Re: [PATCH v5 1/7] s390: ap: kvm: add PQAP interception for AQIC

[Pierre Morel]

On 15/03/2019 14:41, Cornelia Huck wrote:
> On Fri, 15 Mar 2019 14:26:34 +0100
> Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:
>
> > Conclusion:  we must handle this in userland, it will have the benefit
> > to keep old behavior when there is no callback.
> > OLD QEMU will not see change as they will not set aqic facility
> > NEW QEMU will handle this correctly.
> >
> > In this case we also do not need to handle all other tests here but can
> > move it to the callback as Tony wanted.
> >
> > Would you agree with something simple like:
> >
> > static int handle_pqap(struct kvm_vcpu *vcpu)
> > {
> >           int ret = -EOPNOTSUPP;
> >
> >           /* Verify that the hook callback is registered and call it */
> >           if (pqap_hook)
> >                   if (try_module_get(pqap_hook->owner)) {
> >                           ret = pqap_hook->hook(vcpu);
> >                           module_put(pqap_hook->owner);
> >                   }
> >           return ret;
> > }
> >
> > All other tests in QEMU and in the callback.
>
> With the hook checking for priv, fc, etc.? Yeah, might work.
>
> But don't count on my feedback too much right now, better wait for
> others' comments :) I'll resume in April, if needed.

OK, thanks

Pierre

--
Pierre Morel
Linux/KVM/QEMU in BÃblingen - Germany