KVM: s390: unintended fallthrough for external call

We must not fallthrough if the conditions for external call are not met.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index d56da1d..4abf819 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -86,6 +86,7 @@
 			return 0;
 		if (vcpu->arch.sie_block->gcr[0] & 0x2000ul)
 			return 1;
+		return 0;
 	case KVM_S390_INT_EMERGENCY:
 		if (psw_extint_disabled(vcpu))
 			return 0;