Re: [PATCH v2 01/15] perf/x86/lbr: Simplify the exposure check for the LBR_INFO registers

[Like Xu]

Hi Peter, would you help apply this one in your tip/perf tree,
as it doesn't seem to be closely tied to the KVM changes. Thanks.

On 25/11/2022 12:05 pm, Yang Weijiang wrote:
> From: Like Xu <like.xu@xxxxxxxxxxxxxxx>
>
> The x86_pmu.lbr_info is 0 unless explicitly initialized, so there's
> no point checking x86_pmu.intel_cap.lbr_format.
>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Reviewed-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> Signed-off-by: Like Xu <like.xu@xxxxxxxxxxxxxxx>
> Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx>
> ---
>   arch/x86/events/intel/lbr.c | 4 +---
>   1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
> index 4dbde69c423b..e7caabfa1377 100644
> --- a/arch/x86/events/intel/lbr.c
> +++ b/arch/x86/events/intel/lbr.c
> @@ -1606,12 +1606,10 @@ void __init intel_pmu_arch_lbr_init(void)
>    */
>   void x86_perf_get_lbr(struct x86_pmu_lbr *lbr)
>   {
> -	int lbr_fmt = x86_pmu.intel_cap.lbr_format;
> -
>   	lbr->nr = x86_pmu.lbr_nr;
>   	lbr->from = x86_pmu.lbr_from;
>   	lbr->to = x86_pmu.lbr_to;
> -	lbr->info = (lbr_fmt == LBR_FORMAT_INFO) ? x86_pmu.lbr_info : 0;
> +	lbr->info = x86_pmu.lbr_info;
>   }
>   EXPORT_SYMBOL_GPL(x86_perf_get_lbr);
>