* [PATCH v8] xSplice v1 design and implementation.
@ 2016-04-13 21:09 Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 01/25] xsplice: Design document Konrad Rzeszutek Wilk
` (25 more replies)
0 siblings, 26 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
Hey!
Changelog:
v7: since 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 01/27] Revert "libxc/libxl/python/xenstat/ocaml: Use new
[PATCH v8 02/27] Revert "HYPERCALL_version_op. New hypercall mirroring
[PATCH v8 15/27] xsplice, symbols: Implement fast symbol names ->
[PATCH v8 22/27] XENVER_build_id/libxc: Provide ld-embedded build-id
[PATCH v8 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 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 | 2 +
tools/libxc/include/xenctrl.h | 62 ++
tools/libxc/xc_misc.c | 355 ++++++
tools/libxl/libxl.c | 18 +-
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 ++++++++
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 | 39 +-
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/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/xen.lds.S | 28 +
xen/arch/x86/xsplice.c | 264 +++++
xen/common/Kconfig | 28 +
xen/common/Makefile | 3 +
xen/common/kernel.c | 4 +
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/sysctl.h | 193 ++++
xen/include/public/version.h | 3 +
xen/include/xen/elfstructs.h | 7 +
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/tools/symbols.c | 93 +-
xen/xsm/flask/hooks.c | 7 +
xen/xsm/flask/policy/access_vectors | 4 +
67 files changed, 6237 insertions(+), 217 deletions(-)
Andrew Cooper (1):
x86/mm: Introduce modify_xen_mappings()
Konrad Rzeszutek Wilk (15):
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
HYPERCALL_version_op: Add VERSION_build_id to retrieve build-id.
libxl: info: Display build_id of the hypervisor using XEN_VERSION_build_id
xsplice: Print build_id in keyhandler and on bootup.
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] 32+ messages in thread
* [PATCH v8 01/25] xsplice: Design document
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 02/25] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op Konrad Rzeszutek Wilk
` (24 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 02/25] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 01/25] xsplice: Design document Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-20 13:18 ` Ross Lagerwall
2016-04-13 21:09 ` [PATCH v8 03/25] libxc: Implementation of XEN_XSPLICE_op in libxc Konrad Rzeszutek Wilk
` (23 subsequent siblings)
25 siblings, 1 reply; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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 a551756..34fcfb9 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 and VERSION 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 233612e..14ca163 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 0ebb56b..6c0ce7c 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] 32+ messages in thread
* [PATCH v8 03/25] libxc: Implementation of XEN_XSPLICE_op in libxc
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 01/25] xsplice: Design document Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 02/25] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 04/25] xen-xsplice: Tool to manipulate xsplice payloads Konrad Rzeszutek Wilk
` (22 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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 f5a034a..a7937fa 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -2640,6 +2640,68 @@ 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] 32+ messages in thread
* [PATCH v8 04/25] xen-xsplice: Tool to manipulate xsplice payloads
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (2 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 03/25] libxc: Implementation of XEN_XSPLICE_op in libxc Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 05/25] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables lookup Konrad Rzeszutek Wilk
` (21 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 05/25] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables lookup.
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (3 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 04/25] xen-xsplice: Tool to manipulate xsplice payloads Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 06/25] arm/x86/vmap: Add vmalloc_xen, vfree_xen and vm_init_type Konrad Rzeszutek Wilk
` (20 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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 1516abd..4c423de 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] 32+ messages in thread
* [PATCH v8 06/25] arm/x86/vmap: Add vmalloc_xen, vfree_xen and vm_init_type
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (4 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 05/25] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables lookup Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 07/25] x86/mm: Introduce modify_xen_mappings() Konrad Rzeszutek Wilk
` (19 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 07/25] x86/mm: Introduce modify_xen_mappings()
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (5 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 06/25] arm/x86/vmap: Add vmalloc_xen, vfree_xen and vm_init_type Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 08/25] xsplice: Add helper elf routines Konrad Rzeszutek Wilk
` (18 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 08/25] xsplice: Add helper elf routines
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (6 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 07/25] x86/mm: Introduce modify_xen_mappings() Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 09/25] xsplice: Implement payload loading Konrad Rzeszutek Wilk
` (17 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 09/25] xsplice: Implement payload loading
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (7 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 08/25] xsplice: Add helper elf routines Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 10/25] xsplice: Implement support for applying/reverting/replacing patches Konrad Rzeszutek Wilk
` (16 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 10/25] xsplice: Implement support for applying/reverting/replacing patches.
