---

yaml
---
r: 80632
b: refs/heads/master
c: 12b7d28
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c7addb902054195b995114df154e061c7d604f69
+refs/heads/master: 12b7d28fc102b772eb70f98491587ec5ee717baf

trunk/drivers/kvm/kvm.h

@@ -346,6 +346,7 @@ struct kvm_vcpu {
 
 	gfn_t last_pt_write_gfn;
 	int   last_pt_write_count;
+	u64  *last_pte_updated;
 
 	struct kvm_guest_debug guest_debug;
 

trunk/drivers/kvm/mmu.c

@@ -692,6 +692,15 @@ static void kvm_mmu_put_page(struct kvm_mmu_page *page,
 	mmu_page_remove_parent_pte(page, parent_pte);
 }
 
+static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
+{
+	int i;
+
+	for (i = 0; i < KVM_MAX_VCPUS; ++i)
+		if (kvm->vcpus[i])
+			kvm->vcpus[i]->last_pte_updated = NULL;
+}
+
 static void kvm_mmu_zap_page(struct kvm *kvm,
 			     struct kvm_mmu_page *page)
 {
@@ -717,6 +726,7 @@ static void kvm_mmu_zap_page(struct kvm *kvm,
 		kvm_mmu_free_page(kvm, page);
 	} else
 		list_move(&page->link, &kvm->active_mmu_pages);
+	kvm_mmu_reset_last_pte_updated(kvm);
 }
 
 static int kvm_mmu_unprotect_page(struct kvm_vcpu *vcpu, gfn_t gfn)
@@ -1140,6 +1150,13 @@ static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
 				    offset_in_pte);
 }
 
+static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
+{
+	u64 *spte = vcpu->last_pte_updated;
+
+	return !!(spte && (*spte & PT_ACCESSED_MASK));
+}
+
 void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 		       const u8 *new, int bytes)
 {
@@ -1160,13 +1177,15 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 
 	pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes);
 	kvm_mmu_audit(vcpu, "pre pte write");
-	if (gfn == vcpu->last_pt_write_gfn) {
+	if (gfn == vcpu->last_pt_write_gfn
+	    && !last_updated_pte_accessed(vcpu)) {
 		++vcpu->last_pt_write_count;
 		if (vcpu->last_pt_write_count >= 3)
 			flooded = 1;
 	} else {
 		vcpu->last_pt_write_gfn = gfn;
 		vcpu->last_pt_write_count = 1;
+		vcpu->last_pte_updated = NULL;
 	}
 	index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
 	bucket = &vcpu->kvm->mmu_page_hash[index];

trunk/drivers/kvm/paging_tmpl.h

@@ -238,7 +238,12 @@ static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu,
 		FNAME(mark_pagetable_dirty)(vcpu->kvm, walker);
 	}
 
-	spte = PT_PRESENT_MASK | PT_ACCESSED_MASK | PT_DIRTY_MASK;
+	/*
+	 * We don't set the accessed bit, since we sometimes want to see
+	 * whether the guest actually used the pte (in order to detect
+	 * demand paging).
+	 */
+	spte = PT_PRESENT_MASK | PT_DIRTY_MASK;
 	spte |= gpte & PT64_NX_MASK;
 	if (!dirty)
 		access_bits &= ~PT_WRITABLE_MASK;
@@ -291,6 +296,8 @@ static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu,
 	page_header_update_slot(vcpu->kvm, shadow_pte, gaddr);
 	if (!was_rmapped)
 		rmap_add(vcpu, shadow_pte);
+	if (!ptwrite || !*ptwrite)
+		vcpu->last_pte_updated = shadow_pte;
 }
 
 static void FNAME(set_pte)(struct kvm_vcpu *vcpu, pt_element_t gpte,