Re: [PATCH v6 4/4] x86/sev: register tpm-svsm platform device

Borislav Petkov
2025-04-09T18:38:28Z

On Wed, Apr 09, 2025 at 08:22:37AM -0400, James Bottomley wrote:
> Because of the way driver and device matching works in Linux. We have
> to have a struct device because that sits at the he heart of the TPM
> driver binding. If we have a struct device, it has to sit on a bus
> (because that's the Linux design) and if we don't have a bus then we
> have to use a platform device

Thanks for elaborating!

> (or, now, we could use a struct device on the faux bus). Busses can be
> either physical (PCI, GSC, ...) and abstract (virtio, xen, scsi, ...), so
> it's not impossible, if the SVSM has more than one device, that it should
> have it's own SVSM bus which we could then act a bit like the virtio bus and
> the SVSM vTPM struct device could sit on this

I guess we should keep this in mind. Depending on what else needs to talk to
the SVSM in the future...

Thx.

--
Regards/Gruss,
Boris.