Earlier quoted context omitted.
Or adds a guard. They mention perf issues for the workaround but they're notably absent from the microcode commentary. I wonder what this is going to do to the new AMD hardware AWS is trying to roll out, which is supposed to be a substantial performance bump over the previous generation.
It looks like this is a Zen 2-only exploit, so it shouldn't have any impact - AWS are likely already running hardware that isn't vulnerable to this
The way Spectre and Meltdown played out, you'll have to excuse me if I stand outside the blast radius while we figure out if there's a chapter 2, 3 or 4 to this story.
They've proven Zen 2 has this problem. They haven't proven no other AMD processors have it. A bunch of people looking to make names for themselves are probably busily testing every other AMD processor for a similar exploit.