diff options
| author | Avi Kivity <avi@qumranet.com> | 2007-01-05 16:36:45 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.osdl.org> | 2007-01-05 23:55:25 -0800 |
| commit | 9b7a032567ee1128daeebebfc14d3acedfe28c8c (patch) | |
| tree | 292b109ec407041f26371f3cb7de12d06a636592 | |
| parent | da4a00f002239f72b0d7d0eeaa3b60100e2b1438 (diff) | |
| download | lwn-9b7a032567ee1128daeebebfc14d3acedfe28c8c.tar.gz lwn-9b7a032567ee1128daeebebfc14d3acedfe28c8c.zip | |
[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.c | 36 |
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) |