KVM: s390: fix cc for successful PQAP

The various errors that are possible when processing a PQAP
instruction (the absence of a driver hook, an error FROM that
hook), all correctly set the PSW condition code to 3. But if
that processing works successfully, CC0 needs to be set to
convey that everything was fine.

Fix the check so that the guest can examine the condition code
to determine whether GPR1 has meaningful data.

Fixes: e5282de ("s390: ap: kvm: add PQAP interception for AQIC")
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Link: https://lore.kernel.org/r/20231201181657.1614645-1-farman@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20231201181657.1614645-1-farman@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>

Author: efarman

arch/s390/kvm/priv.c

@@ -676,8 +676,12 @@ static int handle_pqap(struct kvm_vcpu *vcpu)
 	if (vcpu->kvm->arch.crypto.pqap_hook) {
 		pqap_hook = *vcpu->kvm->arch.crypto.pqap_hook;
 		ret = pqap_hook(vcpu);
-		if (!ret && vcpu->run->s.regs.gprs[1] & 0x00ff0000)
-			kvm_s390_set_psw_cc(vcpu, 3);
+		if (!ret) {
+			if (vcpu->run->s.regs.gprs[1] & 0x00ff0000)
+				kvm_s390_set_psw_cc(vcpu, 3);
+			else
+				kvm_s390_set_psw_cc(vcpu, 0);
+		}
 		up_read(&vcpu->kvm->arch.crypto.pqap_hook_rwsem);
 		return ret;
 	}