4.20 性能問題、STIBPの有効化よりHT無効化が筋

「Linux 4.20」性能問題、原因はSpectre v2対策STIBPの有効化--トーバルズ氏が変更を要求 - ZDNet Japan
Linux-Kernel Archive: STIBP by default.. Revert?

So why do that STIBP slow-down by default when the people who *really*
care already disabled SMT?

I think we should use the same logic as for L1TF: we default to
something that doesn't kill performance. Warn once about it, and let
the crazy people say "I'd rather take a 50% performance hit than
worry about a theoretical issue".

正論