[tip: x86/cache] x86/resctrl: Display CLOSID for resource group

[tip-bot2 for Babu Moger]

The following commit has been merged into the x86/cache branch of tip:

Commit-ID:     ca8dad225e237493f19b1c5d4a8531f13a9b078f
Gitweb:        https://git.kernel.org/tip/ca8dad225e237493f19b1c5d4a8531f13a9b078f
Author:        Babu Moger <babu.moger@xxxxxxx>
AuthorDate:    Mon, 16 Oct 2023 19:23:06 -05:00
Committer:     Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Tue, 17 Oct 2023 14:05:14 +02:00

x86/resctrl: Display CLOSID for resource group

In x86, hardware uses CLOSID to identify a control group. When a user
creates a control group this information is not visible to the user. It
can help resctrl debugging.

Add CLOSID(ctrl_hw_id) to the control groups display in the resctrl
interface. Users can see this detail when resctrl is mounted with the
"-o debug" option.

Other architectures do not use "CLOSID". Use the names ctrl_hw_id to refer
to "CLOSID" in an effort to keep the naming generic.

For example:
  $cat /sys/fs/resctrl/ctrl_grp1/ctrl_hw_id
  1

Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Reviewed-by: Peter Newman <peternewman@xxxxxxxxxx>
Reviewed-by: Tan Shaopeng <tan.shaopeng@xxxxxxxxxxxxxx>
Reviewed-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Tested-by: Peter Newman <peternewman@xxxxxxxxxx>
Tested-by: Tan Shaopeng <tan.shaopeng@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20231017002308.134480-8-babu.moger@xxxxxxx
---
 Documentation/arch/x86/resctrl.rst     |  4 ++++
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 23 +++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index 68f1161..7412252 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -359,6 +359,10 @@ When control is enabled all CTRL_MON groups will also contain:
 	file. On successful pseudo-locked region creation the mode will
 	automatically change to "pseudo-locked".
 
+"ctrl_hw_id":
+	Available only with debug option. The identifier used by hardware
+	for the control group. On x86 this is the CLOSID.
+
 When monitoring is enabled all MON groups will also contain:
 
 "mon_data":
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 84e0f45..5814a0b 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -779,6 +779,22 @@ static int rdtgroup_tasks_show(struct kernfs_open_file *of,
 	return ret;
 }
 
+static int rdtgroup_closid_show(struct kernfs_open_file *of,
+				struct seq_file *s, void *v)
+{
+	struct rdtgroup *rdtgrp;
+	int ret = 0;
+
+	rdtgrp = rdtgroup_kn_lock_live(of->kn);
+	if (rdtgrp)
+		seq_printf(s, "%u\n", rdtgrp->closid);
+	else
+		ret = -ENOENT;
+	rdtgroup_kn_unlock(of->kn);
+
+	return ret;
+}
+
 #ifdef CONFIG_PROC_CPU_RESCTRL
 
 /*
@@ -1881,6 +1897,13 @@ static struct rftype res_common_files[] = {
 		.seq_show	= rdt_has_sparse_bitmasks_show,
 		.fflags		= RFTYPE_CTRL_INFO | RFTYPE_RES_CACHE,
 	},
+	{
+		.name		= "ctrl_hw_id",
+		.mode		= 0444,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= rdtgroup_closid_show,
+		.fflags		= RFTYPE_CTRL_BASE | RFTYPE_DEBUG,
+	},
 
 };