On Fri, Jul 23 2021, Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote:
> On 22.07.21 19:02, Pierre Morel wrote:
>> We add a KVM extension KVM_CAP_S390_CPU_TOPOLOGY to tell the
>> userland hypervisor it is safe to activate the CPU Topology facility.
>
> I think the old variant of using the CPU model was actually better.
> It was just the patch description that was wrong.
I thought we wanted a cap that userspace can enable to get ptf
intercepts? I'm confused.
>
>> Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
>> ---
>> arch/s390/kvm/kvm-s390.c | 1 +
>> include/uapi/linux/kvm.h | 1 +
>> 2 files changed, 2 insertions(+)
>>
>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>> index b655a7d82bf0..8c695ee79612 100644
>> --- a/arch/s390/kvm/kvm-s390.c
>> +++ b/arch/s390/kvm/kvm-s390.c
>> @@ -568,6 +568,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
>> case KVM_CAP_S390_VCPU_RESETS:
>> case KVM_CAP_SET_GUEST_DEBUG:
>> case KVM_CAP_S390_DIAG318:
>> + case KVM_CAP_S390_CPU_TOPOLOGY:
>> r = 1;
>> break;
>> case KVM_CAP_SET_GUEST_DEBUG2:
>> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
>> index d9e4aabcb31a..081ce0cd44b9 100644
>> --- a/include/uapi/linux/kvm.h
>> +++ b/include/uapi/linux/kvm.h
>> @@ -1112,6 +1112,7 @@ struct kvm_ppc_resize_hpt {
>> #define KVM_CAP_BINARY_STATS_FD 203
>> #define KVM_CAP_EXIT_ON_EMULATION_FAILURE 204
>> #define KVM_CAP_ARM_MTE 205
>> +#define KVM_CAP_S390_CPU_TOPOLOGY 206
>>
>> #ifdef KVM_CAP_IRQ_ROUTING
>>
>>
Regardless of what we end up with: we need documentation for any new cap
:)
