| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <175793564412.709179.8478610566418953842.tip-bot2@tip-bot2>
Date: Mon, 15 Sep 2025 11:27:24 -0000
From: "tip-bot2 for Babu Moger" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Babu Moger <babu.moger@....com>, "Borislav Petkov (AMD)" <bp@...en8.de>,
Reinette Chatre <reinette.chatre@...el.com>, x86@...nel.org,
linux-kernel@...r.kernel.org
Subject: [tip: x86/cache] fs/resctrl: Introduce the interface to modify
assignments in a group
The following commit has been merged into the x86/cache branch of tip:
Commit-ID: 88bee79640aea6192f98c8faae30e0013453479d
Gitweb: https://git.kernel.org/tip/88bee79640aea6192f98c8faae30e0013453479d
Author: Babu Moger <babu.moger@....com>
AuthorDate: Fri, 05 Sep 2025 16:34:28 -05:00
Committer: Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Mon, 15 Sep 2025 12:47:17 +02:00
fs/resctrl: Introduce the interface to modify assignments in a group
Enable the mbm_l3_assignments resctrl file to be used to modify counter
assignments of CTRL_MON and MON groups when the "mbm_event" counter
assignment mode is enabled.
Process the assignment modifications in the following format:
<Event>:<Domain id>=<Assignment state>;<Domain id>=<Assignment state>
Event: A valid MBM event in the
/sys/fs/resctrl/info/L3_MON/event_configs directory.
Domain ID: A valid domain ID. When writing, '*' applies the changes
to all domains.
Assignment states:
_ : Unassign a counter.
e : Assign a counter exclusively.
Examples:
$ 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
To unassign the counter associated with the mbm_total_bytes event on
domain 0:
$ echo "mbm_total_bytes:0=_" > mbm_L3_assignments
$ cat /sys/fs/resctrl/mbm_L3_assignments
mbm_total_bytes:0=_;1=e
mbm_local_bytes:0=e;1=e
To unassign the counter associated with the mbm_total_bytes event on
all the domains:
$ echo "mbm_total_bytes:*=_" > mbm_L3_assignments
$ cat /sys/fs/resctrl/mbm_L3_assignments
mbm_total_bytes:0=_;1=_
mbm_local_bytes:0=e;1=e
Signed-off-by: Babu Moger <babu.moger@....com>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>
Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
---
Documentation/filesystems/resctrl.rst | 151 ++++++++++++++++++++++++-
fs/resctrl/internal.h | 3 +-
fs/resctrl/monitor.c | 139 +++++++++++++++++++++++-
fs/resctrl/rdtgroup.c | 3 +-
4 files changed, 294 insertions(+), 2 deletions(-)
diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index a2b7240..f60f6a9 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -522,7 +522,8 @@ When monitoring is enabled all MON groups may also contain:
Event: A valid MBM event in the
/sys/fs/resctrl/info/L3_MON/event_configs directory.
- Domain ID: A valid domain ID.
+ Domain ID: A valid domain ID. When writing, '*' applies the changes
+ to all the domains.
Assignment states:
@@ -540,6 +541,35 @@ When monitoring is enabled all MON groups may also contain:
mbm_total_bytes:0=e;1=e
mbm_local_bytes:0=e;1=e
+ Assignments can be modified by writing to the interface.
+
+ Examples:
+
+ To unassign the counter associated with the mbm_total_bytes event on domain 0:
+ ::
+
+ # echo "mbm_total_bytes:0=_" > /sys/fs/resctrl/mbm_L3_assignments
+ # cat /sys/fs/resctrl/mbm_L3_assignments
+ mbm_total_bytes:0=_;1=e
+ mbm_local_bytes:0=e;1=e
+
+ To unassign the counter associated with the mbm_total_bytes event on all the domains:
+ ::
+
+ # echo "mbm_total_bytes:*=_" > /sys/fs/resctrl/mbm_L3_assignments
+ # cat /sys/fs/resctrl/mbm_L3_assignments
+ mbm_total_bytes:0=_;1=_
+ mbm_local_bytes:0=e;1=e
+
+ To assign a counter associated with the mbm_total_bytes event on all domains in
+ exclusive mode:
+ ::
+
+ # echo "mbm_total_bytes:*=e" > /sys/fs/resctrl/mbm_L3_assignments
+ # cat /sys/fs/resctrl/mbm_L3_assignments
+ mbm_total_bytes:0=e;1=e
+ mbm_local_bytes:0=e;1=e
+
When the "mba_MBps" mount option is used all CTRL_MON groups will also contain:
"mba_MBps_event":
@@ -1585,6 +1615,125 @@ View the llc occupancy snapshot::
# cat /sys/fs/resctrl/p1/mon_data/mon_L3_00/llc_occupancy
11234000
+
+Examples on working with mbm_assign_mode
+========================================
+
+a. Check if MBM counter assignment mode is supported.
