“The researchers have also noted that the flaw dates back to at least 2006 and that it impacts nearly every AMD chip.”
IOActive’s Sinkclose lets an attacker run code in System Management Mode, the most privileged mode the processor has. Malware planted there likely survives an OS reinstall. AMD has mitigations for data center and Ryzen parts while embedded chips wait. For an infected machine the advice is a one-way ticket to the trash heap. Nearly two decades of silicon shipped with the basement door unlocked.