Re: [PATCH RFC v2 04/18] irq/dev-msi: Introduce APIs to allocate/free dev-msi interrupts

[Jason Gunthorpe]

On Tue, Jul 21, 2020 at 09:02:41AM -0700, Dave Jiang wrote:
> From: Megha Dey <megha.dey@xxxxxxxxx>
> 
> The dev-msi interrupts are to be allocated/freed only for custom devices,
> not standard PCI-MSIX devices.
> 
> These interrupts are device-defined and they are distinct from the already
> existing msi interrupts:
> pci-msi: Standard PCI MSI/MSI-X setup format
> platform-msi: Platform custom, but device-driver opaque MSI setup/control
> arch-msi: fallback for devices not assigned to the generic PCI domain
> dev-msi: device defined IRQ domain for ancillary devices. For e.g. DSA
> portal devices use device specific IMS(Interrupt message store) interrupts.
> 
> dev-msi interrupts are represented by their own device-type. That means
> dev->msi_list is never contended for different interrupt types. It
> will either be all PCI-MSI or all device-defined.

Not sure I follow this, where is the enforcement that only dev-msi or
normal MSI is being used at one time on a single struct device?

Jason