fs/resctrl: Introduce mbm_L3_assignments to list assignments in a group

Introduce the mbm_L3_assignments resctrl file associated with CTRL_MON and MON
resource groups to display the counter assignment states of the resource group
when "mbm_event" counter assignment mode is enabled.

Display the list in the following format:
<Event>:<Domain id>=<Assignment state>;<Domain id>=<Assignment state>

Event: A valid MBM event listed in
      /sys/fs/resctrl/info/L3_MON/event_configs directory.

Domain ID: A valid domain ID.

The assignment state can be one of the following:

_ : No counter assigned.

e : Counter assigned exclusively.

Example:
To list the assignment states for the default group
  $ cd /sys/fs/resctrl
  $ cat /sys/fs/resctrl/mbm_L3_assignments
  mbm_total_bytes:0=e;1=e
  mbm_local_bytes:0=e;1=e

Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com

3 files changed, 57 insertions, 0 deletions

diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index 66c677c1b858..43297b36f5dd 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -416,6 +416,8 @@ int resctrl_mbm_assign_on_mkdir_show(struct kernfs_open_file *of,
 ssize_t resctrl_mbm_assign_on_mkdir_write(struct kernfs_open_file *of, char *buf,
 					  size_t nbytes, loff_t off);
 
+int mbm_L3_assignments_show(struct kernfs_open_file *of, struct seq_file *s, void *v);
+
 #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 9cb334136d21..b692a0ef1710 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -1454,6 +1454,54 @@ out_unlock:
 	return ret;
 }
 
+int mbm_L3_assignments_show(struct kernfs_open_file *of, struct seq_file *s, void *v)
+{
+	struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);
+	struct rdt_mon_domain *d;
+	struct rdtgroup *rdtgrp;
+	struct mon_evt *mevt;
+	int ret = 0;
+	bool sep;
+
+	rdtgrp = rdtgroup_kn_lock_live(of->kn);
+	if (!rdtgrp) {
+		ret = -ENOENT;
+		goto out_unlock;
+	}
+
+	rdt_last_cmd_clear();
+	if (!resctrl_arch_mbm_cntr_assign_enabled(r)) {
+		rdt_last_cmd_puts("mbm_event counter assignment mode is not enabled\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	for_each_mon_event(mevt) {
+		if (mevt->rid != r->rid || !mevt->enabled || !resctrl_is_mbm_event(mevt->evtid))
+			continue;
+
+		sep = false;
+		seq_printf(s, "%s:", mevt->name);
+		list_for_each_entry(d, &r->mon_domains, hdr.list) {
+			if (sep)
+				seq_putc(s, ';');
+
+			if (mbm_cntr_get(r, d, rdtgrp, mevt->evtid) < 0)
+				seq_printf(s, "%d=_", d->hdr.id);
+			else
+				seq_printf(s, "%d=e", d->hdr.id);
+
+			sep = true;
+		}
+		seq_putc(s, '\n');
+	}
+
+out_unlock:
+	rdtgroup_kn_unlock(of->kn);
+
+	return ret;
+}
+
 /**
  * resctrl_mon_resource_init() - Initialise global monitoring structures.
  *
@@ -1512,6 +1560,7 @@ int resctrl_mon_resource_init(void)
 		resctrl_file_fflags_init("event_filter", RFTYPE_ASSIGN_CONFIG);
 		resctrl_file_fflags_init("mbm_assign_on_mkdir", RFTYPE_MON_INFO |
 					 RFTYPE_RES_CACHE);
+		resctrl_file_fflags_init("mbm_L3_assignments", RFTYPE_MON_BASE);
 	}
 
 	return 0;
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 48f98146c099..519aa6acef5b 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -1938,6 +1938,12 @@ static struct rftype res_common_files[] = {
 		.write		= event_filter_write,
 	},
 	{
+		.name		= "mbm_L3_assignments",
+		.mode		= 0444,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= mbm_L3_assignments_show,
+	},
+	{
 		.name		= "mbm_assign_mode",
 		.mode		= 0444,
 		.kf_ops		= &rdtgroup_kf_single_ops,