On Tue, 6 Nov 2018 16:53:37 +0100
Michael Mueller <mimu@xxxxxxxxxxxxx> wrote:
> On 31.10.18 17:39, Cornelia Huck wrote:
> > On Wed, 31 Oct 2018 17:35:11 +0100
> > Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:
> >
> >> On 31/10/2018 15:21, Cornelia Huck wrote:
> >>> On Wed, 31 Oct 2018 15:05:09 +0100
> >>> Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:
> >>>
> >>>> On 25/10/2018 14:37, Michael Mueller wrote:
> >>> The isc space is very limited and has on top of that priority ordering;
> >>> I don't know if the gisa firmware code does have isc-specific semantics
> >>> as well.
> >> Yes it does.
> >>
> >>>
> >>>> Not having it will simplify the code.
> >>>>
> >>>>> +
> >>>>> + return gib->nisc;
> >>>>> +}
> >>>> hum.
> >>>> Will nisc change ?
> >>>> It is hard coded in the call to kvm_s390_gib_init(GAL_ISC)
> >>> Should the nisc maybe be explicitly tied to the adapter type? Or is
> >>> that a global thing? If yes, does this need any differentiation?
> >> It is global and do not need differentiation pro adapter.
> >>
> >>> IIRC, the aiv is a general "adapter interrupt virtualization" facility,
> >>> so different adapter types may be present.
> >> Yes, and it is easier if the host use the same host ISC value for all of
> >> them.
> >> After all the type of adapter is not important for the GIB
> > OK, thanks for clearing that up. I believe we should just go with
> > GAL_ISC directly in that case.
>
> So, you both want me to git rid of the nisc parameter during gib
> initialization as well?
> I'm not convinced. Here is an example how it will be used:
>
> static int ap_ioctl_setirq(struct ap_matrix_mdev *matrix_mdev, struct
> vfio_ap_aqic *parm)
> {
> ...
>
> gal_isc = kvm_s390_gisc_register(matrix_mdev->kvm, matrix_mdev->gisc);
> if (gal_isc < 0)
> return -EIO;
> ...
> aqic_gisa.isc = gal_isc;
> ...
> ret = ap_host_aqic((uint64_t)apqn, aqic2reg(aqic_gisa), p);
> ...
> return (ap_status.rc) ? -EIO : 0;
> }
So, we're calling kvm_s390_gisc_register() and will obtain the isc to
add in the gisa on success. But won't that isc always be the same (as
discussed above)?
>
>
> >>>
> >>>> the NISC is a global value, if the only way to retrieve it is to
> >>>> register we need to keep it local in the space of the registering caller.
> >>>> I mean, registering to the GIB alert and registering an interruption are
> >>>> two different things and can be done in different functions.
> >>>>
> >>>> Shouldn't we just need the GAL_ISC definition?
>
> Pierre,
>
> kvm_s390_gisc_register() is always required to get an GAL interruption
> on the host
> and to be able to reload the mechanism. The function manages the IAM
> restore mask.
> May the function name is missleading?
>
> >>>
> >>
>
