be duplicate conflicting symbols.
>> >>> So, to prevent these symbols from going into the symbol table, I
>> >>> disallowed STT_NOTYPE. Perhaps not the best solution but...
>> >>
>> >> First of all symbols starting with .L aren't meant to and up in the
>> >> symbol table at all (i.e. even that of any intermediate .o file). So
>> >> there's likely (but not necessarily) something wrong with the tool
>> >> chain used (i.e. normally such symbols wouldn't be needed for e.g.
>> >> relocations, as those should get converted to section relative
>> >> ones).
>> >
>> > This is not particular to the xsplice build process. Any version of
>> > GCC+binutils that I've tested with will generate .LC
>> > symbols for strings into the .o file. Clang generates similar .L.str*
>> > symbols, in addition to other useless ones like 'NOTYPE LOCAL DEFAULT
>> > ABS X86_FEATURE_FFXSR'...
>>
>> I can confirm the symbols getting generated in the .s file, ...
>>
>> > Maybe it uses these .LC symbols rather than section relative ones
>> > because they point to a mergeable string section, and merging string
>> > sections would be harder with section relative references?
>>
>> ... but I can't confirm them making it into the .o file, not to speak
>> of being used for relocations. I've tried gcc 4.3.4 as well as 5.3.0
>> (with and without -fPIC).
>
> /home/konrad/xen/xen/arch/x86
> [konrad@build-external x86]$ readelf --symbols microcode.o | grep \.LC
> 50: 0000000000000000 0 NOTYPE LOCAL DEFAULT 12 .LC0
> 51: 00000000000000e8 0 NOTYPE LOCAL DEFAULT 13 .LC5
> 52: 0000000000000110 0 NOTYPE LOCAL DEFAULT 13 .LC6
>
> ?
> (GCC) 4.4.4 20100503 (Red Hat 4.4.4-2)
Ah, this happens only with optimization, and I had tried only
without. Looks to indeed be connected to these strings getting
put into mergeable string sections, instead of just plain .rodata.
>> >> Yet _if_ such symbols make it into the symbol table of a .o, then
>> >> there is no reason for them to not also make it into the runtime
>> >> symbol table. Of course similar ones from different modules then
>> >> shouldn't conflict with one another, and as these are local symbols
>> >> perhaps the reason for them conflicting is that in the process of
>> >> creating the runtime symbol table entries you neglect to prefix them
>> >> with their source or object file names, as is done by
>> >> xen/tools/symbols.c for the core symbol table? Quite obviously the
>> >> symbol name generation should match between core and modules...
>> >>
>> >
>> > The build tool does prefix the required functions and objects with their
>> > source/object file names. The problem is that these are generated
>> > symbols, so even if you had e.g. keyhandler.c#.LC0, keyhandler.c#.LC1,
>> > in the symbol table, they might be completed unrelated if you change the
>> > source even slightly. Having these entries in the symbol table would not
>> > make any sense.
>>
>> Why not? They could still serve as anchor for subsequent patches.
>
>>
>> > Rather than ignoring STT_NOTYPE, an alternative would be to ignore
>> > symbols starting with ".L".
>>
>> That's an option, but as said before, the rules for which symbols to
>> enter into the symbol table should be consistent for core and modules.
>
> And they seem to - see above on the .o file.
Above .o file was a core one, and doesn't tell anyway whether in the
runtime symbol table the local symbols would be properly prefixed by
file name. Or did I misunderstand you?
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 12/27] xsplice: Implement support for applying/reverting/replacing patches.
2016-04-22 7:44 ` Jan Beulich
@ 2016-04-22 10:51 ` Konrad Rzeszutek Wilk
0 siblings, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-22 10:51 UTC (permalink / raw)
To: Jan Beulich
Cc: kevin.tian, sstabellini, keir, jun.nakajima, ross.lagerwall,
andrew.cooper3, mpohlack, julien.grall, suravee.suthikulpanit,
sasha.levin, xen-devel, boris.ostrovsky
> > Ideas?
>
> Well, this presumably being a redundant .section directive
> somewhere it would require seeing the full .c together with the
> intermediate .s in order to tell. But I guess to avoid you spending
> more time on this secondary aspect, let's just drop this for now
> and just put it on the todo list (as long as the thing is tech preview
> we can still alter requirements we place on the actual payloads).
Yes to "Tech Preview". I put it on http://wiki.xen.org/wiki/XSplice#Hypervisor
so I would not forget.
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 17/27] xsplice: Add support for bug frames.
2016-04-22 10:28 ` Jan Beulich
@ 2016-04-22 10:54 ` Konrad Rzeszutek Wilk
2016-04-22 10:58 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-22 10:54 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, ross.lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
On Fri, Apr 22, 2016 at 04:28:42AM -0600, Jan Beulich wrote:
> >>> On 22.04.16 at 12:10, <konrad.wilk@oracle.com> wrote:
> > On Thu, Apr 21, 2016 at 12:49:09AM -0600, Jan Beulich wrote:
> >> >>> On 21.04.16 at 02:29, <konrad.wilk@oracle.com> wrote:
> >> > On Tue, Apr 19, 2016 at 02:17:35PM -0600, Jan Beulich wrote:
> >> >> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:02 AM >>>
> >> >> >+bool_t is_patch(const void *ptr)
> >> >> >+{
> >> >> >+ struct payload *data;
> >> >>
> >> >> You guess it: const.
> >> >>
> >> >> >+ /*
> >> >> >+ * No locking since this list is only ever changed during apply or revert
> >> >> >+ * context.
> >> >> >+ */
> >> >>
> >> >> What if you crash while applying or reverting a patch? Is the list update at
> >> >> least done such that the (then nested) traversal remains safe?
> >> >
> >> > Yes! We only add the struct payload to this applied_list _after_ the
> >> > patching has been done.` Hence if we crashed the list would not contain the
> >> > struct payload that was patching - but would be safe to traverse.
> >>
> >> Well, that only partly answers the question. Patch application to me
> >> means the entire process, i.e. up to and including adding the new
> >> patch to the list (read: the crash could also happen there). Hence
> >> I'd still like it to be made sure that even if the addition has got done
> >> only partially, the list remains traversable. Or IOW, I'm not sure the
> >> standard list macros make any guarantees like that.
> >
> > It does. I've copied-n-pasted the list_add_tail hacking it have an
> > BUG_ON(1):
> >
> > +static inline void __list_add_crash(struct list_head *new,
> > + struct list_head *prev, /* applied list */
> > + struct list_head *next /* applied_list */)
> > +{
> > + next->prev = new; /* applied_list->prev = new */
> > + new->next = next; /* new->next = applied_list */
> > + new->prev = prev; /* new->prev = applied_list */
> > + BUG_ON(1);
> > + prev->next = new; /* applied_list->next=new */
> > +}
>
> This doesn't mean anything - in the absence of the BUG_ON() the
> compiler is free to re-order all four assignments.
/me nods.
>
> > A bit more debugging shows that "is_patch" does not iterate over
> > the list - (which is inline with what I expected!) - so the insertion
> > is safe when crashing.
>
> How does that match up with
>
> bool_t is_patch(const void *ptr)
> {
> struct payload *data;
>
> /*
> * No locking since this list is only ever changed during apply or revert
> * context.
> */
> list_for_each_entry ( data, &applied_list, applied_list )
> ...
>
> i.e. where we started from here? I really think you want to at least
The thing that makes it "safe" (in lieu of your comment about
re-ordering) is that the trap code does:
1289 /* WARN, BUG or ASSERT: decode the filename pointer and line number. */
1290 filename = bug_ptr(bug);
1291 if ( !is_kernel(filename) && !is_patch(filename) )
1292 goto die;
Which means we first try 'is_kernel'. Since the list addition cannot be
part of the payload it will always be part of the hypervisor.
> consider using list_add_rcu() at the insertion site, as your main
> concern is that prev->next shouldn't get updated before new->next.
/me nods. Let me look at that.
>
> Jan
>
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 24/27] xsplice: Stacking build-id dependency checking.
2016-04-22 10:46 ` Konrad Rzeszutek Wilk
@ 2016-04-22 10:55 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-22 10:55 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: keir, ross.lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
>>> On 22.04.16 at 12:46, <konrad.wilk@oracle.com> wrote:
> On Wed, Apr 20, 2016 at 01:49:41AM -0600, Jan Beulich wrote:
>> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
>> >+.PHONY: hello_world_note.o
>> >+hello_world_note.o:
>> >+ $(OBJCOPY) -O binary --only-section=.note.gnu.build-id $(XSPLICE) $@.bin
>> >+ $(OBJCOPY) -I binary -O elf64-x86-64 -B i386:x86-64 \
>> >+ --rename-section=.data=.xsplice.depends -S $@.bin $@
>> >+ rm -f $@.bin
>>
>> ... and here. Thinking about it a second time, wouldn't that then also require
>> entries in .gitignore?
>
> Oddly enough - no. The 11th rune in .gitignore may be doing it:
> 11 *.bin
Ah, good. I should have checked, sorry.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 17/27] xsplice: Add support for bug frames.
2016-04-22 10:54 ` Konrad Rzeszutek Wilk
@ 2016-04-22 10:58 ` Jan Beulich
2016-04-22 11:10 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-22 10:58 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: keir, ross.lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
>>> On 22.04.16 at 12:54, <konrad.wilk@oracle.com> wrote:
> The thing that makes it "safe" (in lieu of your comment about
> re-ordering) is that the trap code does:
>
> 1289 /* WARN, BUG or ASSERT: decode the filename pointer and line
> number. */
> 1290 filename = bug_ptr(bug);
> 1291 if ( !is_kernel(filename) && !is_patch(filename) )
> 1292 goto die;
>
> Which means we first try 'is_kernel'. Since the list addition cannot be
> part of the payload it will always be part of the hypervisor.
I'm sorry, but no. The bug hit (and hence the referenced file name)
may be in some other payload, requiring list traversal.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-22 10:50 ` Jan Beulich
@ 2016-04-22 11:08 ` Konrad Rzeszutek Wilk
2016-04-22 11:18 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-22 11:08 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, Ross Lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
On Fri, Apr 22, 2016 at 04:50:34AM -0600, Jan Beulich wrote:
> >>> On 22.04.16 at 12:28, <konrad.wilk@oracle.com> wrote:
> > On Fri, Apr 22, 2016 at 04:08:10AM -0600, Jan Beulich wrote:
> >> >>> On 22.04.16 at 10:45, <ross.lagerwall@citrix.com> wrote:
> >> > On 04/22/2016 08:51 AM, Jan Beulich wrote:
> >> >>>>> On 22.04.16 at 09:17, <ross.lagerwall@citrix.com> wrote:
> >> >>> On 04/21/2016 01:26 AM, Konrad Rzeszutek Wilk wrote: snip
> >> >>>>>
> >> >>>>>> +static bool_t is_payload_symbol(const struct xsplice_elf
> >> >>>>>> *elf, + const struct
> >> >>>>>> xsplice_elf_sym *sym) +{ + if ( sym->sym->st_shndx ==
> >> >>>>>> SHN_UNDEF || + sym->sym->st_shndx >=
> >> >>>>>> elf->hdr->e_shnum ) + return 0; + + return
> >> >>>>>> (elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) && +
> >> >>>>>> (ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT || +
> >> >>>>>> ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
> >> >>>>>
> >> >>>>> I don't recall having seen a reply to the question on not
> >> >>>>> allowing
> >> >>> STT_NOTYPE here.
> >> >>>>
> >> >>>> Ross, could you elaborate a bit please on this?
> >> >>>
> >> >>>
> >> >>> The payload will typically have many entries like:
> >> >>>
> >> >>> 9: 0000000000000000 0 NOTYPE LOCAL DEFAULT 5 .LC1 10:
> >> >>> 0000000000000006 0 NOTYPE LOCAL DEFAULT 5 .LC2 11:
> >> >>> 000000000000000d 0 NOTYPE LOCAL DEFAULT 5 .LC3 12:
> >> >>> 0000000000000028 0 NOTYPE LOCAL DEFAULT 4 .LC4 13:
> >> >>> 0000000000000058 0 NOTYPE LOCAL DEFAULT 4 .LC5
> >> >>>
> >> >>> used when referencing strings (due to the use of -fPIC). While it
> >> >>> is not a problem for them to go into the symbol table, if more than
> >> >>> one payload is loaded, there will be duplicate conflicting symbols.
