Re: [PATCH v9 1/1] rust: pci: add extended capability and SR-IOV support

[Alexandre Courbot]

On Thu Aug 27, 2026 at 9:18 PM JST, Zhi Wang wrote:
> Rust PCI drivers have no typed interface for locating and accessing PCIe
> extended capabilities.
>
> The SR-IOV extended capability describes VF topology and VF BARs. Expose
> this information through the Rust PCI abstraction so drivers can use the
> existing typed configuration-space accessors instead of raw bindings.
>
> Define ExtCapability to associate a capability ID with a register layout,
> and add ConfigSpace::find_ext_capability() to locate and project that
> layout. Bound the view at the next capability or the end of extended
> configuration space. Add ExtSriovRegs and a decoded VF BAR iterator that
> reads and validates all six VF BAR register slots up front, yields decoded
> BAR addresses and widths in logical order, and keeps the raw
> configuration-space slot advancement internal. Since PCI_EXT_CAP_NEXT() is
> a function-like macro, expose it through a Rust helper.
>
> Keep raw SR-IOV registers private because PCI core owns their state. Expose
> the current First VF Offset through a read-only accessor because the Nova
> GSP ABI needs the raw 16-bit First VF Offset in Routing ID space. The
> pci_iov_virtfn_devfn() helper instead returns the low eight bits of a
> calculated VF Routing ID.
>
> Link: https://lore.kernel.org/rust-for-linux/20260818084633.1673214-2-zhiw@xxxxxxxxxx/
> Cc: Alexandre Courbot <acourbot@xxxxxxxxxx>
> Cc: Gary Guo <gary@xxxxxxxxxxx>
> Signed-off-by: Zhi Wang <zhiw@xxxxxxxxxx>

Reviewed-by: Alexandre Courbot <acourbot@xxxxxxxxxx>