[PATCH RFC v2 06/19] arm_mpam: Support memory-level MSCs and ABMC per class

[Fenghua Yu <fenghuay@nvidia.com>]

Some platforms place MBWU counters on a memory MSC above L3 while CSU
occupancy may remain on the L3 cache MSC. The driver previously assumed
all monitors and ABMC state lived on the L3 resource, which
mis-associates MBA counters, breaks mbm_L3_assignments when multiple
events share a class, and uses the wrong domain ID space for
memory-level MSCs.

Teach MPAM resctrl to map monitor classes to L3 or MBA resources,
initialise ABMC on the resource that owns the MBWU monitor, select the
node-scope MBM total event for memory-side counters, and test
mbm_cntr_assignable instead of inferring assignment support from
whichever monitor happens to share res->class first.

Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Signed-off-by: Fenghua Yu <fenghuay@nvidia.com>
---
 drivers/resctrl/mpam_resctrl.c | 112 ++++++++++++++++++++++++---------
 1 file changed, 81 insertions(+), 31 deletions(-)

diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c
index ca2ae4b5cc8a..47a7b18d841d 100644
--- a/drivers/resctrl/mpam_resctrl.c
+++ b/drivers/resctrl/mpam_resctrl.c
@@ -45,7 +45,7 @@ static struct mpam_resctrl_res mpam_resctrl_controls[RDT_NUM_RESOURCES];
  * to those supported by MPAM.
  * Class pointer may be NULL.
  */
-#define MPAM_MAX_EVENT QOS_L3_MBM_TOTAL_EVENT_ID
+#define MPAM_MAX_EVENT QOS_NODE_MBM_TOTAL_EVENT_ID
 static struct mpam_resctrl_mon mpam_resctrl_counters[MPAM_MAX_EVENT + 1];
 
 #define for_each_mpam_resctrl_mon(mon, eventid)					\
@@ -88,6 +88,11 @@ bool resctrl_arch_alloc_capable(void)
 	return false;
 }
 
+static bool mpam_class_memory(struct mpam_class *class)
+{
+	return class && class->type == MPAM_CLASS_MEMORY && class->level > 3;
+}
+
 bool resctrl_arch_mon_capable(void)
 {
 	struct mpam_resctrl_res *res = &mpam_resctrl_controls[RDT_RESOURCE_L3];
@@ -121,7 +126,13 @@ void resctrl_arch_reset_rmid(struct rdt_resource *r, struct rdt_l3_mon_domain *d
 
 bool resctrl_arch_mbm_cntr_assign_enabled(struct rdt_resource *r)
 {
-	return (r == &mpam_resctrl_controls[RDT_RESOURCE_L3].resctrl_res);
+	/*
+	 * mbm_cntr_assignable is set only when ABMC is initialised on this
+	 * resource. Multiple monitor events may share res->class (e.g.
+	 * occupancy and MBWU), so assignment support must not be inferred
+	 * from mon->assigned_counters via a class lookup on the wrong event.
+	 */
+	return r->mon.mbm_cntr_assignable;
 }
 
 int resctrl_arch_mbm_cntr_assign_set(struct rdt_resource *r, bool enable)
@@ -181,24 +192,41 @@ static void resctrl_reset_task_closids(void)
 	read_unlock(&tasklist_lock);
 }
 
-static void mpam_resctrl_monitor_sync_abmc_vals(struct rdt_resource *l3)
+static struct
+mpam_resctrl_res *mpam_resctrl_res_from_mon(struct mpam_resctrl_mon *mon)
 {
-	struct mpam_resctrl_mon *mon = &mpam_resctrl_counters[QOS_L3_MBM_TOTAL_EVENT_ID];
+	struct mpam_resctrl_res *res;
+	enum resctrl_res_level rid;
 
 	if (!mon->class)
-		return;
+		return NULL;
+
+	for_each_mpam_resctrl_control(res, rid) {
+		if (res->class == mon->class)
+			return res;
+	}
+
+	return NULL;
+}
+
+static struct mpam_resctrl_mon *mpam_resctrl_mbm_total_mon(void)
+{
+	if (mpam_resctrl_counters[QOS_NODE_MBM_TOTAL_EVENT_ID].class)
+		return &mpam_resctrl_counters[QOS_NODE_MBM_TOTAL_EVENT_ID];
+
+	return &mpam_resctrl_counters[QOS_L3_MBM_TOTAL_EVENT_ID];
+}
+
+static void mpam_resctrl_monitor_sync_abmc_vals(struct rdt_resource *r)
+{
+	struct mpam_resctrl_mon *mon = mpam_resctrl_mbm_total_mon();
 
