linux-kernel - Re: [PATCH v5 04/18] x86/intel

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Date:   Wed, 26 Oct 2016 16:15:02 +0200
From:   Borislav Petkov <bp@...e.de>
To:     Fenghua Yu <fenghua.yu@...el.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <h.peter.anvin@...el.com>,
        Ingo Molnar <mingo@...e.hu>, Tony Luck <tony.luck@...el.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Stephane Eranian <eranian@...gle.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Nilay Vaish <nilayvaish@...il.com>, Shaohua Li <shli@...com>,
        David Carrillo-Cisneros <davidcc@...gle.com>,
        Ravi V Shankar <ravi.v.shankar@...el.com>,
        Sai Prakhya <sai.praneeth.prakhya@...el.com>,
        Vikas Shivappa <vikas.shivappa@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>, x86 <x86@...nel.org>
Subject: Re: [PATCH v5 04/18] x86/intel_rdt: Feature discovery

Subject: [PATCH v5 04/18] x86/intel_rdt: Feature discovery

Subject should start with a verb. I.e.,

"x86/cpufeature: Add RDT CPUID feature bits"

On Sat, Oct 22, 2016 at 06:19:51AM -0700, Fenghua Yu wrote:
> From: Fenghua Yu <fenghua.yu@...el.com>
> 
> Check CPUID leaves for all the Resource Director Technology (RDT)
> Cache Allocation Technology (CAT) bits.
> 
> Presence of allocation features:
>   CPUID.(EAX=7H, ECX=0):EBX[bit 15]	X86_FEATURE_RDT_A
> 
> L2 and L3 caches are each separately enabled:
>   CPUID.(EAX=10H, ECX=0):EBX[bit 1]	X86_FEATURE_CAT_L3
>   CPUID.(EAX=10H, ECX=0):EBX[bit 2]	X86_FEATURE_CAT_L2
> 
> L3 cache may support independent control of allocation for
> code and data (CDP = Code/Data Prioritization):
>   CPUID.(EAX=10H, ECX=1):ECX[bit 2]	X86_FEATURE_CDP_L3
> 
> Signed-off-by: Fenghua Yu <fenghua.yu@...el.com>
> ---
>  arch/x86/include/asm/cpufeatures.h | 5 +++++
>  arch/x86/kernel/cpu/scattered.c    | 3 +++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
> index 1188bc8..21f4a7e 100644
> --- a/arch/x86/include/asm/cpufeatures.h
> +++ b/arch/x86/include/asm/cpufeatures.h
> @@ -195,6 +195,10 @@
>  
>  #define X86_FEATURE_INTEL_PT	( 7*32+15) /* Intel Processor Trace */
>  

No newlines when consective bits.

> +#define X86_FEATURE_CAT_L3	( 7*32+16) /* Cache Allocation Technology L3 */
> +#define X86_FEATURE_CAT_L2	( 7*32+17) /* Cache Allocation Technology L2 */
> +#define X86_FEATURE_CDP_L3	( 7*32+18) /* Code and Data Prioritization L3 */

Also, this patch or even better, the whole patchset needs to be at least
test-merged with tip/master to check for conflicting changes. Like this
one here:

#define X86_FEATURE_INTEL_PT    ( 7*32+15) /* Intel Processor Trace */
#define X86_FEATURE_AVX512_4VNNIW (7*32+16) /* AVX-512 Neural Network Instructions */
				   ^^^^^^^

#define X86_FEATURE_AVX512_4FMAPS (7*32+17) /* AVX-512 Multiply Accumulation Single precision */
				   ^^^^^^

#define X86_FEATURE_CAT_L3      ( 7*32+16) /* Cache Allocation Technology L3 */
				  ^^^^^^^
#define X86_FEATURE_CAT_L2      ( 7*32+17) /* Cache Allocation Technology L2 */
				  ^^^^^^^

#define X86_FEATURE_CDP_L3      ( 7*32+18) /* Code and Data Prioritization L3 */


>  /* Virtualization flags: Linux defined, word 8 */
>  #define X86_FEATURE_TPR_SHADOW  ( 8*32+ 0) /* Intel TPR Shadow */
>  #define X86_FEATURE_VNMI        ( 8*32+ 1) /* Intel Virtual NMI */
> @@ -219,6 +223,7 @@
>  #define X86_FEATURE_RTM		( 9*32+11) /* Restricted Transactional Memory */
>  #define X86_FEATURE_CQM		( 9*32+12) /* Cache QoS Monitoring */
>  #define X86_FEATURE_MPX		( 9*32+14) /* Memory Protection Extension */
> +#define X86_FEATURE_RDT_A	( 9*32+15) /* Resource Director Technology Allocation */
>  #define X86_FEATURE_AVX512F	( 9*32+16) /* AVX-512 Foundation */
>  #define X86_FEATURE_AVX512DQ	( 9*32+17) /* AVX-512 DQ (Double/Quad granular) Instructions */
>  #define X86_FEATURE_RDSEED	( 9*32+18) /* The RDSEED instruction */
> diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
> index 8cb57df..11f39a2 100644
> --- a/arch/x86/kernel/cpu/scattered.c
> +++ b/arch/x86/kernel/cpu/scattered.c
> @@ -34,6 +34,9 @@ void init_scattered_cpuid_features(struct cpuinfo_x86 *c)
>  		{ X86_FEATURE_INTEL_PT,		CR_EBX,25, 0x00000007, 0 },
>  		{ X86_FEATURE_APERFMPERF,	CR_ECX, 0, 0x00000006, 0 },
>  		{ X86_FEATURE_EPB,		CR_ECX, 3, 0x00000006, 0 },
> +		{ X86_FEATURE_CAT_L3,		CR_EBX, 1, 0x00000010, 0 },
> +		{ X86_FEATURE_CAT_L2,		CR_EBX, 2, 0x00000010, 0 },
> +		{ X86_FEATURE_CDP_L3,		CR_ECX, 2, 0x00000010, 1 },
>  		{ X86_FEATURE_HW_PSTATE,	CR_EDX, 7, 0x80000007, 0 },
>  		{ X86_FEATURE_CPB,		CR_EDX, 9, 0x80000007, 0 },
>  		{ X86_FEATURE_PROC_FEEDBACK,	CR_EDX,11, 0x80000007, 0 },
> -- 

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--