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

["Chen, Jiqian" <Jiqian.Chen@xxxxxxx>]

On 2024/6/4 14:36, Jan Beulich wrote:
> 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.
Anyway, I agree with you that I need to get mapping from mp_irqs.
I tried to get more debug information from my environment. And I attach them 
here, maybe you can find some problems.
acpi_parse_madt_ioapic_entries
        acpi_table_parse_madt(ACPI_MADT_TYPE_INTERRUPT_OVERRIDE, 
acpi_parse_int_src_ovr, MAX_IRQ_SOURCES);
                acpi_parse_int_src_ovr
                        mp_override_legacy_irq
                                only process two entries, irq 0 gsi 2 and irq 9 
gsi 9
There are only two entries whose type is ACPI_MADT_TYPE_INTERRUPT_OVERRIDE in 
MADT table. Is it normal?
And
acpi_parse_madt_ioapic_entries
        mp_config_acpi_legacy_irqs
                process the other GSIs(< 16), so that the total number of 
mp_irqs is 16.

> 
> Jan

-- 
Best regards,
Jiqian Chen.