Re: [PATCH 0/3] arm64/virt: Add Arm CCA measurement register support

Jason Gunthorpe
2026-04-14T12:30:00Z

On Tue, Apr 14, 2026 at 11:10:51AM +0100, Suzuki K Poulose wrote:

> > Isn't this also sort of incomplete? Doesn't anything serious need
> > signed measurements? Isnt't there alot more data that comes out of RMM
> > than just a few measurement registers?
> As mentioned above, this series adds the support for Runtime Extendible
> Measurements (REM in CCA, RTMR on TDX). The RIM+Platform Attestation is
> already provided via the TSM_REPORT

Okay, but what actual use is this?

Extendable measrements with no log
Measurement read back without signature

What is the use case? What do you imagine any userspace will do with
this? Put it in the cover letter.

I don't think the raw rmm calls are sufficiently developed to be
usable directly by userspace. They are less capable than TPM and even
TPM has a lot of software around it to make it useful.

Jason