Re: [XEN PATCH v10 5/5] domctl: Add XEN_DOMCTL_gsi_permission to grant gsi

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

On Fri, Jun 21, 2024 at 08:20:55AM +0000, Chen, Jiqian wrote:
> On 2024/6/20 18:42, Jan Beulich wrote:
> > On 20.06.2024 11:40, Chen, Jiqian wrote:
> >> On 2024/6/18 17:23, Jan Beulich wrote:
> >>> On 18.06.2024 10:23, Chen, Jiqian wrote:
> >>>> On 2024/6/17 23:32, Jan Beulich wrote:
> >>>>> On 17.06.2024 11:00, Jiqian Chen wrote:
> >>>>>> @@ -1516,14 +1519,39 @@ static void pci_add_dm_done(libxl__egc *egc,
> >>>>>>              rc = ERROR_FAIL;
> >>>>>>              goto out;
> >>>>>>          }
> >>>>>> -        r = xc_domain_irq_permission(ctx->xch, domid, irq, 1);
> >>>>>> +#ifdef CONFIG_X86
> >>>>>> +        /* If dom0 doesn't have PIRQs, need to use 
> >>>>>> xc_domain_gsi_permission */
> >>>>>> +        r = xc_domain_getinfo_single(ctx->xch, 0, &info);
> >>>>>
> >>>>> Hard-coded 0 is imposing limitations. Ideally you would use DOMID_SELF, 
> >>>>> but
> >>>>> I didn't check if that can be used with the underlying hypercall(s). 
> >>>>> Otherwise
> >> From the commit 10ef7a91b5a8cb8c58903c60e2dd16ed490b3bcf, DOMID_SELF is 
> >> not allowed for XEN_DOMCTL_getdomaininfo.
> >> And now XEN_DOMCTL_getdomaininfo gets domain through rcu_lock_domain_by_id.
> >>
> >>>>> you want to pass the actual domid of the local domain here.
> >> What is the local domain here?
> > 
> > The domain your code is running in.
> > 
> >> What is method for me to get its domid?
> > 
> > I hope there's an available function in one of the libraries to do that.
> I didn't find relate function.
> Hi Anthony, do you know?

Yes, I managed to find:
LIBXL_TOOLSTACK_DOMID
That's the value you can use instead of "0" do designate dom0.
(That was harder than necessary to find.)

Cheers,

-- 

Anthony Perard | Vates XCP-ng Developer

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