So the guys from PT security (of Intel ME fame) will do a very interesting BH Asia ‘19 talk, if the abstract is accurate:
“We found that modern Platform Controller Hub (PCH) and CPU contain a full-fledged logic signal analyzer, which allows monitoring the state of internal lines and buses in real time”
“With VISA, we succeeded in partially reconstructing the internal architecture of PCH and, within the chip, discovered dozens of devices that are invisible to the user...”