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (8 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 09/25] xsplice: Implement payload loading Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 11/25] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version' Konrad Rzeszutek Wilk
` (15 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 11/25] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version'.
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (9 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 10/25] xsplice: Implement support for applying/reverting/replacing patches Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 12/25] xsplice, symbols: Implement symbol name resolution on address Konrad Rzeszutek Wilk
` (14 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 12/25] xsplice, symbols: Implement symbol name resolution on address.
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (10 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 11/25] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version' Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 13/25] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup Konrad Rzeszutek Wilk
` (13 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 13/25] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (11 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 12/25] xsplice, symbols: Implement symbol name resolution on address Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 14/25] x86, xsplice: Print payload's symbol name and payload name in backtraces Konrad Rzeszutek Wilk
` (12 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 14/25] x86, xsplice: Print payload's symbol name and payload name in backtraces
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (12 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 13/25] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 15/25] xsplice: Add support for bug frames Konrad Rzeszutek Wilk
` (11 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 15/25] xsplice: Add support for bug frames.
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (13 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 14/25] x86, xsplice: Print payload's symbol name and payload name in backtraces Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 16/25] xsplice: Add support for exception tables Konrad Rzeszutek Wilk
` (10 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 16/25] xsplice: Add support for exception tables.
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (14 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 15/25] xsplice: Add support for bug frames Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 17/25] xsplice: Add support for alternatives Konrad Rzeszutek Wilk
` (9 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 17/25] xsplice: Add support for alternatives
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (15 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 16/25] xsplice: Add support for exception tables Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 18/25] build_id: Provide ld-embedded build-ids Konrad Rzeszutek Wilk
` (8 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 18/25] build_id: Provide ld-embedded build-ids
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (16 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 17/25] xsplice: Add support for alternatives Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 19/25] HYPERCALL_version_op: Add VERSION_build_id to retrieve build-id Konrad Rzeszutek Wilk
` (7 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
Cc: Julien Grall, Stefano Stabellini, Keir Fraser, Jan Beulich,
Konrad Rzeszutek Wilk
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
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v8 19/25] HYPERCALL_version_op: Add VERSION_build_id to retrieve build-id.
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (17 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 18/25] build_id: Provide ld-embedded build-ids Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 20/25] libxl: info: Display build_id of the hypervisor using XEN_VERSION_build_id Konrad Rzeszutek Wilk
` (6 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
Cc: Wei Liu, Daniel De Graaf, Stefano Stabellini, Ian Jackson,
Konrad Rzeszutek Wilk
The VERSION hypercall provides the flexibility to expose
the size of the build-id (so the callers can allocate the
proper size before trying to retrieve it). It also allows
in one nice swoop to retrieve the hypervisor build-id in the
provided buffer.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
v4: New patch.
v5: Rebase - s/VERSION_OP/VERSION/
v6: Add Jan's Ack [provided the version_ops replacement does not need to
be reverted].
---
---
tools/flask/policy/policy/modules/xen/xen.te | 1 +
xen/common/kernel.c | 4 ++++
xen/include/public/version.h | 3 +++
xen/xsm/flask/hooks.c | 3 +++
xen/xsm/flask/policy/access_vectors | 2 ++
5 files changed, 13 insertions(+)
diff --git a/tools/flask/policy/policy/modules/xen/xen.te b/tools/flask/policy/policy/modules/xen/xen.te
index 34fcfb9..28da3bc 100644
--- a/tools/flask/policy/policy/modules/xen/xen.te
+++ b/tools/flask/policy/policy/modules/xen/xen.te
@@ -83,6 +83,7 @@ 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
+ build_id
};
allow dom0_t xen_t:mmu memorymap;
diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index af2674d..14e14ad 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -474,6 +474,10 @@ DO(version_op)(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) arg,
ptr = saved_cmdline;
break;
+ case XEN_VERSION_build_id:
+ rc = xen_build_id(&ptr, &sz);
+ break;
+
default:
rc = -ENOSYS;
}
diff --git a/xen/include/public/version.h b/xen/include/public/version.h
index 78961c9..3f3238f 100644
--- a/xen/include/public/version.h
+++ b/xen/include/public/version.h
@@ -157,6 +157,9 @@ DEFINE_XEN_GUEST_HANDLE(xen_version_op_val_t);
/* arg = char[]. Contains NUL terminated utf-8 string. */
#define XEN_VERSION_commandline 9
+/* arg = void. Contains binary value of hypervisor build-id. */
+#define XEN_VERSION_build_id 10
+
#endif /* __XEN_PUBLIC_VERSION_H__ */
/*
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 14ca163..e199d57 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -1697,6 +1697,9 @@ static int flask_version_op (uint32_t op)
case XEN_VERSION_commandline:
return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
VERSION__COMMANDLINE, NULL);
+ case XEN_VERSION_build_id:
+ return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
+ VERSION__BUILD_ID, NULL);
default:
return -EPERM;
}
diff --git a/xen/xsm/flask/policy/access_vectors b/xen/xsm/flask/policy/access_vectors
index 6c0ce7c..a1e40e6 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -540,4 +540,6 @@ class version
