[PATCH v4 15/15] KVM: SVM: Add AVIC doorbell tracepoint

[Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>]

Add a tracepoint to track number of doorbells being sent
to signal a running vCPU to process IRQ after being injected.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 arch/x86/kvm/svm/avic.c |  4 +++-
 arch/x86/kvm/trace.h    | 18 ++++++++++++++++++
 arch/x86/kvm/x86.c      |  1 +
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 617dd4732a9a..2e59dbe29f79 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -345,8 +345,10 @@ void avic_ring_doorbell(struct kvm_vcpu *vcpu)
 	 */
 	int cpu = READ_ONCE(vcpu->cpu);
 
-	if (cpu != get_cpu())
+	if (cpu != get_cpu()) {
 		wrmsrl(MSR_AMD64_SVM_AVIC_DOORBELL, kvm_cpu_get_apicid(cpu));
+		trace_kvm_avic_doorbell(vcpu->vcpu_id, kvm_cpu_get_apicid(cpu));
+	}
 	put_cpu();
 }
 
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index de4762517569..a47bb0fdea70 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -1479,6 +1479,24 @@ TRACE_EVENT(kvm_avic_kick_vcpu_slowpath,
 		  __entry->icrh, __entry->icrl, __entry->index)
 );
 
+TRACE_EVENT(kvm_avic_doorbell,
+	    TP_PROTO(u32 vcpuid, u32 apicid),
+	    TP_ARGS(vcpuid, apicid),
+
+	TP_STRUCT__entry(
+		__field(u32, vcpuid)
+		__field(u32, apicid)
+	),
+
+	TP_fast_assign(
+		__entry->vcpuid = vcpuid;
+		__entry->apicid = apicid;
+	),
+
+	TP_printk("vcpuid=%u, apicid=%u",
+		  __entry->vcpuid, __entry->apicid)
+);
+
 TRACE_EVENT(kvm_hv_timer_state,
 		TP_PROTO(unsigned int vcpu_id, unsigned int hv_timer_in_use),
 		TP_ARGS(vcpu_id, hv_timer_in_use),
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0febaca80feb..d013f6fc2e33 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -13095,6 +13095,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_avic_unaccelerated_access);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_avic_incomplete_ipi);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_avic_ga_log);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_avic_kick_vcpu_slowpath);
+EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_avic_doorbell);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_apicv_accept_irq);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_vmgexit_enter);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_vmgexit_exit);
-- 
2.25.1