Re: [PATCH v2 06/39] x86/fpu: Add helper for modifying xstate

From: Dave Hansen
Date: Tue Oct 04 2022 - 10:18:52 EST

On 10/3/22 13:05, Edgecombe, Rick P wrote:
> The CET state is xsaves managed. It gets lazily restored before
> returning to userspace with the rest of the fpu stuff. This function
> will force restore all the fpu state to the registers early and lock
> them from being automatically saved/restored. Then the tasks CET state
> can be modified in the MSRs, before unlocking the fpregs. Last time I
> tried to modify the state directly in the xsave buffer when it was
> efficient, but it had issues and Thomas suggested this.

Can you get the gist of this in a comment, please?