Re: [PATCH v3 00/10] rust: pci: add abstractions for SR-IOV capability

Jason Gunthorpe
2026-03-04T14:18:54Z

On Wed, Mar 04, 2026 at 10:47:50AM +0200, Leon Romanovsky wrote:
> On Tue, Mar 03, 2026 at 04:15:20PM -0500, Peter Colberg wrote:
> > Add Rust abstractions for the Single Root I/O Virtualization (SR-IOV)
> > capability of a PCI device. Provide a minimal set of wrappers for the
> > SR-IOV C API to enable and disable SR-IOV for a device, and query if
> > a PCI device is a Physical Function (PF) or Virtual Function (VF).
>
> <...>
>
> > For PF drivers written in C, disabling SR-IOV on remove() may be opted
> > into by setting the flag managed_sriov in the pci_driver structure. For
> > PF drivers written in Rust, disabling SR-IOV on unbind() is mandatory.
>
> Why? Could you explain the rationale behind this difference between C and
> Rust? Let me remind you that SR‑IOV devices which do not disable VFs do so
> for a practical and well‑established reason: maximizing hardware
> utilization.

Personally I think drivers doing this are wrong. That such a driver
bug was allowed to become UAPI is pretty bad. The rust approach is
better.

Jason