-	if (!mon->assigned_counters)
+	if (!mon->class || !mon->assigned_counters)
 		return;
 
-	l3->mon.num_mbm_cntrs = mon->class->props.num_mbwu_mon;
+	r->mon.num_mbm_cntrs = mon->class->props.num_mbwu_mon;
 	if (cdp_enabled)
-		l3->mon.num_mbm_cntrs /= 2;
-
-	/*
-	 * Continue as normal even if enabling cdp causes there to be
-	 * zero counters. This avoids giving resctrl mixed messages.
-	 */
+		r->mon.num_mbm_cntrs /= 2;
 }
 
 int resctrl_arch_set_cdp_enabled(struct rdt_resource *r, struct resctrl_ctrl *ctrl,
@@ -404,6 +432,7 @@ static int resctrl_arch_mon_ctx_alloc_no_wait(enum resctrl_event_id evtid)
 		return mpam_alloc_csu_mon(mon->class);
 	case QOS_L3_MBM_LOCAL_EVENT_ID:
 	case QOS_L3_MBM_TOTAL_EVENT_ID:
+	case QOS_NODE_MBM_TOTAL_EVENT_ID:
 		return USE_PRE_ALLOCATED;
 	default:
 		return -EOPNOTSUPP;
@@ -1160,7 +1189,10 @@ static void mpam_resctrl_pick_counters(void)
 			 * and it's equivalent to mbm_total and so always use
 			 * mbm_total.
 			 */
-			counter_update_class(QOS_L3_MBM_TOTAL_EVENT_ID, class);
+			if (class->type == MPAM_CLASS_MEMORY)
+				counter_update_class(QOS_NODE_MBM_TOTAL_EVENT_ID, class);
+			else
+				counter_update_class(QOS_L3_MBM_TOTAL_EVENT_ID, class);
 		}
 	}
 }
@@ -1187,7 +1219,7 @@ void resctrl_arch_config_cntr(struct rdt_resource *r, struct rdt_l3_mon_domain *
 {
 	struct mpam_resctrl_mon *mon = &mpam_resctrl_counters[evtid];
 
-	if (evtid != QOS_L3_MBM_TOTAL_EVENT_ID) {
+	if (!resctrl_is_mbm_total_event(evtid)) {
 		pr_debug("unexpected event id\n");
 		return;
 	}
@@ -1204,7 +1236,7 @@ void resctrl_arch_config_cntr(struct rdt_resource *r, struct rdt_l3_mon_domain *
 		__config_cntr(mon, cntr_id, CDP_NONE, closid, rmid, assign);
 	}
 
-	resctrl_arch_reset_cntr(r, d, closid, rmid, cntr_id, QOS_L3_MBM_TOTAL_EVENT_ID);
+	resctrl_arch_reset_cntr(r, d, closid, rmid, cntr_id, evtid);
 }
 
 static int mpam_resctrl_control_init(struct mpam_resctrl_res *res)
@@ -1303,10 +1335,10 @@ static int mpam_resctrl_pick_domain_id(int cpu, struct mpam_component *comp)
  */
 static int mpam_resctrl_monitor_init_abmc(struct mpam_resctrl_mon *mon)
 {
-	struct mpam_resctrl_res *res = &mpam_resctrl_controls[RDT_RESOURCE_L3];
 	size_t num_rmid = resctrl_arch_system_num_rmid_idx();
-	struct rdt_resource *l3 = &res->resctrl_res;
 	struct mpam_class *class = mon->class;
+	struct mpam_resctrl_res *res;
+	struct rdt_resource *r;
 	u16 num_mbwu_mon;
 	int *cntrs;
 
@@ -1317,6 +1349,12 @@ static int mpam_resctrl_monitor_init_abmc(struct mpam_resctrl_mon *mon)
 	}
 	memset(rmid_array, -1, num_rmid * sizeof(*rmid_array));
 
