Re: [PATCH RFC 3/3] tsm: Add TVM Measurement Sample Code

From: Mikko Ylinen
Date: Thu Oct 24 2024 - 13:22:41 EST


On Sat, Sep 14, 2024 at 01:10:33PM -0400, James Bottomley wrote:
> On Sat, 2024-09-14 at 11:36 -0500, Xing, Cedric wrote:
>
> > Also, MRs are arch dependent and may also vary from gen to gen. I'm
> > afraid this might bring in more chaos than order.
>
> I think I understand this. All measurement registers are simply
> equivalent to PCRs in terms of the mathematical definition of how they
> extend. Exactly what measurements go into a PCR and how they are

Given this, would it be reasonable to go back to the digest based
input ABI idea where user space would use the TSM provider specifc
hash algo to prepare the input? The kernel eventlog for each MR (or
some notification mechanism to user space) would be provided just to
keep the digest ordering. Apps would map their inputs to that digest
list when doing attestation (in whatever format they choose).

On that note, we have the CCC kernel SIG call again Friday this week. If
we get enough people interested in this topic on the call, we could
brainstorm this a bit further.

-- Regards, Mikko