+::
+
+ # mount -t resctrl resctrl /sys/fs/resctrl/
+
+ # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
+ [mbm_event]
+ default
+
+The "mbm_event" mode is detected and enabled.
+
+b. Check how many assignable counters are supported.
+::
+
+ # cat /sys/fs/resctrl/info/L3_MON/num_mbm_cntrs
+ 0=32;1=32
+
+c. Check how many assignable counters are available for assignment in each domain.
+::
+
+ # cat /sys/fs/resctrl/info/L3_MON/available_mbm_cntrs
+ 0=30;1=30
+
+d. To list the default group's assign states.
+::
+
+ # cat /sys/fs/resctrl/mbm_L3_assignments
+ mbm_total_bytes:0=e;1=e
+ mbm_local_bytes:0=e;1=e
+
+e. To unassign the counter associated with the mbm_total_bytes event on domain 0.
+::
+
+ # echo "mbm_total_bytes:0=_" > /sys/fs/resctrl/mbm_L3_assignments
+ # cat /sys/fs/resctrl/mbm_L3_assignments
+ mbm_total_bytes:0=_;1=e
+ mbm_local_bytes:0=e;1=e
+
+f. To unassign the counter associated with the mbm_total_bytes event on all domains.
+::
+
+ # echo "mbm_total_bytes:*=_" > /sys/fs/resctrl/mbm_L3_assignments
+ # cat /sys/fs/resctrl/mbm_L3_assignment
+ mbm_total_bytes:0=_;1=_
+ mbm_local_bytes:0=e;1=e
+
+g. To assign a counter associated with the mbm_total_bytes event on all domains in
+exclusive mode.
+::
+
+ # echo "mbm_total_bytes:*=e" > /sys/fs/resctrl/mbm_L3_assignments
+ # cat /sys/fs/resctrl/mbm_L3_assignments
+ mbm_total_bytes:0=e;1=e
+ mbm_local_bytes:0=e;1=e
+
+h. Read the events mbm_total_bytes and mbm_local_bytes of the default group. There is
+no change in reading the events with the assignment.
+::
+
+ # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_total_bytes
+ 779247936
+ # cat /sys/fs/resctrl/mon_data/mon_L3_01/mbm_total_bytes
+ 562324232
+ # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_bytes
+ 212122123
+ # cat /sys/fs/resctrl/mon_data/mon_L3_01/mbm_local_bytes
+ 121212144
+
+i. Check the event configurations.
+::
+
+ # cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_total_bytes/event_filter
+ local_reads,remote_reads,local_non_temporal_writes,remote_non_temporal_writes,
+ local_reads_slow_memory,remote_reads_slow_memory,dirty_victim_writes_all
+
+ # cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_local_bytes/event_filter
+ local_reads,local_non_temporal_writes,local_reads_slow_memory
+
+j. Change the event configuration for mbm_local_bytes.
+::
+
+ # echo "local_reads, local_non_temporal_writes, local_reads_slow_memory, remote_reads" >
+ /sys/fs/resctrl/info/L3_MON/event_configs/mbm_local_bytes/event_filter
+
+ # cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_local_bytes/event_filter
+ local_reads,local_non_temporal_writes,local_reads_slow_memory,remote_reads
+
+k. Now read the local events again. The first read may come back with "Unavailable"
+status. The subsequent read of mbm_local_bytes will display the current value.
+::
+
+ # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_bytes
+ Unavailable
+ # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_bytes
+ 2252323
+ # cat /sys/fs/resctrl/mon_data/mon_L3_01/mbm_local_bytes
+ Unavailable
+ # cat /sys/fs/resctrl/mon_data/mon_L3_01/mbm_local_bytes
+ 1566565
+
+l. Users have the option to go back to 'default' mbm_assign_mode if required. This can be
+done using the following command. Note that switching the mbm_assign_mode may reset all
+the MBM counters (and thus all MBM events) of all the resctrl groups.
+::
+
+ # echo "default" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
+ # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
+ mbm_event
+ [default]
+
+m. Unmount the resctrl filesystem.
+::
+
+ # umount /sys/fs/resctrl/
+
Intel RDT Errata
================
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index 43297b3..c69b1da 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -418,6 +418,9 @@ ssize_t resctrl_mbm_assign_on_mkdir_write(struct kernfs_open_file *of, char *buf
int mbm_L3_assignments_show(struct kernfs_open_file *of, struct seq_file *s, void *v);
+ssize_t mbm_L3_assignments_write(struct kernfs_open_file *of, char *buf, size_t nbytes,
+ loff_t off);
+
#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 b692a0e..f388dbc 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -1502,6 +1502,145 @@ out_unlock:
return ret;
}
+/*
+ * mbm_get_mon_event_by_name() - Return the mon_evt entry for the matching
+ * event name.
