Re: [Qemu-devel] [PATCH v3 6/7] s390x/kvm: handle AP instruction interception

[Tony Krowiak]

On 03/26/2018 08:01 AM, Halil Pasic wrote:
> On 03/26/2018 11:03 AM, Pierre Morel wrote:
> > > > +int ap_device_handle_pqap(S390CPU *cpu)
> > > > +{
> > > > +    CPUS390XState *env = &cpu->env;
> > > > +    int fc = 4 & (env->regs[0] >> 24);
> > > > +
> > > > +    /*
> > > > +     * The Query Configuration Information (QCI) function (fc == 4) does not
> > > > +     * set a response code in reg 1, so check for that along with the
> > > > +     * AP feature.
> > > > +     */
> > > > +    if ((fc != 4) && s390_has_feat(S390_FEAT_AP)) {
> > > > +        env->regs[1] = 0x10000;
> > > > +
> > > > +        return 0;
> > > > +    }
> > > This would imply an operation exception in case fc==4, which sounds very
> > > wrong.
> Yes, operation exception is a wrong response under the condition
> (fc == 4) && s390_has_feat(S390_FEAT_AP).
See my response to Pierre:
Message ID: <address@hidden>
> @David:
> FYI Tony is likely to respond after Wednesday as he is on vacation right
> now.
>
> > It depends but I think that the S390_FEAT_AP_QUERY_CONFIG_INFO must be tested
> > to know what to answer.
> > If the feature is there, QCI must be answered correctly.
> >
> > there are also some error situations to handle in all three functions.
> I agree.
>
> Regards,
> Halil