Re: [RFC XEN PATCH v8 5/5] domctl: Add XEN_DOMCTL_gsi_permission to grant gsi

[Jan Beulich <jbeulich@xxxxxxxx>]

On 04.06.2024 08:33, Chen, Jiqian wrote:
> On 2024/6/4 14:12, Jan Beulich wrote:
>> On 04.06.2024 08:01, Chen, Jiqian wrote:
>>> On 2024/6/4 13:55, Jan Beulich wrote:
>>>> On 04.06.2024 05:04, Chen, Jiqian wrote:
>>>>> On 2024/5/30 23:51, Jan Beulich wrote:
>>>>>> On 30.05.2024 13:19, Chen, Jiqian wrote:
>>>>>>> It seems only Legacy irq and gsi[0:15] has a mapping in mp_irqs.
>>>>>>> Other gsi can be considered 1:1 mapping with irq? Or are there other 
>>>>>>> places reflect the mapping between irq and gsi?
>>>>>>
>>>>>> It may be uncommon to have overrides for higher GSIs, but I don't think 
>>>>>> ACPI
>>>>>> disallows that.
>>>>> Do you suggest me to add overrides for higher GSIs into array mp_irqs?
>>>>
>>>> Why "add"? That's what mp_override_legacy_irq() already does, isn't it?
>>> No. mp_override_legacy_irq only overrides for gsi < 16, but not for gsi >= 
>>> 16(I dump all mappings from array mp_irqs).
>>
>> I assume you mean you observe so ...
> No, after starting xen pvh dom0, I dump all entries from mp_irqs.

IOW really your answer is "yes" ...

>>> In my environment, gsi of my dGPU is 24.
>>
>> ... on one specific system?

... to this question I raised. Whatever you dump on any number of
systems, there's always the chance that there's another system
where things are different.

>> The function is invoked from
>> acpi_parse_int_src_ovr(), and I can't spot any restriction to
>> IRQs less than 16 there.
> I didn't see any restriction too, but from the dump results, there are only 
> 16 entries, see previous email. 

Hence why I tried to point out that going from observations on a
particular system isn't enough.

Jan