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Commit 9b7a0325 authored by Avi Kivity's avatar Avi Kivity Committed by Linus Torvalds
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[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: default avatarAvi Kivity <avi@qumranet.com>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent da4a00f0

drivers/kvm/mmu.c

+36 −0
Original line number Diff line number Diff line
@@ -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)