Re: [PATCH 2/2] gpu: nova-core: add fwctl driver for firmware control interface

[Jason Gunthorpe <jgg@nvidia.com>]

On Mon, Mar 30, 2026 at 01:42:07PM -0400, Joel Fernandes wrote:

> Just trying to confirm my understanding: Doesn't that mean
> NV2080_CTRL_CMD_VGPU_MGR_INTERNAL_PGPU_ADD_VGPU_TYPE becomes a part of UAPI
> then?

Yes.

> On the one hand, there is the argument that userspace should not
> deal with GSP-RM specific commands directly (lest they change in the
> future or get removed or whatever, and nova-core is the
> abstraction. On the other hand, I think idea behind fwctl is as
> Jason put it above. So which path is correct and makes sense for
> nova-core?

If you use fwctl it should be as I described, it is not an generic
interface to send SW command to the kernel, the commands have to be
delivered to FW.

> These are transport-layer headers for the GSP RPC message queue, MCTP provides
> packet framing (it is a standard protocol like networking protocols) and NVDM is
> NVIDIA specific header carried inside MCTP. IMO they are internal to the
> nova-core <-> GSP transport and should be filled in by the kernel driver, not
> exposed to userspace.

That makes more sense to me. I would expect only the actual payload to
be part of fwctl. Any transport details must be managed by the kernel.

Jason