Re: [PATCH 09/11] PCI: add matching checks for driver_override binding

[Jason Gunthorpe]

On Tue, Jun 08, 2021 at 03:26:43PM -0600, Alex Williamson wrote:
> > drivers that specifically opt into this feature and the driver now has
> > the opportunity to provide a proper match table that indicates what HW
> > it can properly support. vfio-pci continues to support everything.
> 
> In doing so, this also breaks the new_id method for vfio-pci.  

Does it? How? The driver_override flag is per match entry not for the
entire device so new_id added things will work the same as before as
their new match entry's flags will be zero.

> Sorry, with so many userspace regressions, crippling the
> driver_override interface with an assumption of such a narrow focus,
> creating a vfio specific match flag, I don't see where this can go.
> Thanks,

On the other hand it overcomes all the objections from the last go
round: how userspace figures out which driver to use with
driver_override and integrating the universal driver into the scheme.

pci_stub could be delt with by marking it for driver_override like
vfio_pci.

But driverctl as a general tool working with any module is not really
addressable.

Is the only issue the blocking of the arbitary binding? That is not a
critical peice of this, IIRC

Jason