Re: [PATCH v5 0/3] rust: add `bitfield!` macro

[Yury Norov <yury.norov@gmail.com>]

On Sat, Jun 06, 2026 at 09:43:03PM +0900, Alexandre Courbot wrote:
> This is the continuation of the `bitfield!` macro which started
> alongside the `register!` one before being temporarily integrated into
> it [1].
> 
> This series extracts `bitfield!` from `register!`, adds unit tests for
> the new macro, and replaces the `register!` macro rules with the
> extracted version.
> 
> I have removed the `nova-core` patches, because the Blackwell support
> that has been added this cycle (and thus not visible from `rust-next`)
> introduces more uses of the Nova-local `bitfield!` macro that this
> series intended to remove. If these new uses are not updated, then
> `nova-core` won't build, thus to avoid conflicts and/or build breakages
> I think it is preferable to merge them during the next cycle.
> 
> This version is based on `rust-next`, with [2] applied.
> 
> A tree with this branch and its dependencies is available at [3].
> 
> [1] https://lore.kernel.org/all/20260120-register-v1-0-723a1743b557@nvidia.com/
> [2] https://lore.kernel.org/all/20260417031531.315281-1-ynorov@nvidia.com/
> [3] https://github.com/Gnurou/linux/tree/b4/bitfield
> 
> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>

Thanks for the work!

Reviewed-by: Yury Norov <ynorov@nvidia.com>

> ---
> Changes in v5:
> - Squash the fixup patches into the one extracting the `bitfield!` macro.
> - Remove the `nova-core` patches to avoid a conflict/build breakage on
>   -rc1.
> - Improve the unit tests per Yury's feedback:
>   - Use a consistent test axis where each test focuses on a single thing.
>   - Rename members to generic name including range for readability.
>   - Add test exercising `try_with`.
>   - Add test checking that unallocated bits are left untouched.
> - Link to v4: https://patch.msgid.link/20260527-bitfield-v4-0-e8821d4efbde@nvidia.com
> 
> Changes in v4:
> - Inline private bitfield accessor methods.
> - Fully qualify types in `bitfield!` macro.
> - Rename `RUST_KERNEL_BITFIELD_KUNIT_TEST` to `RUST_BITFIELD_KUNIT_TEST`.
> - Link to v3: https://patch.msgid.link/20260501-bitfield-v3-0-aa1076c3337d@nvidia.com
> 
> Changes in v3:
> - Split patch 1 into the addition of the `bitfield!` macro and its use
>   in the `io` module.
> - Mention reserved field names in `bitfield!`'s doccomment.
> - Properly order fields in the KUnit test.
> - Add a Kconfig option for building the KUnit tests.
> - Document behavior on non-covered bits.
> - Document support for signed fields and storage types (TL;DR: not
>   supported).
> - Move `nova-core`'s `bitfield` module deletion into its own patch.
> - Link to v2: https://patch.msgid.link/20260409-bitfield-v2-0-23ac400071cb@nvidia.com
> 
> ---
> Alexandre Courbot (2):
>       rust: extract `bitfield!` macro from `register!`
>       rust: io: use the `bitfield!` macro in `register!`
> 
> Joel Fernandes (1):
>       rust: bitfield: Add KUnit tests for bitfield
> 
>  MAINTAINERS                |   7 +
>  rust/kernel/Kconfig.test   |  10 +
>  rust/kernel/bitfield.rs    | 862 +++++++++++++++++++++++++++++++++++++++++++++
>  rust/kernel/io/register.rs | 246 +------------
>  rust/kernel/lib.rs         |   1 +
>  5 files changed, 882 insertions(+), 244 deletions(-)
> ---
> base-commit: 72d33b8bfeacbfdccf2cda4650e8e002def036f8
> change-id: 20260408-bitfield-6e18254f4fdc
> prerequisite-message-id: 20260417031531.315281-1-ynorov@nvidia.com
> prerequisite-patch-id: 403e34bb92b42d3f31ed972e11896d18902585e3
> prerequisite-patch-id: 42ae775aa6762a9e28ff31c5f69a0b65a7b40dcc
> prerequisite-patch-id: 19b3e535962348f7627ede57ea829b34abda08c7
> 
> Best regards,
> --  
> Alexandre Courbot <acourbot@nvidia.com>