RE: [patch RFC 1/5] x86/CPU: Sync CPU feature flags late

From: Van De Ven, Arjan
Date: Tue Jan 09 2018 - 20:39:27 EST



> In other words, if you use late microcode loading for getting IBRS, you
> don't get ALTERNATIVE patching and its benefits?
>
> I'll also profess some microcode ignorance here. Is "late microcode
> patching" *all* of the stuff we do from the OS, or do we have early and
> late Linux loading in addition to what the BIOS can do?

the early boot loader level stuff is much better generally (but does not work when the microcode comes out after the system booted... like really long uptimes)