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authorAvi Kivity <avi@qumranet.com>2007-01-06 03:36:45 +0300
committerLinus Torvalds <torvalds@woody.osdl.org>2007-01-06 10:55:25 +0300
commit9b7a032567ee1128daeebebfc14d3acedfe28c8c (patch)
tree292b109ec407041f26371f3cb7de12d06a636592
parentda4a00f002239f72b0d7d0eeaa3b60100e2b1438 (diff)
downloadlinux-sunxi-9b7a032567ee1128daeebebfc14d3acedfe28c8c.tar.xz
[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>
-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)
void kvm_mmu_pre_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes)
{
+ gfn_t gfn = gpa >> PAGE_SHIFT;
+ struct kvm_mmu_page *page;
+ struct kvm_mmu_page *child;
+ struct hlist_node *node;
+ struct hlist_head *bucket;
+ unsigned index;
+ u64 *spte;
+ u64 pte;
+ unsigned offset = offset_in_page(gpa);
+ unsigned page_offset;
+ int level;
+
pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes);
+ index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
+ bucket = &vcpu->kvm->mmu_page_hash[index];
+ hlist_for_each_entry(page, node, bucket, hash_link) {
+ if (page->gfn != gfn || page->role.metaphysical)
+ continue;
+ page_offset = offset;
+ level = page->role.level;
+ if (page->role.glevels == PT32_ROOT_LEVEL) {
+ page_offset <<= 1; /* 32->64 */
+ page_offset &= ~PAGE_MASK;
+ }
+ spte = __va(page->page_hpa);
+ spte += page_offset / sizeof(*spte);
+ pte = *spte;
+ if (is_present_pte(pte)) {
+ if (level == PT_PAGE_TABLE_LEVEL)
+ rmap_remove(vcpu->kvm, spte);
+ else {
+ child = page_header(pte & PT64_BASE_ADDR_MASK);
+ mmu_page_remove_parent_pte(child, spte);
+ }
+ }
+ *spte = 0;
+ }
}
void kvm_mmu_post_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes)