Re: [PATCH 09/11] x86/pti: enable global pages for shared areas

[Linus Torvalds]

On Mon, Apr 2, 2018 at 10:27 AM, Dave Hansen
<dave.hansen@xxxxxxxxxxxxxxx> wrote:
>
> +       /*
> +        * The cpu_entry_area is shared between the user and kernel
> +        * page tables.  All of its ptes can safely be global.
> +        */
> +       if (boot_cpu_has(X86_FEATURE_PGE))
> +               pte = pte_set_flags(pte, _PAGE_GLOBAL);

So this is where the quesion of "why is this conditional" is valid.

We could set _PAGE_GLOBAL unconditionally, not bothering with testing
X86_FEATURE_PGE.

                Linus