Re: [PATCH v6 4/5] perf: CXL Performance Monitoring Unit driver

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

Hi Namhyung,

> > +static int cxl_pmu_event_init(struct perf_event *event)
> > +{
> > +       struct cxl_pmu_info *info = pmu_to_cxl_pmu_info(event->pmu);
> > +
> > +       event->cpu = info->on_cpu;  
> 
> Why not change the event->cpu after validation is done?

Sure. Whilst I think it's harmless,
it logically makes more sense to do it a few lines later
so I'll move it to the end of this function.


> 
> Thanks,
> Namhyung
> 
> 
> > +       /* Top level type sanity check - is this a Hardware Event being requested */
> > +       if (event->attr.type != event->pmu->type)
> > +               return -ENOENT;
> > +
> > +       if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
> > +               return -EOPNOTSUPP;
> > +       /* TODO: Validation of any filter */
> > +
> > +       /*
> > +        * Verify that it is possible to count what was requested. Either must
> > +        * be a fixed counter that is a precise match or a configurable counter
> > +        * where this is a subset.
> > +        */
> > +       return cxl_pmu_get_event_idx(event, NULL, NULL);
> > +}