> >> >>> So, to prevent these symbols from going into the symbol table, I
> >> >>> disallowed STT_NOTYPE. Perhaps not the best solution but...
> >> >>
> >> >> First of all symbols starting with .L aren't meant to and up in the
> >> >> symbol table at all (i.e. even that of any intermediate .o file). So
> >> >> there's likely (but not necessarily) something wrong with the tool
> >> >> chain used (i.e. normally such symbols wouldn't be needed for e.g.
> >> >> relocations, as those should get converted to section relative
> >> >> ones).
> >> >
> >> > This is not particular to the xsplice build process. Any version of
> >> > GCC+binutils that I've tested with will generate .LC
> >> > symbols for strings into the .o file. Clang generates similar .L.str*
> >> > symbols, in addition to other useless ones like 'NOTYPE LOCAL DEFAULT
> >> > ABS X86_FEATURE_FFXSR'...
> >>
> >> I can confirm the symbols getting generated in the .s file, ...
> >>
> >> > Maybe it uses these .LC symbols rather than section relative ones
> >> > because they point to a mergeable string section, and merging string
> >> > sections would be harder with section relative references?
> >>
> >> ... but I can't confirm them making it into the .o file, not to speak
> >> of being used for relocations. I've tried gcc 4.3.4 as well as 5.3.0
> >> (with and without -fPIC).
> >
> > /home/konrad/xen/xen/arch/x86
> > [konrad@build-external x86]$ readelf --symbols microcode.o | grep \.LC
> > 50: 0000000000000000 0 NOTYPE LOCAL DEFAULT 12 .LC0
> > 51: 00000000000000e8 0 NOTYPE LOCAL DEFAULT 13 .LC5
> > 52: 0000000000000110 0 NOTYPE LOCAL DEFAULT 13 .LC6
> >
> > ?
> > (GCC) 4.4.4 20100503 (Red Hat 4.4.4-2)
>
> Ah, this happens only with optimization, and I had tried only
> without. Looks to indeed be connected to these strings getting
> put into mergeable string sections, instead of just plain .rodata.
>
> >> >> Yet _if_ such symbols make it into the symbol table of a .o, then
> >> >> there is no reason for them to not also make it into the runtime
> >> >> symbol table. Of course similar ones from different modules then
> >> >> shouldn't conflict with one another, and as these are local symbols
> >> >> perhaps the reason for them conflicting is that in the process of
> >> >> creating the runtime symbol table entries you neglect to prefix them
> >> >> with their source or object file names, as is done by
> >> >> xen/tools/symbols.c for the core symbol table? Quite obviously the
> >> >> symbol name generation should match between core and modules...
> >> >>
> >> >
> >> > The build tool does prefix the required functions and objects with their
> >> > source/object file names. The problem is that these are generated
> >> > symbols, so even if you had e.g. keyhandler.c#.LC0, keyhandler.c#.LC1,
> >> > in the symbol table, they might be completed unrelated if you change the
> >> > source even slightly. Having these entries in the symbol table would not
> >> > make any sense.
> >>
> >> Why not? They could still serve as anchor for subsequent patches.
> >
> >>
> >> > Rather than ignoring STT_NOTYPE, an alternative would be to ignore
> >> > symbols starting with ".L".
> >>
> >> That's an option, but as said before, the rules for which symbols to
> >> enter into the symbol table should be consistent for core and modules.
> >
> > And they seem to - see above on the .o file.
>
> Above .o file was a core one, and doesn't tell anyway whether in the
> runtime symbol table the local symbols would be properly prefixed by
> file name. Or did I misunderstand you?
I had 'built_in.o' or 'prelink.o' as the final one in mind - in which the
.LCx are present. But I think you are thinking about 'xen-syms' output.
Looking at the Makefile runes we hit this:
127 $(TARGET)-syms: prelink.o xen.lds $(BASEDIR)/common/symbols-dummy.o
128 $(LD) $(LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
129 $(BASEDIR)/common/symbols-dummy.o -o $(@D)/.$(@F).0
And that ends up causing the .xen-syms.0 file to drop all the .LC0.
However we can't do that. We _have_ to produce an relocatable object
and not do the final linking (so we append -r to the linker invocation).
If we do not:
ld: warning: cannot find entry symbol _start; defaulting to 0000000000400144
xen_hello_world.o:(.xsplice.funcs+0x10): undefined reference to `xen_extra_version'
ld: xen_hello_world.xsplice: hidden symbol `xen_extra_version' isn't defined
make[3]: *** [xen_hello_world.xsplice] Error 1
I tried for fun to use strip:
xen/xen/arch/x86/test> strip --strip-symbol=".LC0" xen_replace_world.xsplice
strip: not stripping symbol `.LC0' because it is named in a relocation
But it has some hard rules about it.
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 17/27] xsplice: Add support for bug frames.
2016-04-22 10:58 ` Jan Beulich
@ 2016-04-22 11:10 ` Konrad Rzeszutek Wilk
0 siblings, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-22 11:10 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, ross.lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
On Fri, Apr 22, 2016 at 04:58:19AM -0600, Jan Beulich wrote:
> >>> On 22.04.16 at 12:54, <konrad.wilk@oracle.com> wrote:
> > The thing that makes it "safe" (in lieu of your comment about
> > re-ordering) is that the trap code does:
> >
> > 1289 /* WARN, BUG or ASSERT: decode the filename pointer and line
> > number. */
> > 1290 filename = bug_ptr(bug);
> > 1291 if ( !is_kernel(filename) && !is_patch(filename) )
> > 1292 goto die;
> >
> > Which means we first try 'is_kernel'. Since the list addition cannot be
> > part of the payload it will always be part of the hypervisor.
>
> I'm sorry, but no. The bug hit (and hence the referenced file name)
> may be in some other payload, requiring list traversal.
Ah yes! Let me dig in the rcu list to thwart the compiler from
re-ordering.
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-22 10:08 ` Jan Beulich
2016-04-22 10:28 ` Konrad Rzeszutek Wilk
@ 2016-04-22 11:13 ` Ross Lagerwall
2016-04-22 11:24 ` Jan Beulich
2016-04-22 14:17 ` Konrad Rzeszutek Wilk
1 sibling, 2 replies; 126+ messages in thread
From: Ross Lagerwall @ 2016-04-22 11:13 UTC (permalink / raw)
To: Jan Beulich; +Cc: keir, andrew.cooper3, mpohlack, xen-devel, sasha.levin
On 04/22/2016 11:08 AM, Jan Beulich wrote:
>>>> On 22.04.16 at 10:45, <ross.lagerwall@citrix.com> wrote:
>> On 04/22/2016 08:51 AM, Jan Beulich wrote:
>>>>>> On 22.04.16 at 09:17, <ross.lagerwall@citrix.com> wrote:
>>>> On 04/21/2016 01:26 AM, Konrad Rzeszutek Wilk wrote: snip
>>>>>>
>>>>>>> +static bool_t is_payload_symbol(const struct xsplice_elf
>>>>>>> *elf, + const struct
>>>>>>> xsplice_elf_sym *sym) +{ + if ( sym->sym->st_shndx ==
>>>>>>> SHN_UNDEF || + sym->sym->st_shndx >=
>>>>>>> elf->hdr->e_shnum ) + return 0; + + return
>>>>>>> (elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) && +
>>>>>>> (ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT || +
>>>>>>> ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
>>>>>>
>>>>>> I don't recall having seen a reply to the question on not
>>>>>> allowing
>>>> STT_NOTYPE here.
>>>>>
>>>>> Ross, could you elaborate a bit please on this?
>>>>
>>>>
>>>> The payload will typically have many entries like:
>>>>
>>>> 9: 0000000000000000 0 NOTYPE LOCAL DEFAULT 5 .LC1 10:
>>>> 0000000000000006 0 NOTYPE LOCAL DEFAULT 5 .LC2 11:
>>>> 000000000000000d 0 NOTYPE LOCAL DEFAULT 5 .LC3 12:
>>>> 0000000000000028 0 NOTYPE LOCAL DEFAULT 4 .LC4 13:
>>>> 0000000000000058 0 NOTYPE LOCAL DEFAULT 4 .LC5
>>>>
>>>> used when referencing strings (due to the use of -fPIC). While it
>>>> is not a problem for them to go into the symbol table, if more than
>>>> one payload is loaded, there will be duplicate conflicting symbols.
>>>> So, to prevent these symbols from going into the symbol table, I
>>>> disallowed STT_NOTYPE. Perhaps not the best solution but...
>>>
>>> First of all symbols starting with .L aren't meant to and up in the
>>> symbol table at all (i.e. even that of any intermediate .o file). So
>>> there's likely (but not necessarily) something wrong with the tool
>>> chain used (i.e. normally such symbols wouldn't be needed for e.g.
>>> relocations, as those should get converted to section relative
>>> ones).
>>
>> This is not particular to the xsplice build process. Any version of
>> GCC+binutils that I've tested with will generate .LC
>> symbols for strings into the .o file. Clang generates similar .L.str*
>> symbols, in addition to other useless ones like 'NOTYPE LOCAL DEFAULT
>> ABS X86_FEATURE_FFXSR'...
>
> I can confirm the symbols getting generated in the .s file, ...
>
>> Maybe it uses these .LC symbols rather than section relative ones
>> because they point to a mergeable string section, and merging string
>> sections would be harder with section relative references?
>
> ... but I can't confirm them making it into the .o file, not to speak
> of being used for relocations. I've tried gcc 4.3.4 as well as 5.3.0
> (with and without -fPIC).
I've looked into this a little further. The only .LC* symbols left in
the .o file are the ones which are used in bug_frame relas. These
symbols do not make it into the core symbol table because the relas are
dropped when the xen binary is linked just before tools/symbols is run.
Obviously we can't drop the rela sections for xsplice because it needs
to be relocatable.
>
>>> Yet _if_ such symbols make it into the symbol table of a .o, then
>>> there is no reason for them to not also make it into the runtime
>>> symbol table. Of course similar ones from different modules then
>>> shouldn't conflict with one another, and as these are local symbols
>>> perhaps the reason for them conflicting is that in the process of
>>> creating the runtime symbol table entries you neglect to prefix them
>>> with their source or object file names, as is done by
>>> xen/tools/symbols.c for the core symbol table? Quite obviously the
>>> symbol name generation should match between core and modules...
>>>
>>
>> The build tool does prefix the required functions and objects with their
>> source/object file names. The problem is that these are generated
>> symbols, so even if you had e.g. keyhandler.c#.LC0, keyhandler.c#.LC1,
>> in the symbol table, they might be completed unrelated if you change the
>> source even slightly. Having these entries in the symbol table would not
>> make any sense.
>
> Why not? They could still serve as anchor for subsequent patches.
They're not useful because they're autogenerated and the numbering may
change from build to build. So two patch modules may have conflicting
symbols just because they happen to use the same .LCx symbol.
>
>> Rather than ignoring STT_NOTYPE, an alternative would be to ignore
>> symbols starting with ".L".
>
> That's an option, but as said before, the rules for which symbols to
> enter into the symbol table should be consistent for core and modules.
>
Yes. And, as best I can tell, .L symbols are not in the core table so
this would then make it consistent for modules.
--
Ross Lagerwall
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-22 11:08 ` Konrad Rzeszutek Wilk
@ 2016-04-22 11:18 ` Jan Beulich
2016-04-24 21:41 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-22 11:18 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: keir, Ross Lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
>>> On 22.04.16 at 13:08, <konrad.wilk@oracle.com> wrote:
> On Fri, Apr 22, 2016 at 04:50:34AM -0600, Jan Beulich wrote:
>> >>> On 22.04.16 at 12:28, <konrad.wilk@oracle.com> wrote:
>> > On Fri, Apr 22, 2016 at 04:08:10AM -0600, Jan Beulich wrote:
>> >> >>> On 22.04.16 at 10:45, <ross.lagerwall@citrix.com> wrote:
>> >> > Rather than ignoring STT_NOTYPE, an alternative would be to ignore
>> >> > symbols starting with ".L".
>> >>
>> >> That's an option, but as said before, the rules for which symbols to
>> >> enter into the symbol table should be consistent for core and modules.
>> >
>> > And they seem to - see above on the .o file.
