[PATCH v12 23/26] x86/resctrl: Introduce mbm_L3_assignments to list assignments in a group

[Babu Moger]

The interface displays the assignment states for each group when
mbm_cntr_assign mode is enabled.

The list is displayed in the following format:
<Event configuration>:<Domain id>=<Assignment type>

Event configuration: A valid event configuration listed in the
/sys/fs/resctrl/info/L3_MON/counter_configs directory.

Domain ID: A valid domain ID number.

The assignment type can be one of the following:

_ : No event configuration assigned

e : Event configuration assigned in exclusive mode

Example:
$cd /sys/fs/resctrl
$cat mbm_L3_assignments
mbm_total_bytes:0=e;1=e
mbm_local_bytes:0=e;1=e

Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v12: New patch:
     Assignment interface moved inside the group based the discussion
     https://lore.kernel.org/lkml/CALPaoCiii0vXOF06mfV=kVLBzhfNo0SFqt4kQGwGSGVUqvr2Dg@xxxxxxxxxxxxxx/#t
---
 Documentation/arch/x86/resctrl.rst     | 27 +++++++++++++++
 arch/x86/kernel/cpu/resctrl/monitor.c  |  1 +
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 48 ++++++++++++++++++++++++++
 3 files changed, 76 insertions(+)

diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index a67f09323da0..31085b4e15f6 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -503,6 +503,33 @@ When the "mba_MBps" mount option is used all CTRL_MON groups will also contain:
 	/sys/fs/resctrl/info/L3_MON/mon_features changes the input
 	event.
 
+"mbm_L3_assignments":
+	The interface displays the assignment states for each group when
+	mbm_cntr_assign mode is enabled.
+
+	The list is displayed in the following format:
+
+	<Event configuration>:<Domain id>=<Assignment type>
+
+	Event configuration: A valid event configuration listed in the
+	/sys/fs/resctrl/info/L3_MON/counter_configs directory.
+
+	Domain ID: A valid domain ID number.
+
+	Assignment types:
+
+	_ : No event configuration assigned
+
+	e : Event configuration assigned in exclusive mode
+
+	Example:
+	::
+
+	 # cd /sys/fs/resctrl
+	 # cat mbm_L3_assignments
+	 mbm_total_bytes:0=e;1=e
+	 mbm_local_bytes:0=e;1=e
+
 Resource allocation rules
 -------------------------
 
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 4e22563dda60..0c6fd5f6ec19 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -1266,6 +1266,7 @@ int __init resctrl_mon_resource_init(void)
 		resctrl_file_fflags_init("available_mbm_cntrs", RFTYPE_MON_INFO);
 		resctrl_file_fflags_init("event_filter", RFTYPE_MON_CONFIG);
 		resctrl_file_fflags_init("mbm_assign_on_mkdir", RFTYPE_MON_INFO);
+		resctrl_file_fflags_init("mbm_L3_assignments", RFTYPE_MON_BASE);
 	}
 
 	return 0;
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 3e440ace60e0..ee1c949c2436 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2083,6 +2083,48 @@ static ssize_t event_filter_write(struct kernfs_open_file *of, char *buf,
 	return ret ?: nbytes;
 }
 
+static 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;
+	int i, ret = 0;
+	bool sep;
+
+	rdtgrp = rdtgroup_kn_lock_live(of->kn);
+	if (!rdtgrp)
+		return -ENOENT;
+
+	rdt_last_cmd_clear();
+	if (!resctrl_arch_mbm_cntr_assign_enabled(r)) {
+		rdt_last_cmd_puts("mbm_cntr_assign mode not enabled\n");
+		ret = -ENOENT;
+		goto assign_out;
+	}
+
+	for (i = 0; i < NUM_MBM_ASSIGN_CONFIGS; i++) {
+		sep = false;
+		seq_printf(s, "%s:", mbm_assign_configs[i].name);
+		list_for_each_entry(d, &r->mon_domains, hdr.list) {
+			if (sep)
+				seq_puts(s, ";");
+
+			if (mbm_cntr_get(r, d, rdtgrp, mbm_assign_configs[i].evtid) >= 0)
+				seq_printf(s, "%d=e", d->hdr.id);
+			else
+				seq_printf(s, "%d=_", d->hdr.id);
+
+			sep = true;
+		}
+		seq_puts(s, "\n");
+	}
+
+assign_out:
+	rdtgroup_kn_unlock(of->kn);
+
+	return ret;
+}
+
 /* rdtgroup information files for one cache resource. */
 static struct rftype res_common_files[] = {
 	{
@@ -2202,6 +2244,12 @@ static struct rftype res_common_files[] = {
 		.seq_show	= event_filter_show,
 		.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,
-- 
2.34.1