[PATCH 2/4] KVM: x86: Introduce trace_kvm_hv_hypercall_done()

[Vitaly Kuznetsov <vkuznets@redhat.com>]

Hypercall failures are unusual with potentially far going consequences
so it would be useful to see their results when tracing.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 arch/x86/kvm/hyperv.c |  1 +
 arch/x86/kvm/trace.h  | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index cb7e045905a5..2945b93dbadd 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2016,6 +2016,7 @@ static void kvm_hv_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)
 
 static int kvm_hv_hypercall_complete(struct kvm_vcpu *vcpu, u64 result)
 {
+	trace_kvm_hv_hypercall_done(result);
 	kvm_hv_hypercall_set_result(vcpu, result);
 	++vcpu->stat.hypercalls;
 	return kvm_skip_emulated_instruction(vcpu);
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index b484141ea15b..03ebe368333e 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -92,6 +92,21 @@ TRACE_EVENT(kvm_hv_hypercall,
 		  __entry->outgpa)
 );
 
+TRACE_EVENT(kvm_hv_hypercall_done,
+	TP_PROTO(u64 result),
+	TP_ARGS(result),
+
+	TP_STRUCT__entry(
+		__field(__u64, result)
+	),
+
+	TP_fast_assign(
+		__entry->result	= result;
+	),
+
+	TP_printk("result 0x%llx", __entry->result)
+);
+
 /*
  * Tracepoint for Xen hypercall.
  */
-- 
2.31.1