x86/resctrl: Move mba_mbps_default_event init to filesystem code

mba_mbps_default_event is initialised based on whether mbm_local or mbm_total
is supported. In the case of both, it is initialised to mbm_local.
mba_mbps_default_event is initialised in core.c's get_rdt_mon_resources(),
while all the readers are in rdtgroup.c.

After this code is split into architecture-specific and filesystem code,
get_rdt_mon_resources() remains part of the architecture code, which would
mean mba_mbps_default_event has to be exposed by the filesystem code.

Move the initialisation to the filesystem's resctrl_mon_resource_init().

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64
Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20250311183715.16445-22-james.morse@arm.com

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

@@ -923,11 +923,6 @@ static __init bool get_rdt_mon_resources(void)
 	if (!rdt_mon_features)
 		return false;
 
-	if (resctrl_arch_is_mbm_local_enabled())
-		mba_mbps_default_event = QOS_L3_MBM_LOCAL_EVENT_ID;
-	else if (resctrl_arch_is_mbm_total_enabled())
-		mba_mbps_default_event = QOS_L3_MBM_TOTAL_EVENT_ID;
-
 	return !rdt_get_mon_l3_config(r);
 }
 

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

@@ -1213,6 +1213,11 @@ int __init resctrl_mon_resource_init(void)
 					 RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
 	}
 
+	if (resctrl_arch_is_mbm_local_enabled())
+		mba_mbps_default_event = QOS_L3_MBM_LOCAL_EVENT_ID;
+	else if (resctrl_arch_is_mbm_total_enabled())
+		mba_mbps_default_event = QOS_L3_MBM_TOTAL_EVENT_ID;
+
 	return 0;
 }