>>
>> Above .o file was a core one, and doesn't tell anyway whether in the
>> runtime symbol table the local symbols would be properly prefixed by
>> file name. Or did I misunderstand you?
>
> I had 'built_in.o' or 'prelink.o' as the final one in mind - in which the
> .LCx are present. But I think you are thinking about 'xen-syms' output.
>
> Looking at the Makefile runes we hit this:
> 127 $(TARGET)-syms: prelink.o xen.lds $(BASEDIR)/common/symbols-dummy.o
> 128 $(LD) $(LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
> 129 $(BASEDIR)/common/symbols-dummy.o -o $(@D)/.$(@F).0
>
> And that ends up causing the .xen-syms.0 file to drop all the .LC0.
That's odd: I don't know of us telling the linker to do so, and imo
it shouldn't do this by default. But yes, linkers often do strange
things...
> However we can't do that. We _have_ to produce an relocatable object
> and not do the final linking (so we append -r to the linker invocation).
Of course.
> I tried for fun to use strip:
> xen/xen/arch/x86/test> strip --strip-symbol=".LC0" xen_replace_world.xsplice
> strip: not stripping symbol `.LC0' because it is named in a relocation
Which it is rightfully saying.
So with the linker stripping .LC* (and why knows what else), you
stripping them when building the runtime symbol table would be
fine with me, provided we can somehow identify in the linker why
this stripping happens, and which precise set of symbols get
stripped (which you should then match in our code).
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-22 11:13 ` Ross Lagerwall
@ 2016-04-22 11:24 ` Jan Beulich
2016-04-22 21:10 ` Konrad Rzeszutek Wilk
2016-04-22 14:17 ` Konrad Rzeszutek Wilk
1 sibling, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-22 11:24 UTC (permalink / raw)
To: Ross Lagerwall; +Cc: keir, andrew.cooper3, mpohlack, xen-devel, sasha.levin
>>> On 22.04.16 at 13:13, <ross.lagerwall@citrix.com> wrote:
> On 04/22/2016 11:08 AM, Jan Beulich wrote:
>>>>> On 22.04.16 at 10:45, <ross.lagerwall@citrix.com> wrote:
>>> On 04/22/2016 08:51 AM, Jan Beulich wrote:
>>>>>>> On 22.04.16 at 09:17, <ross.lagerwall@citrix.com> wrote:
>>>>> On 04/21/2016 01:26 AM, Konrad Rzeszutek Wilk wrote: snip
>>>>>>>
>>>>>>>> +static bool_t is_payload_symbol(const struct xsplice_elf
>>>>>>>> *elf, + const struct
>>>>>>>> xsplice_elf_sym *sym) +{ + if ( sym->sym->st_shndx ==
>>>>>>>> SHN_UNDEF || + sym->sym->st_shndx >=
>>>>>>>> elf->hdr->e_shnum ) + return 0; + + return
>>>>>>>> (elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) && +
>>>>>>>> (ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT || +
>>>>>>>> ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
>>>>>>>
>>>>>>> I don't recall having seen a reply to the question on not
>>>>>>> allowing
>>>>> STT_NOTYPE here.
>>>>>>
>>>>>> Ross, could you elaborate a bit please on this?
>>>>>
>>>>>
>>>>> The payload will typically have many entries like:
>>>>>
>>>>> 9: 0000000000000000 0 NOTYPE LOCAL DEFAULT 5 .LC1 10:
>>>>> 0000000000000006 0 NOTYPE LOCAL DEFAULT 5 .LC2 11:
>>>>> 000000000000000d 0 NOTYPE LOCAL DEFAULT 5 .LC3 12:
>>>>> 0000000000000028 0 NOTYPE LOCAL DEFAULT 4 .LC4 13:
>>>>> 0000000000000058 0 NOTYPE LOCAL DEFAULT 4 .LC5
>>>>>
>>>>> used when referencing strings (due to the use of -fPIC). While it
>>>>> is not a problem for them to go into the symbol table, if more than
>>>>> one payload is loaded, there will be duplicate conflicting symbols.
>>>>> So, to prevent these symbols from going into the symbol table, I
>>>>> disallowed STT_NOTYPE. Perhaps not the best solution but...
>>>>
>>>> First of all symbols starting with .L aren't meant to and up in the
>>>> symbol table at all (i.e. even that of any intermediate .o file). So
>>>> there's likely (but not necessarily) something wrong with the tool
>>>> chain used (i.e. normally such symbols wouldn't be needed for e.g.
>>>> relocations, as those should get converted to section relative
>>>> ones).
>>>
>>> This is not particular to the xsplice build process. Any version of
>>> GCC+binutils that I've tested with will generate .LC
>>> symbols for strings into the .o file. Clang generates similar .L.str*
>>> symbols, in addition to other useless ones like 'NOTYPE LOCAL DEFAULT
>>> ABS X86_FEATURE_FFXSR'...
>>
>> I can confirm the symbols getting generated in the .s file, ...
>>
>>> Maybe it uses these .LC symbols rather than section relative ones
>>> because they point to a mergeable string section, and merging string
>>> sections would be harder with section relative references?
>>
>> ... but I can't confirm them making it into the .o file, not to speak
>> of being used for relocations. I've tried gcc 4.3.4 as well as 5.3.0
>> (with and without -fPIC).
>
> I've looked into this a little further. The only .LC* symbols left in
> the .o file are the ones which are used in bug_frame relas.
Not according to what I see - there are certainly also .text
relocations referencing .LC*.
> These
> symbols do not make it into the core symbol table because the relas are
> dropped when the xen binary is linked just before tools/symbols is run.
> Obviously we can't drop the rela sections for xsplice because it needs
> to be relocatable.
As per my earlier reply to Konrad, there must be more to this. I.e.
"normal" local symbols won't get dropped together with relocations
referencing them getting resolved.
>>> The build tool does prefix the required functions and objects with their
>>> source/object file names. The problem is that these are generated
>>> symbols, so even if you had e.g. keyhandler.c#.LC0, keyhandler.c#.LC1,
>>> in the symbol table, they might be completed unrelated if you change the
>>> source even slightly. Having these entries in the symbol table would not
>>> make any sense.
>>
>> Why not? They could still serve as anchor for subsequent patches.
>
> They're not useful because they're autogenerated and the numbering may
> change from build to build.
That's not of interest.
> So two patch modules may have conflicting
> symbols just because they happen to use the same .LCx symbol.
Not if they're, as mentioned before, get properly prefixed with the
respective file name.
But as said in reply to Konrad, I'm fine with them getting dropped
as long as our rule matches ld's (which btw may be arch dependent).
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-22 11:13 ` Ross Lagerwall
2016-04-22 11:24 ` Jan Beulich
@ 2016-04-22 14:17 ` Konrad Rzeszutek Wilk
1 sibling, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-22 14:17 UTC (permalink / raw)
To: Ross Lagerwall
Cc: keir, andrew.cooper3, mpohlack, Jan Beulich, xen-devel, sasha.levin
On Fri, Apr 22, 2016 at 12:13:02PM +0100, Ross Lagerwall wrote:
> On 04/22/2016 11:08 AM, Jan Beulich wrote:
> >>>>On 22.04.16 at 10:45, <ross.lagerwall@citrix.com> wrote:
> >>On 04/22/2016 08:51 AM, Jan Beulich wrote:
> >>>>>>On 22.04.16 at 09:17, <ross.lagerwall@citrix.com> wrote:
> >>>>On 04/21/2016 01:26 AM, Konrad Rzeszutek Wilk wrote: snip
> >>>>>>
> >>>>>>>+static bool_t is_payload_symbol(const struct xsplice_elf
> >>>>>>>*elf, + const struct
> >>>>>>>xsplice_elf_sym *sym) +{ + if ( sym->sym->st_shndx ==
> >>>>>>>SHN_UNDEF || + sym->sym->st_shndx >=
> >>>>>>>elf->hdr->e_shnum ) + return 0; + + return
> >>>>>>>(elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) && +
> >>>>>>>(ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT || +
> >>>>>>>ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
> >>>>>>
> >>>>>>I don't recall having seen a reply to the question on not
> >>>>>>allowing
> >>>>STT_NOTYPE here.
> >>>>>
> >>>>>Ross, could you elaborate a bit please on this?
> >>>>
> >>>>
> >>>>The payload will typically have many entries like:
> >>>>
> >>>>9: 0000000000000000 0 NOTYPE LOCAL DEFAULT 5 .LC1 10:
> >>>>0000000000000006 0 NOTYPE LOCAL DEFAULT 5 .LC2 11:
> >>>>000000000000000d 0 NOTYPE LOCAL DEFAULT 5 .LC3 12:
> >>>>0000000000000028 0 NOTYPE LOCAL DEFAULT 4 .LC4 13:
> >>>>0000000000000058 0 NOTYPE LOCAL DEFAULT 4 .LC5
> >>>>
> >>>>used when referencing strings (due to the use of -fPIC). While it
> >>>>is not a problem for them to go into the symbol table, if more than
> >>>>one payload is loaded, there will be duplicate conflicting symbols.
> >>>>So, to prevent these symbols from going into the symbol table, I
> >>>>disallowed STT_NOTYPE. Perhaps not the best solution but...
> >>>
> >>>First of all symbols starting with .L aren't meant to and up in the
> >>>symbol table at all (i.e. even that of any intermediate .o file). So
> >>>there's likely (but not necessarily) something wrong with the tool
> >>>chain used (i.e. normally such symbols wouldn't be needed for e.g.
> >>>relocations, as those should get converted to section relative
> >>>ones).
> >>
> >>This is not particular to the xsplice build process. Any version of
> >>GCC+binutils that I've tested with will generate .LC
> >>symbols for strings into the .o file. Clang generates similar .L.str*
> >>symbols, in addition to other useless ones like 'NOTYPE LOCAL DEFAULT
> >>ABS X86_FEATURE_FFXSR'...
> >
> >I can confirm the symbols getting generated in the .s file, ...
> >
> >>Maybe it uses these .LC symbols rather than section relative ones
> >>because they point to a mergeable string section, and merging string
> >>sections would be harder with section relative references?
> >
> >... but I can't confirm them making it into the .o file, not to speak
> >of being used for relocations. I've tried gcc 4.3.4 as well as 5.3.0
> >(with and without -fPIC).
>
> I've looked into this a little further. The only .LC* symbols left in the .o
> file are the ones which are used in bug_frame relas. These symbols do not
> make it into the core symbol table because the relas are dropped when the
> xen binary is linked just before tools/symbols is run. Obviously we can't
> drop the rela sections for xsplice because it needs to be relocatable.
In my case I seem to have one of the test-cases have one the .text
section.
That is:
File: arch/x86/test/xen_bye_world.xsplice
Relocation section '.rela.text' at offset 0x11a8 contains 1 entries:
Offset Info Type Sym. Value Sym. Name + Addend
000000000007 001300000002 R_X86_64_PC32 0000000000000000 .LC0 - 4
Which .. is related to the string:
Disassembly of section .text:
0000000000000000 <xen_bye_world>:
0: 55 push %rbp
1: 48 89 e5 mov %rsp,%rbp
4: 48 8d 05 00 00 00 00 lea 0x0(%rip),%rax # b <xen_bye_world+0xb>
b: c9 leaveq
c: c3 retq
Which we obviously do need.
>
> >
> >>>Yet _if_ such symbols make it into the symbol table of a .o, then
> >>>there is no reason for them to not also make it into the runtime
> >>>symbol table. Of course similar ones from different modules then
> >>>shouldn't conflict with one another, and as these are local symbols
> >>>perhaps the reason for them conflicting is that in the process of
> >>>creating the runtime symbol table entries you neglect to prefix them
> >>>with their source or object file names, as is done by
> >>>xen/tools/symbols.c for the core symbol table? Quite obviously the
> >>>symbol name generation should match between core and modules...
> >>>
> >>
> >>The build tool does prefix the required functions and objects with their
> >>source/object file names. The problem is that these are generated
> >>symbols, so even if you had e.g. keyhandler.c#.LC0, keyhandler.c#.LC1,
> >>in the symbol table, they might be completed unrelated if you change the
> >>source even slightly. Having these entries in the symbol table would not
> >>make any sense.
> >
> >Why not? They could still serve as anchor for subsequent patches.
>
> They're not useful because they're autogenerated and the numbering may
> change from build to build. So two patch modules may have conflicting
> symbols just because they happen to use the same .LCx symbol.
