[PATCH RFC v2 02/19] resctrl: Expose MBA MBM counter assignment sysfs

[Fenghua Yu <fenghuay@nvidia.com>]

When MBWU monitoring is backed by an MBA resource, userspace still
needs the same counter-assignment interface as on L3, but keyed to MBA
domains and exposed as mbm_NODE_assignments rather than
mbm_L3_assignments.

Add the MBA-side sysfs hooks and initialise MBA monitor metadata during
resctrl_mon_init() so mbm_* file visibility follows the resource being
configured.

Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Signed-off-by: Fenghua Yu <fenghuay@nvidia.com>
---
 fs/resctrl/internal.h |  5 +++++
 fs/resctrl/monitor.c  | 27 +++++++++++++++++++++++++--
 fs/resctrl/rdtgroup.c | 11 ++++++++---
 3 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index af2e6e0b2af8..32c7d53790ec 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -480,6 +480,11 @@ struct resctrl_ctrl *resctrl_resource_ctrl_get_default(struct rdt_resource *r);
 const char *resctrl_ctrl_name_str(enum resctrl_ctrl_name name);
 bool resctrl_ctrl_is_default(struct resctrl_ctrl *ctrl);
 
+int mbm_NODE_assignments_show(struct kernfs_open_file *of, struct seq_file *s, void *v);
+
+ssize_t mbm_NODE_assignments_write(struct kernfs_open_file *of, char *buf,
+				   size_t nbytes, loff_t off);
+
 #ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK
 int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp);
 
diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
index 2b5654f05480..5865a509174c 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -538,6 +538,7 @@ static int __mon_event_count(struct rdtgroup *rdtgrp, struct rmid_read *rr)
 {
 	switch (rr->r->rid) {
 	case RDT_RESOURCE_L3:
+	case RDT_RESOURCE_MBA:
 		WARN_ON_ONCE(rr->evt->any_cpu);
 		if (rr->hdr)
 			return __l3_mon_event_count(rdtgrp, rr);
@@ -1741,6 +1742,12 @@ int mbm_L3_assignments_show(struct kernfs_open_file *of, struct seq_file *s, voi
 				    resctrl_arch_get_resource(RDT_RESOURCE_L3));
 }
 
+int mbm_NODE_assignments_show(struct kernfs_open_file *of, struct seq_file *s, void *v)
+{
+	return mbm_assignments_show(of, s, v,
+				    resctrl_arch_get_resource(RDT_RESOURCE_MBA));
+}
+
 /*
  * mbm_get_mon_event_by_name() - Return the mon_evt entry for the matching
  * event name.
@@ -1890,6 +1897,13 @@ ssize_t mbm_L3_assignments_write(struct kernfs_open_file *of, char *buf,
 			resctrl_arch_get_resource(RDT_RESOURCE_L3));
 }
 
+ssize_t mbm_NODE_assignments_write(struct kernfs_open_file *of, char *buf,
+				   size_t nbytes, loff_t off)
+{
+	return mbm_assignments_write(of, buf, nbytes, off,
+			resctrl_arch_get_resource(RDT_RESOURCE_MBA));
+}
+
 static int closid_num_dirty_rmid_alloc(struct rdt_resource *r)
 {
 	if (IS_ENABLED(CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID)) {
@@ -1933,7 +1947,7 @@ static void resctrl_mon_resource_init(struct rdt_resource *r)
 {
 	unsigned long fflags;
 
-	fflags = RFTYPE_RES_CACHE;
+	fflags = (r->rid == RDT_RESOURCE_MBA) ? RFTYPE_RES_MB : RFTYPE_RES_CACHE;
 
 	if (resctrl_arch_is_evt_configurable(QOS_L3_MBM_TOTAL_EVENT_ID)) {
 		mon_event_all[QOS_L3_MBM_TOTAL_EVENT_ID].configurable = true;
@@ -1969,7 +1983,10 @@ static void resctrl_mon_resource_init(struct rdt_resource *r)
 			resctrl_file_mode_init("event_filter", 0644);
 		resctrl_file_fflags_init("mbm_assign_on_mkdir", RFTYPE_MON_INFO |
 					 fflags);
-		resctrl_file_fflags_init("mbm_L3_assignments", RFTYPE_MON_BASE);
+		if (r->rid == RDT_RESOURCE_MBA)
+			resctrl_file_fflags_init("mbm_NODE_assignments", RFTYPE_MON_BASE);
+		else
+			resctrl_file_fflags_init("mbm_L3_assignments", RFTYPE_MON_BASE);
 		resctrl_file_fflags_init("mbm_assign_mode", RFTYPE_MON_INFO |
 					 fflags);
 	}
@@ -2002,6 +2019,12 @@ int resctrl_mon_init(void)
 
 	resctrl_mon_resource_init(r);
 
+	r = resctrl_arch_get_resource(RDT_RESOURCE_MBA);
+	if (!r->mon_capable)
+		return 0;
+
+	resctrl_mon_resource_init(r);
+
 	return 0;
 }
 
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index a658e4958562..a0635888a0a0 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -2307,6 +2307,13 @@ static struct rftype res_common_files[] = {
 		.seq_show	= mbm_L3_assignments_show,
 		.write		= mbm_L3_assignments_write,
 	},
+	{
+		.name		= "mbm_NODE_assignments",
+		.mode		= 0644,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= mbm_NODE_assignments_show,
+		.write		= mbm_NODE_assignments_write,
+	},
 	{
 		.name		= "mbm_assign_mode",
 		.mode		= 0644,
@@ -5199,10 +5206,8 @@ int resctrl_online_ctrl_domain(struct rdt_resource *r, struct resctrl_ctrl *ctrl
 
 	mutex_lock(&rdtgroup_mutex);
 
-	if (supports_mba_mbps(ctrl) && r->rid == RDT_RESOURCE_MBA) {
-		/* RDT_RESOURCE_MBA is never mon_capable */
+	if (supports_mba_mbps(ctrl) && r->rid == RDT_RESOURCE_MBA)
 		err = mba_sc_domain_allocate(r, d);
-	}
 
 	mutex_unlock(&rdtgroup_mutex);
 
-- 
2.53.0