doc: update documents for "--rtvm" parameter
This patch update documents for "--rtvm" parameter.
@@ -318,6 +318,15 @@ Here are descriptions for each of these ``acrn-dm`` command line parameters:
* - :kbd:`--lapic_pt`
- This option is to create a VM with lapic pass-through.
With this option, a VM is created with LAPIC_PASSTHROUGH and
- IOREQ_COMPLETION_POLLING mode. This kind of VM is generally for realtime scenarios.
+ IOREQ_COMPLETION_POLLING mode. This kind of VM is generally for hard realtime scenarios.
+
+ By default, DM will create VM without this option.
+
+ * - :kbd:`--rtvm`
+ - This option is to create a VM with realtime attribute.
+ With this option, a VM is created with GUEST_FLAG_RT and GUEST_FLAG_IOREQ_COMPLETION_POLLING
+ mode. This kind of VM is generally for soft realtime scenarios (without lapic_pt) or hard
+ realtime scenarios (with lapic_pt). This kind of VM can't be interfered by SOS during runtime.
+ It can only be poweroff from inside of itself.
By default, DM will create VM without this option.
