On Wed, Jul 07 2021, Janis Schoetterl-Glausch <scgl@xxxxxxxxxxxxxxxxxx> wrote: > On 7/7/21 10:54 AM, Cornelia Huck wrote: > > [...] > >> >>>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >>>> index b655a7d82bf0..aadd589a3755 100644 >>>> --- a/arch/s390/kvm/kvm-s390.c >>>> +++ b/arch/s390/kvm/kvm-s390.c >>>> @@ -3200,6 +3200,8 @@ static int kvm_s390_vcpu_setup(struct kvm_vcpu *vcpu) >>>> vcpu->arch.sie_block->ecb |= ECB_SRSI; >>>> if (test_kvm_facility(vcpu->kvm, 73)) >>>> vcpu->arch.sie_block->ecb |= ECB_TE; >> >> Maybe add >> >> /* no facility bit, but safe as the hardware may ignore it */ >> >> or something like that, so that we don't stumble over that in the future? > > Well, the hardware being allowed to ignore the bit makes its introduction > without an indication forward compatible because it does not require vSIE to be adapted. > The reserved bits are implicitly set to 0 which means new features are disabled > by default and one observes all the interception one expects. > > Maybe this: > > /* no facility bit, can opt in because we do not need > to observe specification exception intercepts */ > > ? Works for me as well. > >> >>>> + if (!kvm_is_ucontrol(vcpu->kvm)) >>>> + vcpu->arch.sie_block->ecb |= ECB_SPECI; >>>> >>>> if (test_kvm_facility(vcpu->kvm, 8) && vcpu->kvm->arch.use_pfmfi) >>>> vcpu->arch.sie_block->ecb2 |= ECB2_PFMFI; >> >> Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx> >>
