Re: SVSM vTPM specification

[Dionna Amalie Glaze <dionnaglaze@google.com>]

> >
> > Hmm, do we need also something like SNP_GET_EXT_REPORT which also
> > returns the cert-chain stored in the host kernel? Or modify this call to
> > also return the certs?
>
> Yes, good catch. I believe we do. Adding two more parameters (maybe change
> this to a struct now?) for Cert Data GPA and Cert Data size is the way to
> go. We want the Cert Data that is associated with the attestation report
> that was generated, in an "atomic" way. Once live migration is available,
> the VM could theoretically be migrated in between two functions calls and
> then the VCEK wouldn't match.
>
> Thanks,
> Tom
>
> >

I thought that TPM2_EC_Emphemeral would get the EC public key and
Tspi_Key_GetPubKey could be used to get the SRK public key. I might be
mistaken, but I believe the TPM has commands for this already, so the
vTPM protocol doesn't need an extra entrypoint. The TPM keys shouldn't
change through live migration, so querying separately should work.

-- 
-Dionna Glaze, PhD (she/her)