Re: [PATCH v2 2/7] Documentation: s390-diag.rst: make diag500 a generic KVM hypercall

David Hildenbrand
2024-10-15T08:32:48Z

On 15.10.24 10:21, Heiko Carstens wrote:
> On Tue, Oct 15, 2024 at 10:16:20AM +0200, David Hildenbrand wrote:
>> On 15.10.24 10:12, Heiko Carstens wrote:
>>> On Mon, Oct 14, 2024 at 09:35:27PM +0200, David Hildenbrand wrote:
>>>> On 14.10.24 20:04, Heiko Carstens wrote:
>>> "If only there would be a query subcode available, so that the program
>>> check handling would not be necessary; but in particular my new subcode
>>> is not worth adding it" :)
>>>
>>> Anyway, I do not care too much.
>>>
>>
>> Okay, I see your point: it would allow for removing the program check
>> handling from the STORAGE LIMIT invocation.
>>
>> ... if only we wouldn't need the exact same program check handling for the
>> new query subfunction :P
>
> Yeah yeah, but I think you got that this might help in the future.

Right. Adding it later also doesn't quite help to get rid of the checks
here, because some user space might implement STORAGE LIMIT without QUERY.

So strategically, the right approach would indeed be to add QUERY now.

Thoughts from the KVM folks? Unfortunately subfunction 0 is taken, which
is usually QUERY IIRC.

--
Cheers,

David / dhildenb