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

Jason Gunthorpe <[email protected]> Wed, 4 Mar 2026 10:18:52 -0400

Newsgroups	org.kernel.vger.linux-fpga,dev.linux.lists.driver-core,org.freedesktop.lists.dri-devel,org.freedesktop.lists.nouveau,org.kernel.vger.linux-doc,org.kernel.vger.linux-kernel,org.kernel.vger.linux-pci,org.kernel.vger.rust-for-linux
Message-ID	<[email protected]>

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