Re: [patch V2 00/28] x86/speculation: Remedy the STIBP/IBPB overhead

From: Ingo Molnar
Date: Mon Nov 26 2018 - 08:37:46 EST



* Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:

> Thats hopefully the final version of this. Changes since V1:
>
> - Renamed the command line option and related code to spectre_v2_user= as
> suggested by Josh.
>
> - Thought more about the back to back optimization and finally left the
> IBPB code in switch_mm().
>
> It still removes the ptrace check for the always IBPB case. That's
> substantial overhead for dubious value now that the default is
> conditional (prctl/seccomp) IBPB.
>
> - Added two options which allow conditional STIBP and IBPB always mode.
>
> - Addressed the review comments

With the typo review feedback outlined in the discussions:

Reviewed-by: Ingo Molnar <mingo@xxxxxxxxxx>

Thanks,

Ingo