KVM: PMU: warn when pin control is set in eventsel msr

Print warning once if pin control bit is set in eventsel msr since
emulation does not support it yet.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 3e48c1d..6af9a54 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -210,6 +210,9 @@
 	unsigned config, type = PERF_TYPE_RAW;
 	u8 event_select, unit_mask;
 
+	if (eventsel & ARCH_PERFMON_EVENTSEL_PIN_CONTROL)
+		printk_once("kvm pmu: pin control bit is ignored\n");
+
 	pmc->eventsel = eventsel;
 
 	stop_counter(pmc);