guest_handle
# Xen command line.
commandline
+# Build id of the hypervisor
+ 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] 32+ messages in thread
* [PATCH v8 20/25] libxl: info: Display build_id of the hypervisor using XEN_VERSION_build_id
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (18 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 19/25] HYPERCALL_version_op: Add VERSION_build_id to retrieve build-id Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 21/25] xsplice: Print build_id in keyhandler and on bootup Konrad Rzeszutek Wilk
` (5 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
Cc: Wei Liu, Stefano Stabellini, 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>
Acked-by: Wei Liu <wei.liu2@citrix.com>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@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!
---
---
tools/libxl/libxl.c | 18 ++++++++++++++++--
tools/libxl/libxl.h | 6 ++++++
tools/libxl/libxl_types.idl | 1 +
tools/libxl/xl_cmdimpl.c | 1 +
4 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index d232473..ab6acac 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -5374,6 +5374,7 @@ const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx)
GC_INIT(ctx);
char *buf;
xen_version_op_val_t val = 0;
+ int r;
libxl_version_info *info = &ctx->version_info;
if (info->xen_version_extra != NULL)
@@ -5416,8 +5417,21 @@ const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx)
info->virt_start = val;
- (void)libxl__xc_version_wrapper(gc, XEN_VERSION_commandline, buf,
- info->pagesize, &info->commandline);
+ if (libxl__xc_version_wrapper(gc, XEN_VERSION_commandline, buf,
+ info->pagesize, &info->commandline) < 0)
+ goto out;
+
+ r = xc_version(ctx->xch, XEN_VERSION_build_id, buf, info->pagesize);
+ if (r < 0) {
+ info->build_id = libxl__strdup(NOGC, "");
+ } else 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", buf[i]);
+ }
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] 32+ messages in thread
* [PATCH v8 21/25] xsplice: Print build_id in keyhandler and on bootup.
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (19 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 20/25] libxl: info: Display build_id of the hypervisor using XEN_VERSION_build_id Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 22/25] xsplice: Stacking build-id dependency checking Konrad Rzeszutek Wilk
` (4 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v8 22/25] xsplice: Stacking build-id dependency checking.
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (20 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 21/25] xsplice: Print build_id in keyhandler and on bootup Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 23/25] xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE Konrad Rzeszutek Wilk
` (3 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* [PATCH v8 23/25] xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (21 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 22/25] xsplice: Stacking build-id dependency checking Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 24/25] xsplice: Prevent duplicate payloads from being loaded Konrad Rzeszutek Wilk
` (2 subsequent siblings)
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v8 24/25] xsplice: Prevent duplicate payloads from being loaded.
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (22 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 23/25] xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 25/25] MAINTAINERS/xsplice: Add myself and Ross as the maintainers Konrad Rzeszutek Wilk
2016-04-13 21:57 ` [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v8 25/25] MAINTAINERS/xsplice: Add myself and Ross as the maintainers.
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (23 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 24/25] xsplice: Prevent duplicate payloads from being loaded Konrad Rzeszutek Wilk
@ 2016-04-13 21:09 ` Konrad Rzeszutek Wilk
2016-04-13 21:57 ` [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
25 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:09 UTC (permalink / raw)
To: konrad, xen-devel, sasha.levin, andrew.cooper3, ross.lagerwall, mpohlack
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] 32+ messages in thread
* Re: [PATCH v8] xSplice v1 design and implementation.
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
` (24 preceding siblings ...)
2016-04-13 21:09 ` [PATCH v8 25/25] MAINTAINERS/xsplice: Add myself and Ross as the maintainers Konrad Rzeszutek Wilk
@ 2016-04-13 21:57 ` Konrad Rzeszutek Wilk
2016-04-13 22:01 ` Konrad Rzeszutek Wilk
25 siblings, 1 reply; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 21:57 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: Andrew Cooper, xen.org, Martin Pohlack, Ross Lagerwall,
Julien Grall, Jan Beulich, sasha.levin, Xen-devel
> *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.
