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authorRusty Russell <rusty@rustcorp.com.au>2009-03-30 23:55:23 -0400
committerRusty Russell <rusty@rustcorp.com.au>2009-03-30 07:25:24 -0400
commitb7ff99ea53cd16de8f6166c0e98f19a7c6ca67ee (patch)
treefed5a3cf8fc8061967e60b5bbf32e81f3c742822 /arch/x86/lguest/boot.c
parent6afbdd059c27330eccbd85943354f94c2b83a7fe (diff)
lguest: wire up pte_update/pte_update_defer
Impact: intermittent guest segv/crash fix I've been seeing random guest bad address crashes and segmentation faults: bisect led to 4f98a2fee8 (vmscan: split LRU lists into anon & file sets), but that's a red herring. It turns out that lguest never hooked up the pte_update/pte_update_defer calls, so our ptes were not always in sync. After the vmscan commit, the bug became reproducible; now a fsck in a 64MB guest causes reproducible pagetable corruption. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: jeremy@xensource.com Cc: virtualization@lists.osdl.org Cc: stable@kernel.org
Diffstat (limited to 'arch/x86/lguest/boot.c')
-rw-r--r--arch/x86/lguest/boot.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index 9fe4ddaa8f6f..7822d29b02c7 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -490,11 +490,17 @@ static void lguest_write_cr4(unsigned long val)
490 * into a process' address space. We set the entry then tell the Host the 490 * into a process' address space. We set the entry then tell the Host the
491 * toplevel and address this corresponds to. The Guest uses one pagetable per 491 * toplevel and address this corresponds to. The Guest uses one pagetable per
492 * process, so we need to tell the Host which one we're changing (mm->pgd). */ 492 * process, so we need to tell the Host which one we're changing (mm->pgd). */
493static void lguest_pte_update(struct mm_struct *mm, unsigned long addr,
494 pte_t *ptep)
495{
496 lazy_hcall(LHCALL_SET_PTE, __pa(mm->pgd), addr, ptep->pte_low);
497}
498
493static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr, 499static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr,
494 pte_t *ptep, pte_t pteval) 500 pte_t *ptep, pte_t pteval)
495{ 501{
496 *ptep = pteval; 502 *ptep = pteval;
497 lazy_hcall(LHCALL_SET_PTE, __pa(mm->pgd), addr, pteval.pte_low); 503 lguest_pte_update(mm, addr, ptep);
498} 504}
499 505
500/* The Guest calls this to set a top-level entry. Again, we set the entry then 506/* The Guest calls this to set a top-level entry. Again, we set the entry then
@@ -1040,6 +1046,8 @@ __init void lguest_init(void)
1040 pv_mmu_ops.read_cr3 = lguest_read_cr3; 1046 pv_mmu_ops.read_cr3 = lguest_read_cr3;
1041 pv_mmu_ops.lazy_mode.enter = paravirt_enter_lazy_mmu; 1047 pv_mmu_ops.lazy_mode.enter = paravirt_enter_lazy_mmu;
1042 pv_mmu_ops.lazy_mode.leave = lguest_leave_lazy_mode; 1048 pv_mmu_ops.lazy_mode.leave = lguest_leave_lazy_mode;
1049 pv_mmu_ops.pte_update = lguest_pte_update;
1050 pv_mmu_ops.pte_update_defer = lguest_pte_update;
1043 1051
1044#ifdef CONFIG_X86_LOCAL_APIC 1052#ifdef CONFIG_X86_LOCAL_APIC
1045 /* apic read/write intercepts */ 1053 /* apic read/write intercepts */