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.
