No, but the concern with Intel and AMD security coprocessors isn't a hardware supply chain attack (like what NSA's TAO unit does with hardware interdiction), it

No, but the concern with Intel and AMD security coprocessors isn't a hardware supply chain attack (like what NSA's TAO unit does with hardware interdiction), it's with a component that we can reasonably assume to be untrustworthy that is guaranteed to be present in every CPU as a "feature". We cannot read the source of CSME or AMD ST firmware. We cannot inspect what it is doing. I can read the source of all firmware for all parts of my CPU. I can inspect what it is doing. This is what the benefit really boils down to - it's not a guarantee of security, but it is a guarantee you can actually audit what your silicon is doing.