From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: konrad@kernel.org, xen-devel@lists.xenproject.org,
sasha.levin@oracle.com, andrew.cooper3@citrix.com,
ross.lagerwall@citrix.com, mpohlack@amazon.de
Cc: George Dunlap <george.dunlap@eu.citrix.com>,
Jan Beulich <JBeulich@suse.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: [PATCH v9 09/27] x86/mm: Introduce modify_xen_mappings()
Date: Mon, 25 Apr 2016 11:34:56 -0400 [thread overview]
Message-ID: <1461598514-5440-10-git-send-email-konrad.wilk@oracle.com> (raw)
In-Reply-To: <1461598514-5440-1-git-send-email-konrad.wilk@oracle.com>
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 changing 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.
v9: Add missing second 'are'.
---
---
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 633f0dc..2bb920b 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 are not destroying mappings, or not done with the L2E,
+ * skip the empty&free check.
+ */
+ if ( (nf & _PAGE_PRESENT) || ((v != e) && (l1_table_offset(v) != 0)) )
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
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next prev parent reply other threads:[~2016-04-25 15:36 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-25 15:34 [PATCH 9] xSplice v1 design and implementation Konrad Rzeszutek Wilk
2016-04-25 15:34 ` [PATCH v9 01/27] Revert "libxc/libxl/python/xenstat/ocaml: Use new XEN_VERSION hypercall" Konrad Rzeszutek Wilk
2016-04-25 15:48 ` Jan Beulich
2016-04-25 15:53 ` Wei Liu
2016-04-25 15:34 ` [PATCH v9 02/27] Revert "HYPERCALL_version_op. New hypercall mirroring XENVER_ but sane." Konrad Rzeszutek Wilk
2016-04-25 15:34 ` [PATCH v9 03/27] xsplice: Design document Konrad Rzeszutek Wilk
2016-04-25 15:34 ` [PATCH v9 04/27] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op Konrad Rzeszutek Wilk
2016-04-26 7:48 ` Ross Lagerwall
2016-04-26 7:52 ` Ross Lagerwall
2016-04-26 10:21 ` Jan Beulich
2016-04-26 17:50 ` Konrad Rzeszutek Wilk
2016-04-27 6:51 ` Jan Beulich
2016-04-27 13:47 ` Konrad Rzeszutek Wilk
2016-04-27 14:11 ` Jan Beulich
2016-04-25 15:34 ` [PATCH v9 05/27] libxc: Implementation of XEN_XSPLICE_op in libxc Konrad Rzeszutek Wilk
2016-04-26 7:51 ` Ross Lagerwall
2016-04-25 15:34 ` [PATCH v9 06/27] xen-xsplice: Tool to manipulate xsplice payloads Konrad Rzeszutek Wilk
2016-04-26 7:49 ` Ross Lagerwall
2016-04-25 15:34 ` [PATCH v9 07/27] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables lookup Konrad Rzeszutek Wilk
2016-04-26 10:31 ` Jan Beulich
2016-04-25 15:34 ` [PATCH v9 08/27] arm/x86/vmap: Add v[z|m]alloc_xen and vm_init_type Konrad Rzeszutek Wilk
2016-04-26 10:47 ` Jan Beulich
2016-04-27 2:38 ` Konrad Rzeszutek Wilk
2016-04-27 7:12 ` Jan Beulich
2016-04-27 13:46 ` Konrad Rzeszutek Wilk
2016-04-27 14:15 ` Jan Beulich
2016-04-25 15:34 ` Konrad Rzeszutek Wilk [this message]
2016-04-25 15:34 ` [PATCH v9 10/27] xsplice: Add helper elf routines Konrad Rzeszutek Wilk
2016-04-26 10:05 ` Ross Lagerwall
2016-04-26 11:52 ` Jan Beulich
2016-04-26 12:37 ` Jan Beulich
2016-04-27 1:59 ` Konrad Rzeszutek Wilk
2016-04-27 7:27 ` Jan Beulich
2016-04-27 14:00 ` Konrad Rzeszutek Wilk
2016-04-27 4:06 ` Konrad Rzeszutek Wilk
2016-04-27 7:52 ` Jan Beulich
2016-04-27 18:45 ` Konrad Rzeszutek Wilk
