linux-kernel - [PATCH v14 30/32] fs/resctrl: Hide the BMEC related files when mbm

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Message-ID: <4769751d1de7c4f66b1c7f3c5ea7eeeb49951363.1749848715.git.babu.moger@amd.com>
Date: Fri, 13 Jun 2025 16:05:14 -0500
From: Babu Moger <babu.moger@....com>
To: <babu.moger@....com>, <corbet@....net>, <tony.luck@...el.com>,
	<reinette.chatre@...el.com>, <Dave.Martin@....com>, <james.morse@....com>,
	<tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
	<dave.hansen@...ux.intel.com>
CC: <x86@...nel.org>, <hpa@...or.com>, <akpm@...ux-foundation.org>,
	<rostedt@...dmis.org>, <paulmck@...nel.org>, <thuth@...hat.com>,
	<ardb@...nel.org>, <gregkh@...uxfoundation.org>, <seanjc@...gle.com>,
	<thomas.lendacky@....com>, <pawan.kumar.gupta@...ux.intel.com>,
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	<linux-kernel@...r.kernel.org>
Subject: [PATCH v14 30/32] fs/resctrl: Hide the BMEC related files when mbm_event mode is enabled

BMEC (Bandwidth Monitoring Event Configuration) and mbm_event mode do not
work simultaneously.

When mbm_event mode is enabled, hide BMEC-related files to avoid confusion
and update the mon_features display accordingly.

The files /sys/fs/resctrl/info/L3_MON/mbm_total_bytes_config and
/sys/fs/resctrl/info/L3_MON/mbm_local_bytes_config will not be visible
when mbm_event mode is enabled.

Suggested-by: Reinette Chatre <reinette.chatre@...el.com>
Signed-off-by: Babu Moger <babu.moger@....com>
---
v14: Updated the changelog for change in mbm_assign_modes.
     Added check in rdt_mon_features_show to hide bmec related feature.

v13: New patch to hide BMEC related files.
---
 fs/resctrl/rdtgroup.c | 42 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 92bb8f3adfae..8c67e0897f25 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -1164,7 +1164,8 @@ static int rdt_mon_features_show(struct kernfs_open_file *of,
 		if (mevt->rid != r->rid || !mevt->enabled)
 			continue;
 		seq_printf(seq, "%s\n", mevt->name);
-		if (mevt->configurable)
+		if (mevt->configurable &&
+		    !resctrl_arch_mbm_cntr_assign_enabled(r))
 			seq_printf(seq, "%s_config\n", mevt->name);
 	}
 
@@ -1813,6 +1814,38 @@ static ssize_t mbm_local_bytes_config_write(struct kernfs_open_file *of,
 	return ret ?: nbytes;
 }
 
+/**
+ * resctrl_bmec_files_show() — Controls the visibility of BMEC-related resctrl
+ * files. When @show is true, the files are displayed; when false, the files
+ * are hidden.
+ */
+static void resctrl_bmec_files_show(struct rdt_resource *r, bool show)
+{
+	struct kernfs_node *kn_config, *l3_mon_kn;
+	char name[32];
+
+	sprintf(name, "%s_MON", r->name);
+	l3_mon_kn = kernfs_find_and_get(kn_info, name);
+	if (!l3_mon_kn)
+		return;
+
+	kn_config = kernfs_find_and_get(l3_mon_kn, "mbm_total_bytes_config");
+	if (kn_config) {
+		kernfs_get(kn_config);
+		kernfs_show(kn_config, show);
+		kernfs_put(kn_config);
+	}
+
+	kn_config = kernfs_find_and_get(l3_mon_kn, "mbm_local_bytes_config");
+	if (kn_config) {
+		kernfs_get(kn_config);
+		kernfs_show(kn_config, show);
+		kernfs_put(kn_config);
+	}
+
+	kernfs_put(l3_mon_kn);
+}
+
 static int resctrl_mbm_assign_mode_show(struct kernfs_open_file *of,
 					struct seq_file *s, void *v)
 {
@@ -2808,6 +2841,13 @@ static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
 			ret = resctrl_mkdir_counter_configs(r, name);
 			if (ret)
 				goto out_destroy;
+
+			/*
+			 * Hide BMEC related files if mbm_event mode
+			 * is enabled.
+			 */
+			if (resctrl_arch_mbm_cntr_assign_enabled(r))
+				resctrl_bmec_files_show(r, false);
 		}
 	}
 
-- 
2.34.1