[nickpsecurity]

That point was reached back in 90's when first security evaluations of Intel architecture were done, found tons of black boxes like SMM, and said to ditch it for security or virtualization. Invisible Things did a good job demonstrating an old risk but people should've ditched it long ago.

If you want verifiable hardware, look up the VAMP processor as it has everything from design descriptions to formal proofs of correctness. Not sure about its availability. SPARC and RISC-V are very open with open-source implementations available with Linux and compiler support. So, there's a solution if people ever want to put the work in.