+ */
+static struct mon_evt *mbm_get_mon_event_by_name(struct rdt_resource *r, char *name)
+{
+ struct mon_evt *mevt;
+
+ for_each_mon_event(mevt) {
+ if (mevt->rid == r->rid && mevt->enabled &&
+ resctrl_is_mbm_event(mevt->evtid) &&
+ !strcmp(mevt->name, name))
+ return mevt;
+ }
+
+ return NULL;
+}
+
+static int rdtgroup_modify_assign_state(char *assign, struct rdt_mon_domain *d,
+ struct rdtgroup *rdtgrp, struct mon_evt *mevt)
+{
+ int ret = 0;
+
+ if (!assign || strlen(assign) != 1)
+ return -EINVAL;
+
+ switch (*assign) {
+ case 'e':
+ ret = rdtgroup_assign_cntr_event(d, rdtgrp, mevt);
+ break;
+ case '_':
+ rdtgroup_unassign_cntr_event(d, rdtgrp, mevt);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
+static int resctrl_parse_mbm_assignment(struct rdt_resource *r, struct rdtgroup *rdtgrp,
+ char *event, char *tok)
+{
+ struct rdt_mon_domain *d;
+ unsigned long dom_id = 0;
+ char *dom_str, *id_str;
+ struct mon_evt *mevt;
+ int ret;
+
+ mevt = mbm_get_mon_event_by_name(r, event);
+ if (!mevt) {
+ rdt_last_cmd_printf("Invalid event %s\n", event);
+ return -ENOENT;
+ }
+
+next:
+ if (!tok || tok[0] == '\0')
+ return 0;
+
+ /* Start processing the strings for each domain */
+ dom_str = strim(strsep(&tok, ";"));
+
+ id_str = strsep(&dom_str, "=");
+
+ /* Check for domain id '*' which means all domains */
+ if (id_str && *id_str == '*') {
+ ret = rdtgroup_modify_assign_state(dom_str, NULL, rdtgrp, mevt);
+ if (ret)
+ rdt_last_cmd_printf("Assign operation '%s:*=%s' failed\n",
+ event, dom_str);
+ return ret;
+ } else if (!id_str || kstrtoul(id_str, 10, &dom_id)) {
+ rdt_last_cmd_puts("Missing domain id\n");
+ return -EINVAL;
+ }
+
+ /* Verify if the dom_id is valid */
+ list_for_each_entry(d, &r->mon_domains, hdr.list) {
+ if (d->hdr.id == dom_id) {
+ ret = rdtgroup_modify_assign_state(dom_str, d, rdtgrp, mevt);
+ if (ret) {
+ rdt_last_cmd_printf("Assign operation '%s:%ld=%s' failed\n",
+ event, dom_id, dom_str);
+ return ret;
+ }
+ goto next;
+ }
+ }
+
+ rdt_last_cmd_printf("Invalid domain id %ld\n", dom_id);
+ return -EINVAL;
+}
+
+ssize_t mbm_L3_assignments_write(struct kernfs_open_file *of, char *buf,
+ size_t nbytes, loff_t off)
+{
+ struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);
+ struct rdtgroup *rdtgrp;
+ char *token, *event;
+ int ret = 0;
+
+ /* Valid input requires a trailing newline */
+ if (nbytes == 0 || buf[nbytes - 1] != '\n')
+ return -EINVAL;
+
+ buf[nbytes - 1] = '\0';
+
+ rdtgrp = rdtgroup_kn_lock_live(of->kn);
+ if (!rdtgrp) {
+ rdtgroup_kn_unlock(of->kn);
+ return -ENOENT;
+ }
+ rdt_last_cmd_clear();
+
+ if (!resctrl_arch_mbm_cntr_assign_enabled(r)) {
+ rdt_last_cmd_puts("mbm_event mode is not enabled\n");
+ rdtgroup_kn_unlock(of->kn);
+ return -EINVAL;
+ }
+
+ while ((token = strsep(&buf, "\n")) != NULL) {
+ /*
+ * The write command follows the following format:
+ * "<Event>:<Domain ID>=<Assignment state>"
+ * Extract the event name first.
+ */
+ event = strsep(&token, ":");
+
+ ret = resctrl_parse_mbm_assignment(r, rdtgrp, event, token);
+ if (ret)
+ break;
+ }
+
+ rdtgroup_kn_unlock(of->kn);
+
+ return ret ?: nbytes;
+}
+
/**
* resctrl_mon_resource_init() - Initialise global monitoring structures.
*
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 519aa6a..bd4a115 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -1939,9 +1939,10 @@ static struct rftype res_common_files[] = {
},
{
.name = "mbm_L3_assignments",
- .mode = 0444,
+ .mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = mbm_L3_assignments_show,
+ .write = mbm_L3_assignments_write,
},
{
.name = "mbm_assign_mode",
Powered by blists - more mailing lists