Re: [qemu-s390x] [PATCH v2] s390x/cpumodel: model PTFF subfunctions for Multiple-epoch facility

[David Hildenbrand]

On 05.02.2018 12:22, Christian Borntraeger wrote:
> Looks sane on a z14.
> Tested-by: Christian Borntraeger <address@hidden>
> 
> 
> On 02/05/2018 11:29 AM, David Hildenbrand wrote:
>> --- a/target/s390x/kvm.c
>> +++ b/target/s390x/kvm.c
>> @@ -2221,6 +2221,14 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, 
>> Error **errp)
>>          return;
>>      }
>>
>> +    /* PTFF subfunctions might be indicated although kernel support missing 
>> */
>> +    if (!test_bit(S390_FEAT_MULTIPLE_EPOCH, model->features)) {
>> +        clear_bit(S390_FEAT_PTFF_QSIE, model->features);
>> +        clear_bit(S390_FEAT_PTFF_QTOUE, model->features);
>> +        clear_bit(S390_FEAT_PTFF_STOE, model->features);
>> +        clear_bit(S390_FEAT_PTFF_STOUE, model->features);
>> +    }
>> +
>>      /* with cpu model support, CMM is only indicated if really available */
>>      if (kvm_s390_cmma_available()) {
>>          set_bit(S390_FEAT_CMM, model->features);
>>
> 
> Do you also want to add something to check_consistency ?
> 
> Right now the following user error 
> -cpu z14,mepoch=off,mepochptff=on
> is accepted.
> On the other hand we also have no consistency checks for other subfunctions.
> 

Thought about that, but that implies that a CPU model runable now, will
not run without warnings. Especially if migrating. We could add such
checks if we would push this into stable.

-- 

Thanks,

David / dhildenb