linux-kernel - Re: [PATCH v2 4/6] x86/mtrr: Fix PAT init handling when MTRR MSR is disabled

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Date:	Tue, 22 Mar 2016 16:02:13 -0600
From:	Toshi Kani <toshi.kani@....com>
To:	Borislav Petkov <bp@...e.de>
Cc:	mingo@...nel.org, hpa@...or.com, tglx@...utronix.de,
	mcgrof@...e.com, jgross@...e.com, paul.gortmaker@...driver.com,
	konrad.wilk@...cle.com, elliott@....com, x86@...nel.org,
	xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 4/6] x86/mtrr: Fix PAT init handling when MTRR MSR is
 disabled

On Tue, 2016-03-22 at 18:01 +0100, Borislav Petkov wrote:
> Subject: [PATCH v2 4/6] x86/mtrr: Fix PAT init handling when MTRR MSR is
> disabled
> 
> s/ MSR//

Will do.

> On Wed, Mar 16, 2016 at 06:46:57PM -0600, Toshi Kani wrote:
> > get_mtrr_state() calls pat_init() on BSP even if MTRR is disabled
> > by its MSR.
> 
> s/by its MSR//

Will do.

> > This causes pat_init() to be called on BSP only since APs do not call
> 
> This doesn't cause that - get_mtrr_state() is called only on the BSP by
> mtrr_bp_init().

Right, I will change it to "results" or something.

> > pat_init() when MTRR is disabled. This inconsistency between BSP and
> > APs leads undefined behavior.
> 
>       leads to

Will do.

> > Move BSP's PAT init code from get_mtrr_state() to mtrr_bp_pat_init().
> > Change mtrr_bp_init() to call mtrr_bp_pat_init() if MTRR is enabled.
> 
> No need for those.

OK.

> > This keeps BSP's calling condition to pat_init() consistent with AP's,
> > mtrr_ap_init() and mtrr_aps_init().
> 
> This one is fine.

:-)

Thanks,
-Toshi