Re: [RFC 2/6] drivers: pci: Change CONFIG_SPDM to a dependency

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Fri, 22 Nov 2024 11:23:54 -0600
Bjorn Helgaas <helgaas@kernel.org> wrote:

> On Fri, Nov 22, 2024 at 03:30:40PM +0000, Jonathan Cameron wrote:
> >   
> > > > diff --git a/lib/Kconfig b/lib/Kconfig
> > > > index 68f46e4a72a6..4db9bc8e29f8 100644
> > > > --- a/lib/Kconfig
> > > > +++ b/lib/Kconfig
> > > > @@ -739,6 +739,21 @@ config LWQ_TEST
> > > >  	help
> > > >            Run boot-time test of light-weight queuing.
> > > >  
> > > > +config SPDM
> > > > +	bool "SPDM"    
> > > 
> > > If this appears in a menuconfig or similar menu, I think expanding
> > > "SPDM" would be helpful to users.  
> > 
> > Not sure it will!  Security Protocol and Data Model
> > which to me is completely useless for hinting what it is ;)
> > 
> > Definitely keep (SPDM) on end of expanded name as I suspect most
> > people can't remember the terms (I had to look it up ;)  
> 
> Agree that the expansion doesn't add a whole lot, but I do think the
> unadorned "SPDM" config prompt is not quite enough since this is in
> the "Library routines" section and there's no useful context at all.
> 
> Maybe a hint that it's related to PCIe (although I'm not sure it's
> *only* PCIe?) or device authentication or even some kind of general
> "security" connection?

It's much broader than PCIe (I believe originated in USB before
being standardized?)

Maybe something like...

SPDM for security related message exchange (with devices)

Attempting to distill the text in the Introduction of the spec.

"The Security Protocol and Data Model (SPDM) Specification defines messages, data objects, and sequences for
performing message exchanges over a variety of transport and physical media. The description of message
exchanges includes authentication and provisioning of hardware identities, measurement for firmware identities,
session key exchange protocols to enable confidentiality with integrity-protected data communication, and other
related capabilities. The SPDM enables efficient access to low-level security capabilities and operations. Other
mechanisms, including non-DMTF-defined mechanisms, can use the SPDM"

So clear as mud ;)

J


> 
> I admit that you're in good company; "parman" and "objagg" have zero
> context and not even any help text at all.
> 
> Bjorn