Documentation/x86: Documentation for MON group move feature

Describe new support for moving MON groups to a new parent CTRL_MON
group and its restrictions.
Signed-off-by: Peter Newman <peternewman@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20230419125015.693566-4-peternewman@google.com

Documentation/arch/x86/resctrl.rst

@@ -287,6 +287,13 @@ Removing a directory will move all tasks and cpus owned by the group it
 represents to the parent. Removing one of the created CTRL_MON groups
 will automatically remove all MON groups below it.
 
+Moving MON group directories to a new parent CTRL_MON group is supported
+for the purpose of changing the resource allocations of a MON group
+without impacting its monitoring data or assigned tasks. This operation
+is not allowed for MON groups which monitor CPUs. No other move
+operation is currently allowed other than simply renaming a CTRL_MON or
+MON group.
+
 All groups contain the following files:
 
 "tasks":