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 <[email protected]>
Reviewed-by: Tony Krowiak <[email protected]>
Reviewed-by: Halil Pasic <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Janosch Frank <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Christian Borntraeger <[email protected]>

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;
 	}