KVM: MMU: improve spte audit

Both audit_mappings() and audit_sptes_have_rmaps() need to walk vcpu's page
table, so we can do these checking in a spte walking
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/mmu_audit.c

@@ -19,23 +19,24 @@
 
 static const char *audit_msg;
 
-typedef void (*inspect_spte_fn) (struct kvm *kvm, u64 *sptep);
+typedef void (*inspect_spte_fn) (struct kvm_vcpu *vcpu, u64 *sptep, int level);
 
-static void __mmu_spte_walk(struct kvm *kvm, struct kvm_mmu_page *sp,
-			    inspect_spte_fn fn)
+static void __mmu_spte_walk(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
+			    inspect_spte_fn fn, int level)
 {
 	int i;
 
 	for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
-		u64 ent = sp->spt[i];
+		u64 *ent = sp->spt;
 
-		if (is_shadow_present_pte(ent)) {
-			if (!is_last_spte(ent, sp->role.level)) {
+		fn(vcpu, ent + i, level);
+
+		if (is_shadow_present_pte(ent[i]) &&
+		      !is_last_spte(ent[i], level)) {
 			struct kvm_mmu_page *child;
-				child = page_header(ent & PT64_BASE_ADDR_MASK);
-				__mmu_spte_walk(kvm, child, fn);
-			} else
-				fn(kvm, &sp->spt[i]);
+
+			child = page_header(ent[i] & PT64_BASE_ADDR_MASK);
+			__mmu_spte_walk(vcpu, child, fn, level - 1);
 		}
 	}
 }
@@ -47,21 +48,25 @@ static void mmu_spte_walk(struct kvm_vcpu *vcpu, inspect_spte_fn fn)
 
 	if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
 		return;
+
 	if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
 		hpa_t root = vcpu->arch.mmu.root_hpa;
+
 		sp = page_header(root);
-		__mmu_spte_walk(vcpu->kvm, sp, fn);
+		__mmu_spte_walk(vcpu, sp, fn, PT64_ROOT_LEVEL);
 		return;
 	}
+
 	for (i = 0; i < 4; ++i) {
 		hpa_t root = vcpu->arch.mmu.pae_root[i];
 
 		if (root && VALID_PAGE(root)) {
 			root &= PT64_BASE_ADDR_MASK;
 			sp = page_header(root);
-			__mmu_spte_walk(vcpu->kvm, sp, fn);
+			__mmu_spte_walk(vcpu, sp, fn, 2);
 		}
 	}
+
 	return;
 }
 
@@ -75,15 +80,8 @@ static void walk_all_active_sps(struct kvm *kvm, sp_handler fn)
 		fn(kvm, sp);
 }
 
-static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
-				gva_t va, int level)
+static void audit_mappings(struct kvm_vcpu *vcpu, u64 *sptep, int level)
 {
-	u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
-	int i;
-	gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
-
-	for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
-		u64 *sptep = pt + i;
 	struct kvm_mmu_page *sp;
 	gfn_t gfn;
 	pfn_t pfn;
@@ -111,8 +109,7 @@ static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
 		return;
 	}
 
-		if (!is_shadow_present_pte(*sptep) ||
-		      !is_last_spte(*sptep, level))
+	if (!is_shadow_present_pte(*sptep) || !is_last_spte(*sptep, level))
 		return;
 
 	gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt);
@@ -124,31 +121,14 @@ static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
 	}
 
 	hpa =  pfn << PAGE_SHIFT;
-
 	if ((*sptep & PT64_BASE_ADDR_MASK) != hpa)
 		printk(KERN_ERR "xx audit error: (%s) levels %d"
-					   " gva %lx pfn %llx hpa %llx ent %llxn",
+				   "pfn %llx hpa %llx ent %llxn",
 				   audit_msg, vcpu->arch.mmu.root_level,
-					   va, pfn, hpa, *sptep);
-	}
+				   pfn, hpa, *sptep);
 }
 
-static void audit_mappings(struct kvm_vcpu *vcpu)
-{
-	unsigned i;
-
-	if (vcpu->arch.mmu.root_level == 4)
-		audit_mappings_page(vcpu, vcpu->arch.mmu.root_hpa, 0, 4);
-	else
-		for (i = 0; i < 4; ++i)
-			if (vcpu->arch.mmu.pae_root[i] & PT_PRESENT_MASK)
-				audit_mappings_page(vcpu,
-						    vcpu->arch.mmu.pae_root[i],
-						    i << 30,
-						    2);
-}
-
-void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep)
+static void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep)
 {
 	unsigned long *rmapp;
 	struct kvm_mmu_page *rev_sp;
@@ -180,9 +160,10 @@ void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep)
 	}
 }
 
-void audit_sptes_have_rmaps(struct kvm_vcpu *vcpu)
+static void audit_sptes_have_rmaps(struct kvm_vcpu *vcpu, u64 *sptep, int level)
 {
-	mmu_spte_walk(vcpu, inspect_spte_has_rmap);
+	if (is_shadow_present_pte(*sptep) && is_last_spte(*sptep, level))
+		inspect_spte_has_rmap(vcpu->kvm, sptep);
 }
 
 static void check_mappings_rmap(struct kvm *kvm, struct kvm_mmu_page *sp)
@@ -234,13 +215,22 @@ static void audit_all_active_sps(struct kvm *kvm)
 	walk_all_active_sps(kvm, audit_sp);
 }
 
+static void audit_spte(struct kvm_vcpu *vcpu, u64 *sptep, int level)
+{
+	audit_sptes_have_rmaps(vcpu, sptep, level);
+	audit_mappings(vcpu, sptep, level);
+}
+
+static void audit_vcpu_spte(struct kvm_vcpu *vcpu)
+{
+	mmu_spte_walk(vcpu, audit_spte);
+}
+
 static void kvm_mmu_audit(void *ignore, struct kvm_vcpu *vcpu, int audit_point)
 {
 	audit_msg = audit_point_name[audit_point];
 	audit_all_active_sps(vcpu->kvm);
-	if (strcmp("pre pte write", audit_msg) != 0)
-		audit_mappings(vcpu);
-	audit_sptes_have_rmaps(vcpu);
+	audit_vcpu_spte(vcpu);
 }
 
 static bool mmu_audit;