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Commit bf3f8e86 authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: mmu: add missing dirty page tracking cases 



We fail to mark a page dirty in three cases:

- setting the accessed bit in a pte
- setting the dirty bit in a pte
- emulating a write into a pagetable

This fix adds the missing cases.

Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent bb648a0d

drivers/kvm/paging_tmpl.h

+13 −2
Original line number Diff line number Diff line
@@ -128,8 +128,10 @@ static int FNAME(walk_addr)(struct guest_walker *walker, 
			goto access_error;

#endif



		if (!(*ptep & PT_ACCESSED_MASK))

			*ptep |= PT_ACCESSED_MASK; 	/* avoid rmw */

		if (!(*ptep & PT_ACCESSED_MASK)) {

			mark_page_dirty(vcpu->kvm, table_gfn);

			*ptep |= PT_ACCESSED_MASK;

		}



		if (walker->level == PT_PAGE_TABLE_LEVEL) {

			walker->gfn = (*ptep & PT_BASE_ADDR_MASK)
@@ -185,6 +187,12 @@ static void FNAME(release_walker)(struct guest_walker *walker) 
		kunmap_atomic(walker->table, KM_USER0);

}



static void FNAME(mark_pagetable_dirty)(struct kvm *kvm,

					struct guest_walker *walker)

{

	mark_page_dirty(kvm, walker->table_gfn[walker->level - 1]);

}



static void FNAME(set_pte)(struct kvm_vcpu *vcpu, u64 guest_pte,

			   u64 *shadow_pte, u64 access_bits, gfn_t gfn)

{
@@ -348,12 +356,15 @@ static int FNAME(fix_write_pf)(struct kvm_vcpu *vcpu, 
	} else if (kvm_mmu_lookup_page(vcpu, gfn)) {

		pgprintk("%s: found shadow page for %lx, marking ro\n",

			 __FUNCTION__, gfn);

		mark_page_dirty(vcpu->kvm, gfn);

		FNAME(mark_pagetable_dirty)(vcpu->kvm, walker);

		*guest_ent |= PT_DIRTY_MASK;

		*write_pt = 1;

		return 0;

	}

	mark_page_dirty(vcpu->kvm, gfn);

	*shadow_ent |= PT_WRITABLE_MASK;

	FNAME(mark_pagetable_dirty)(vcpu->kvm, walker);

	*guest_ent |= PT_DIRTY_MASK;

	rmap_add(vcpu, shadow_ent);