On Thu, Aug 12, 2021 at 04:51:26PM -0300, Jason Gunthorpe wrote: > On Thu, Aug 12, 2021 at 10:57:07AM -0500, Bjorn Helgaas wrote: > > On Thu, Aug 12, 2021 at 10:27:28AM -0300, Jason Gunthorpe wrote: > > > On Wed, Aug 11, 2021 at 02:07:37PM -0500, Bjorn Helgaas wrote: > > > > On Thu, Aug 05, 2021 at 09:23:57PM -0300, Jason Gunthorpe wrote: > > > > > > Do the other bus types have a flag analogous to > > > > PCI_ID_F_VFIO_DRIVER_OVERRIDE? If we're doing something similar to > > > > other bus types, it'd be nice if the approach were similar. > > > > > > They could, this series doesn't attempt it. I expect the approach to > > > be similar as driver_override was copied from PCI to other > > > busses. When this is completed I hope to take a look at it. > > > > I think this would make more sense as two patches: > > > > - Add a "PCI_ID_DRIVER_OVERRIDE" flag. This is not VFIO-specific, > > since nothing in PCI depends on the VFIO-ness of drivers that use > > the flag. The only point here is that driver id_table entries > > with this flag only match when driver_override matches the driver. > > This would require using two flags, one to indicate the above to the > PCI code and another to indicate the vfio_pci string to > file2alias. This doesn't seem justified at this point, IMHO. I don't think it requires two flags. do_pci_entry() has: if (flags & PCI_ID_F_VFIO_DRIVER_OVERRIDE) strcpy(alias, "vfio_pci:"); I'm just proposing a rename: s/PCI_ID_F_VFIO_DRIVER_OVERRIDE/PCI_ID_DRIVER_OVERRIDE/ > > - Update file2alias.c to export the flags and the "vfio_pci:" alias. > > This seems to be the only place where VFIO comes into play, and > > putting it in a separate patch will make it much smaller and it > > will be clear how it could be extended for other buses. > > Well, I don't want to see a flag called PCI_ID_DRIVER_OVERRIDE mapped > to the string "vfio_pci", that is just really confusing. Hahaha, I see, that's fair :) It confused me for a long time why you wanted "VFIO" in the flag name because from the kernel's point of view, the flag is not related to any VFIO-ness. It's only related to a special variety of driver_override, and VFIO happens to be one user of it. I think a separate patch that maps the flag to "vfio_pci" would be less confusing because without the distractions of the PCI core changes, it will be obvious that "vfio_" is a file2alias thing that's there for userspace convenience, not for kernel reasons. Do you envision any other prefixes in the future? I hope we don't have to clutter pci_match_device() with checking multiple flags. Maybe the problem is that the modules.alias entry includes "vfio_" -- maybe we need a more generic prefix with just the idea of an "alternate" driver. Bjorn