>
> >
> >>Rather than ignoring STT_NOTYPE, an alternative would be to ignore
> >>symbols starting with ".L".
> >
> >That's an option, but as said before, the rules for which symbols to
> >enter into the symbol table should be consistent for core and modules.
> >
>
> Yes. And, as best I can tell, .L symbols are not in the core table so this
> would then make it consistent for modules.
>
> --
> Ross Lagerwall
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 15/27] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup
2016-04-19 19:52 ` Jan Beulich
@ 2016-04-22 15:21 ` Konrad Rzeszutek Wilk
2016-04-25 8:38 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-22 15:21 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, ross.lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
On Tue, Apr 19, 2016 at 01:52:33PM -0600, Jan Beulich wrote:
> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:02 AM >>>
> >NEW CODE:
> >
> >To make that work we add three tables:
>
> Why three? Two (or a single one with element pairs) ought to be sufficient:
> Afaict you could just have (symbol-address,symbol-offset) pairs which you
> then sort and search by name (using symbols_expand_symbol() on
> symbol-offset, which in turn you store using the result of get_symbol_offset()
> during setup of the table).
>
> >1) symbols_addresses_index_sorted[0..symbols_num_syms]. The values are
> >indicies into symbols_addresses array. This is a 1-1 table:
> >
> >symbols_addresses_index_sorted:
> >.long 6315
> >.long 6097
> >
> >To get the address of a symbol at offset 0 in symbols_name_sorted
> >(see below) we look in symbols_addresses_index_sorted[0] to get
> >6315 and then look in symbols_addresses_index[6315] to find it.
> >
> >2) The symbols_names_sorted stream - same format as symbols_names but
> >constructued by sorting the <type>[filename#]<symbol> by <symbol>,
> >then [filename#] and lastly type. Recall that symbol_names is sorted
> >based on addresses of the symbols.
>
> Why would you treat the <filename># prefix specially? The full thing is the
> symbol you should care about imo.
>
> >3) To make it simpler to search we also add an symbols_markers_sorted
> >array (of size symbols_num_syms/255).
>
> >Searching for symbols is simplified as we can do a binary search
> >on symbol_names_sorted (and using symbols_markers_sorted). Since the
> >symbols are sorted it takes on average 13 calls to symbols_expand_symbol.
> >
> >Doing small tests (search for five different symbols) using the old
> >and new mechanism show 2ms vs 0ms improvement.
>
> What does "2m vs 0ms" improvement mean here? If you mean to say that on
> some symbols there's no gain at all, then I'd question whether millisecond
> granularity is enough to see an improvement.
>
> With the basic data question above I'm not going to look at the actual code
> for now; I'll leave this until either I understand why the suggested variant
> can't work, or until a future version implementing that one.
Here is what I came up using your idea. Do you want me to add 'Suggested-by' Jan on it?
From 37173f674e4bce0bc0515d28b2536d29c55b7e7f Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Date: Thu, 21 Apr 2016 16:47:43 -0400
Subject: [PATCH] xsplice, symbols: Implement fast symbol names -> virtual
addresses lookup
The current mechanism is geared towards fast virtual address ->
symbol names lookup. This is fine for the normal use cases
(BUG_ON, WARN_ON, etc), but for xSplice - where we need to find
hypervisor symbols - it is slow.
To understand this patch, a description of the existing
method is explained first. For folks familar go to 'NEW CODE:'.
HOW IT WORKS:
The symbol table lookup mechanism uses a simple encoding mechanism
where it extracts the common ascii characters that the symbol's use.
This saves us space. The lookup mechanism is geared towards looking
up symbols based on address. We have one 0..N (where N is
the number of symbols, so 6849 for example) table:
symbols_addresses[0..N]
And an 1-1 (in a loose fashion) of the symbols (encoded) in a
symbols_names stream of size N.
The N is variable (later on that below)
The symbols_names are sorted based on symbols_addresses, which
means that the decoded entries inside symbols_names are not in
ascending or descending order.
There is also the encoding mechanism - the table of 255 entries
called symbols_token_index[]. And the symbols_token_table which
is an stream of ASCIIZ characters, such as (it really
is not a table as the values are variable):
@0 .asciz "credit"
@6 .asciz "mask"
..
@300 .asciz "S"
And the symbols_token_index:
@0 .short 0
@1 .short 7
@2 .short 12
@4 .short 16
...
@84 .short 300
The relationship between them is that the symbols_token_index
gives us the offset to symbols_token_table.
The symbol_names[] array is a stream of encoded values. Each value
follows the same pattern - <len> followed by <encoding values>.
And the another <len> followed by <encoding values>.
Hence to find the right one you need to read <len>, add <len>
(to skip over), read <len>, add <len>, and so on until one
finds the right tuple offset.
The <encoding values> are the indicies into the symbols_token_index.
Meaning if you have:
0x04, 0x54, 0xda, 0xe2, 0x74
[4, 84, 218, 226, 116 in human numbering]
The 0x04 tells us that the symbol is four bytes past this one (so next
symbol offset starts at 5). If we lookup symbols_token_index[84] we get 300.
symbols_token[300] gets us the "S". And so on, the string eventually
end up being decode to be 'S_stext'. The first character is the type,
then optionally follwed by the filename (and # right after filename)
and then lastly the symbol, such as:
tvpmu_intel.c#core2_vpmu_do_interrupt
Keep in mind that there are two fixed sized tables:
symbols_addresses[0..symbols_num_syms], and
symbols_markers[0..symbols_num_syms/255].
The symbols_markers is used to speed searching for the right address.
It gives us the offsets within symbol_names that start at the <len><encoded value>.
The way to find a symbol based on the address is:
1) Figure out the 'tuple offset' from symbols_address[0..symbols_num_syms].
This table is sorted by virtual addresses so finding the value is simple.
2) Get starting offset of symbol_names by retrieving value of
symbol_markers['tuple offset' / 255].
3). Iterate up to 'tuple_offset & 255' in symbols_markers stream starting
at 'offset'.
4). Decode the <len><encoded value>
This however does not work very well if we want to search the other
way - we have the symbol name and want to find the address.
NEW CODE:
To make that work we add one fixed size table called symbols_sorted_offsets which
has two elements: offset in symbol stream, offset in the symbol-address.
This whole array is sorted on the original symbol name (in case of collision
we also take into account the type).
The values are for example:
symbols_sorted_offsets:
.long 83363, 6302 # [.bss, len=5]
.long 80459, 6084 # [.data, len=5]
..
[The # added for clarity]
Which makes it incredibly easy to get in the symbols_names and also
symbols_addresses (or symbols_offsets)
Searching for symbols is simplified as we can do a binary search
on symbols_sorted_offsets. Since the symbols are sorted it takes on
average 13 calls to symbols_expand_symbol.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
CC: Keir Fraser <keir@xen.org>
CC: Jan Beulich <jbeulich@suse.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
v8: New
- Remove the debug code
- Return the 'mid' index in symbol_addresses, not the 'low'.
v9:
- Make it return void*
- Ditch the old implementation. Use a single fixed-size array
with two uint32_t values - offset in stream and offset in address.
---
xen/arch/x86/Makefile | 3 +++
xen/common/Kconfig | 12 ++++++++++
xen/common/symbols-dummy.c | 5 ++++
xen/common/symbols.c | 42 +++++++++++++++++++++++++++++++++
xen/include/xen/symbols.h | 10 ++++++++
xen/tools/symbols.c | 59 ++++++++++++++++++++++++++++++++++++++++++++--
6 files changed, 129 insertions(+), 2 deletions(-)
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index fdf4202..f8b1b23 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -74,6 +74,9 @@ efi-y := $(shell if [ ! -r $(BASEDIR)/include/xen/compile.h -o \
ifdef CONFIG_XSPLICE
all_symbols = --all-symbols
+ifdef CONFIG_FAST_SYMBOL_LOOKUP
+all_symbols = --all-symbols --add-extra-sorted
+endif
else
all_symbols =
endif
diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index 692ef51..e4f86c2 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -200,4 +200,16 @@ config XSPLICE
If unsure, say Y.
+config FAST_SYMBOL_LOOKUP
+ bool "Fast symbol lookup (bigger binary)"
+ default y
+ depends on XSPLICE
+ ---help---
+ When searching for symbol addresses we can use the built-in system
+ that is optimized for searching symbols using addresses as the key.
+ However using it for the inverse (find address using the symbol name)
+ it is slow. This extra data and code (~55kB) speeds up the search.
+ The only user of this is xSplice.
+
+ If unsure, say Y.
endmenu
diff --git a/xen/common/symbols-dummy.c b/xen/common/symbols-dummy.c
index 5090c3b..044dfd3 100644
--- a/xen/common/symbols-dummy.c
+++ b/xen/common/symbols-dummy.c
@@ -5,6 +5,7 @@
#include <xen/config.h>
#include <xen/types.h>
+#include <xen/symbols.h>
#ifdef SYMBOLS_ORIGIN
const unsigned int symbols_offsets[1];
@@ -14,6 +15,10 @@ const unsigned long symbols_addresses[1];
const unsigned int symbols_num_syms;
const u8 symbols_names[1];
+#ifdef CONFIG_FAST_SYMBOL_LOOKUP
+const struct symbol_offset symbols_sorted_offsets[1];
+#endif
+
const u8 symbols_token_table[1];
const u16 symbols_token_index[1];
diff --git a/xen/common/symbols.c b/xen/common/symbols.c
index 18bbfef..789d90e 100644
--- a/xen/common/symbols.c
+++ b/xen/common/symbols.c
@@ -31,6 +31,10 @@ extern const unsigned long symbols_addresses[];
extern const unsigned int symbols_num_syms;
extern const u8 symbols_names[];
+#ifdef CONFIG_FAST_SYMBOL_LOOKUP
+extern const struct symbol_offset symbols_sorted_offsets[];
+#endif
+
extern const u8 symbols_token_table[];
extern const u16 symbols_token_index[];
@@ -208,8 +212,45 @@ int xensyms_read(uint32_t *symnum, char *type,
return 0;
}
+#ifdef CONFIG_FAST_SYMBOL_LOOKUP
void *symbols_lookup_by_name(const char *symname)
{
+ char namebuf[KSYM_NAME_LEN + 1];
+ unsigned long low, high;
+ static const char *filename_token = "#";
+
+ if ( *symname == '\0' )
+ return NULL;
+
+ /* Unsupported search for filename in symbol right now. */
+ if ( strpbrk(symname, filename_token) )
+ return NULL;
+
+ low = 0;
+ high = symbols_num_syms;
+ while ( low < high )
+ {
+ unsigned long mid = low + ((high - low) / 2);
+ const struct symbol_offset *s;
+ int rc;
+
+ s = &symbols_sorted_offsets[mid];
+ (void)symbols_expand_symbol(s->stream, namebuf);
+ /* Format is: [filename]#<symbol>. symbols_expand_symbol eats type.*/
+ rc = strcmp(symname, namebuf);
+ if ( rc < 0 )
+ high = mid;
+ else if ( rc > 0 )
+ low = mid + 1;
+ else
+ return (void *)symbols_address(s->addr);
+ }
+ return NULL;
+}
+
+#else
+void *symbols_lookup_by_name(const char *symname)
+ {
char name[KSYM_NAME_LEN + 1];
uint32_t symnum = 0;
char type;
@@ -232,6 +273,7 @@ void *symbols_lookup_by_name(const char *symname)
return NULL;
}
+#endif
/*
* Local variables:
* mode: C
diff --git a/xen/include/xen/symbols.h b/xen/include/xen/symbols.h
index 2122a5d..d4c4e1c 100644
--- a/xen/include/xen/symbols.h
+++ b/xen/include/xen/symbols.h
@@ -25,4 +25,14 @@ int xensyms_read(uint32_t *symnum, char *type,
void *symbols_lookup_by_name(const char *symname);
+#ifdef CONFIG_FAST_SYMBOL_LOOKUP
+/*
+ * A sorted (by symbols) lookup table table to symbols_names (stream)
+ * and symbols_address (or offset).