>
$#@@#A@!
As you can see this cover letter has no relation to the patches! This
mentions 27 patches while this
patchbomb has 25.
When I did git format-patch I did it in one directory while in another
shell I did git send-email (and of course in a different directory).
My sincere apologies for doing this - resending the _proper_ patchset as v8.1
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^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v8] xSplice v1 design and implementation.
2016-04-13 21:57 ` [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
@ 2016-04-13 22:01 ` Konrad Rzeszutek Wilk
0 siblings, 0 replies; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-13 22:01 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: Andrew Cooper, xen.org, Martin Pohlack, Ross Lagerwall,
Julien Grall, Jan Beulich, sasha.levin, Xen-devel
>
> $#@@#A@!
>
> As you can see this cover letter has no relation to the patches! This
> mentions 27 patches while this
> patchbomb has 25.
>
> When I did git format-patch I did it in one directory while in another
> shell I did git send-email (and of course in a different directory).
>
> My sincere apologies for doing this - resending the _proper_ patchset as v8.1
The difference between 8 and 8.1 is that v8 had:
2db214e libxl: info: Display build_id of the hypervisor using
XEN_VERSION_build_id
3f576af HYPERCALL_version_op: Add VERSION_build_id to retrieve build-id.
while v8.1 has:
b7645b7 Revert "HYPERCALL_version_op. New hypercall mirroring XENVER_ but sane."
9c0b76f Revert "libxc/libxl/python/xenstat/ocaml: Use new XEN_VERSION hypercall"
769362b libxl: info: Display build_id of the hypervisor.
151f3d2 XENVER_build_id/libxc: Provide ld-embedded build-id
The rest of the patches are the same.
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^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v8 02/25] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op
2016-04-13 21:09 ` [PATCH v8 02/25] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op Konrad Rzeszutek Wilk
@ 2016-04-20 13:18 ` Ross Lagerwall
2016-04-22 18:06 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 32+ messages in thread
From: Ross Lagerwall @ 2016-04-20 13:18 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk, konrad, xen-devel, sasha.levin,
andrew.cooper3, mpohlack
Cc: Wei Liu, Daniel De Graaf, Stefano Stabellini, Ian Jackson
On 04/13/2016 10:09 PM, Konrad Rzeszutek Wilk wrote:
snip
> +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);
> + }
I think you need something like: rc = -EINVAL;
here. Otherwise running "xen-xsplice unload <patch>" on an applied patch
succeeds but fails to do anything.
> +
> + 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)
--
Ross Lagerwall
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^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v8 02/25] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op
2016-04-20 13:18 ` Ross Lagerwall
@ 2016-04-22 18:06 ` Konrad Rzeszutek Wilk
2016-04-25 9:03 ` Jan Beulich
0 siblings, 1 reply; 32+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-04-22 18:06 UTC (permalink / raw)
To: Ross Lagerwall
Cc: Stefano Stabellini, Wei Liu, andrew.cooper3, Ian Jackson,
mpohlack, xen-devel, sasha.levin, Daniel De Graaf
On Wed, Apr 20, 2016 at 02:18:48PM +0100, Ross Lagerwall wrote:
> On 04/13/2016 10:09 PM, Konrad Rzeszutek Wilk wrote:
> snip
> >+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);
> >+ }
>
> I think you need something like: rc = -EINVAL;
> here. Otherwise running "xen-xsplice unload <patch>" on an applied patch
> succeeds but fails to do anything.
/me nods. Fixed.
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^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v8 02/25] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op
2016-04-22 18:06 ` Konrad Rzeszutek Wilk
@ 2016-04-25 9:03 ` Jan Beulich
2016-04-25 9:13 ` Ross Lagerwall
0 siblings, 1 reply; 32+ messages in thread
From: Jan Beulich @ 2016-04-25 9:03 UTC (permalink / raw)
To: Ross Lagerwall, Konrad Rzeszutek Wilk
Cc: Stefano Stabellini, Wei Liu, andrew.cooper3, Ian Jackson,
mpohlack, sasha.levin, xen-devel, Daniel De Graaf
>>> On 22.04.16 at 20:06, <konrad.wilk@oracle.com> wrote:
> On Wed, Apr 20, 2016 at 02:18:48PM +0100, Ross Lagerwall wrote:
>> On 04/13/2016 10:09 PM, Konrad Rzeszutek Wilk wrote:
>> snip
>> >+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);
>> >+ }
>>
>> I think you need something like: rc = -EINVAL;
>> here. Otherwise running "xen-xsplice unload <patch>" on an applied patch
>> succeeds but fails to do anything.
