Re: [RFC PATCH v2 1/1] platform-msi: Add platform check for subdevice irq domain

[Lu Baolu]

On 1/7/21 12:01 AM, Leon Romanovsky wrote:
> On Wed, Jan 06, 2021 at 11:23:39AM -0400, Jason Gunthorpe wrote:
> > On Wed, Jan 06, 2021 at 12:40:17PM +0200, Leon Romanovsky wrote:
> >
> > > I asked what will you do when QEMU will gain needed functionality?
> > > Will you remove QEMU from this list? If yes, how such "new" kernel will
> > > work on old QEMU versions?
> >
> > The needed functionality is some VMM hypercall, so presumably new
> > kernels that support calling this hypercall will be able to discover
> > if the VMM hypercall exists and if so superceed this entire check.
>
> Let's not speculate, do we have well-known path?

All these (hypercall detect and invoke) will be done in
pci_subdevice_msi_create_irq_domain(). It will be transparent to the
callers.

> Will such patch be taken to stable@/distros?

It will not be taken to stable. For distros, it depends. They can
backport if they want to support the feature.

Best regards,
baolu