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Subject: Re: [PATCH v2 07/33] x86/intel_rdt: Add support for Cache Allocation
 detection
To: Fenghua Yu <fenghua.yu@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        "H. Peter Anvin" <h.peter.anvin@intel.com>,
        Ingo Molnar <mingo@elte.hu>, Tony Luck <tony.luck@intel.com>,
        Peter Zijlstra <peterz@infradead.org>, Tejun Heo <tj@kernel.org>,
        Borislav Petkov <bp@suse.de>, Stephane Eranian <eranian@google.com>,
        Marcelo Tosatti <mtosatti@redhat.com>,
        David Carrillo-Cisneros <davidcc@google.com>, Shaohua Li <shli@fb.com>,
        Ravi V Shankar <ravi.v.shankar@intel.com>,
        Vikas Shivappa <vikas.shivappa@linux.intel.com>,
        Sai Prakhya <sai.praneeth.prakhya@intel.com>
References: <1473328647-33116-1-git-send-email-fenghua.yu@intel.com>
 <1473328647-33116-8-git-send-email-fenghua.yu@intel.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
From: Dave Hansen <dave.hansen@intel.com>
Message-ID: <57D88052.60404@intel.com>
Date: Tue, 13 Sep 2016 15:40:18 -0700
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On 09/08/2016 02:57 AM, Fenghua Yu wrote:
> --- a/arch/x86/include/asm/disabled-features.h
> +++ b/arch/x86/include/asm/disabled-features.h
> @@ -57,6 +57,7 @@
>  #define DISABLED_MASK15	0
>  #define DISABLED_MASK16	(DISABLE_PKU|DISABLE_OSPKE)
>  #define DISABLED_MASK17	0
> -#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 18)
> +#define DISABLED_MASK18	0
> +#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 19)

Are you sure you don't want to add RDT to disabled-features.h?  You have
a config option for it, so it seems like you should also be able to
optimize some of these checks away when the config option is off.