Re: [PATCH v1 1/2] perf/x86: Avoid inadvertent casts to x86_hybrid_pmu

[Mi, Dapeng]

On 3/12/2026 1:48 PM, Ian Rogers wrote:
> The patch:
> https://lore.kernel.org/lkml/20260311075201.2951073-2-dapeng1.mi@xxxxxxxxxxxxxxx/
> showed it was pretty easy to accidentally cast non-x86 PMUs to
> x86_hybrid_pmus. Add a BUG_ON for that case. Restructure is_x86_event
> and add an is_x86_pmu to facilitate this.
>
> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> ---
> Only build tested.
> ---
>  arch/x86/events/core.c       | 16 ----------------
>  arch/x86/events/perf_event.h | 19 ++++++++++++++++++-
>  2 files changed, 18 insertions(+), 17 deletions(-)
>
> diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
> index 03ce1bc7ef2e..6c6567dc6c88 100644
> --- a/arch/x86/events/core.c
> +++ b/arch/x86/events/core.c
> @@ -774,22 +774,6 @@ void x86_pmu_enable_all(int added)
>  	}
>  }
>  
> -int is_x86_event(struct perf_event *event)
> -{
> -	/*
> -	 * For a non-hybrid platforms, the type of X86 pmu is
> -	 * always PERF_TYPE_RAW.
> -	 * For a hybrid platform, the PERF_PMU_CAP_EXTENDED_HW_TYPE
> -	 * is a unique capability for the X86 PMU.
> -	 * Use them to detect a X86 event.
> -	 */
> -	if (event->pmu->type == PERF_TYPE_RAW ||
> -	    event->pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE)
> -		return true;
> -
> -	return false;
> -}
> -
>  struct pmu *x86_get_pmu(unsigned int cpu)
>  {
>  	struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
> diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
> index fad87d3c8b2c..f1123c95d174 100644
> --- a/arch/x86/events/perf_event.h
> +++ b/arch/x86/events/perf_event.h
> @@ -115,7 +115,23 @@ static inline bool is_topdown_event(struct perf_event *event)
>  	return is_metric_event(event) || is_slots_event(event);
>  }
>  
> -int is_x86_event(struct perf_event *event);
> +static inline bool is_x86_pmu(struct pmu *pmu)
> +{
> +	/*
> +	 * For a non-hybrid platforms, the type of X86 pmu is
> +	 * always PERF_TYPE_RAW.
> +	 * For a hybrid platform, the PERF_PMU_CAP_EXTENDED_HW_TYPE
> +	 * is a unique capability for the X86 PMU.
> +	 * Use them to detect a X86 event.
> +	 */
> +	return pmu->type == PERF_TYPE_RAW ||
> +	      (pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE);
> +}
> +
> +static inline bool is_x86_event(struct perf_event *event)
> +{
> +	return is_x86_pmu(event->pmu);
> +}
>  
>  static inline bool check_leader_group(struct perf_event *leader, int flags)
>  {
> @@ -779,6 +795,7 @@ struct x86_hybrid_pmu {
>  
>  static __always_inline struct x86_hybrid_pmu *hybrid_pmu(struct pmu *pmu)
>  {
> +	BUG_ON(!is_x86_pmu(pmu));
>  	return container_of(pmu, struct x86_hybrid_pmu, pmu);
>  }
>  

LGTM.

Reviewed-by: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx>