linux-kernel - Re: [PATCH v1 4/4] x86/msr: Do not allow writes to MSR_IA32_ENERGY_PERF

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Message-ID: <f259f033-c62e-e1a2-2f46-85b7961ac0ad@linuxfoundation.org>
Date:   Fri, 30 Oct 2020 11:12:50 -0600
From:   Shuah Khan <skhan@...uxfoundation.org>
To:     Borislav Petkov <bp@...en8.de>, X86 ML <x86@...nel.org>
Cc:     Thomas Renninger <trenn@...e.com>, Shuah Khan <shuah@...nel.org>,
        Len Brown <lenb@...nel.org>, linux-pm@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>,
        Shuah Khan <skhan@...uxfoundation.org>
Subject: Re: [PATCH v1 4/4] x86/msr: Do not allow writes to
 MSR_IA32_ENERGY_PERF_BIAS

On 10/29/20 1:02 PM, Borislav Petkov wrote:
> From: Borislav Petkov <bp@...e.de>
> 
> Now that all in-kernel-tree users are converted to using the sysfs file,
> remove the MSR from the "allowlist".
> 
> Signed-off-by: Borislav Petkov <bp@...e.de>
> ---
>   arch/x86/kernel/msr.c | 3 ---
>   1 file changed, 3 deletions(-)
> 
> diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
> index c0d409810658..b1147862730c 100644
> --- a/arch/x86/kernel/msr.c
> +++ b/arch/x86/kernel/msr.c
> @@ -99,9 +99,6 @@ static int filter_write(u32 reg)
>   	if (!__ratelimit(&fw_rs))
>   		return 0;
>   
> -	if (reg == MSR_IA32_ENERGY_PERF_BIAS)
> -		return 0;
> -
>   	pr_err("Write to unrecognized MSR 0x%x by %s (pid: %d). Please report to x86@...nel.org.\n",
>   	       reg, current->comm, current->pid);
>   
> 

Thanks. Looks good to me.

Reviewed-by: Shuah Khan <skhan@...uxfoundation.org>

thanks,
-- Shuah