Re: [PATCH 1/2] x86/mm/pat: Change pat_disable() to emulate PAT table

From: Borislav Petkov
Date: Tue Mar 15 2016 - 11:48:03 EST

On Tue, Mar 15, 2016 at 09:43:15AM -0600, Toshi Kani wrote:
> > Please use on init paths boot_cpu_has(X86_FEATURE_PAT) and on fast paths
> > static_cpu_has(X86_FEATURE_PAT). No more of that cpu_has_XXX ugliness.
> 'cpu_has_pat' is defined as 'boot_cpu_has(X86_FEATURE_PAT)'. ÂDo you mean
> it should explicitly use 'boot_cpu_has(X86_FEATURE_PAT)'?

No, read what I said.

We use boot_cpu_has(<feature_bit>) on slow paths (i.e., init, bootup,
etc), where speed is not that important. static_cpu_has(<feature_bit>)
is an optimized version which should be used in hot paths.


ECO tip #101: Trim your mails when you reply.