Re: [PATCH v2 0/5] rust: pci: add config space read/write support, take 1

["Alexandre Courbot" <acourbot@nvidia.com>]

On Fri Oct 17, 2025 at 6:02 AM JST, Zhi Wang wrote:
> In the NVIDIA vGPU RFC [1], the PCI configuration space access is
> required in nova-core for preparing gspVFInfo when vGPU support is
> enabled. This series is the following up of the discussion with Danilo
> for how to introduce support of PCI configuration space access in Rust
> PCI abstrations. Bascially, we are thinking of introducing another
> backend for PCI configuration space access similar with Kernel::Io.
>
> This ideas of this series are:
>
> - Factor out a common trait 'Io' for other accessors to share the
>   same compiling/runtime check like before.
>
> - Factor the MMIO read/write macros from the define_read! and
>   define_write! macros. Thus, define_{read, write}! can be used in other
>   backend.
>
> - Add a helper to query configuration space size. This is mostly for
>   runtime check.
>
> - Implement the PCI configuration space access backend in PCI
>   abstractions.
>
> v2:
>
> - Factor out common trait as 'Io' and keep the rest routines in original
>   'Io' as 'Mmio'. (Danilo)
>
> - Rename 'IoRaw' to 'MmioRaw'. Update the bus MMIO implemention to use
>   'MmioRaw'.
>
> - Intorduce pci::Device<Bound>::config_space(). (Danilo)
>
> - Implement both infallible and fallible read/write routines, the device
>   driver devicdes which version should be used.
>
> Moving forward:
>
> - Define and use register! macros.
> - Introduce { cap, ecap } search and read.
>
> RFC v1:
> https://lore.kernel.org/all/20251010080330.183559-1-zhiw@nvidia.com/

One small nit: the title of this series 

    [PATCH v2 0/5] rust: pci: add config space read/write support, take 1

Is a tad confusing. How can this be take 1, if this is a v2? Also there
is no v1, the previous revision was a RFC.

Technically this should have been [PATCH 0/5] or [PATCH v1 0/5]. `b4` is
great to avoid this kind of problems, and a huge time saver generally
speaking. Can't recommend it enough.