Re: [PATCH] vfio/pci: Separate SR-IOV VF dev_set

[Jason Gunthorpe <jgg@nvidia.com>]

On Thu, Jul 03, 2025 at 06:10:19AM +0000, Tian, Kevin wrote:
> > From: Jason Gunthorpe <jgg@nvidia.com>
> > Sent: Thursday, July 3, 2025 1:56 AM
> > 
> > On Wed, Jul 02, 2025 at 11:50:32AM -0600, Alex Williamson wrote:
> > > I haven't tried it, but it may be possible to trigger a hot reset
> > > on a user owned PF while there are open VFs.  If that is possible, I
> > > wonder if it isn't just a userspace problem though, it doesn't seem
> > > there's anything fundamentally wrong with it from a vfio perspective.
> > > The vf-token already indicates at the kernel level that there is
> > > collaboration between PF and VF userspace drivers.
> > 
> > I think it will disable SRIOV and that will leave something of a
> > mess. Arguably we should be blocking resets that disable SRIOV inside
> > vfio?
> > 
> 
> Is there any reset which doesn't disable SRIOV? According to PCIe
> spec both conventional reset and FLR targeting a PF clears the
> VF enable bit.

This is my understanding, I think there might be a little hole here in
the vfio SRIOV support?

Jason