2016-04-25 15:34 ` [PATCH v9 11/27] xsplice: Implement payload loading Konrad Rzeszutek Wilk
2016-04-26 10:48 ` Ross Lagerwall
2016-04-26 13:39 ` Jan Beulich
2016-04-27 1:47 ` Konrad Rzeszutek Wilk
2016-04-27 7:57 ` Jan Beulich
2016-04-27 3:28 ` Konrad Rzeszutek Wilk
2016-04-27 8:28 ` Jan Beulich
2016-04-27 15:48 ` Konrad Rzeszutek Wilk
2016-04-27 16:06 ` Jan Beulich
2016-04-27 16:14 ` Jan Beulich
2016-04-27 18:40 ` Konrad Rzeszutek Wilk
2016-04-25 15:34 ` [PATCH v9 12/27] xsplice: Implement support for applying/reverting/replacing patches Konrad Rzeszutek Wilk
2016-04-26 15:21 ` Jan Beulich
2016-04-27 3:39 ` Konrad Rzeszutek Wilk
2016-04-27 8:36 ` Jan Beulich
2016-05-11 9:51 ` Martin Pohlack
2016-05-11 13:56 ` Konrad Rzeszutek Wilk
2016-04-25 15:35 ` [PATCH v9 13/27] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version' Konrad Rzeszutek Wilk
2016-04-26 15:31 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 14/27] xsplice, symbols: Implement symbol name resolution on address Konrad Rzeszutek Wilk
2016-04-26 15:48 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 15/27] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup Konrad Rzeszutek Wilk
2016-04-26 15:53 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 16/27] x86, xsplice: Print payload's symbol name and payload name in backtraces Konrad Rzeszutek Wilk
2016-04-26 11:06 ` Ross Lagerwall
2016-04-26 12:41 ` Jan Beulich
2016-04-26 12:48 ` Ross Lagerwall
2016-04-26 13:41 ` Jan Beulich
2016-04-27 3:31 ` Konrad Rzeszutek Wilk
2016-04-27 8:37 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 17/27] xsplice: Add support for bug frames Konrad Rzeszutek Wilk
2016-04-26 11:05 ` Ross Lagerwall
2016-04-26 13:08 ` Ross Lagerwall
2016-04-26 15:58 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 18/27] xsplice: Add support for exception tables Konrad Rzeszutek Wilk
2016-04-26 16:01 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 19/27] xsplice: Add support for alternatives Konrad Rzeszutek Wilk
2016-04-27 8:58 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 20/27] build_id: Provide ld-embedded build-ids Konrad Rzeszutek Wilk
2016-04-25 15:35 ` [PATCH v9 21/27] xsplice: Print build_id in keyhandler and on bootup Konrad Rzeszutek Wilk
2016-04-25 15:35 ` [PATCH v9 22/27] XENVER_build_id/libxc: Provide ld-embedded build-id Konrad Rzeszutek Wilk
2016-04-25 15:35 ` [PATCH v9 23/27] libxl: info: Display build_id of the hypervisor Konrad Rzeszutek Wilk
2016-04-25 15:35 ` [PATCH v9 24/27] xsplice: Stacking build-id dependency checking Konrad Rzeszutek Wilk
2016-04-27 9:27 ` Jan Beulich
2016-04-27 16:36 ` Konrad Rzeszutek Wilk
2016-04-28 9:47 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 25/27] xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE Konrad Rzeszutek Wilk
2016-04-25 15:35 ` [PATCH v9 26/27] xsplice: Prevent duplicate payloads from being loaded Konrad Rzeszutek Wilk
2016-04-27 9:31 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 27/27] MAINTAINERS/xsplice: Add myself and Ross as the maintainers Konrad Rzeszutek Wilk
2016-04-25 15:41 ` [PATCH 9] xSplice v1 design and implementation Jan Beulich
2016-04-25 15:47 ` Konrad Rzeszutek Wilk
2016-04-25 15:54 ` Jan Beulich
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