KVM: s390: Check for PSTATE when handling DIAGNOSE

DIAGNOSE is a privileged instruction and thus we must make sure that we are
in supervisor mode before taking any other actions.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c
index 1c01a99..3074475 100644
--- a/arch/s390/kvm/diag.c
+++ b/arch/s390/kvm/diag.c
@@ -132,6 +132,9 @@
 {
 	int code = (vcpu->arch.sie_block->ipb & 0xfff0000) >> 16;
 
+	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
+		return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
+
 	trace_kvm_s390_handle_diag(vcpu, code);
 	switch (code) {
 	case 0x10: