Re: [PATCH RFC 00/20] attestation: Add a common subsystem and TDX support

[Jarkko Sakkinen]

On Sat, Oct 17, 2026 at 05:34:07PM -0300, Jason Gunthorpe wrote:
> > +Jarkko
> > The TPM driver is pretty entrenched and heavily used by different user
> > space applications, so it seems really ambitious to bundle in TPM
> > here.
> 
> By "ROT agility" I mean if you want to do an extend operation you
> should not have to know the details of the HW holding the "PCR".
> 
> One of the APIs offered here is a HW agnostic extend that can be used
> to build ROT agility into user space programs that are doing
> logging. That's systemd-pcr-extend for example.
> 
> The extent of the TPM support is to be able to issue a PCR extend
> triggered with a TPM command by the agnostic API. Not ambitious at
> all.

I wish I had a better picture what is going on.

I don't have capacity to heavily on this but can help sorting out
issues if they are put better into nutshell.

I would recommend to at least check out tpm2-protocol because when
I did it my main use case was exactly protocol interceptor. It is
designed from the bottom for that one use case. Plus zero cost
memory usage can be casted to a raw pointer.

Br, Jarkko