Re: [patch V2 27/33] genirq/msi: Provide constants for PCI/IMS support

[Jason Gunthorpe]

On Thu, Nov 24, 2022 at 10:10:05AM +0100, Thomas Gleixner wrote:
> On Thu, Nov 24 2022 at 03:01, Kevin Tian wrote:
> >> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> >> @@ -15,6 +15,7 @@ struct device;
> >>   */
> >>  enum msi_domain_ids {
> >>  	MSI_DEFAULT_DOMAIN,
> >> +	MSI_SECONDARY_DOMAIN,
> >>  	MSI_MAX_DEVICE_IRQDOMAINS,
> >
> > SECONDARY or be explicit IMS? Are we envisioning non-IMS usages to
> > occupy this slot in the future?
> 
> I'm not really decided on that. Whatever the name or use-case for a
> secondary domain is. Not, that this is not restricted to PCI.

This is hierarchical right? So if a pci_device spawns an
auxiliary_device, its driver could stick a msi domain on the
MSI_DEFAULT_DOMAIN of the aux device as a child of the PCI device's
domain?

I don't know if we need per "ADI" msi domains, but it seems OK to me
to hav have two slots for now and be general about what can go in
those slots

Jason