KVM: MMU: audit: allow audit more guests at the same time

It only allows to audit one guest in the system since:
- 'audit_point' is a glob variable
- mmu_audit_disable() is called in kvm_mmu_destroy(), so audit is disabled
  after a guest exited

this patch fix those issues then allow to audit more guests at the same time

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

3 files changed, 39 insertions, 30 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 95f026be8b5e..aa75f21a9fba 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -461,6 +461,10 @@ struct kvm_arch {
         /* fields used by HYPER-V emulation */
         u64 hv_guest_os_id;
         u64 hv_hypercall;
+
+        #ifdef CONFIG_KVM_MMU_AUDIT
+        int audit_point;
+        #endif
 };
 
 struct kvm_vm_stat {
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index e558795fccd5..892ffc603ff9 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3534,13 +3534,6 @@ static void mmu_destroy_caches(void)
                 kmem_cache_destroy(mmu_page_header_cache);
 }
 
-void kvm_mmu_module_exit(void)
-{
-        mmu_destroy_caches();
-        percpu_counter_destroy(&kvm_total_used_mmu_pages);
-        unregister_shrinker(&mmu_shrinker);
-}
-
 int kvm_mmu_module_init(void)
 {
         pte_chain_cache = kmem_cache_create("kvm_pte_chain",
@@ -3733,12 +3726,6 @@ int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4])
 }
 EXPORT_SYMBOL_GPL(kvm_mmu_get_spte_hierarchy);
 
-#ifdef CONFIG_KVM_MMU_AUDIT
-#include "mmu_audit.c"
-#else
-static void mmu_audit_disable(void) { }
-#endif
-
 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
 {
         ASSERT(vcpu);
@@ -3746,5 +3733,18 @@ void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
         destroy_kvm_mmu(vcpu);
         free_mmu_pages(vcpu);
         mmu_free_memory_caches(vcpu);
+}
+
+#ifdef CONFIG_KVM_MMU_AUDIT
+#include "mmu_audit.c"
+#else
+static void mmu_audit_disable(void) { }
+#endif
+
+void kvm_mmu_module_exit(void)
+{
+        mmu_destroy_caches();
+        percpu_counter_destroy(&kvm_total_used_mmu_pages);
+        unregister_shrinker(&mmu_shrinker);
         mmu_audit_disable();
 }
diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c
index ba2bcdde6221..5f6223b8bcf7 100644
--- a/arch/x86/kvm/mmu_audit.c
+++ b/arch/x86/kvm/mmu_audit.c
@@ -19,11 +19,9 @@
 
 #include <linux/ratelimit.h>
 
-static int audit_point;
-
-#define audit_printk(fmt, args...)              \
+#define audit_printk(kvm, fmt, args...)         \
         printk(KERN_ERR "audit: (%s) error: "   \
-                fmt, audit_point_name[audit_point], ##args)
+                fmt, audit_point_name[kvm->arch.audit_point], ##args)
 
 typedef void (*inspect_spte_fn) (struct kvm_vcpu *vcpu, u64 *sptep, int level);
 
@@ -97,18 +95,21 @@ static void audit_mappings(struct kvm_vcpu *vcpu, u64 *sptep, int level)
 
         if (sp->unsync) {
                 if (level != PT_PAGE_TABLE_LEVEL) {
-                        audit_printk("unsync sp: %p level = %d\n", sp, level);
+                        audit_printk(vcpu->kvm, "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);
+                        audit_printk(vcpu->kvm, "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);
+                audit_printk(vcpu->kvm, "notrap spte in direct sp: %p\n",
+                             sp);
                 return;
         }
 
@@ -125,8 +126,9 @@ static void audit_mappings(struct kvm_vcpu *vcpu, u64 *sptep, int level)
 
         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);
+                audit_printk(vcpu->kvm, "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)
@@ -142,8 +144,8 @@ static void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep)
         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",
+                audit_printk(kvm, "no memslot for gfn %llx\n", gfn);
+                audit_printk(kvm, "index %ld of sp (gfn=%llx)\n",
                        (long int)(sptep - rev_sp->spt), rev_sp->gfn);
                 dump_stack();
                 return;
@@ -153,7 +155,8 @@ static void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep)
         if (!*rmapp) {
                 if (!printk_ratelimit())
                         return;
-                audit_printk("no rmap for writable spte %llx\n", *sptep);
+                audit_printk(kvm, "no rmap for writable spte %llx\n",
+                             *sptep);
                 dump_stack();
         }
 }
@@ -168,8 +171,9 @@ 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);
+        if (vcpu->kvm->arch.audit_point == AUDIT_POST_SYNC && sp->unsync)
+                audit_printk(vcpu->kvm, "meet unsync sp(%p) after sync "
+                             "root.\n", sp);
 }
 
 static void check_mappings_rmap(struct kvm *kvm, struct kvm_mmu_page *sp)
@@ -202,8 +206,9 @@ static void audit_write_protection(struct kvm *kvm, struct kvm_mmu_page *sp)
         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);
+                        audit_printk(kvm, "shadow page has writable "
+                                     "mappings: gfn %llx role %x\n",
+                                     sp->gfn, sp->role.word);
                 spte = rmap_next(kvm, rmapp, spte);
         }
 }
@@ -238,7 +243,7 @@ static void kvm_mmu_audit(void *ignore, struct kvm_vcpu *vcpu, int point)
         if (!__ratelimit(&ratelimit_state))
                 return;
 
-        audit_point = point;
+        vcpu->kvm->arch.audit_point = point;
         audit_all_active_sps(vcpu->kvm);
         audit_vcpu_spte(vcpu);
 }