arm64/mpam: resctrl: Add rmid file in resctrl sysfs

hulk inclusion
category: feature
bugzilla: 34278
CVE: NA

-------------------------------------------------

rmid is used to mark each resctrl group for monitoring, anyhow, also
following corresponding resctrl group's configuration, we export rmid
sysfile to resctrl sysfs for any usage elsewhere such as SMMU io, user
can get rmid from a resctrl group and set this rmid to a target io
through SMMU driver if SMMU MPAM implemented, so make related io devices
can be monitored or accomplish aimed configuration for resource's usage.
Signed-off-by: NWang ShaoBo <bobo.shaobowang@huawei.com>
Reviewed-by: NXiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: NCheng Jian <cj.chengjian@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>

arch/arm64/kernel/mpam/mpam_resctrl.c

@@ -1733,6 +1733,29 @@ static int resctrl_group_tasks_show(struct kernfs_open_file *of,
 	return ret;
 }
 
+static int resctrl_group_rmid_show(struct kernfs_open_file *of,
+			       struct seq_file *s, void *v)
+{
+	int ret = 0;
+	struct rdtgroup *rdtgrp;
+	u32 flag, times;
+
+	hw_alloc_times_validate(times, flag);
+
+	rdtgrp = resctrl_group_kn_lock_live(of->kn);
+	if (rdtgrp) {
+		if (flag)
+			seq_printf(s, "%u-%u\n", rdtgrp->mon.rmid,
+				rdtgrp->mon.rmid + 1);
+		else
+			seq_printf(s, "%u\n", rdtgrp->mon.rmid);
+	} else
+		ret = -ENOENT;
+	resctrl_group_kn_unlock(of->kn);
+
+	return ret;
+}
+
 /* rdtgroup information files for one cache resource. */
 static struct rftype res_specific_files[] = {
 	{
@@ -1830,6 +1853,13 @@ static struct rftype res_specific_files[] = {
 		.seq_show	= resctrl_group_tasks_show,
 		.fflags		= RFTYPE_BASE,
 	},
+	{
+		.name		= "rmid",
+		.mode		= 0444,
+		.kf_ops		= &resctrl_group_kf_single_ops,
+		.seq_show	= resctrl_group_rmid_show,
+		.fflags		= RFTYPE_BASE,
+	},
 	{
 		.name		= "schemata",
 		.mode		= 0644,