Re: [PATCH v2 1/2] rust: pci: skip probing VFs if driver doesn't support VFs

Jason Gunthorpe
2025-10-02T21:04:42Z

On Thu, Oct 02, 2025 at 09:36:17PM +0200, Danilo Krummrich wrote:
> If we want to obtain the driver's private data from a device outside the scope
> of bus callbacks, we always need to ensure that the device is guaranteed to be
> bound and we also need to prove the type of the private data, since a device
> structure can't be generic over its bound driver.

pci_iov_get_pf_drvdata() does both of these things - this is what it
is for. Please don't open code it :(

> > Certain conditions may be workable, some drivers seem to have
> > preferences not to call disable, though I think that is wrong :\
>
> I fully agree! I was told that this is because apparently some PF drivers are
> only loaded to enable SR-IOV and then removed to shrink the potential attack
> surface. Personally, I think that's slightly paranoid, if the driver would not
> do anything else than enable / disable SR-IOV, but I think we can work around
> this use-case if people really want it.

I've heard worse reasons than that. If that is the interest I'd
suggest they should just use VFIO and leave a userspace stub
process..

Jason