Re: [PATCH v3 5/5] pci: Suspend iommu function prior to resetting a device

Jason Gunthorpe
2025-08-28T18:46:17Z

On Thu, Aug 28, 2025 at 08:08:13AM -0700, Nicolin Chen wrote:
> On Thu, Aug 28, 2025 at 09:51:49AM -0300, Jason Gunthorpe wrote:
> > On Fri, Aug 22, 2025 at 11:50:58AM -0700, Nicolin Chen wrote:
> >
> > > It feels like we need a no-fail re-attach operation, or at least an
> > > unlikely-to-fail one. I recall years ago we tried a can_attach op
> > > to test the compatibility but it didn't get merged. Maybe we'd need
> > > it so that a concurrent attach can test compatibility, allowing the
> > > re-attach in iommu_dev_reset_done() to more likely succeed.
> >
> > This is probably the cleanest option to split these things
>
> Yea, that could avoid failing a concurrent attach_dev during FLR
> unless the dryrun fails, helping non-SRIOV cases too.
>
> So, next version could have some new preparatory patches:
> - Pass in old domain to attach_dev
> - Add a can_attach_dev op

I wouldn't make this more complicated, just focus on the signal device
case here then we move on from there

Just adding can_attach_dev is big series on its own

Jason