Re: [PATCH 2/3] x86/speculation: Support Automatic IBRS

[Peter Zijlstra]

On Fri, Nov 04, 2022 at 10:52:13PM +0100, Borislav Petkov wrote:
> On Fri, Nov 04, 2022 at 04:36:50PM -0500, Kim Phillips wrote:
> >  - Allow for spectre_v2=autoibrs in the kernel command line,
> >    reverting to auto-selection if the feature isn't available.
> 
> Why?
> 
> What the whole logic here should do is enable autoibrs when detected
> automatically, without the need for the user to even select it as it is
> the superior mitigation.

Well; perhaps the whole autoibrs thing should be mapped to the existing
eIBRS options. AFAICT this is the same thing under a new name, no need
to invent yet more options. bugs.c is quite insane enough already.