Re: [PATCH] s390x: pv: Fence additional unavailable SCLP facilities for PV guests

[Janosch Frank]

On 12/8/20 5:19 PM, David Hildenbrand wrote:
> On 08.12.20 17:11, Christian Borntraeger wrote:
>>
>>
>> On 08.12.20 15:55, David Hildenbrand wrote:
>>> On 08.12.20 14:29, Christian Borntraeger wrote:
>>>>
>>>>
>>>> On 04.12.20 09:36, Janosch Frank wrote:
>>>>> There's no VSIE support for a protected guest, so let's better not
>>>>> advertise it and its support facilities.
>>>>>
>>>>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>>>>
>>>> Looks sane. Assuming that all features that depend on SIE are named 
>>>> S390_FEAT_SIE_*
>>>> this should take care of everything. (i compared to gen-facilities.c)
>>>
>>> We could add dependency checks to
>>> target/s390x/cpu_models.c:check_consistency()
>>
>> That could be an additional patch, right?
> 
> Yeah sure.
> 
>>
>>>
>>> What about
>>>
>>> DEF_FEAT(ESOP, "esop", SCLP_CONF_CHAR, 46,
>>> "Enhanced-suppression-on-protection facility")
>>
>> ESOP does make sense independent from SIE see chapter 3-15 in the POP
>> in "Suppression on Protection"
>>
> 
> Rings a bell :)
> 
>>
>>> DEF_FEAT(HPMA2, "hpma2", SCLP_CONF_CHAR, 90, "Host page management
>>> assist 2 Facility")
>>
>> Right. We should also fence of hpma2.
> 
> I was also wondering about CMM, but as the guest senses it by executing
> the instruction, protected guests will never see it I assume.
> 

Yep, it's a operation exception.