RE: [PATCH v3 1/2] x86: Enable fast strings on Intel if BIOS hasn'talready

[Yu, Fenghua]

> -----Original Message-----
> From: Andy Lutomirski [mailto:luto@xxxxxxx]
> Sent: Tuesday, August 09, 2011 5:41 AM
> To: x86@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Cc: Yu, Fenghua; Matthew Garrett; Len Brown; linux-
> acpi@xxxxxxxxxxxxxxx; 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@xxxxxxx>
> ---
>  arch/x86/kernel/cpu/intel.c |   28 +++++++++++++++++++++++-----
>  1 files changed, 23 insertions(+), 5 deletions(-)

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

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