[MODERATED] Re: [patch 05/15] Hidden 5

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Sun, May 13, 2018 at 04:00:53PM +0200, speck for Thomas Gleixner wrote:
> Subject: [patch 05/15] x86/cpufeatures: Add FEATURE_ZEN
> From: Thomas Gleixner <tglx@linutronix.de>
> 
> Add a ZEN feature bit so family-dependent static_cpu_has() optimizations
> can be built for ZEN.

.. In the future this may cover other architectures as well. Would it make
sense to call this something more generic? Say

X86_FEATURE_SSBD_SYNC_SMT

?
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
>  arch/x86/include/asm/cpufeatures.h |    1 +
>  arch/x86/kernel/cpu/amd.c          |    1 +
>  2 files changed, 2 insertions(+)
> 
> --- a/arch/x86/include/asm/cpufeatures.h
> +++ b/arch/x86/include/asm/cpufeatures.h
> @@ -218,6 +218,7 @@
>  #define X86_FEATURE_IBRS		( 7*32+25) /* Indirect Branch Restricted Speculation */
>  #define X86_FEATURE_IBPB		( 7*32+26) /* Indirect Branch Prediction Barrier */
>  #define X86_FEATURE_STIBP		( 7*32+27) /* Single Thread Indirect Branch Predictors */
> +#define X86_FEATURE_ZEN			( 7*32+28) /* "" CPU is AMD family 0x17 (Zen) */
>  
>  /* Virtualization flags: Linux defined, word 8 */
>  #define X86_FEATURE_TPR_SHADOW		( 8*32+ 0) /* Intel TPR Shadow */
> --- a/arch/x86/kernel/cpu/amd.c
> +++ b/arch/x86/kernel/cpu/amd.c
> @@ -812,6 +812,7 @@ static void init_amd_bd(struct cpuinfo_x
>  
>  static void init_amd_zn(struct cpuinfo_x86 *c)
>  {
> +	set_cpu_cap(c, X86_FEATURE_ZEN);
>  	/*
>  	 * Fix erratum 1076: CPB feature bit not being set in CPUID. It affects
>  	 * all up to and including B1.
>