KVM: Trace exception injection

Often an exception can help point out where things start to go wrong.

Signed-off-by: Avi Kivity <avi@redhat.com>

2 files changed, 35 insertions, 0 deletions

diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index d10b359a21f3..32c912c40bf8 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -219,6 +219,38 @@ TRACE_EVENT(kvm_inj_virq,
         TP_printk("irq %u", __entry->irq)
 );
 
+#define EXS(x) { x##_VECTOR, "#" #x }
+
+#define kvm_trace_sym_exc                                               \
+        EXS(DE), EXS(DB), EXS(BP), EXS(OF), EXS(BR), EXS(UD), EXS(NM),  \
+        EXS(DF), EXS(TS), EXS(NP), EXS(SS), EXS(GP), EXS(PF),           \
+        EXS(MF), EXS(MC)
+
+/*
+ * Tracepoint for kvm interrupt injection:
+ */
+TRACE_EVENT(kvm_inj_exception,
+        TP_PROTO(unsigned exception, bool has_error, unsigned error_code),
+        TP_ARGS(exception, has_error, error_code),
+
+        TP_STRUCT__entry(
+                __field(        u8,     exception       )
+                __field(        u8,     has_error       )
+                __field(        u32,    error_code      )
+        ),
+
+        TP_fast_assign(
+                __entry->exception      = exception;
+                __entry->has_error      = has_error;
+                __entry->error_code     = error_code;
+        ),
+
+        TP_printk("%s (0x%x)",
+                  __print_symbolic(__entry->exception, kvm_trace_sym_exc),
+                  /* FIXME: don't print error_code if not present */
+                  __entry->has_error ? __entry->error_code : 0)
+);
+
 /*
  * Tracepoint for page fault.
  */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 74e70d975ffa..a1cf87fe9f3a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4237,6 +4237,9 @@ static void inject_pending_event(struct kvm_vcpu *vcpu)
 {
         /* try to reinject previous events if any */
         if (vcpu->arch.exception.pending) {
+                trace_kvm_inj_exception(vcpu->arch.exception.nr,
+                                        vcpu->arch.exception.has_error_code,
+                                        vcpu->arch.exception.error_code);
                 kvm_x86_ops->queue_exception(vcpu, vcpu->arch.exception.nr,
                                           vcpu->arch.exception.has_error_code,
                                           vcpu->arch.exception.error_code);