Re: [PATCH v2 03/10] PCI/LUO: Forward prepare()/freeze()/cancel() callbacks to driver

Pasha Tatashin
2025-10-03T16:28:38Z

On Fri, Oct 3, 2025 at 12:16 PM Jason Gunthorpe <jgg@ziepe.ca> wrote:
>
> On Fri, Oct 03, 2025 at 09:03:36AM -0700, David Matlack wrote:
> > > Shutting down enough of the PF kernel driver to safely kexec is almost
> > > the same as unbinding it completely.
> >
> > I think it's totally fair to tell us to replace pci-pf-stub with
> > vfio-pci. That gets rid of one PF driver.
> >
> > idpf cannot be easily replaced with vfio-pci, since the PF is also
> > used for host networking.
>
> Run host networking on a VF instead?

There is a plan for this, but not immediately. In upstream, I suspect
vfio-pci is all we need, and other drivers can be added when it really
necessary.

>
> > Brian Vazquez from Google will be giving a
> > talk about the idpf support at LPC so we can revisit this topic there.
> > We took the approach of only preserving the SR-IOV configuration in
> > the PF, everything else gets reset (so no DMA mapping preservation, no
> > driver state preservation, etc.).
>
> Yes, that's pretty much what you'd have to do, it sure would be nice
> to have some helper to manage this to minimize driver work. It really
> is remove the existing driver and just leave it idle unless luo fails
> then rebind it..
>
> > We haven't looked into nvme yet so we'll have to revisit that discussion later.
>
> Put any host storage on a NVMe VF?
>
> Jason