+ */
+struct symbol_offset {
+ uint32_t stream; /* .. in the compressed stream.*/
+ uint32_t addr; /* .. and in the fixed size address array. */
+};
+#endif
#endif /*_XEN_SYMBOLS_H*/
diff --git a/xen/tools/symbols.c b/xen/tools/symbols.c
index 196db74..78d9ef8 100644
--- a/xen/tools/symbols.c
+++ b/xen/tools/symbols.c
@@ -40,6 +40,10 @@ struct sym_entry {
unsigned long long addr;
unsigned int len;
unsigned char *sym;
+ char *orig_symbol;
+ unsigned int addr_idx;
+ unsigned int stream_offset;
+ unsigned char type;
};
#define SYMBOL_NAME(s) ((char *)(s)->sym + 1)
@@ -47,8 +51,10 @@ static struct sym_entry *table;
static unsigned int table_size, table_cnt;
static unsigned long long _stext, _etext, _sinittext, _einittext, _sextratext, _eextratext;
static int all_symbols = 0;
+static int extra_sorted = 0;
static char symbol_prefix_char = '\0';
static enum { fmt_bsd, fmt_sysv } input_format;
+static int compare_name(const void *p1, const void *p2);
int token_profit[0x10000];
@@ -174,9 +180,13 @@ static int read_symbol(FILE *in, struct sym_entry *s)
sym = stpcpy(sym, filename);
*sym++ = '#';
}
+
strcpy(sym, str);
+ if (extra_sorted) {
+ s->orig_symbol = strdup(SYMBOL_NAME(s));
+ s->type = stype; /* As s->sym[0] ends mangled. */
+ }
s->sym[0] = stype;
rc = 0;
skip_tail:
@@ -276,6 +286,27 @@ static int expand_symbol(unsigned char *data, int len, char *result)
return total;
}
+/* Sort by original (non mangled) symbol name, then type. */
+static int compare_name_orig(const void *p1, const void *p2)
+{
+ const struct sym_entry *sym1 = p1;
+ const struct sym_entry *sym2 = p2;
+ int rc;
+
+ rc = strcmp(sym1->orig_symbol, sym2->orig_symbol);
+
+ if (!rc) {
+ if (sym1->type < sym2->type)
+ rc = -1;
+ else if (sym1->type > sym2->type)
+ rc = 1;
+ else
+ rc = 0;
+ }
+
+ return rc;
+}
+
static void write_src(void)
{
unsigned int i, k, off;
@@ -325,6 +356,7 @@ static void write_src(void)
printf(", 0x%02x", table[i].sym[k]);
printf("\n");
+ table[i].stream_offset = off;
off += table[i].len + 1;
}
printf("\n");
@@ -334,7 +366,6 @@ static void write_src(void)
printf("\t.long\t%d\n", markers[i]);
printf("\n");
- free(markers);
output_label("symbols_token_table");
off = 0;
@@ -350,6 +381,27 @@ static void write_src(void)
for (i = 0; i < 256; i++)
printf("\t.short\t%d\n", best_idx[i]);
printf("\n");
+
+ if (!extra_sorted) {
+ free(markers);
+ return;
+ }
+
+ /* Sorted by original symbol names, filename, and lastly type. */
+ qsort(table, table_cnt, sizeof(*table), compare_name_orig);
+
+ output_label("symbols_sorted_offsets");
+ /* An fixed sized array with two entries: offset in the
+ * compressed stream (for symbol name), and offset in
+ * symbols_addresses (or symbols_offset). */
+ for (i = 0; i < table_cnt; i++) {
+ printf("\t.long %d", table[i].stream_offset);
+ printf(", %d", table[i].addr_idx);
+ printf("\n");
+ }
+ printf("\n");
+
+ free(markers);
}
@@ -410,6 +462,7 @@ static void compress_symbols(unsigned char *str, int idx)
len = table[i].len;
p1 = table[i].sym;
+ table[i].addr_idx = i;
/* find the token on the symbol */
p2 = memmem_pvt(p1, len, str, 2);
if (!p2) continue;
@@ -561,6 +614,8 @@ int main(int argc, char **argv)
input_format = fmt_sysv;
else if (strcmp(argv[i], "--sort") == 0)
unsorted = true;
+ else if (strcmp(argv[i], "--add-extra-sorted") == 0)
+ extra_sorted = 1;
else if (strcmp(argv[i], "--warn-dup") == 0)
warn_dup = true;
else
--
2.5.0
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^ permalink raw reply related [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 19/27] xsplice: Add support for alternatives
2016-04-20 6:28 ` Jan Beulich
2016-04-21 0:30 ` Konrad Rzeszutek Wilk
2016-04-21 0:31 ` Konrad Rzeszutek Wilk
@ 2016-04-22 16:06 ` Konrad Rzeszutek Wilk
2 siblings, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-22 16:06 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, andrew.cooper3, mpohlack, ross.lagerwall, sasha.levin, xen-devel
> >+ return -EINVAL;
> >+ }
> >+
> >+ start = sec->load_addr;
> >+ end = sec->load_addr + sec->sec->sh_size;
> >+
> >+ for ( a = start; a < end; a++ )
> >+ {
> >+ unsigned long instr = (unsigned long)(&a->instr_offset + a->instr_offset);
> >+ unsigned long replacement = (unsigned long)(&a->repl_offset + a->repl_offset);
> >+
> >+ if ( (instr < region->start && instr >= region->end) ||
> >+ (replacement < region->start && replacement >= region->end) )
> >+ {
> >+ dprintk(XENLOG_ERR, XSPLICE "%s Alt patching outside payload: 0x%lx!\n",
>
> %#lx please
To drop on the casting I changed the instr and replacement to be 'const void *'
(and also made region->start, and end be const void * as well) so this instead
of being %#lx ended up being %p.
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 20/27] build_id: Provide ld-embedded build-ids
2016-04-21 6:59 ` Jan Beulich
2016-04-21 20:30 ` Konrad Rzeszutek Wilk
@ 2016-04-22 16:16 ` Konrad Rzeszutek Wilk
1 sibling, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-22 16:16 UTC (permalink / raw)
To: Jan Beulich
Cc: sstabellini, keir, ross.lagerwall, andrew.cooper3, mpohlack,
mpohlack, julien.grall, sasha.levin, xen-devel
On Thu, Apr 21, 2016 at 12:59:00AM -0600, Jan Beulich wrote:
> >>> On 21.04.16 at 02:33, <konrad.wilk@oracle.com> wrote:
> > On Wed, Apr 20, 2016 at 01:14:17AM -0600, Jan Beulich wrote:
> >> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 04/14/16 12:03 AM >>>
> >> >--- a/Config.mk
> >> >+++ b/Config.mk
> >> >@@ -126,6 +126,17 @@ endef
> >> >check-$(gcc) = $(call cc-ver-check,CC,0x040100,"Xen requires at least gcc-4.1")
> >> >$(eval $(check-y))
> >> >
> >> >+ld-ver-build-id = $(shell $(1) --build-id 2>&1 | \
> >> >+ grep -q unrecognized && echo n || echo y)
> >>
> >> What about localized binutils?
> >
> > I couldn't find the localized entries for binutils, but that may change
> > in the future.
> >
> > Do you think it would be better to go back to the version check?
>
> No, definitely not. Just that you shouldn't look at textual output
> imo, but at the linker actually groking the option.
>
Which in retrospective is easy:
diff --git a/Config.mk b/Config.mk
index aa64028..d0bcb70 100644
--- a/Config.mk
+++ b/Config.mk
@@ -127,7 +127,7 @@ check-$(gcc) = $(call cc-ver-check,CC,0x040100,"Xen requires at least gcc-4.1")
$(eval $(check-y))
ld-ver-build-id = $(shell $(1) --build-id 2>&1 | \
- grep -q unrecognized && echo n || echo y)
+ grep -q build-id && echo n || echo y)
export XEN_HAS_BUILD_ID ?= n
ifeq ($(call ld-ver-build-id,$(LD)),n)
[konrad@localhost xen]$
> > Or look at this at some pointer later - since you mentioned you were
> > OK with giving an Ack even as is?
>
> Yes, looking at this later is fine, as long as it doesn't get forgotten.
>
> Jan
>
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^ permalink raw reply related [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 12/27] xsplice: Implement support for applying/reverting/replacing patches.
2016-04-19 6:27 ` Jan Beulich
2016-04-21 0:28 ` Konrad Rzeszutek Wilk
@ 2016-04-22 17:26 ` Konrad Rzeszutek Wilk
2016-04-25 7:55 ` Jan Beulich
1 sibling, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-22 17:26 UTC (permalink / raw)
To: Jan Beulich
Cc: kevin.tian, sstabellini, keir, jun.nakajima, andrew.cooper3,
mpohlack, ross.lagerwall, julien.grall, suravee.suthikulpanit,
sasha.levin, xen-devel, boris.ostrovsky
> >+/* Defines an outstanding patching action. */
> >+struct xsplice_work
> >+{
> >+ atomic_t semaphore; /* Used for rendezvous. */
> >+ atomic_t irq_semaphore; /* Used to signal all IRQs disabled. */
>
> Why do you, btw, need two of them? I would seem to me that having just one
> for both purposes should be fine.
The 'semaphore' is used to get all of the CPUs synced up in the code. Once
they have been synced up (so semaphore == total_cpus-1) we go to the next stage
where all of them disable their IRQs -- and the master patches. Once the patching
is done all of them renable their IRQs.
I am not exactly sure how I would reuse the 'semaphore' on the second part of this
(disable IRQs).
Let me ponder this over the weekend with some crayons and paper..
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-22 11:24 ` Jan Beulich
@ 2016-04-22 21:10 ` Konrad Rzeszutek Wilk
2016-04-25 6:41 ` Ross Lagerwall
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-22 21:10 UTC (permalink / raw)
To: Jan Beulich
Cc: Keir Fraser, Andrew Cooper, Martin Pohlack, Ross Lagerwall,
Xen-devel, sasha.levin
> As per my earlier reply to Konrad, there must be more to this. I.e.
> "normal" local symbols won't get dropped together with relocations
> referencing them getting resolved.
Correct. These .LCx symbols only cover .rodata.* sections. Any other
local symbols:
[konrad@x230 x86]$ readelf --symbols prelink.o |grep bad_hypercall
8946: 0000000000145549 0 NOTYPE LOCAL DEFAULT 1 compat_bad_hypercall
8967: 0000000000145c79 0 NOTYPE LOCAL DEFAULT 1 bad_hypercall
don't get dropped and do show up in the binary (nm --defined finds them).
While .LC matches the type:
9147: 00000000000008c0 0 NOTYPE LOCAL DEFAULT 33 .LC5
They are in four other sections:
konrad@x230 x86]$ readelf --symbols prelink.o |grep LC | awk '{print
$7}' | sort | uniq
22
23
33
34
[22] .rodata.str1.1 PROGBITS 0000000000000000 0019d500
000000000000a088 0000000000000001 AMS 0 0 1
[23] .rodata.str1.8 PROGBITS 0000000000000000 001a7588
0000000000020a31 0000000000000001 AMS 0 0 8
[33] .init.rodata.str1 PROGBITS 0000000000000000 001d5a78
0000000000000a1e 0000000000000001 AMS 0 0 1
[34] .init.rodata.str1 PROGBITS 0000000000000000 001d6498
0000000000002331 0000000000000001 AMS 0 0 8
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-22 11:18 ` Jan Beulich
@ 2016-04-24 21:41 ` Konrad Rzeszutek Wilk
2016-04-25 8:02 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-24 21:41 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, andrew.cooper3, mpohlack, Ross Lagerwall, sasha.levin, xen-devel
On Fri, Apr 22, 2016 at 05:18:16AM -0600, Jan Beulich wrote:
> >>> On 22.04.16 at 13:08, <konrad.wilk@oracle.com> wrote:
> > On Fri, Apr 22, 2016 at 04:50:34AM -0600, Jan Beulich wrote:
> >> >>> On 22.04.16 at 12:28, <konrad.wilk@oracle.com> wrote:
> >> > On Fri, Apr 22, 2016 at 04:08:10AM -0600, Jan Beulich wrote:
> >> >> >>> On 22.04.16 at 10:45, <ross.lagerwall@citrix.com> wrote:
> >> >> > Rather than ignoring STT_NOTYPE, an alternative would be to ignore
> >> >> > symbols starting with ".L".
> >> >>
> >> >> That's an option, but as said before, the rules for which symbols to
> >> >> enter into the symbol table should be consistent for core and modules.
> >> >
> >> > And they seem to - see above on the .o file.
