[Hmm, are there missing posts on FPMurphy’s blog? I seem to recall more recent posts, but don’t see them now, and only see this February-era post (which I think may be news to me): ]

A UEFI Shell tool for the CPUID instruction:

https://github.com/fpmurphy/UEFI-Utilities-2018/blob/master/MyApps/Cpuid/Cpuid.c

https://blog.fpmurphy.com/2018/02/simple-cpuid-utility-for-uefi-shell.html