KVM: VMX: Improve error reporting during invalid guest state emulation

If instruction emulation fails, report it properly to userspace.
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/vmx.c

@@ -4996,8 +4996,12 @@ static int handle_invalid_guest_state(struct kvm_vcpu *vcpu)
 			goto out;
 		}
 
-		if (err != EMULATE_DONE)
+		if (err != EMULATE_DONE) {
+			vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+			vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
+			vcpu->run->internal.ndata = 0;
 			return 0;
+		}
 
 		if (signal_pending(current))
 			goto out;