KVM: MMU: move audit to a separate file

Move the audit code from arch/x86/kvm/mmu.c to arch/x86/kvm/mmu_audit.c

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 297 insertions, 0 deletions

diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c
new file mode 100644
index 000000000000..fb8a461333c5
--- /dev/null
+++ b/arch/x86/kvm/mmu_audit.c
@@ -0,0 +1,297 @@
+/*
+ * mmu_audit.c:
+ *
+ * Audit code for KVM MMU
+ *
+ * Copyright (C) 2006 Qumranet, Inc.
+ * Copyright 2010 Red Hat, Inc. and/or its affilates.
+ *
+ * Authors:
+ *   Yaniv Kamay  <yaniv@qumranet.com>
+ *   Avi Kivity   <avi@qumranet.com>
+ *   Marcelo Tosatti <mtosatti@redhat.com>
+ *   Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+static const char *audit_msg;
+
+typedef void (*inspect_spte_fn) (struct kvm *kvm, u64 *sptep);
+
+static void __mmu_spte_walk(struct kvm *kvm, struct kvm_mmu_page *sp,
+			    inspect_spte_fn fn)
+{
+	int i;
+
+	for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
+		u64 ent = sp->spt[i];
+
+		if (is_shadow_present_pte(ent)) {
+			if (!is_last_spte(ent, sp->role.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]);
+		}
+	}
+}
+
+static void mmu_spte_walk(struct kvm_vcpu *vcpu, inspect_spte_fn fn)
+{
+	int i;
+	struct kvm_mmu_page *sp;
+
+	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);
+		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);
+		}
+	}
+	return;
+}
+
+static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
+				gva_t va, 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;
+		hpa_t hpa;
+
+		sp = page_header(__pa(sptep));
+
+		if (sp->unsync) {
+			if (level != PT_PAGE_TABLE_LEVEL) {
+				printk(KERN_ERR "audit: (%s) error: unsync sp: %p level = %d\n",
+						audit_msg, sp, level);
+				return;
+			}
+
+			if (*sptep == shadow_notrap_nonpresent_pte) {
+				printk(KERN_ERR "audit: (%s) error: notrap spte in unsync sp: %p\n",
+						audit_msg, sp);
+				return;
+			}
+		}
+
+		if (sp->role.direct && *sptep == shadow_notrap_nonpresent_pte) {
+			printk(KERN_ERR "audit: (%s) error: notrap spte in direct sp: %p\n",
+					audit_msg, sp);
+			return;
+		}
+
+		if (!is_shadow_present_pte(*sptep) ||
+		      !is_last_spte(*sptep, level))
+			return;
+
+		gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt);
+		pfn = gfn_to_pfn_atomic(vcpu->kvm, gfn);
+
+		if (is_error_pfn(pfn)) {
+			kvm_release_pfn_clean(pfn);
+			return;
+		}
+
+		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",
+					   audit_msg, vcpu->arch.mmu.root_level,
+					   va, 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)
+{
+	unsigned long *rmapp;
+	struct kvm_mmu_page *rev_sp;
+	gfn_t gfn;
+
+
+	rev_sp = page_header(__pa(sptep));
+	gfn = kvm_mmu_page_get_gfn(rev_sp, sptep - rev_sp->spt);
+
+	if (!gfn_to_memslot(kvm, gfn)) {
+		if (!printk_ratelimit())
+			return;
+		printk(KERN_ERR "%s: no memslot for gfn %llx\n",
+				 audit_msg, gfn);
+		printk(KERN_ERR "%s: index %ld of sp (gfn=%llx)\n",
+		       audit_msg, (long int)(sptep - rev_sp->spt),
+				rev_sp->gfn);
+		dump_stack();
+		return;
+	}
+
+	rmapp = gfn_to_rmap(kvm, gfn, rev_sp->role.level);
+	if (!*rmapp) {
+		if (!printk_ratelimit())
+			return;
+		printk(KERN_ERR "%s: no rmap for writable spte %llx\n",
+				 audit_msg, *sptep);
+		dump_stack();
+	}
+}
+
+void audit_sptes_have_rmaps(struct kvm_vcpu *vcpu)
+{
+	mmu_spte_walk(vcpu, inspect_spte_has_rmap);
+}
+
+static void check_mappings_rmap(struct kvm_vcpu *vcpu)
+{
+	struct kvm_mmu_page *sp;
+	int i;
+
+	list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
+		u64 *pt = sp->spt;
+
+		if (sp->role.level != PT_PAGE_TABLE_LEVEL)
+			continue;
+
+		for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
+			if (!is_rmap_spte(pt[i]))
+				continue;
+
+			inspect_spte_has_rmap(vcpu->kvm, &pt[i]);
+		}
+	}
+	return;
+}
+
+static void audit_rmap(struct kvm_vcpu *vcpu)
+{
+	check_mappings_rmap(vcpu);
+}
+
+static void audit_write_protection(struct kvm_vcpu *vcpu)
+{
+	struct kvm_mmu_page *sp;
+	struct kvm_memory_slot *slot;
+	unsigned long *rmapp;
+	u64 *spte;
+
+	list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
+		if (sp->role.direct)
+			continue;
+		if (sp->unsync)
+			continue;
+		if (sp->role.invalid)
+			continue;
+
+		slot = gfn_to_memslot(vcpu->kvm, sp->gfn);
+		rmapp = &slot->rmap[sp->gfn - slot->base_gfn];
+
+		spte = rmap_next(vcpu->kvm, rmapp, NULL);
+		while (spte) {
+			if (is_writable_pte(*spte))
+				printk(KERN_ERR "%s: (%s) shadow page has "
+				"writable mappings: gfn %llx role %x\n",
+			       __func__, audit_msg, sp->gfn,
+			       sp->role.word);
+			spte = rmap_next(vcpu->kvm, rmapp, spte);
+		}
+	}
+}
+
+static void kvm_mmu_audit(void *ignore, struct kvm_vcpu *vcpu, int audit_point)
+{
+	audit_msg = audit_point_name[audit_point];
+	audit_rmap(vcpu);
+	audit_write_protection(vcpu);
+	if (strcmp("pre pte write", audit_msg) != 0)
+		audit_mappings(vcpu);
+	audit_sptes_have_rmaps(vcpu);
+}
+
+static bool mmu_audit;
+
+static void mmu_audit_enable(void)
+{
+	int ret;
+
+	if (mmu_audit)
+		return;
+
+	ret = register_trace_kvm_mmu_audit(kvm_mmu_audit, NULL);
+	WARN_ON(ret);
+
+	mmu_audit = true;
+}
+
+static void mmu_audit_disable(void)
+{
+	if (!mmu_audit)
+		return;
+
+	unregister_trace_kvm_mmu_audit(kvm_mmu_audit, NULL);
+	tracepoint_synchronize_unregister();
+	mmu_audit = false;
+}
+
+static int mmu_audit_set(const char *val, const struct kernel_param *kp)
+{
+	int ret;
+	unsigned long enable;
+
+	ret = strict_strtoul(val, 10, &enable);
+	if (ret < 0)
+		return -EINVAL;
+
+	switch (enable) {
+	case 0:
+		mmu_audit_disable();
+		break;
+	case 1:
+		mmu_audit_enable();
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static struct kernel_param_ops audit_param_ops = {
+	.set = mmu_audit_set,
+	.get = param_get_bool,
+};
+
+module_param_cb(mmu_audit, &audit_param_ops, &mmu_audit, 0644);