Re: [PATCH v3 2/3] s390x: KVM: Implementation of Multiprocessor Topology-Change-Report

[Pierre Morel]

On 8/31/21 4:03 PM, David Hildenbrand wrote:
> On 03.08.21 10:26, Pierre Morel wrote:

...snip...


> > @@ -819,6 +820,23 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, 
> > struct kvm_enable_cap *cap)
> >           icpt_operexc_on_all_vcpus(kvm);
> >           r = 0;
> >           break;
> > +    case KVM_CAP_S390_CPU_TOPOLOGY:
> > +        mutex_lock(&kvm->lock);
> > +        if (kvm->created_vcpus) {
> > +            r = -EBUSY;
> > +        } else {
> > +            set_kvm_facility(kvm->arch.model.fac_mask, 11);
> > +            set_kvm_facility(kvm->arch.model.fac_list, 11);
> > +            r = 0;
> > +        }
> > +        mutex_unlock(&kvm->lock);
> > +        VM_EVENT(kvm, 3, "ENABLE: CPU TOPOLOGY %s",
> > +             r ? "(not available)" : "(success)");
> > +        break;
> > +
> > +        r = -EINVAL;
> > +        break;
> > +
> >       default:
> >           r = -EINVAL;
> >           break;

This above enables the facility 11.

...snip...

> > @@ -3198,6 +3239,11 @@ static int kvm_s390_vcpu_setup(struct kvm_vcpu 
> > *vcpu)
> >           vcpu->arch.sie_block->ecb |= ECB_HOSTPROTINT;
> >       if (test_kvm_facility(vcpu->kvm, 9))
> >           vcpu->arch.sie_block->ecb |= ECB_SRSI;
> > +
> > +    /* PTF needs both host and guest facilities to enable 
> > interpretation */
> > +    if (test_kvm_facility(vcpu->kvm, 11) && test_facility(11))
> > +        vcpu->arch.sie_block->ecb |= ECB_PTF;
>
>
> Again, doesn't test_kvm_facility(vcpu->kvm, 11) imply that we have host 
> support by checking fac_mask?

--
Pierre Morel
IBM Lab Boeblingen