+	res = mpam_resctrl_res_from_mon(mon);
+	if (!res)
+		return -EINVAL;
+
+	r = &res->resctrl_res;
+
 	num_mbwu_mon = class->props.num_mbwu_mon;
 	cntrs = __alloc_mbwu_array(mon->class, num_mbwu_mon);
 	if (IS_ERR(cntrs))
@@ -1324,12 +1362,12 @@ static int mpam_resctrl_monitor_init_abmc(struct mpam_resctrl_mon *mon)
 	mon->assigned_counters = cntrs;
 	mon->mbwu_idx_to_mon = no_free_ptr(rmid_array);
 
-	l3->mon.mbm_cntr_assignable = true;
-	l3->mon.mbm_assign_on_mkdir = true;
-	l3->mon.mbm_cntr_configurable = false;
-	l3->mon.mbm_cntr_assign_fixed = true;
+	r->mon.mbm_cntr_assignable = true;
+	r->mon.mbm_assign_on_mkdir = true;
+	r->mon.mbm_cntr_configurable = false;
+	r->mon.mbm_cntr_assign_fixed = true;
 
-	mpam_resctrl_monitor_sync_abmc_vals(l3);
+	mpam_resctrl_monitor_sync_abmc_vals(r);
 
 	return 0;
 }
@@ -1337,8 +1375,15 @@ static int mpam_resctrl_monitor_init_abmc(struct mpam_resctrl_mon *mon)
 static int mpam_resctrl_monitor_init(struct mpam_resctrl_mon *mon,
 				     enum resctrl_event_id type)
 {
-	struct mpam_resctrl_res *res = &mpam_resctrl_controls[RDT_RESOURCE_L3];
-	struct rdt_resource *l3 = &res->resctrl_res;
+	struct mpam_resctrl_res *res;
+	struct rdt_resource *r;
+
+	if (mpam_class_memory(mon->class))
+		res = &mpam_resctrl_controls[RDT_RESOURCE_MBA];
+	else
+		res = &mpam_resctrl_controls[RDT_RESOURCE_L3];
+
+	r = &res->resctrl_res;
 
 	lockdep_assert_cpus_held();
 
@@ -1365,8 +1410,13 @@ static int mpam_resctrl_monitor_init(struct mpam_resctrl_mon *mon,
 	 * monitoring class.
 	 * Setting name is necessary on monitor only platforms.
 	 */
-	l3->name = "L3";
-	l3->mon_scope = RESCTRL_L3_CACHE;
+	if (mpam_class_memory(mon->class)) {
+		r->name = "MB";
+		r->mon_scope = RESCTRL_NODE;
+	} else {
+		r->name = "L3";
+		r->mon_scope = RESCTRL_L3_CACHE;
+	}
 
 	/*
 	 * num-rmid is the upper bound for the number of monitoring groups that
@@ -1376,9 +1426,9 @@ static int mpam_resctrl_monitor_init(struct mpam_resctrl_mon *mon,
 	 * this does mean userspace needs to know the architecture to correctly
 	 * interpret this value.
 	 */
-	l3->mon.num_rmid = resctrl_arch_system_num_rmid_idx();
+	r->mon.num_rmid = resctrl_arch_system_num_rmid_idx();
 
-	if (type == QOS_L3_MBM_TOTAL_EVENT_ID) {
+	if (type == QOS_L3_MBM_TOTAL_EVENT_ID || type == QOS_NODE_MBM_TOTAL_EVENT_ID) {
 		int err;
 
 		err = mpam_resctrl_monitor_init_abmc(mon);
@@ -1386,13 +1436,13 @@ static int mpam_resctrl_monitor_init(struct mpam_resctrl_mon *mon,
 			return err;
 
 		static_assert(MAX_EVT_CONFIG_BITS == 0x7f);
-		l3->mon.mbm_cfg_mask = MAX_EVT_CONFIG_BITS;
+		r->mon.mbm_cfg_mask = MAX_EVT_CONFIG_BITS;
 	}
 
 	if (!resctrl_enable_mon_event(type, false, 0, NULL))
 		return -EINVAL;
 
-	l3->mon_capable = true;
+	r->mon_capable = true;
 
 	return 0;
 }
-- 
2.53.0