Re: [RFC XEN PATCH v9 5/5] domctl: Add XEN_DOMCTL_gsi_permission to grant gsi

[Jan Beulich <jbeulich@suse.com>]

On 14.06.2024 05:11, Chen, Jiqian wrote:
> On 2024/6/13 20:51, Anthony PERARD wrote:
>> On Wed, Jun 12, 2024 at 10:55:14AM +0000, Chen, Jiqian wrote:
>>> On 2024/6/12 18:34, Jan Beulich wrote:
>>>> On 12.06.2024 12:12, Chen, Jiqian wrote:
>>>>> On 2024/6/11 22:39, Jan Beulich wrote:
>>>>>> On 07.06.2024 10:11, Jiqian Chen wrote:
>>>>>>> +    r = xc_domain_gsi_permission(ctx->xch, domid, gsi, map);
>>>>>>
>>>>>> Looking at the hypervisor side, this will fail for PV Dom0. In which case imo
>>>>>> you better would avoid making the call in the first place.
>>>>> Yes, for PV dom0, the errno is EOPNOTSUPP, then it will do below xc_domain_irq_permission.
>>>>
>>>> Hence why call xc_domain_gsi_permission() at all on a PV Dom0?
>>> Is there a function to distinguish that current dom0 is PV or PVH dom0 in tools/libs?
>>
>> That might have never been needed before, so probably not. There's
>> libxl__domain_type() but if that works with dom0 it might return "HVM"
>> for PVH dom0. So if xc_domain_getinfo_single() works and give the right
>> info about dom0, libxl__domain_type() could be extended to deal with
>> dom0 I guess. I don't know if there's a good way to find out which
>> flavor of dom0 is running.
> Thanks Anthony!
> I think here we really need to check is that whether current domain has PIRQ flag(X86_EMU_USE_PIRQ) or not.
> And it seems xc_domain_gsi_permission already return the information.

By way of failing, if I'm not mistaken? As indicated before, I don't
think you should invoke the function when it's clear it's going to fail.

Jan

> If current domain has no PIRQs, then I should use xc_domain_gsi_permission to grant permission, otherwise I should
> keep the original function xc_domain_irq_permission.
> 
>>
>> Cheers,
>>
>