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@@ -0,0 +1,297 @@
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+/*
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+ * mmu_audit.c:
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+ *
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+ * Audit code for KVM MMU
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+ *
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+ * Copyright (C) 2006 Qumranet, Inc.
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+ * Copyright 2010 Red Hat, Inc. and/or its affilates.
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+ *
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+ * Authors:
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+ * Yaniv Kamay <yaniv@qumranet.com>
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+ * Avi Kivity <avi@qumranet.com>
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+ * Marcelo Tosatti <mtosatti@redhat.com>
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+ * Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
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+ *
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+ * This work is licensed under the terms of the GNU GPL, version 2. See
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+ * the COPYING file in the top-level directory.
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+ *
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+ */
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+
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+static const char *audit_msg;
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+
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+typedef void (*inspect_spte_fn) (struct kvm *kvm, u64 *sptep);
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+
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+static void __mmu_spte_walk(struct kvm *kvm, struct kvm_mmu_page *sp,
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+ inspect_spte_fn fn)
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+{
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+ int i;
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+
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+ for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
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+ u64 ent = sp->spt[i];
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+
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+ if (is_shadow_present_pte(ent)) {
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+ if (!is_last_spte(ent, sp->role.level)) {
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+ struct kvm_mmu_page *child;
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+ child = page_header(ent & PT64_BASE_ADDR_MASK);
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+ __mmu_spte_walk(kvm, child, fn);
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+ } else
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+ fn(kvm, &sp->spt[i]);
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+ }
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+ }
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+}
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+
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+static void mmu_spte_walk(struct kvm_vcpu *vcpu, inspect_spte_fn fn)
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+{
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+ int i;
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+ struct kvm_mmu_page *sp;
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+
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+ if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
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+ return;
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+ if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
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+ hpa_t root = vcpu->arch.mmu.root_hpa;
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+ sp = page_header(root);
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+ __mmu_spte_walk(vcpu->kvm, sp, fn);
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+ return;
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+ }
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+ for (i = 0; i < 4; ++i) {
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+ hpa_t root = vcpu->arch.mmu.pae_root[i];
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+
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+ if (root && VALID_PAGE(root)) {
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+ root &= PT64_BASE_ADDR_MASK;
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+ sp = page_header(root);
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+ __mmu_spte_walk(vcpu->kvm, sp, fn);
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+ }
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+ }
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+ return;
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+}
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+
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+static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
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+ gva_t va, int level)
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+{
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+ u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
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+ int i;
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+ gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
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+
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+ for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
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+ u64 *sptep = pt + i;
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+ struct kvm_mmu_page *sp;
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+ gfn_t gfn;
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+ pfn_t pfn;
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+ hpa_t hpa;
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+
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+ sp = page_header(__pa(sptep));
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+
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+ if (sp->unsync) {
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+ if (level != PT_PAGE_TABLE_LEVEL) {
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+ printk(KERN_ERR "audit: (%s) error: unsync sp: %p level = %d\n",
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+ audit_msg, sp, level);
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+ return;
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+ }
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+
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+ if (*sptep == shadow_notrap_nonpresent_pte) {
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+ printk(KERN_ERR "audit: (%s) error: notrap spte in unsync sp: %p\n",
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+ audit_msg, sp);
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+ return;
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+ }
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+ }
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+
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+ if (sp->role.direct && *sptep == shadow_notrap_nonpresent_pte) {
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+ printk(KERN_ERR "audit: (%s) error: notrap spte in direct sp: %p\n",
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+ audit_msg, sp);
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+ return;
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+ }
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+
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+ if (!is_shadow_present_pte(*sptep) ||
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+ !is_last_spte(*sptep, level))
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+ return;
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+
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+ gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt);
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+ pfn = gfn_to_pfn_atomic(vcpu->kvm, gfn);
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+
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+ if (is_error_pfn(pfn)) {
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+ kvm_release_pfn_clean(pfn);
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+ return;
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+ }
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+
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+ hpa = pfn << PAGE_SHIFT;
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+
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+ if ((*sptep & PT64_BASE_ADDR_MASK) != hpa)
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+ printk(KERN_ERR "xx audit error: (%s) levels %d"
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+ " gva %lx pfn %llx hpa %llx ent %llxn",
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+ audit_msg, vcpu->arch.mmu.root_level,
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+ va, pfn, hpa, *sptep);
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+ }
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+}
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+
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+static void audit_mappings(struct kvm_vcpu *vcpu)
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+{
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+ unsigned i;
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+
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+ if (vcpu->arch.mmu.root_level == 4)
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+ audit_mappings_page(vcpu, vcpu->arch.mmu.root_hpa, 0, 4);
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+ else
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+ for (i = 0; i < 4; ++i)
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+ if (vcpu->arch.mmu.pae_root[i] & PT_PRESENT_MASK)
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+ audit_mappings_page(vcpu,
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+ vcpu->arch.mmu.pae_root[i],
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+ i << 30,
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+ 2);
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+}
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+
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+void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep)
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+{
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+ unsigned long *rmapp;
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+ struct kvm_mmu_page *rev_sp;
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+ gfn_t gfn;
