On Thu, Aug 01, 2024 at 04:58:23AM +0000, Mingwei Zhang wrote:
> @@ -5941,8 +5942,21 @@ void perf_put_mediated_pmu(void)
> }
> EXPORT_SYMBOL_GPL(perf_put_mediated_pmu);
>
> +static void perf_switch_interrupt(bool enter, u32 guest_lvtpc)
> +{
> + /* Mediated passthrough PMU should have PASSTHROUGH_VPMU cap. */
> + if (!passthru_pmu)
> + return;
> +
> + if (passthru_pmu->switch_interrupt &&
> + try_module_get(passthru_pmu->module)) {
> + passthru_pmu->switch_interrupt(enter, guest_lvtpc);
> + module_put(passthru_pmu->module);
> + }
> +}
Should we move the whole module reference to perf_pmu_(,un}register() ?
> @@ -11842,7 +11860,21 @@ int perf_pmu_register(struct pmu *pmu, const char *name, int type)
> if (!pmu->event_idx)
> pmu->event_idx = perf_event_idx_default;
>
> - list_add_rcu(&pmu->entry, &pmus);
> + /*
> + * Initialize passthru_pmu with the core pmu that has
> + * PERF_PMU_CAP_PASSTHROUGH_VPMU capability.
> + */
> + if (pmu->capabilities & PERF_PMU_CAP_PASSTHROUGH_VPMU) {
> + if (!passthru_pmu)
> + passthru_pmu = pmu;
> +
> + if (WARN_ONCE(passthru_pmu != pmu, "Only one passthrough PMU is supported\n")) {
> + ret = -EINVAL;
> + goto free_dev;
Why impose this limit? Changelog also fails to explain this.
> + }
> + }
> +
> + list_add_tail_rcu(&pmu->entry, &pmus);
> atomic_set(&pmu->exclusive_cnt, 0);
> ret = 0;
> unlock:
> --
> 2.46.0.rc1.232.g9752f9e123-goog
>
