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Comment by ComputerGuru | Hacker News Reader

No details on the performance impact of the microcode update. Presumably it disables speculative execution of vzeroupper?

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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.

> 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.

I am OOTL on this one, do you have some information you could share?

There has been a long trickle of similar bugs to Spectre/Meltdown coming out long after the initial bugs and "fixes" were published. (The early fixes were all, in some sense, incomplete.)

There was a list of vulnerabilities in this comment up top: https://news.ycombinator.com/item?id=36849914

AWS does offer Zen 2 based EC2 instances though (C5a family for example).

shouldn't have any effect, the new amd hardware is zen 4 and this only affects zen 2

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