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authorAvi Kivity <avi@qumranet.com>2007-01-05 19:36:45 -0500
committerLinus Torvalds <torvalds@woody.osdl.org>2007-01-06 02:55:25 -0500
commit9b7a032567ee1128daeebebfc14d3acedfe28c8c (patch)
tree292b109ec407041f26371f3cb7de12d06a636592 /drivers/kvm
parentda4a00f002239f72b0d7d0eeaa3b60100e2b1438 (diff)
[PATCH] KVM: MMU: Zap shadow page table entries on writes to guest page tables
Iterate over all shadow pages which correspond to a the given guest page table and remove the mappings. A subsequent page fault will reestablish the new mapping. Signed-off-by: Avi Kivity <avi@qumranet.com> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/kvm')
-rw-r--r--drivers/kvm/mmu.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index bce7eb21f739..6dbd83b86623 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -958,7 +958,43 @@ int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
958 958
959void kvm_mmu_pre_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes) 959void kvm_mmu_pre_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes)
960{ 960{
961 gfn_t gfn = gpa >> PAGE_SHIFT;
962 struct kvm_mmu_page *page;
963 struct kvm_mmu_page *child;
964 struct hlist_node *node;
965 struct hlist_head *bucket;
966 unsigned index;
967 u64 *spte;
968 u64 pte;
969 unsigned offset = offset_in_page(gpa);
970 unsigned page_offset;
971 int level;
972
961 pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes); 973 pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes);
974 index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
975 bucket = &vcpu->kvm->mmu_page_hash[index];
976 hlist_for_each_entry(page, node, bucket, hash_link) {
977 if (page->gfn != gfn || page->role.metaphysical)
978 continue;
979 page_offset = offset;
980 level = page->role.level;
981 if (page->role.glevels == PT32_ROOT_LEVEL) {
982 page_offset <<= 1; /* 32->64 */
983 page_offset &= ~PAGE_MASK;
984 }
985 spte = __va(page->page_hpa);
986 spte += page_offset / sizeof(*spte);
987 pte = *spte;
988 if (is_present_pte(pte)) {
989 if (level == PT_PAGE_TABLE_LEVEL)
990 rmap_remove(vcpu->kvm, spte);
991 else {
992 child = page_header(pte & PT64_BASE_ADDR_MASK);
993 mmu_page_remove_parent_pte(child, spte);
994 }
995 }
996 *spte = 0;
997 }
962} 998}
963 999
964void kvm_mmu_post_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes) 1000void kvm_mmu_post_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes)