KVM: MMU: audit: replace mmu audit tracepoint with jump-label

The tracepoint is only used to audit mmu code, it should not be exposed to
user, let us replace it with jump-label.

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index d737443cdfdbc9df0f0437622f32533a8783a393..62f69dbf6b52475adba3b06a4a67033641ff1a11 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -68,6 +68,12 @@ char *audit_point_name[] = {
        "post sync"
 };
 
+#ifdef CONFIG_KVM_MMU_AUDIT
+static void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point);
+#else
+static void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point) { }
+#endif
+
 #undef MMU_DEBUG
 
 #ifdef MMU_DEBUG
@@ -2852,12 +2858,12 @@ static void mmu_sync_roots(struct kvm_vcpu *vcpu)
                return;
 
        vcpu_clear_mmio_info(vcpu, ~0ul);
-       trace_kvm_mmu_audit(vcpu, AUDIT_PRE_SYNC);
+       kvm_mmu_audit(vcpu, AUDIT_PRE_SYNC);
        if (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL) {
                hpa_t root = vcpu->arch.mmu.root_hpa;
                sp = page_header(root);
                mmu_sync_children(vcpu, sp);
-               trace_kvm_mmu_audit(vcpu, AUDIT_POST_SYNC);
+               kvm_mmu_audit(vcpu, AUDIT_POST_SYNC);
                return;
        }
        for (i = 0; i < 4; ++i) {
@@ -2869,7 +2875,7 @@ static void mmu_sync_roots(struct kvm_vcpu *vcpu)
                        mmu_sync_children(vcpu, sp);
                }
        }
-       trace_kvm_mmu_audit(vcpu, AUDIT_POST_SYNC);
+       kvm_mmu_audit(vcpu, AUDIT_POST_SYNC);
 }
 
 void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
@@ -3667,7 +3673,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 
        spin_lock(&vcpu->kvm->mmu_lock);
        ++vcpu->kvm->stat.mmu_pte_write;
-       trace_kvm_mmu_audit(vcpu, AUDIT_PRE_PTE_WRITE);
+       kvm_mmu_audit(vcpu, AUDIT_PRE_PTE_WRITE);
 
        mask.cr0_wp = mask.cr4_pae = mask.nxe = 1;
        for_each_gfn_indirect_valid_sp(vcpu->kvm, sp, gfn, node) {
@@ -3700,7 +3706,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
        }
        mmu_pte_write_flush_tlb(vcpu, zap_page, remote_flush, local_flush);
        kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
-       trace_kvm_mmu_audit(vcpu, AUDIT_POST_PTE_WRITE);
+       kvm_mmu_audit(vcpu, AUDIT_POST_PTE_WRITE);
        spin_unlock(&vcpu->kvm->mmu_lock);
 }
 

diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c
index 746ec259d02490bf7b7ce552560ff37e170d9825..5df6736a5afbf756dec277bef9bcedc231e57817 100644 (file)
--- a/arch/x86/kvm/mmu_audit.c
+++ b/arch/x86/kvm/mmu_audit.c
@@ -224,30 +224,29 @@ 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 bool mmu_audit;
+static struct jump_label_key mmu_audit_key;
+
+static void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point)
 {
        static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
 
-       if (!__ratelimit(&ratelimit_state))
-               return;
+       if (static_branch((&mmu_audit_key))) {
+               if (!__ratelimit(&ratelimit_state))
+                       return;
 
-       vcpu->kvm->arch.audit_point = point;
-       audit_all_active_sps(vcpu->kvm);
-       audit_vcpu_spte(vcpu);
+               vcpu->kvm->arch.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);
-
+       jump_label_inc(&mmu_audit_key);
        mmu_audit = true;
 }
 
@@ -256,8 +255,7 @@ static void mmu_audit_disable(void)
        if (!mmu_audit)
                return;
 
-       unregister_trace_kvm_mmu_audit(kvm_mmu_audit, NULL);
-       tracepoint_synchronize_unregister();
+       jump_label_dec(&mmu_audit_key);
        mmu_audit = false;
 }
 

diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h
index eed67f34146d66557d5f5668a1f7c37191dd50a2..89fb0e81322a96d996d1fd554ec9c1d6c55553f6 100644 (file)
--- a/arch/x86/kvm/mmutrace.h
+++ b/arch/x86/kvm/mmutrace.h
@@ -243,25 +243,6 @@ TRACE_EVENT(
        TP_printk("addr:%llx gfn %llx access %x", __entry->addr, __entry->gfn,
                  __entry->access)
 );
-
-TRACE_EVENT(
-       kvm_mmu_audit,
-       TP_PROTO(struct kvm_vcpu *vcpu, int audit_point),
-       TP_ARGS(vcpu, audit_point),
-
-       TP_STRUCT__entry(
-               __field(struct kvm_vcpu *, vcpu)
-               __field(int, audit_point)
-       ),
-
-       TP_fast_assign(
-               __entry->vcpu = vcpu;
-               __entry->audit_point = audit_point;
-       ),
-
-       TP_printk("vcpu:%d %s", __entry->vcpu->cpu,
-                 audit_point_name[__entry->audit_point])
-);
 #endif /* _TRACE_KVMMMU_H */
 
 #undef TRACE_INCLUDE_PATH

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 52e9d58cec2b3cbf447ffd1dd7a90be6a0fcbda3..15610285ebb647075e17a1388e031128eb764329 100644 (file)
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -632,7 +632,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
        if (mmu_notifier_retry(vcpu, mmu_seq))
                goto out_unlock;
 
-       trace_kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT);
+       kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT);
        kvm_mmu_free_some_pages(vcpu);
        if (!force_pt_level)
                transparent_hugepage_adjust(vcpu, &walker.gfn, &pfn, &level);
@@ -643,7 +643,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
                 sptep, *sptep, emulate);
 
        ++vcpu->stat.pf_fixed;
-       trace_kvm_mmu_audit(vcpu, AUDIT_POST_PAGE_FAULT);
+       kvm_mmu_audit(vcpu, AUDIT_POST_PAGE_FAULT);
        spin_unlock(&vcpu->kvm->mmu_lock);
 
        return emulate;