Re: [PATCH RFC 0/3] tsm: Unified Measurement Register ABI for TVMs

From: James Bottomley
Date: Wed Sep 11 2024 - 08:06:40 EST


On Tue, 2024-09-10 at 23:01 -0500, Xing, Cedric wrote:
> On 9/10/2024 12:09 PM, Jean-Philippe Brucker wrote:
> > Hi Cedric,
> >
> > On Sat, Sep 07, 2024 at 11:56:18PM -0500, Cedric Xing wrote:
> > > Patch 2 introduces event log support for RTMRs, addressing the
> > > fact that the standalone values of RTMRs, which represent the
> > > cumulative digests of sequential events, are not fully
> > > informative on their own.
> >
> > Would each event_log include the events that firmware wrote before
> > Linux?
>  
> No. The log format proposed here is textual and incompatible with
> TCG2 log format.
>
> The proposed log format is based on the CoCo event log -
> https://github.com/confidential-containers/guest-components/issues/495
> .

Given that AMD is planning to use the SVSM-vTPM for post launch
measurements, not supporting TPMs in any form would make this Intel
only on x86 and thus not very "unified". Microsoft also tends to do
attestations partly via the vTPM in its L1 openHCL component (even for
TDX) and thus would also have difficulty adopting this proposal.

Regards,

James