KVM: ignore reads from AMDs C1E enabled MSR

If the Linux kernel detects an C1E capable AMD processor (K8 RevF and
higher), it will access a certain MSR on every attempt to go to halt.
Explicitly handle this read and return 0 to let KVM run a Linux guest
with the native AMD host CPU propagated to the guest.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/x86.c

@@ -1038,6 +1038,7 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
 	case MSR_P6_EVNTSEL0:
 	case MSR_P6_EVNTSEL1:
 	case MSR_K7_EVNTSEL0:
+	case MSR_K8_INT_PENDING_MSG:
 		data = 0;
 		break;
 	case MSR_MTRRcap: