Re: [PATCH v2 0/4] Firmware LSM hook

[Leon Romanovsky <leon@kernel.org>]

On Wed, Apr 15, 2026 at 05:40:04PM -0400, Paul Moore wrote:
> On Wed, Apr 15, 2026 at 9:47 AM Jason Gunthorpe <jgg@ziepe.ca> wrote:
> > On Tue, Apr 14, 2026 at 04:27:58PM -0400, Paul Moore wrote:
> > > On Mon, Apr 13, 2026 at 7:19 PM Jason Gunthorpe <jgg@ziepe.ca> wrote:
> > > > On Mon, Apr 13, 2026 at 06:36:06PM -0400, Paul Moore wrote:
> > > > > On Mon, Apr 13, 2026 at 12:42 PM Jason Gunthorpe <jgg@ziepe.ca> wrote:
> > > > > > On Sun, Apr 12, 2026 at 09:38:35PM -0400, Paul Moore wrote:
> 
> ...

<...>

> > > > > so that only the firmware would need to parse the request.  If we
> > > > > wanted to adopt a secmark-esque approach, one could develop a second
> > > > > parsing mechanism that would be responsible for assigning a LSM label
> > > > > to the request, and then pass the firmware request to the LSM, but I
> > > > > do worry a bit about the added complexity associated with keeping the
> > > > > parser sync'd with the driver/fw.
> > > >
> > > > In practice it would be like iptables, the parser would be entirely
> > > > programmed by userspace and there is nothing to keep in sync.
> > >
> > > You've mentioned a few times now that the firmware/request will vary
> > > across not only devices, but firmware revisions too,
> >
> > I never said firmware revisions, part of the requirement is strong ABI
> > compatability in these packets.
> 
> That was my mistake; it was Leon.
> 
> Leon mentioned that different firmware revisions would have different
> parameters for a given opcode, and that one would need to inspect
> those parameters to properly filter the command.  Is that not true, or
> am I misreading or misunderstanding Leon's comments?
> 
> https://lore.kernel.org/all/20260310175759.GD12611@unreal

Right, I said that. The mlx5–FW interface is stable, but that does not
mean it can never change. The contract is that any upstream driver
release must continue to operate correctly with released firmware.

To support this, there are cases where the driver and firmware
negotiate during device initialization to determine whether a given
feature is supported and specific maibox fields are valid.

Thanks