> >>
> >> Above .o file was a core one, and doesn't tell anyway whether in the
> >> runtime symbol table the local symbols would be properly prefixed by
> >> file name. Or did I misunderstand you?
> >
> > I had 'built_in.o' or 'prelink.o' as the final one in mind - in which the
> > .LCx are present. But I think you are thinking about 'xen-syms' output.
> >
> > Looking at the Makefile runes we hit this:
> > 127 $(TARGET)-syms: prelink.o xen.lds $(BASEDIR)/common/symbols-dummy.o
> > 128 $(LD) $(LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
> > 129 $(BASEDIR)/common/symbols-dummy.o -o $(@D)/.$(@F).0
> >
> > And that ends up causing the .xen-syms.0 file to drop all the .LC0.
>
> That's odd: I don't know of us telling the linker to do so, and imo
> it shouldn't do this by default. But yes, linkers often do strange
> things...
>
> > However we can't do that. We _have_ to produce an relocatable object
> > and not do the final linking (so we append -r to the linker invocation).
>
> Of course.
>
> > I tried for fun to use strip:
> > xen/xen/arch/x86/test> strip --strip-symbol=".LC0" xen_replace_world.xsplice
> > strip: not stripping symbol `.LC0' because it is named in a relocation
>
> Which it is rightfully saying.
>
> So with the linker stripping .LC* (and why knows what else), you
> stripping them when building the runtime symbol table would be
> fine with me, provided we can somehow identify in the linker why
> this stripping happens, and which precise set of symbols get
> stripped (which you should then match in our code).
I spoke over the weekend with Dan Jacobowitz (who in the past worked
on binutils) who mentioned that ELF visibility is what one should
pay attention to. And that we shouldn't need to look at LOCAL symbols
at all if we are resolving between objects.
Also he mentions that the handling of .L* symbols is special since
they're intermediate artifacts of assembly. They're ... "even more local".
Digging in the binutils over the weekend I found:
/* Return whether a symbol name implies a local symbol. Most targets
use this function for the is_local_label_name entry point, but some
override it. */
_bfd_elf_is_local_label_name (bfd *abfd ATTRIBUTE_UNUSED,
const char *name)
{
/* Normal local symbols start with ``.L''. */
if (name[0] == '.' && name[1] == 'L')
return TRUE;
..
The function prototype is suppose to adhere to:
DESCRIPTION
Return TRUE if a symbol with the name @var{name} in the BFD
@var{abfd} is a compiler generated local label,
Looking at the callchain I saw:
/* Link an input file into the linker output file. This function
handles all the sections and relocations of the input file at once.
This is so that we only have to read the local symbols once, and
don't have to keep them in memory. */
static bfd_boolean
elf_link_input_bfd (..
And inside there is a big loop in which:
/* See if we are discarding symbols with this name. */
if ((flinfo->info->strip == strip_some
&& (bfd_hash_lookup (flinfo->info->keep_hash, name, FALSE, FALSE)
== NULL))
|| (((flinfo->info->discard == discard_sec_merge
&& (isec->flags & SEC_MERGE) && !flinfo->info->relocatable)
|| flinfo->info->discard == discard_l)
&& bfd_is_local_label_name (input_bfd, name)))
continue;
Which really matches with what I see - that is the .LCx symbols are in
mergable sections:
[konrad@x230 x86]$ readelf --symbols prelink.o |grep LC | awk '{print $7}' | sort | uniq
22
23
33
34
[22] .rodata.str1.1 PROGBITS 0000000000000000 0019d500
000000000000a088 0000000000000001 AMS 0 0 1
[23] .rodata.str1.8 PROGBITS 0000000000000000 001a7588
0000000000020a31 0000000000000001 AMS 0 0 8
[33] .init.rodata.str1 PROGBITS 0000000000000000 001d5a78
0000000000000a1e 0000000000000001 AMS 0 0 1
[34] .init.rodata.str1 PROGBITS 0000000000000000 001d6498
0000000000002331 0000000000000001 AMS 0 0 8
[22] .rodata.str1.1 PROGBITS 0000000000000000 0019d500
000000000000a088 0000000000000001 AMS 0 0 1
[23] .rodata.str1.8 PROGBITS 0000000000000000 001a7588
0000000000020a31 0000000000000001 AMS 0 0 8
[33] .init.rodata.str1 PROGBITS 0000000000000000 001d5a78
0000000000000a1e 0000000000000001 AMS 0 0 1
[34] .init.rodata.str1 PROGBITS 0000000000000000 001d6498
0000000000002331 0000000000000001 AMS 0 0 8
And when we do the final linking:
ld -melf_x86_64 -T xen.lds -N prelink.o --build-id=sha1 \
/tmp/xen/xen/common/symbols-dummy.o -o /tmp/xen/xen/.xen-syms.0
The xen.lds.S linker has:
.rodata : {
..
*(.rodata.*)
} :text
which collapses these.
(For fun I wrote a seperate entry:
.rodata.str : {
__lc_start = .;
*(.rodata.str1.8)
__lc_end = .;
} :text
and sure enough - that section (.rodata.str) is there and looks. There
are no symbols for it - except the __lc_start and __lc_end.
So coming back to this discussion - the code has this:
static bool_t is_payload_symbol(const struct xsplice_elf *elf,
const struct xsplice_elf_sym *sym)
{
if ( sym->sym->st_shndx == SHN_UNDEF ||
sym->sym->st_shndx >= elf->hdr->e_shnum )
return 0;
return (elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) &&
(ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT ||
ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
}
You OK with it being the way it is? I would naturally include a
comment about these local symbols like .L*
?
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-22 21:10 ` Konrad Rzeszutek Wilk
@ 2016-04-25 6:41 ` Ross Lagerwall
2016-04-25 8:15 ` Jan Beulich
0 siblings, 1 reply; 126+ messages in thread
From: Ross Lagerwall @ 2016-04-25 6:41 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk, Jan Beulich
Cc: Keir Fraser, Andrew Cooper, Martin Pohlack, Xen-devel, sasha.levin
On 04/22/2016 10:10 PM, Konrad Rzeszutek Wilk wrote:
>> As per my earlier reply to Konrad, there must be more to this. I.e.
>> "normal" local symbols won't get dropped together with relocations
>> referencing them getting resolved.
>
> Correct. These .LCx symbols only cover .rodata.* sections. Any other
> local symbols:
>
> [konrad@x230 x86]$ readelf --symbols prelink.o |grep bad_hypercall
> 8946: 0000000000145549 0 NOTYPE LOCAL DEFAULT 1 compat_bad_hypercall
> 8967: 0000000000145c79 0 NOTYPE LOCAL DEFAULT 1 bad_hypercall
>
> don't get dropped and do show up in the binary (nm --defined finds them).
>
> While .LC matches the type:
> 9147: 00000000000008c0 0 NOTYPE LOCAL DEFAULT 33 .LC5
>
> They are in four other sections:
> konrad@x230 x86]$ readelf --symbols prelink.o |grep LC | awk '{print
> $7}' | sort | uniq
> 22
> 23
> 33
> 34
>
> [22] .rodata.str1.1 PROGBITS 0000000000000000 0019d500
> 000000000000a088 0000000000000001 AMS 0 0 1
> [23] .rodata.str1.8 PROGBITS 0000000000000000 001a7588
> 0000000000020a31 0000000000000001 AMS 0 0 8
> [33] .init.rodata.str1 PROGBITS 0000000000000000 001d5a78
> 0000000000000a1e 0000000000000001 AMS 0 0 1
> [34] .init.rodata.str1 PROGBITS 0000000000000000 001d6498
> 0000000000002331 0000000000000001 AMS 0 0 8
>
With some helpful investigation by Konrad, I've found this snippet in
binutils:
/* See if we are discarding symbols with this name. */
if ((flinfo->info->strip == strip_some
&& (bfd_hash_lookup (flinfo->info->keep_hash, name, FALSE, FALSE)
== NULL))
|| (((flinfo->info->discard == discard_sec_merge
&& (isec->flags & SEC_MERGE)
&& !bfd_link_relocatable (flinfo->info))
|| flinfo->info->discard == discard_l)
&& bfd_is_local_label_name (input_bfd, name)))
continue;
The default value for info->discard is discard_sec_merge, so:
Local labels referring to a mergeable section are discarded when the
output is not relocatable.
A local label is defined as:
1) Starts with .X (for i386 unixware compilers)
2) Starts with .L
3) Starts with .. (for SRV4 compilers)
4) Starts with _.L_ (for older buggy GCC)
5) Matches L0^A.*
6) Matches L[0-9]+{^A|^B}[0-9]* (for assembler generated local labels)
So to match what is used by the default hypervisor build, I think we
should change the check to discard when the symbol matches (2), (5), or
(6) above and refers to a mergeable section. The above rules are defined
in _bfd_elf_is_local_label_name and elf_i386_is_local_label_name.
--
Ross Lagerwall
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 12/27] xsplice: Implement support for applying/reverting/replacing patches.
2016-04-22 17:26 ` Konrad Rzeszutek Wilk
@ 2016-04-25 7:55 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-25 7:55 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: kevin.tian, sstabellini, keir, suravee.suthikulpanit,
andrew.cooper3, mpohlack, ross.lagerwall, julien.grall,
jun.nakajima, sasha.levin, xen-devel, boris.ostrovsky
>>> On 22.04.16 at 19:26, <konrad.wilk@oracle.com> wrote:
>> >+/* Defines an outstanding patching action. */
>> >+struct xsplice_work
>> >+{
>> >+ atomic_t semaphore; /* Used for rendezvous. */
>> >+ atomic_t irq_semaphore; /* Used to signal all IRQs disabled. */
>>
>> Why do you, btw, need two of them? I would seem to me that having just one
>> for both purposes should be fine.
>
> The 'semaphore' is used to get all of the CPUs synced up in the code. Once
> they have been synced up (so semaphore == total_cpus-1) we go to the next
> stage
> where all of them disable their IRQs -- and the master patches. Once the
> patching
> is done all of them renable their IRQs.
>
> I am not exactly sure how I would reuse the 'semaphore' on the second part
> of this
> (disable IRQs).
Right now you have
+ timeout = xsplice_work.timeout + NOW();
+ if ( xsplice_spin(&xsplice_work.semaphore, timeout, cpus, "CPU") )
+ goto abort;
+
+ /* All CPUs are waiting, now signal to disable IRQs. */
+ xsplice_work.ready = 1;
+ smp_wmb();
+
+ atomic_inc(&xsplice_work.irq_semaphore);
This atomic_inc() could simply become
atomic_set(&xsplice_work.semaphore, 0), while at the same time
getting moved up ahead of the setting of xsplice_work.ready (with
suitable addition of barriers).
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-24 21:41 ` Konrad Rzeszutek Wilk
@ 2016-04-25 8:02 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-25 8:02 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: keir, andrew.cooper3, mpohlack, Ross Lagerwall, xen-devel, sasha.levin
>>> On 24.04.16 at 23:41, <konrad@kernel.org> wrote:
> I spoke over the weekend with Dan Jacobowitz (who in the past worked
> on binutils) who mentioned that ELF visibility is what one should
> pay attention to. And that we shouldn't need to look at LOCAL symbols
> at all if we are resolving between objects.
Well, in general that's correct, but xSplice intentionally hooks up to
all the symbols available (including local ones in the core image).
> Also he mentions that the handling of .L* symbols is special since
> they're intermediate artifacts of assembly. They're ... "even more local".
>
> Digging in the binutils over the weekend I found:
>
> /* Return whether a symbol name implies a local symbol. Most targets
> use this function for the is_local_label_name entry point, but some
> override it. */
>
>
> _bfd_elf_is_local_label_name (bfd *abfd ATTRIBUTE_UNUSED,
> const char *name)
> {
> /* Normal local symbols start with ``.L''. */
> if (name[0] == '.' && name[1] == 'L')
> return TRUE;
> ..
Yes, that's then what we want to match in behavior (as also
suggested by Ross in his reply).
> Looking at the callchain I saw:
>
> /* Link an input file into the linker output file. This function
> handles all the sections and relocations of the input file at once.
> This is so that we only have to read the local symbols once, and
> don't have to keep them in memory. */
>
> static bfd_boolean
> elf_link_input_bfd (..
