On 12/7/23 11:11 AM, Eric Farman wrote:
On Thu, 2023-12-07 at 10:39 -0500, Anthony Krowiak wrote:
On 12/1/23 1:16 PM, Eric Farman wrote:
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: e5282de93105 ("s390: ap: kvm: add PQAP interception for
AQIC")
Signed-off-by: Eric Farman <farman@xxxxxxxxxxxxx>
---
arch/s390/kvm/priv.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 621a17fd1a1b..f875a404a0a0 100644
--- a/arch/s390/kvm/priv.c
+++ b/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);
+ }
The cc is not set if pqap_hook returns a non-zero rc; however, this
point may be moot given the only non-zero rc is -EOPNOTSUPP. I'm a
bit
foggy on what happens when non-zero return codes are passed up the
stack.
Right, a non-zero RC will get reflected to the interception handlers,
where EOPNOTSUPP instructs control to be given to userspace. So not
setting a condition code is correct here, as userspace will be expected
to do that.
Thanks for confirming that. With that said:
Reviewed-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
up_read(&vcpu->kvm->arch.crypto.pqap_hook_rwsem);
return ret;
}
