Re: [PATCH 0/8] rust: pci: add abstractions for SR-IOV capability

[Zhi Wang <zhiw@nvidia.com>]

On Wed, 19 Nov 2025 17:19:04 -0500
Peter Colberg <pcolberg@redhat.com> wrote:

Hi Peter:

Thanks for the patches. :) I will test them with nova-core and come back
with Tested-bys.

Nit: Let's use "kernel vertical" styles on imports. [1]

[1] https://lore.kernel.org/all/20251105120352.77603-1-dakr@kernel.org/

> 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).
> 
> Using the #[vtable] attribute, extend the pci::Driver trait with an
> optional bus callback sriov_configure() that is invoked when a
> user-space application writes the number of VFs to the sysfs file
> `sriov_numvfs` to enable SR-IOV, or zero to disable SR-IOV [1].
> 
> Add a method physfn() to return the Physical Function (PF) device for
> a Virtual Function (VF) device in the bound device context. Unlike
> for a PCI driver written in C, guarantee that when a VF device is
> bound to a driver, the underlying PF device is bound to a driver, too.
> 
> When a device with enabled VFs is unbound from a driver, invoke the
> sriov_configure() callback to disable SR-IOV before the unbind()
> callback. To ensure the guarantee is upheld, call disable_sriov()
> to remove all VF devices if the driver has not done so already.
> 
> This series is based on Danilo Krummrich's series "Device::drvdata()
> and driver/driver interaction (auxiliary)" applied to
> driver-core-next, which similarly guarantees that when an auxiliary
> bus device is bound to a driver, the underlying parent device is
> bound to a driver, too [2].
> 
> Add an SR-IOV driver sample that exercises the SR-IOV capability using
> QEMU's 82576 (igb) emulation and was used to test the abstractions
> [3].
> 
> [1] https://docs.kernel.org/PCI/pci-iov-howto.html
> [2]
> https://lore.kernel.org/rust-for-linux/20251020223516.241050-1-dakr@kernel.org/
> [3] https://www.qemu.org/docs/master/system/devices/igb.html
> 
> Signed-off-by: Peter Colberg <pcolberg@redhat.com>
> ---
> John Hubbard (1):
>       rust: pci: add is_virtfn(), to check for VFs
> 
> Peter Colberg (7):
>       rust: pci: add is_physfn(), to check for PFs
>       rust: pci: add {enable,disable}_sriov(), to control SR-IOV
> capability rust: pci: add num_vf(), to return number of VFs
>       rust: pci: add vtable attribute to pci::Driver trait
>       rust: pci: add bus callback sriov_configure(), to control
> SR-IOV from sysfs rust: pci: add physfn(), to return PF device for VF
> device samples: rust: add SR-IOV driver sample
> 
>  MAINTAINERS                           |   1 +
>  rust/kernel/pci.rs                    | 148
> ++++++++++++++++++++++++++++++++++ samples/rust/Kconfig
>    |  11 +++ samples/rust/Makefile                 |   1 +
>  samples/rust/rust_dma.rs              |   1 +
>  samples/rust/rust_driver_auxiliary.rs |   1 +
>  samples/rust/rust_driver_pci.rs       |   1 +
>  samples/rust/rust_driver_sriov.rs     | 107 ++++++++++++++++++++++++
>  8 files changed, 271 insertions(+)
> ---
> base-commit: e4addc7cc2dfcc19f1c8c8e47f3834b22cb21559
> change-id: 20251026-rust-pci-sriov-ca8f501b2ae3
> 
> Best regards,