Re: [PATCH v4 05/38] perf: Add generic exclude_guest support

[Peter Zijlstra]

On Mon, Mar 24, 2025 at 05:30:45PM +0000, Mingwei Zhang wrote:

> @@ -6040,6 +6041,71 @@ void perf_put_mediated_pmu(void)
>  }
>  EXPORT_SYMBOL_GPL(perf_put_mediated_pmu);
>  
> +static inline void perf_host_exit(struct perf_cpu_context *cpuctx)
> +{
> +	perf_ctx_disable(&cpuctx->ctx, EVENT_GUEST);
> +	ctx_sched_out(&cpuctx->ctx, NULL, EVENT_GUEST);
> +	perf_ctx_enable(&cpuctx->ctx, EVENT_GUEST);
> +	if (cpuctx->task_ctx) {
> +		perf_ctx_disable(cpuctx->task_ctx, EVENT_GUEST);
> +		task_ctx_sched_out(cpuctx->task_ctx, NULL, EVENT_GUEST);
> +		perf_ctx_enable(cpuctx->task_ctx, EVENT_GUEST);
> +	}
> +}
> +
> +/* When entering a guest, schedule out all exclude_guest events. */
> +void perf_guest_enter(void)
> +{
> +	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
> +
> +	lockdep_assert_irqs_disabled();
> +
> +	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
> +
> +	if (WARN_ON_ONCE(__this_cpu_read(perf_in_guest)))
> +		goto unlock;
> +
> +	perf_host_exit(cpuctx);
> +
> +	__this_cpu_write(perf_in_guest, true);
> +
> +unlock:
> +	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
> +}
> +EXPORT_SYMBOL_GPL(perf_guest_enter);
> +
> +static inline void perf_host_enter(struct perf_cpu_context *cpuctx)
> +{
> +	perf_ctx_disable(&cpuctx->ctx, EVENT_GUEST);
> +	if (cpuctx->task_ctx)
> +		perf_ctx_disable(cpuctx->task_ctx, EVENT_GUEST);
> +
> +	perf_event_sched_in(cpuctx, cpuctx->task_ctx, NULL, EVENT_GUEST);
> +
> +	if (cpuctx->task_ctx)
> +		perf_ctx_enable(cpuctx->task_ctx, EVENT_GUEST);
> +	perf_ctx_enable(&cpuctx->ctx, EVENT_GUEST);
> +}
> +
> +void perf_guest_exit(void)
> +{
> +	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
> +
> +	lockdep_assert_irqs_disabled();
> +
> +	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
> +
> +	if (WARN_ON_ONCE(!__this_cpu_read(perf_in_guest)))
> +		goto unlock;
> +
> +	perf_host_enter(cpuctx);
> +
> +	__this_cpu_write(perf_in_guest, false);
> +unlock:
> +	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
> +}
> +EXPORT_SYMBOL_GPL(perf_guest_exit);

This naming is confusing on purpose? Pick either guest/host and stick
with it.