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+
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+
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+ rev_sp = page_header(__pa(sptep));
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+ gfn = kvm_mmu_page_get_gfn(rev_sp, sptep - rev_sp->spt);
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+
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+ if (!gfn_to_memslot(kvm, gfn)) {
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+ if (!printk_ratelimit())
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+ return;
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+ printk(KERN_ERR "%s: no memslot for gfn %llx\n",
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+ audit_msg, gfn);
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+ printk(KERN_ERR "%s: index %ld of sp (gfn=%llx)\n",
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+ audit_msg, (long int)(sptep - rev_sp->spt),
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+ rev_sp->gfn);
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+ dump_stack();
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+ return;
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+ }
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+
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+ rmapp = gfn_to_rmap(kvm, gfn, rev_sp->role.level);
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+ if (!*rmapp) {
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+ if (!printk_ratelimit())
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+ return;
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+ printk(KERN_ERR "%s: no rmap for writable spte %llx\n",
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+ audit_msg, *sptep);
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+ dump_stack();
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+ }
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+}
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+
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+void audit_sptes_have_rmaps(struct kvm_vcpu *vcpu)
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+{
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+ mmu_spte_walk(vcpu, inspect_spte_has_rmap);
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+}
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+
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+static void check_mappings_rmap(struct kvm_vcpu *vcpu)
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+{
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+ struct kvm_mmu_page *sp;
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+ int i;
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+
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+ list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
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+ u64 *pt = sp->spt;
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+
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+ if (sp->role.level != PT_PAGE_TABLE_LEVEL)
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+ continue;
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+
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+ for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
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+ if (!is_rmap_spte(pt[i]))
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+ continue;
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+
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+ inspect_spte_has_rmap(vcpu->kvm, &pt[i]);
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+ }
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+ }
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+ return;
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+}
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+
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+static void audit_rmap(struct kvm_vcpu *vcpu)
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+{
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+ check_mappings_rmap(vcpu);
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+}
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+
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+static void audit_write_protection(struct kvm_vcpu *vcpu)
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+{
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+ struct kvm_mmu_page *sp;
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+ struct kvm_memory_slot *slot;
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+ unsigned long *rmapp;
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+ u64 *spte;
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+
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+ list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
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+ if (sp->role.direct)
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+ continue;
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+ if (sp->unsync)
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+ continue;
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+ if (sp->role.invalid)
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+ continue;
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+
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+ slot = gfn_to_memslot(vcpu->kvm, sp->gfn);
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+ rmapp = &slot->rmap[sp->gfn - slot->base_gfn];
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+
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+ spte = rmap_next(vcpu->kvm, rmapp, NULL);
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+ while (spte) {
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+ if (is_writable_pte(*spte))
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+ printk(KERN_ERR "%s: (%s) shadow page has "
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+ "writable mappings: gfn %llx role %x\n",
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+ __func__, audit_msg, sp->gfn,
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+ sp->role.word);
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+ spte = rmap_next(vcpu->kvm, rmapp, spte);
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+ }
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+ }
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+}
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+
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+static void kvm_mmu_audit(void *ignore, struct kvm_vcpu *vcpu, int audit_point)
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+{
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+ audit_msg = audit_point_name[audit_point];
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+ audit_rmap(vcpu);
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+ audit_write_protection(vcpu);
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+ if (strcmp("pre pte write", audit_msg) != 0)
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+ audit_mappings(vcpu);
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+ audit_sptes_have_rmaps(vcpu);
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+}
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+
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+static bool mmu_audit;
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+
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+static void mmu_audit_enable(void)
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+{
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+ int ret;
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+
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+ if (mmu_audit)
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+ return;
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+
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+ ret = register_trace_kvm_mmu_audit(kvm_mmu_audit, NULL);
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+ WARN_ON(ret);
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+
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+ mmu_audit = true;
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+}
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+
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+static void mmu_audit_disable(void)
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+{
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+ if (!mmu_audit)
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+ return;
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+
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+ unregister_trace_kvm_mmu_audit(kvm_mmu_audit, NULL);
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+ tracepoint_synchronize_unregister();
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+ mmu_audit = false;
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+}
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+
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+static int mmu_audit_set(const char *val, const struct kernel_param *kp)
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+{
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+ int ret;
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+ unsigned long enable;
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+
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+ ret = strict_strtoul(val, 10, &enable);
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+ if (ret < 0)
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+ return -EINVAL;
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+
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+ switch (enable) {
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+ case 0:
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+ mmu_audit_disable();
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+ break;
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+ case 1:
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+ mmu_audit_enable();
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+ break;
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+ default:
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+ return -EINVAL;
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+ }
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+
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+ return 0;
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+}
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+
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+static struct kernel_param_ops audit_param_ops = {
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+ .set = mmu_audit_set,
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+ .get = param_get_bool,
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+};
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+
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+module_param_cb(mmu_audit, &audit_param_ops, &mmu_audit, 0644);
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Xiao Guangrong