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

[Peter Colberg <pcolberg@redhat.com>]

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,
-- 
Peter Colberg <pcolberg@redhat.com>