linux-kernel - Re: [PATCH] x86, cpu: X86_FEATURE_NOPL should be disabled on 32-bit only

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Message-ID: <a3fce0e5-e6c5-4bf0-b8c0-4954825a7065@email.android.com>
Date:	Sun, 03 Oct 2010 11:19:18 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Borislav Petkov <bp@...en8.de>
CC:	Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>,
	lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86, cpu: X86_FEATURE_NOPL should be disabled on 32-bit only

I think we actually need to set it on 64 bits.

"Borislav Petkov" <bp@...en8.de> wrote:

>ba0593bf553c450a03dbc5f8c1f0ff58b778a0c8 cleared the aforementioned
>cpuid bit only on 32-bit due to various problems with Virtual PC. This
>somehow got lost during the 32- + 64-bit merge so restore the feature
>bit on 64-bit.
>
>Signed-off-by: Borislav Petkov <bp@...en8.de>
>---
> arch/x86/kernel/cpu/common.c |    2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
>
>diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
>index caa967d..9a2cfeb 100644
>--- a/arch/x86/kernel/cpu/common.c
>+++ b/arch/x86/kernel/cpu/common.c
>@@ -713,7 +713,9 @@ void __init early_cpu_init(void)
>  */
> static void __cpuinit detect_nopl(struct cpuinfo_x86 *c)
> {
>+#ifdef CONFIG_X86_32
> 	clear_cpu_cap(c, X86_FEATURE_NOPL);
>+#endif
> }
> 
> static void __cpuinit generic_identify(struct cpuinfo_x86 *c)
>-- 
>1.7.2.3
>
>-- 
>Regards/Gruss,
>    Boris.

-- 
Sent from my mobile phone.  Please pardon any lack of formatting.
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