linux-kernel - Re: [PATCH v2 5/6] x86/xen,pat: Remove PAT table init code from Xen

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Date:	Wed, 23 Mar 2016 07:08:14 +0100
From:	Juergen Gross <jgross@...e.com>
To:	Borislav Petkov <bp@...e.de>, Toshi Kani <toshi.kani@....com>
Cc:	mingo@...nel.org, hpa@...or.com, tglx@...utronix.de,
	mcgrof@...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 5/6] x86/xen,pat: Remove PAT table init code from Xen

On 22/03/16 18:02, Borislav Petkov wrote:
> On Wed, Mar 16, 2016 at 06:46:58PM -0600, Toshi Kani wrote:
>> Xen supports PAT without MTRR for its guests.  In order to
>> enable WC attribute, it was necessary for xen_start_kernel()
>> to call pat_init_cache_modes() to update PAT table before
>> starting guest kernel.
>>
>> Now that the kernel initializes PAT table to the BIOS handoff
>> state when MTRR is disabled, this Xen-specific PAT init code
>> is no longer necessary.  Delete it from xen_start_kernel().
>>
>> Also change pat_init_cache_modes() to a static function since
>> PAT table should not be tweaked by other modules.
>>
>> Signed-off-by: Toshi Kani <toshi.kani@....com>
>> Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
>> Cc: Borislav Petkov <bp@...e.de>
>> Cc: Luis R. Rodriguez <mcgrof@...e.com>
>> Cc: Juergen Gross <jgross@...e.com>
>> Cc: Ingo Molnar <mingo@...nel.org>
>> Cc: H. Peter Anvin <hpa@...or.com>
>> Cc: Thomas Gleixner <tglx@...utronix.de>
>> ---
>>  arch/x86/include/asm/pat.h |    1 -
>>  arch/x86/mm/pat.c          |    2 +-
>>  arch/x86/xen/enlighten.c   |    9 ---------
>>  3 files changed, 1 insertion(+), 11 deletions(-)
> 
> Jürgen, ack?

Yes, seems to be okay.

Acked-by: Juergen Gross <jgross@...e.com>


Juergen