diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
index 916f7a9d5658..5fbcc64e50ce 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -1456,7 +1456,7 @@ int resctrl_mbm_assign_mode_show(struct kernfs_open_file *of,
 		else
 			seq_puts(s, "[default]\n");
 
-		if (!IS_ENABLED(CONFIG_RESCTRL_ASSIGN_FIXED)) {
+		if (!r->mon.mbm_cntr_assign_fixed) {
 			if (enabled)
 				seq_puts(s, "default\n");
 			else
@@ -1507,6 +1507,12 @@ ssize_t resctrl_mbm_assign_mode_write(struct kernfs_open_file *of, char *buf,
 	}
 
 	if (enable != resctrl_arch_mbm_cntr_assign_enabled(r)) {
+		if (r->mon.mbm_cntr_assign_fixed) {
+			ret = -EINVAL;
+			rdt_last_cmd_puts("Counter assignment mode is not configurable\n");
+			goto out_unlock;
+		}
+
 		ret = resctrl_arch_mbm_cntr_assign_set(r, enable);
 		if (ret)
 			goto out_unlock;
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 06e8c72e8660..73ff522448a0 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -294,6 +294,7 @@ enum resctrl_schema_fmt {
  * @mbm_assign_on_mkdir:	True if counters should automatically be assigned to MBM
  *				events of monitor groups created via mkdir.
  * @mbm_cntr_configurable:	True if assignable counters are configurable.
+ * @mbm_cntr_assign_fixed:	True if the counter assignment mode is fixed.
  */
 struct resctrl_mon {
 	u32			num_rmid;
@@ -302,6 +303,7 @@ struct resctrl_mon {
 	bool			mbm_cntr_assignable;
 	bool			mbm_assign_on_mkdir;
 	bool			mbm_cntr_configurable;
+	bool			mbm_cntr_assign_fixed;
 };
 
 /**