>
> /me nods. Fixed.
I don't follow: There's no path out of the if()'s body, and a proper
error indicator gets handed to the caller via the two return
statements. Why would this need converting to -EINVAL?
Jan
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^ permalink raw reply [flat|nested] 32+ messages in thread
* Re: [PATCH v8 02/25] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op
2016-04-25 9:03 ` Jan Beulich
@ 2016-04-25 9:13 ` Ross Lagerwall
0 siblings, 0 replies; 32+ messages in thread
From: Ross Lagerwall @ 2016-04-25 9:13 UTC (permalink / raw)
To: Jan Beulich, Konrad Rzeszutek Wilk
Cc: Stefano Stabellini, Wei Liu, andrew.cooper3, Ian Jackson,
mpohlack, sasha.levin, xen-devel, Daniel De Graaf
On 04/25/2016 10:03 AM, Jan Beulich wrote:
>>>> On 22.04.16 at 20:06, <konrad.wilk@oracle.com> wrote:
>> On Wed, Apr 20, 2016 at 02:18:48PM +0100, Ross Lagerwall wrote:
>>> On 04/13/2016 10:09 PM, Konrad Rzeszutek Wilk wrote:
>>> snip
>>>> +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);
>>>> + }
>>>
>>> I think you need something like: rc = -EINVAL;
>>> here. Otherwise running "xen-xsplice unload <patch>" on an applied patch
>>> succeeds but fails to do anything.
>>
>> /me nods. Fixed.
>
> I don't follow: There's no path out of the if()'s body, and a proper
> error indicator gets handed to the caller via the two return
> statements. Why would this need converting to -EINVAL?
>
I intended that line to be inserted after the if statement to set a
default return value for the unhandled paths through the following
switch(), not to change the if().
--
Ross Lagerwall
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^ permalink raw reply [flat|nested] 32+ messages in thread
end of thread, other threads:[~2016-04-25 9:13 UTC | newest]
Thread overview: 32+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-04-13 21:09 [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 01/25] xsplice: Design document Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 02/25] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op Konrad Rzeszutek Wilk
2016-04-20 13:18 ` Ross Lagerwall
2016-04-22 18:06 ` Konrad Rzeszutek Wilk
2016-04-25 9:03 ` Jan Beulich
2016-04-25 9:13 ` Ross Lagerwall
2016-04-13 21:09 ` [PATCH v8 03/25] libxc: Implementation of XEN_XSPLICE_op in libxc Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 04/25] xen-xsplice: Tool to manipulate xsplice payloads Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 05/25] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables lookup Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 06/25] arm/x86/vmap: Add vmalloc_xen, vfree_xen and vm_init_type Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 07/25] x86/mm: Introduce modify_xen_mappings() Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 08/25] xsplice: Add helper elf routines Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 09/25] xsplice: Implement payload loading Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 10/25] xsplice: Implement support for applying/reverting/replacing patches Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 11/25] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version' Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 12/25] xsplice, symbols: Implement symbol name resolution on address Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 13/25] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 14/25] x86, xsplice: Print payload's symbol name and payload name in backtraces Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 15/25] xsplice: Add support for bug frames Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 16/25] xsplice: Add support for exception tables Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 17/25] xsplice: Add support for alternatives Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 18/25] build_id: Provide ld-embedded build-ids Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 19/25] HYPERCALL_version_op: Add VERSION_build_id to retrieve build-id Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 20/25] libxl: info: Display build_id of the hypervisor using XEN_VERSION_build_id Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 21/25] xsplice: Print build_id in keyhandler and on bootup Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 22/25] xsplice: Stacking build-id dependency checking Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 23/25] xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 24/25] xsplice: Prevent duplicate payloads from being loaded Konrad Rzeszutek Wilk
2016-04-13 21:09 ` [PATCH v8 25/25] MAINTAINERS/xsplice: Add myself and Ross as the maintainers Konrad Rzeszutek Wilk
2016-04-13 21:57 ` [PATCH v8] xSplice v1 design and implementation Konrad Rzeszutek Wilk
2016-04-13 22:01 ` Konrad Rzeszutek Wilk
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