KVM: PPC: Make Performance Counters work

When we get a performance counter interrupt we need to route it on to the
Linux handler after we got out of the guest context. We also need to tell
our handling code that this particular interrupt doesn't need treatment.

So let's add those two bits in, making perf work while having a KVM guest
running.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/powerpc/kvm/book3s.c

@@ -873,6 +873,9 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 		vcpu->stat.ext_intr_exits++;
 		r = RESUME_GUEST;
 		break;
+	case BOOK3S_INTERRUPT_PERFMON:
+		r = RESUME_GUEST;
+		break;
 	case BOOK3S_INTERRUPT_PROGRAM:
 	{
 		enum emulation_result er;

arch/powerpc/kvm/book3s_interrupts.S

@@ -228,6 +228,8 @@ no_dcbz32_off:
 	beq	call_linux_handler
 	cmpwi	r12, BOOK3S_INTERRUPT_DECREMENTER
 	beq	call_linux_handler
+	cmpwi	r12, BOOK3S_INTERRUPT_PERFMON
+	beq	call_linux_handler
 
 	/* Back to EE=1 */
 	mtmsr	r6