>
> And inside there is a big loop in which:
>
> /* See if we are discarding symbols with this name. */
> if ((flinfo->info->strip == strip_some
> && (bfd_hash_lookup (flinfo->info->keep_hash, name, FALSE, FALSE)
> == NULL))
> || (((flinfo->info->discard == discard_sec_merge
> && (isec->flags & SEC_MERGE) && !flinfo->info->relocatable)
> || flinfo->info->discard == discard_l)
> && bfd_is_local_label_name (input_bfd, name)))
> continue;
>
> Which really matches with what I see - that is the .LCx symbols are in
> mergable sections:
> [...]
> So coming back to this discussion - the code has this:
>
> static bool_t is_payload_symbol(const struct xsplice_elf *elf,
> const struct xsplice_elf_sym *sym)
> {
> if ( sym->sym->st_shndx == SHN_UNDEF ||
> sym->sym->st_shndx >= elf->hdr->e_shnum )
> return 0;
>
> return (elf->sec[sym->sym->st_shndx].sec->sh_flags & SHF_ALLOC) &&
> (ELF64_ST_TYPE(sym->sym->st_info) == STT_OBJECT ||
> ELF64_ST_TYPE(sym->sym->st_info) == STT_FUNC);
> }
>
> You OK with it being the way it is? I would naturally include a
> comment about these local symbols like .L*
But that's what is there already, or am I overlooking some change
you did to it? I.e. STT_NOTYPE are still not being considered, and
there's still no dependency on the .L name prefix.
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address.
2016-04-25 6:41 ` Ross Lagerwall
@ 2016-04-25 8:15 ` Jan Beulich
0 siblings, 0 replies; 126+ messages in thread
From: Jan Beulich @ 2016-04-25 8:15 UTC (permalink / raw)
To: Ross Lagerwall, Konrad Rzeszutek Wilk
Cc: Keir Fraser, Andrew Cooper, Martin Pohlack, Xen-devel, sasha.levin
>>> On 25.04.16 at 08:41, <ross.lagerwall@citrix.com> wrote:
> On 04/22/2016 10:10 PM, Konrad Rzeszutek Wilk wrote:
>>> As per my earlier reply to Konrad, there must be more to this. I.e.
>>> "normal" local symbols won't get dropped together with relocations
>>> referencing them getting resolved.
>>
>> Correct. These .LCx symbols only cover .rodata.* sections. Any other
>> local symbols:
>>
>> [konrad@x230 x86]$ readelf --symbols prelink.o |grep bad_hypercall
>> 8946: 0000000000145549 0 NOTYPE LOCAL DEFAULT 1
> compat_bad_hypercall
>> 8967: 0000000000145c79 0 NOTYPE LOCAL DEFAULT 1 bad_hypercall
>>
>> don't get dropped and do show up in the binary (nm --defined finds them).
>>
>> While .LC matches the type:
>> 9147: 00000000000008c0 0 NOTYPE LOCAL DEFAULT 33 .LC5
>>
>> They are in four other sections:
>> konrad@x230 x86]$ readelf --symbols prelink.o |grep LC | awk '{print
>> $7}' | sort | uniq
>> 22
>> 23
>> 33
>> 34
>>
>> [22] .rodata.str1.1 PROGBITS 0000000000000000 0019d500
>> 000000000000a088 0000000000000001 AMS 0 0 1
>> [23] .rodata.str1.8 PROGBITS 0000000000000000 001a7588
>> 0000000000020a31 0000000000000001 AMS 0 0 8
>> [33] .init.rodata.str1 PROGBITS 0000000000000000 001d5a78
>> 0000000000000a1e 0000000000000001 AMS 0 0 1
>> [34] .init.rodata.str1 PROGBITS 0000000000000000 001d6498
>> 0000000000002331 0000000000000001 AMS 0 0 8
>>
>
> With some helpful investigation by Konrad, I've found this snippet in
> binutils:
>
> /* See if we are discarding symbols with this name. */
> if ((flinfo->info->strip == strip_some
> && (bfd_hash_lookup (flinfo->info->keep_hash, name, FALSE, FALSE)
> == NULL))
> || (((flinfo->info->discard == discard_sec_merge
> && (isec->flags & SEC_MERGE)
> && !bfd_link_relocatable (flinfo->info))
> || flinfo->info->discard == discard_l)
> && bfd_is_local_label_name (input_bfd, name)))
> continue;
>
> The default value for info->discard is discard_sec_merge, so:
> Local labels referring to a mergeable section are discarded when the
> output is not relocatable.
> A local label is defined as:
> 1) Starts with .X (for i386 unixware compilers)
> 2) Starts with .L
> 3) Starts with .. (for SRV4 compilers)
> 4) Starts with _.L_ (for older buggy GCC)
> 5) Matches L0^A.*
> 6) Matches L[0-9]+{^A|^B}[0-9]* (for assembler generated local labels)
>
> So to match what is used by the default hypervisor build, I think we
> should change the check to discard when the symbol matches (2), (5), or
> (6) above and refers to a mergeable section. The above rules are defined
> in _bfd_elf_is_local_label_name and elf_i386_is_local_label_name.
Yes. (Note that we don't really care about
elf_i386_is_local_label_name(), as we don't have a 32-bit
hypervisor anymore.)
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 15/27] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup
2016-04-22 15:21 ` Konrad Rzeszutek Wilk
@ 2016-04-25 8:38 ` Jan Beulich
2016-04-25 14:12 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 126+ messages in thread
From: Jan Beulich @ 2016-04-25 8:38 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: keir, ross.lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
>>> On 22.04.16 at 17:21, <konrad.wilk@oracle.com> wrote:
> Here is what I came up using your idea. Do you want me to add 'Suggested-by'
> Jan on it?
I'll leave that up to you; it was really just a vague idea that I gave...
> --- a/xen/arch/x86/Makefile
> +++ b/xen/arch/x86/Makefile
> @@ -74,6 +74,9 @@ efi-y := $(shell if [ ! -r $(BASEDIR)/include/xen/compile.h -o \
>
> ifdef CONFIG_XSPLICE
> all_symbols = --all-symbols
> +ifdef CONFIG_FAST_SYMBOL_LOOKUP
> +all_symbols = --all-symbols --add-extra-sorted
> +endif
> else
> all_symbols =
> endif
This now even more calls for using the common list model, at least as
later cleanup.
> --- a/xen/common/symbols-dummy.c
> +++ b/xen/common/symbols-dummy.c
> @@ -5,6 +5,7 @@
>
> #include <xen/config.h>
> #include <xen/types.h>
> +#include <xen/symbols.h>
>
> #ifdef SYMBOLS_ORIGIN
> const unsigned int symbols_offsets[1];
> @@ -14,6 +15,10 @@ const unsigned long symbols_addresses[1];
> const unsigned int symbols_num_syms;
> const u8 symbols_names[1];
>
> +#ifdef CONFIG_FAST_SYMBOL_LOOKUP
> +const struct symbol_offset symbols_sorted_offsets[1];
> +#endif
Oh, nice - you even do the sorting at build time!
> --- a/xen/common/symbols.c
> +++ b/xen/common/symbols.c
> @@ -31,6 +31,10 @@ extern const unsigned long symbols_addresses[];
> extern const unsigned int symbols_num_syms;
> extern const u8 symbols_names[];
>
> +#ifdef CONFIG_FAST_SYMBOL_LOOKUP
> +extern const struct symbol_offset symbols_sorted_offsets[];
> +#endif
No need for an #ifdef around just a declaration.
> @@ -208,8 +212,45 @@ int xensyms_read(uint32_t *symnum, char *type,
> return 0;
> }
>
> +#ifdef CONFIG_FAST_SYMBOL_LOOKUP
> void *symbols_lookup_by_name(const char *symname)
> {
> + char namebuf[KSYM_NAME_LEN + 1];
> + unsigned long low, high;
> + static const char *filename_token = "#";
It's being used just once, so I don't see the value of this. But if you
want to retain it, please at least make it an array instead of a pointer.
> + if ( *symname == '\0' )
> + return NULL;
> +
> + /* Unsupported search for filename in symbol right now. */
> + if ( strpbrk(symname, filename_token) )
> + return NULL;
That's unfortunate - why are you filtering these out? (Related to
the earlier comment - this could even be strchr(), with no need at
all for a string literal.)
> + low = 0;
> + high = symbols_num_syms;
> + while ( low < high )
> + {
> + unsigned long mid = low + ((high - low) / 2);
> + const struct symbol_offset *s;
> + int rc;
> +
> + s = &symbols_sorted_offsets[mid];
> + (void)symbols_expand_symbol(s->stream, namebuf);
> + /* Format is: [filename]#<symbol>. symbols_expand_symbol eats type.*/
[<filename>#]<symbol>
And what relevance does the type part of the comment have here?
> + rc = strcmp(symname, namebuf);
So looking at this I really don't see why you filter filename prefixed
input names above.
> + if ( rc < 0 )
> + high = mid;
> + else if ( rc > 0 )
> + low = mid + 1;
> + else
> + return (void *)symbols_address(s->addr);
> + }
> + return NULL;
> +}
> +
> +#else
> +void *symbols_lookup_by_name(const char *symname)
> + {
Please put the #ifdef/#else/#endif inside the function body, to
avoid duplicating code as much as possible. Putting them outside
would be needed primarily if the function type varied between the
two instances.
> +/* Sort by original (non mangled) symbol name, then type. */
> +static int compare_name_orig(const void *p1, const void *p2)
> +{
> + const struct sym_entry *sym1 = p1;
> + const struct sym_entry *sym2 = p2;
> + int rc;
> +
> + rc = strcmp(sym1->orig_symbol, sym2->orig_symbol);
> +
> + if (!rc) {
> + if (sym1->type < sym2->type)
> + rc = -1;
> + else if (sym1->type > sym2->type)
> + rc = 1;
> + else
> + rc = 0;
How about just "rc = sym1->type - sym2->type"?
> @@ -350,6 +381,27 @@ static void write_src(void)
> for (i = 0; i < 256; i++)
> printf("\t.short\t%d\n", best_idx[i]);
> printf("\n");
> +
> + if (!extra_sorted) {
> + free(markers);
> + return;
> + }
> +
> + /* Sorted by original symbol names, filename, and lastly type. */
> + qsort(table, table_cnt, sizeof(*table), compare_name_orig);
> +
> + output_label("symbols_sorted_offsets");
> + /* An fixed sized array with two entries: offset in the
"A fixed size ..."
> + * compressed stream (for symbol name), and offset in
> + * symbols_addresses (or symbols_offset). */
> + for (i = 0; i < table_cnt; i++) {
> + printf("\t.long %d", table[i].stream_offset);
> + printf(", %d", table[i].addr_idx);
> + printf("\n");
How about making this just a single printf()? Also both are unsigned,
so please at least %u, but even better %#x.
> @@ -561,6 +614,8 @@ int main(int argc, char **argv)
> input_format = fmt_sysv;
> else if (strcmp(argv[i], "--sort") == 0)
> unsorted = true;
> + else if (strcmp(argv[i], "--add-extra-sorted") == 0)
> + extra_sorted = 1;
s/extra/name/ ?
Or --sort-by-name?
Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
* Re: [PATCH v8.1 15/27] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup
2016-04-25 8:38 ` Jan Beulich
@ 2016-04-25 14:12 ` Konrad Rzeszutek Wilk
0 siblings, 0 replies; 126+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-25 14:12 UTC (permalink / raw)
To: Jan Beulich
Cc: keir, ross.lagerwall, andrew.cooper3, mpohlack, sasha.levin, xen-devel
On Mon, Apr 25, 2016 at 02:38:57AM -0600, Jan Beulich wrote:
> >>> On 22.04.16 at 17:21, <konrad.wilk@oracle.com> wrote:
> > Here is what I came up using your idea. Do you want me to add 'Suggested-by'
> > Jan on it?
>
> I'll leave that up to you; it was really just a vague idea that I gave...
>
> > --- a/xen/arch/x86/Makefile
> > +++ b/xen/arch/x86/Makefile
> > @@ -74,6 +74,9 @@ efi-y := $(shell if [ ! -r $(BASEDIR)/include/xen/compile.h -o \
> >
> > ifdef CONFIG_XSPLICE
> > all_symbols = --all-symbols
> > +ifdef CONFIG_FAST_SYMBOL_LOOKUP
> > +all_symbols = --all-symbols --add-extra-sorted
> > +endif
> > else
> > all_symbols =
> > endif
>
> This now even more calls for using the common list model, at least as
> later cleanup.
