linux-kernel - Re: [PATCH v2] x86/mm/kaiser: Disable global pages by default with KAISER

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Date:   Mon, 27 Nov 2017 14:27:21 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Rik van Riel <riel@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org, bp@...e.de,
        moritz.lipp@...k.tugraz.at, daniel.gruss@...k.tugraz.at,
        michael.schwarz@...k.tugraz.at, richard.fellner@...dent.tugraz.at,
        luto@...nel.org, torvalds@...ux-foundation.org,
        keescook@...gle.com, hughd@...gle.com, x86@...nel.org
Subject: Re: [PATCH v2] x86/mm/kaiser: Disable global pages by default with
 KAISER


* Thomas Gleixner <tglx@...utronix.de> wrote:

> On Mon, 27 Nov 2017, Ingo Molnar wrote:
> > * Thomas Gleixner <tglx@...utronix.de> wrote:
> > > On Sun, 26 Nov 2017, Ingo Molnar wrote:
> > > >  * Disable global pages for anything using the default
> > > >  * __PAGE_KERNEL* macros.
> > > >  *
> > > >  * PGE will still be enabled and _PAGE_GLOBAL may still be used carefully
> > > >  * for a few selected kernel mappings which must be visible to userspace,
> > > >  * when KAISER is enabled, like the entry/exit code and data.
> > > >  */
> > > > #ifdef CONFIG_KAISER
> > > > #define __PAGE_KERNEL_GLOBAL	0
> > > > #else
> > > > #define __PAGE_KERNEL_GLOBAL	_PAGE_GLOBAL
> > > > #endif
> > > > 
> > > > ... and I've added your Reviewed-by tag which I assume now applies?
> > > 
> > > Ideally we replace the whole patch with the __supported_pte_mask one which
> > > I posted as a delta patch.
> > 
> > Yeah, so I squashed these two patches:
> > 
> >   09d76fc407e0: x86/mm/kaiser: Disable global pages by default with KAISER
> >   bac79112ee4a: x86/mm/kaiser: Simplify disabling of global pages
> > 
> > into a single patch, which results in the single patch below, with an updated 
> > changelog that reflects the cleanups. I kept Dave's authorship and credited you 
> > for the simplification.
> > 
> > Note that the squashed commit had some whitespace noise which I skipped, further 
> > simplifying the patch.
> > 
> > Is it OK this way? If yes then I'll reshuffle the tree with this variant.
> 
> Yes.

Ok, new version pushed out to -tip:WIP.x86/mm.

Thanks,

	Ingo