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Subject[PATCH 1/13] KVM: mmu: add missing dirty page tracking cases
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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: Avi Kivity <avi@qumranet.com>

Index: linux-2.6/drivers/kvm/paging_tmpl.h
===================================================================
--- linux-2.6.orig/drivers/kvm/paging_tmpl.h
+++ linux-2.6/drivers/kvm/paging_tmpl.h
@@ -128,8 +128,10 @@ static int FNAME(walk_addr)(struct guest
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
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 kv
} 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);

-
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