OK, put it on the Wiki.
>
> > --- a/xen/common/symbols-dummy.c
> > +++ b/xen/common/symbols-dummy.c
> > @@ -5,6 +5,7 @@
> >
> > #include <xen/config.h>
> > #include <xen/types.h>
> > +#include <xen/symbols.h>
> >
> > #ifdef SYMBOLS_ORIGIN
> > const unsigned int symbols_offsets[1];
> > @@ -14,6 +15,10 @@ const unsigned long symbols_addresses[1];
> > const unsigned int symbols_num_syms;
> > const u8 symbols_names[1];
> >
> > +#ifdef CONFIG_FAST_SYMBOL_LOOKUP
> > +const struct symbol_offset symbols_sorted_offsets[1];
> > +#endif
>
> Oh, nice - you even do the sorting at build time!
:-)
..snip..
> > +#ifdef CONFIG_FAST_SYMBOL_LOOKUP
> > void *symbols_lookup_by_name(const char *symname)
> > {
..snip..
> > + /* Unsupported search for filename in symbol right now. */
> > + if ( strpbrk(symname, filename_token) )
> > + return NULL;
>
> That's unfortunate - why are you filtering these out? (Related to
> the earlier comment - this could even be strchr(), with no need at
> all for a string literal.)
This was an artificat of the earlier version. Removed it all now.
>
> > + low = 0;
> > + high = symbols_num_syms;
> > + while ( low < high )
> > + {
> > + unsigned long mid = low + ((high - low) / 2);
> > + const struct symbol_offset *s;
> > + int rc;
> > +
> > + s = &symbols_sorted_offsets[mid];
> > + (void)symbols_expand_symbol(s->stream, namebuf);
> > + /* Format is: [filename]#<symbol>. symbols_expand_symbol eats type.*/
>
> [<filename>#]<symbol>
>
> And what relevance does the type part of the comment have here?
Artifact of the older version - Where I was searching for #.
.. snip.p
I removed the comment.
> > + for (i = 0; i < table_cnt; i++) {
> > + printf("\t.long %d", table[i].stream_offset);
> > + printf(", %d", table[i].addr_idx);
> > + printf("\n");
>
> How about making this just a single printf()? Also both are unsigned,
> so please at least %u, but even better %#x.
I would rather have it as %u. As when debugging this I found it quite
useful for these values to be decimal as I could edit the .xen-sym.0.S file
and see in the editor where it would match up with the symbols_addresses
or the symbol_names in a quite easy way. Doing it in hex means doing extra
calculations.
>
> > @@ -561,6 +614,8 @@ int main(int argc, char **argv)
> > input_format = fmt_sysv;
> > else if (strcmp(argv[i], "--sort") == 0)
> > unsorted = true;
> > + else if (strcmp(argv[i], "--add-extra-sorted") == 0)
> > + extra_sorted = 1;
>
> s/extra/name/ ?
>
> Or --sort-by-name?
>
> Jan
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^ permalink raw reply [flat|nested] 126+ messages in thread
end of thread, other threads:[~2016-04-25 14:12 UTC | newest]
Thread overview: 126+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-04-13 22:01 [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 01/27] Revert "libxc/libxl/python/xenstat/ocaml: Use new XEN_VERSION hypercall" Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 02/27] Revert "HYPERCALL_version_op. New hypercall mirroring XENVER_ but sane." Konrad Rzeszutek Wilk
2016-04-14 16:14 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 03/27] xsplice: Design document Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 04/27] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op Konrad Rzeszutek Wilk
2016-04-14 16:36 ` Jan Beulich
2016-04-15 2:28 ` Konrad Rzeszutek Wilk
2016-04-17 8:05 ` Jan Beulich
2016-04-18 7:48 ` Konrad Rzeszutek Wilk
2016-04-18 16:33 ` Jan Beulich
2016-04-19 10:14 ` Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 05/27] libxc: Implementation of XEN_XSPLICE_op in libxc Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 06/27] xen-xsplice: Tool to manipulate xsplice payloads Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 07/27] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables lookup Konrad Rzeszutek Wilk
2016-04-14 16:50 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 08/27] arm/x86/vmap: Add vmalloc_xen, vfree_xen and vm_init_type Konrad Rzeszutek Wilk
2016-04-17 20:17 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 09/27] x86/mm: Introduce modify_xen_mappings() Konrad Rzeszutek Wilk
2016-04-14 4:07 ` Jan Beulich
2016-04-14 13:34 ` Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 10/27] xsplice: Add helper elf routines Konrad Rzeszutek Wilk
2016-04-17 20:55 ` Jan Beulich
2016-04-18 5:53 ` Konrad Rzeszutek Wilk
2016-04-18 6:23 ` Jan Beulich
2016-04-20 16:07 ` Konrad Rzeszutek Wilk
2016-04-20 16:59 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 11/27] xsplice: Implement payload loading Konrad Rzeszutek Wilk
2016-04-18 6:16 ` Jan Beulich
2016-04-20 15:59 ` Konrad Rzeszutek Wilk
2016-04-20 17:05 ` Jan Beulich
2016-04-20 17:36 ` Konrad Rzeszutek Wilk
2016-04-21 6:41 ` Jan Beulich
2016-04-21 15:15 ` Konrad Rzeszutek Wilk
2016-04-21 15:36 ` Jan Beulich
2016-04-21 16:47 ` Konrad Rzeszutek Wilk
2016-04-22 7:40 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 12/27] xsplice: Implement support for applying/reverting/replacing patches Konrad Rzeszutek Wilk
2016-04-19 6:27 ` Jan Beulich
2016-04-21 0:28 ` Konrad Rzeszutek Wilk
2016-04-21 6:44 ` Jan Beulich
2016-04-21 20:27 ` Konrad Rzeszutek Wilk
2016-04-22 7:44 ` Jan Beulich
2016-04-22 10:51 ` Konrad Rzeszutek Wilk
2016-04-22 17:26 ` Konrad Rzeszutek Wilk
2016-04-25 7:55 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 13/27] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version' Konrad Rzeszutek Wilk
2016-04-19 17:40 ` Jan Beulich
2016-04-20 16:10 ` Konrad Rzeszutek Wilk
2016-04-20 17:06 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 14/27] xsplice, symbols: Implement symbol name resolution on address Konrad Rzeszutek Wilk
2016-04-19 19:31 ` Jan Beulich
2016-04-20 12:55 ` Ross Lagerwall
2016-04-21 0:26 ` Konrad Rzeszutek Wilk
2016-04-21 6:46 ` Jan Beulich
[not found] ` <CACJDEmrucgYZpCDv3EAkDJUOtdcP9P2T=Vine1o2pzUmwJDY1w@mail.gmail.com>
[not found] ` <CACJDEmrzieYh6__MHJH_okoZPk+RA56PuQKv-oid0j1t1po1oQ@mail.gmail.com>
[not found] ` <CACJDEmrdi3sTZjGowkvGP67-_DH3+TLvArC8qZfArsyPb6fpuA@mail.gmail.com>
[not found] ` <CACJDEmrQ6onv-xqYOi3nekioCSASb4c1eZHJ-rzMxU3Wa7SXTQ@mail.gmail.com>
2016-04-21 13:56 ` Konrad Rzeszutek Wilk
2016-04-21 14:25 ` Jan Beulich
2016-04-22 7:17 ` Ross Lagerwall
2016-04-22 7:51 ` Jan Beulich
2016-04-22 8:45 ` Ross Lagerwall
2016-04-22 10:08 ` Jan Beulich
2016-04-22 10:28 ` Konrad Rzeszutek Wilk
2016-04-22 10:50 ` Jan Beulich
2016-04-22 11:08 ` Konrad Rzeszutek Wilk
2016-04-22 11:18 ` Jan Beulich
2016-04-24 21:41 ` Konrad Rzeszutek Wilk
2016-04-25 8:02 ` Jan Beulich
2016-04-22 11:13 ` Ross Lagerwall
2016-04-22 11:24 ` Jan Beulich
2016-04-22 21:10 ` Konrad Rzeszutek Wilk
2016-04-25 6:41 ` Ross Lagerwall
2016-04-25 8:15 ` Jan Beulich
2016-04-22 14:17 ` Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 15/27] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup Konrad Rzeszutek Wilk
2016-04-19 19:52 ` Jan Beulich
2016-04-22 15:21 ` Konrad Rzeszutek Wilk
2016-04-25 8:38 ` Jan Beulich
2016-04-25 14:12 ` Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 16/27] x86, xsplice: Print payload's symbol name and payload name in backtraces Konrad Rzeszutek Wilk
2016-04-19 20:09 ` Jan Beulich
2016-04-13 22:01 ` [PATCH v8.1 17/27] xsplice: Add support for bug frames Konrad Rzeszutek Wilk
2016-04-19 20:17 ` Jan Beulich
2016-04-21 0:29 ` Konrad Rzeszutek Wilk
2016-04-21 6:49 ` Jan Beulich
2016-04-22 10:10 ` Konrad Rzeszutek Wilk
2016-04-22 10:28 ` Jan Beulich
2016-04-22 10:54 ` Konrad Rzeszutek Wilk
2016-04-22 10:58 ` Jan Beulich
2016-04-22 11:10 ` Konrad Rzeszutek Wilk
2016-04-13 22:01 ` [PATCH v8.1 18/27] xsplice: Add support for exception tables Konrad Rzeszutek Wilk
2016-04-19 20:31 ` Jan Beulich
2016-04-13 22:02 ` [PATCH v8.1 19/27] xsplice: Add support for alternatives Konrad Rzeszutek Wilk
2016-04-20 6:28 ` Jan Beulich
2016-04-21 0:30 ` Konrad Rzeszutek Wilk
2016-04-21 6:55 ` Jan Beulich
2016-04-21 0:31 ` Konrad Rzeszutek Wilk
2016-04-21 6:56 ` Jan Beulich
2016-04-22 16:06 ` Konrad Rzeszutek Wilk
2016-04-13 22:02 ` [PATCH v8.1 20/27] build_id: Provide ld-embedded build-ids Konrad Rzeszutek Wilk
2016-04-20 7:14 ` Jan Beulich
2016-04-21 0:33 ` Konrad Rzeszutek Wilk
2016-04-21 6:59 ` Jan Beulich
2016-04-21 20:30 ` Konrad Rzeszutek Wilk
2016-04-22 16:16 ` Konrad Rzeszutek Wilk
2016-04-13 22:02 ` [PATCH v8.1 21/27] xsplice: Print build_id in keyhandler and on bootup Konrad Rzeszutek Wilk
2016-04-13 22:02 ` [PATCH v8.1 22/27] XENVER_build_id/libxc: Provide ld-embedded build-id Konrad Rzeszutek Wilk
2016-04-14 15:03 ` Wei Liu
2016-04-14 15:04 ` Daniel De Graaf
2016-04-20 7:19 ` Jan Beulich
2016-04-13 22:02 ` [PATCH v8.1 23/27] libxl: info: Display build_id of the hypervisor Konrad Rzeszutek Wilk
2016-04-14 15:06 ` Wei Liu
2016-04-13 22:02 ` [PATCH v8.1 24/27] xsplice: Stacking build-id dependency checking Konrad Rzeszutek Wilk
2016-04-20 7:49 ` Jan Beulich
2016-04-22 10:46 ` Konrad Rzeszutek Wilk
2016-04-22 10:55 ` Jan Beulich
2016-04-13 22:02 ` [PATCH v8.1 25/27] xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE Konrad Rzeszutek Wilk
2016-04-20 11:12 ` Jan Beulich
2016-04-13 22:02 ` [PATCH v8.1 26/27] xsplice: Prevent duplicate payloads from being loaded Konrad Rzeszutek Wilk
2016-04-20 11:16 ` Jan Beulich
2016-04-13 22:02 ` [PATCH v8.1 27/27] MAINTAINERS/xsplice: Add myself and Ross as the maintainers Konrad Rzeszutek Wilk
2016-04-14 14:26 ` [PATCH v8.1] xSplice v1 design and implementation Konrad Rzeszutek Wilk
2016-04-14 14:29 ` Julien Grall
2016-04-14 15:12 ` Andrew Cooper
2016-04-14 15:17 ` Jan Beulich
2016-04-15 0:55 ` Konrad Rzeszutek Wilk
2016-04-17 8:00 ` Jan Beulich
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