Re: [PATCH v5 0/8] Introduce fwctl subystem

[Saeed Mahameed <saeed@kernel.org>]

On 04 Mar 10:00, Jason Gunthorpe wrote:
>On Mon, Mar 03, 2025 at 05:53:58PM -0800, Jakub Kicinski wrote:
>> On Thu, 27 Feb 2025 20:26:28 -0400 Jason Gunthorpe wrote:
>> > v5:
>> >  - Move hunks between patches to make more sense
>> >  - Rename ucmd_buffer to fwctl_ucmd_buffer
>> >  - Update comments and commit messages
>> >  - Copyright to 2025
>> >  - Drop bxnt WIP patches
>> >  - Allow a NULL ops->info
>> >  - Decode more op codes for mlx5 and the sub-operation for
>> >    MLX5_CMD_OP_ACCESS_REG/_USER
>>
>> Did you address my feedback? I asked for the mlx5 support to only be
>> enabled in RDMA is in use. Saeed who wrote the mlx5 parts of this
>> patchset clearly admitted on v4:

When I said fwctl is not needed for netdev, I meant that it will not be used
for netdev object configuration and as I said before FW will block that
anyways. fwctl in mlx5 is not only for RDMA, So I don't know how to address
your comment. 

Not to mention that fwctl is a very great tool to debug netdev problems.

>
>I never agreed to that formulation. I suggested that perhaps runtime
>configurations where netdev is the only driver using the HW could be
>disabled (ie a netdev exclusion, not a rdma inclusion).
>
>However, there is not agreement on this from Saeed who is responsible
>for mlx5:
>
> https://lore.kernel.org/all/Z7z0ADkimCkhr7Xz@x130/
>
>I also surveyed other stakeholders on a netdev-exclusion proposal and
>did not hear support. You need to convince people this is a good idea.
>
>However, I would agree fwctl should not accept any fwctl drivers for
>simple networking devices. However, "smart nics" and RDMA capable
>devices are in-scope.
>

>I could also probably agree to using kconfig to disable fwctl drivers
>on kernels that statically compile out rdma, vdpa, nvme and related,
>though I agree with Saeed that it seems to lack technical merit.
>
>> Greg, I've been asking for this interface to be scoped to when RDMA
>> (/CXL/storage) is in enabled on these NICs since pretty much the first
>> RFC.
>
>You only started asking for this more limited approach in v4. All your
>previous arguments were that fwctl should be entirely killed for any
>networking HW.
>
>Jason
>