On Thu, 25 Jan 2018 17:51:24 +0100
Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote:
> On 01/25/2018 05:17 PM, Cornelia Huck wrote:
> > On Thu, 25 Jan 2018 17:12:59 +0100
> > Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote:
> >
> >> On 01/25/2018 04:47 PM, Cornelia Huck wrote:
> >>> On Thu, 25 Jan 2018 16:43:27 +0100
> >>> Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote:
> >>>
> >>>> On 01/25/2018 04:31 PM, David Hildenbrand wrote:
> >>>> [...]
> >>>>>> struct kvm_s390_vsie {
> >>>>>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> >>>>>> index 68d7eef..efde264 100644
> >>>>>> --- a/arch/s390/kvm/kvm-s390.c
> >>>>>> +++ b/arch/s390/kvm/kvm-s390.c
> >>>>>> @@ -2518,6 +2518,8 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
> >>>>>> vcpu->arch.sie_block->icpua = id;
> >>>>>> spin_lock_init(&vcpu->arch.local_int.lock);
> >>>>>> vcpu->arch.sie_block->gd = (u32)(u64)kvm->arch.gisa;
> >>>>>> + if (vcpu->arch.sie_block->gd && sclp.has_gisaf)
> >>>>>> + vcpu->arch.sie_block->gd |= GISA_FORMAT1;
> >>>>>> seqcount_init(&vcpu->arch.cputm_seqcount);
> >>>>>>
> >>>>>> rc = kvm_vcpu_init(vcpu, kvm, id);
> >>>>>>
> >>>>>
> >>>>> So, what does this bring us? We don't seem to be using any new GISA-1
> >>>>> features.
> >>>>
> >>>> Preparation for device pass-through interrupt forwarding.
> >>>>
> >>>
> >>> Should we start out with a dual format-0/format-1 gisa block, then?
> >>> IIUC, you'll switch to gisa-1 if the facility is there and gisa-1 can
> >>> do anything that gisa-0 can do?
> >>
> >> There might be systems that only have gisa-0, so I think having both makes
> >> sense.
> >>
> >
> > Yes, that's what I meant. Just do it earlier in the series - this patch
> > feels like an afterthought with no real user.
>
> I added
>
> A format-1 can do everything that format-0 can and we will need it
> for real HW passthrough. As there are systems with only format-0
> we keep both variants.
>
> to the patch description. Maybe its now a bit less odd?
Also fine with me.
(I'll do a proper review round through the patches later.)
