KVM: s390: fix diagnose code extraction

commit 743db27c upstream.

The diagnose code to be used is the contents of the base register (if not
zero), plus the displacement. The current code ignores the base register
contents. So let's fix that...
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/s390/kvm/diag.c

@@ -130,7 +130,7 @@ static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
 
 int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
 {
-	int code = (vcpu->arch.sie_block->ipb & 0xfff0000) >> 16;
+	int code = kvm_s390_get_base_disp_rs(vcpu) & 0xffff;
 
 	trace_kvm_s390_handle_diag(vcpu, code);
 	switch (code) {