Re: [Qemu-devel] [PATCH v4 3/5] s390x/cpumodel: Set up CPU model for AP device support

[Tony Krowiak <akrowiak@linux.vnet.ibm.com>]

On 04/18/2018 04:59 AM, David Hildenbrand wrote:
> On 18.04.2018 09:40, Cornelia Huck wrote:
>> On Tue, 17 Apr 2018 20:21:31 +0200
>> Christian Borntraeger <borntraeger@de.ibm.com> wrote:
>>
>>> On 04/16/2018 05:44 PM, David Hildenbrand wrote:
>>>>    
>>>>>   
>>>>> diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c
>>>>> index 0cdbc15..0d5b0f7 100644
>>>>> --- a/target/s390x/gen-features.c
>>>>> +++ b/target/s390x/gen-features.c
>>>>> @@ -447,6 +447,9 @@ static uint16_t full_GEN12_GA1[] = {
>>>>>       S390_FEAT_ADAPTER_INT_SUPPRESSION,
>>>>>       S390_FEAT_EDAT_2,
>>>>>       S390_FEAT_SIDE_EFFECT_ACCESS_ESOP2,
>>>>> +    S390_FEAT_AP_QUERY_CONFIG_INFO,
>>>>> +    S390_FEAT_AP_FACILITIES_TEST,
>>>>> +    S390_FEAT_AP,
>>>>>   };
>>>>>     
>>>> Now I have to ask a very stupid question:
>>>>
>>>> I heard that the execution controls in the SIE block for AP are one of
>>>> the oldest ones we have around. How can it be that the AP feature cannot
>>>> be used before zEC12?
>>> It was a suggestion from the crypto team due to testability. Nobody has a z196
>>> with the older cards.
>>>
>> Might be worth adding a note to that respect?
>>
> We used to have the CPU model stick as close as possible to the real CPU
> models.
>
> Support statements should cover in specific products what is expected to
> work and what not.
>
> So is there any real (!support statement / !testability) reason to not
> allow this feature on older CPU models that also had support for it?

I'll discuss it with the team and get back to you.

>