Re: [PATCH v2 6/8] cxl/mem: Enable commands via CEL

[Dan Williams]

On Thu, Feb 11, 2021 at 9:45 AM Ben Widawsky <ben.widawsky@xxxxxxxxx> wrote:
[..]
> > > +   if (mbox_cmd.size_out > sizeof(gsl)) {
> > > +           dev_warn(dev, "%zu excess logs\n",
> > > +                    (mbox_cmd.size_out - sizeof(gsl)) /
> > > +                            sizeof(struct gsl_entry));
> >
> > This could well happen given spec seems to allow for other
> > entries defined by other specs.
>
> Interesting. When I read the spec before (multiple times) I was certain it said
> other UUIDs aren't allowed. You're correct though that the way it is worded,
> this is a bad check. AIUI, the spec permits any UUID and as such I think we
> should remove tainting for unknown UUIDs. Let me put the exact words:
>
> Table 169 & 170
> "Log Identifier: UUID representing the log to retrieve data for. The following
>  Log Identifier UUIDs are defined in this specification"
>
> To me this implies UUIDs from other (not "this") specifications are permitted.
>
> Dan, I'd like your opinion here. I'm tempted to change the current WARN to a
> dev_dbg or somesuch.

Yeah, sounds ok, and the command is well defined to be a read-only,
zero-side-effect affair. If a vendor did really want to sneak in a
proprietary protocol over this interface it would be quite awkward.