--- /dev/null
+/*
+ * mmu_audit.c:
+ *
+ * Audit code for KVM MMU
+ *
+ * Copyright (C) 2006 Qumranet, Inc.
+ * Copyright 2010 Red Hat, Inc. and/or its affiliates.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/ratelimit.h>
+
+static int audit_point;
+
+#define audit_printk(fmt, args...) \
+ printk(KERN_ERR "audit: (%s) error: " \
+ fmt, audit_point_name[audit_point], ##args)
+
+typedef void (*inspect_spte_fn) (struct kvm_vcpu *vcpu, u64 *sptep, int level);
+
+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;
+
+ 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[i] & PT64_BASE_ADDR_MASK);
+ __mmu_spte_walk(vcpu, child, fn, level - 1);
+ }
+ }
+}
+
+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.root_level == PT64_ROOT_LEVEL) {
+ hpa_t root = vcpu->arch.mmu.root_hpa;
+
+ sp = page_header(root);
+ __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, sp, fn, 2);
+ }
+ }
+
+ return;
+}
+
+typedef void (*sp_handler) (struct kvm *kvm, struct kvm_mmu_page *sp);
+
+static void walk_all_active_sps(struct kvm *kvm, sp_handler fn)
+{
+ struct kvm_mmu_page *sp;
+
+ list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link)
+ fn(kvm, sp);
+}
+
+static void audit_mappings(struct kvm_vcpu *vcpu, u64 *sptep, int level)
+{
+ 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) {
+ audit_printk("unsync sp: %p level = %d\n", sp, level);
+ return;
+ }
+
+ if (*sptep == shadow_notrap_nonpresent_pte) {
+ audit_printk("notrap spte in unsync sp: %p\n", sp);
+ return;
+ }
+ }
+
+ if (sp->role.direct && *sptep == shadow_notrap_nonpresent_pte) {
+ audit_printk("notrap spte in direct sp: %p\n", 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)
+ audit_printk("levels %d pfn %llx hpa %llx ent %llxn",
+ vcpu->arch.mmu.root_level, pfn, hpa, *sptep);
+}
+
+static 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;
+ audit_printk("no memslot for gfn %llx\n", gfn);
+ audit_printk("index %ld of sp (gfn=%llx)\n",
+ (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;
+ audit_printk("no rmap for writable spte %llx\n", *sptep);
+ dump_stack();
+ }
+}
+
+static void audit_sptes_have_rmaps(struct kvm_vcpu *vcpu, u64 *sptep, int level)
+{
+ if (is_shadow_present_pte(*sptep) && is_last_spte(*sptep, level))
+ inspect_spte_has_rmap(vcpu->kvm, sptep);
+}
+
+static void audit_spte_after_sync(struct kvm_vcpu *vcpu, u64 *sptep, int level)
+{
+ struct kvm_mmu_page *sp = page_header(__pa(sptep));
+
+ if (audit_point == AUDIT_POST_SYNC && sp->unsync)
+ audit_printk("meet unsync sp(%p) after sync root.\n", sp);
+}
+
+static void check_mappings_rmap(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+ int i;
+
+ if (sp->role.level != PT_PAGE_TABLE_LEVEL)
+ return;
+
+ for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
+ if (!is_rmap_spte(sp->spt[i]))
+ continue;
+
+ inspect_spte_has_rmap(kvm, sp->spt + i);
+ }
+}
+
+static void audit_write_protection(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+ struct kvm_memory_slot *slot;
+ unsigned long *rmapp;
+ u64 *spte;
+
+ if (sp->role.direct || sp->unsync || sp->role.invalid)
+ return;
+
+ slot = gfn_to_memslot(kvm, sp->gfn);
+ rmapp = &slot->rmap[sp->gfn - slot->base_gfn];
+
+ spte = rmap_next(kvm, rmapp, NULL);
+ while (spte) {
+ if (is_writable_pte(*spte))
+ audit_printk("shadow page has writable mappings: gfn "
+ "%llx role %x\n", sp->gfn, sp->role.word);
+ spte = rmap_next(kvm, rmapp, spte);
+ }
+}
+
+static void audit_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+ check_mappings_rmap(kvm, sp);
+ audit_write_protection(kvm, sp);
+}
+
+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);
+ audit_spte_after_sync(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 point)
+{
+ static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
+
+ if (!__ratelimit(&ratelimit_state))
+ return;
+
+ audit_point = point;
+ audit_all_active_sps(vcpu->kvm);
+ audit_vcpu_spte(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);
projects / mv-sheeva.git / blobdiff