Delegate measurement information to TCG standards

Hi y'all, I'm not particularly familiar with this format but did learn from Jon Lange on the SVSM call that this is carrying measurement-specific data. I'd like to see what we can do about delegating those measurement specifics to the reference integrity manifest (RIM) information model that you can feed through the SP800155 unmeasured event type. The IETF is working on standardizing a CBOR-based actualization of the information model to deprecate the signed XML format the TCG previously specified, which they call CoRIM.

If IGVM can be expanded to specify QemuFwCfg file contents, then we can pass along signed IGVM measurement information to the user through a standard channel via the tcgSp800155PlatformIdEvent3 unmeasured event added in the TCG PC Client Platform Firmware Profile Version 1.06 Revision 52. Say we pass in the events via etc/sp800155evts, vis a vis https://github.com/tianocore/edk2/pull/5738.

I don't know how "generic" IGVM needs to be, since QemuFwCfg is something we use in our non-Qemu VMM at Google. Is this something y'all think is within IGVM's scope?

Start by reviewing the proposed QemuFwCfg file contents and the etc/sp800155evts event path, then compare the referenced TCG SP800-155 and EDK2 PR 5738 material. Done means establishing whether IGVM should carry RIM or CoRIM measurement information and defining the scope of that support.