linux-kernel - RE: [PATCH v3 1/2] x86: Enable fast strings on Intel if BIOS hasn't already

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Message-ID: <493994B35A117E4F832F97C4719C4C040132CE80CE@orsmsx505.amr.corp.intel.com>
Date:	Tue, 9 Aug 2011 08:40:06 -0700
From:	"Yu, Fenghua" <fenghua.yu@...el.com>
To:	Andy Lutomirski <luto@....EDU>, "x86@...nel.org" <x86@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:	Matthew Garrett <mjg59@...f.ucam.org>, Len Brown <lenb@...nel.org>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	Ingo Molnar <mingo@...e.hu>,
	"Anvin, H Peter" <h.peter.anvin@...el.com>
Subject: RE: [PATCH v3 1/2] x86: Enable fast strings on Intel if BIOS hasn't
 already

> -----Original Message-----
> From: Andy Lutomirski [mailto:luto@....EDU]
> Sent: Tuesday, August 09, 2011 5:41 AM
> To: x86@...nel.org; linux-kernel@...r.kernel.org
> Cc: Yu, Fenghua; Matthew Garrett; Len Brown; linux-
> acpi@...r.kernel.org; Ingo Molnar; Andy Lutomirski
> Subject: [PATCH v3 1/2] x86: Enable fast strings on Intel if BIOS
> hasn't already
> 
> Intel SDM volume 3A, 8.4.2 says:
> 
>   Software can disable fast-string operation by clearing the
>   fast-string-enable bit (bit 0) of IA32_MISC_ENABLE MSR.
>   However, Intel recomments that system software always enable
>   fast-string operation.
> 
> The Intel DQ67SW board (with latest BIOS) disables fast string
> operations if TXT is enabled.  A Lenovo X220 disables it regardless
> of TXT setting.  I doubt I'm the only person with a dumb BIOS like
> this.
> 
> Signed-off-by: Andy Lutomirski <luto@....edu>
> ---
>  arch/x86/kernel/cpu/intel.c |   28 +++++++++++++++++++++++-----
>  1 files changed, 23 insertions(+), 5 deletions(-)

Signed-off-by: Fenghua Yu <fenghua.yu@...el.com>

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