x86/resctrl: Support monitor configuration

Add a new field in struct mon_evt to support Bandwidth Monitoring Event
Configuration (BMEC) and also update the "mon_features" display.

The resctrl file "mon_features" will display the supported events
and files that can be used to configure those events if monitor
configuration is supported.

Before the change:

$ cat /sys/fs/resctrl/info/L3_MON/mon_features
llc_occupancy
mbm_total_bytes
mbm_local_bytes

After the change when BMEC is supported:

$ cat /sys/fs/resctrl/info/L3_MON/mon_features
llc_occupancy
mbm_total_bytes
mbm_total_bytes_config
mbm_local_bytes
mbm_local_bytes_config

Signed-off-by: Babu Moger <[e-mail]>
Signed-off-by: Borislav Petkov (AMD) <[e-mail]>
Reviewed-by: Reinette Chatre <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/x86/kernel/cpu/resctrl/internal.h

···
  * struct mon_evt - Entry in the event list of a resource
  * @evtid:		event id
  * @name:		name of the event
+ * @configurable:	true if the event is configurable
  * @list:		entry in &rdt_resource->evt_list
  */
 struct mon_evt {
 	enum resctrl_event_id	evtid;
 	char			*name;
+	bool			configurable;
 	struct list_head	list;
 };
 

arch/x86/kernel/cpu/resctrl/monitor.c

···
 	if (ret)
 		return ret;
 
+	if (rdt_cpu_has(X86_FEATURE_BMEC)) {
+		if (rdt_cpu_has(X86_FEATURE_CQM_MBM_TOTAL))
+			mbm_total_event.configurable = true;
+		if (rdt_cpu_has(X86_FEATURE_CQM_MBM_LOCAL))
+			mbm_local_event.configurable = true;
+	}
+
 	l3_mon_evt_init(r);
 
 	r->mon_capable = true;

arch/x86/kernel/cpu/resctrl/rdtgroup.c

···
 	struct rdt_resource *r = of->kn->parent->priv;
 	struct mon_evt *mevt;
 
-	list_for_each_entry(mevt, &r->evt_list, list)
+	list_for_each_entry(mevt, &r->evt_list, list) {
 		seq_printf(seq, "%s\n", mevt->name);
+		if (mevt->configurable)
+			seq_printf(seq, "%s_config\n", mevt->name);
+	}
 
 	return 0;
 }