linux-kernel - Re: [PATCH 1/2] x86: Fix typo preventing msr_set/clear

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Message-ID: <20140509075452.GA16058@pd.tnic>
Date:	Fri, 9 May 2014 09:54:52 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Andres Freund <andres@...razel.de>
Cc:	Borislav Petkov <bp@...e.de>, x86@...nel.org,
	linux-kernel@...r.kernel.org,
	"H. Peter Anvin" <hpa@...ux.intel.com>,
	Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 1/2] x86: Fix typo preventing msr_set/clear_bit from
 having an effect

On Fri, May 09, 2014 at 03:29:16AM +0200, Andres Freund wrote:
> Due to a typo the msr accessor function introduced in
> 22085a66c2fab6cf9b9393c056a3600a6b4735de didn't have any lasting
> effects because they accidentally wrote the old value back.
> 
> After c0a639ad0bc6b178b46996bd1f821a04643e2bde this at the very least
> this causes cpuid limits not to be lifted on some cpus leading to
> missing capabilities for those.
> 
> Signed-off-by: Andres Freund <andres@...razel.de>
> Cc: Borislav Petkov <bp@...e.de>
> Cc: H. Peter Anvin <hpa@...ux.intel.com>
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> ---
>  arch/x86/lib/msr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/lib/msr.c b/arch/x86/lib/msr.c
> index db9db44..4362373 100644
> --- a/arch/x86/lib/msr.c
> +++ b/arch/x86/lib/msr.c
> @@ -76,7 +76,7 @@ static inline int __flip_bit(u32 msr, u8 bit, bool set)
>  	if (m1.q == m.q)
>  		return 0;
>  
> -	err = msr_write(msr, &m);
> +	err = msr_write(msr, &m1);
>  	if (err)
>  		return err;

Good catch, thanks, and sorry about the screwup! :-[

Acked-by: Borislav Petkov <bp@...e.de>

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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