acrn-hypervisor/doc/tutorials/enable_s5.rst

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.. _enable-s5:
Enable S5 in ACRN
#################
Introduction
************
S5 is one of the `ACPI sleep states <http://acpi.sourceforge.net/documentation/sleep.html>`_
that refers to the system being shut down (although some power may still be
supplied to certain devices). In this document, S5 means the function to
shut down the **User VMs**, **the Service VM**, the hypervisor, and the
hardware. In most cases, directly shutting down the power of a computer
system is not advisable because it can damage some components. It can cause
corruption and put the system in an unknown or unstable state. On ACRN, the
User VM must be shut down before powering off the Service VM. Especially for
some use cases, where User VMs could be used in industrial control or other
high safety requirement environment, a graceful system shutdown such as the
ACRN S5 function is required.
S5 Architecture
***************
ACRN provides a mechanism to trigger the S5 state transition throughout the system.
It uses a vUART channel to communicate between the Service and User VMs.
The diagram below shows the overall architecture:
.. figure:: images/s5_overall_architecture.png
:align: center
S5 overall architecture
- **Scenario I**:
The User VM's serial port device (``ttySn``) is emulated in the
Device Model, the channel from the Service VM to the User VM:
.. graphviz:: images/s5-scenario-1.dot
:name: s5-scenario-1
- **Scenario II**:
The User VM's (like RT-Linux or other RT-VMs) serial port device
(``ttySn``) is emulated in the Hypervisor,
the channel from the Service OS to the User VM:
.. graphviz:: images/s5-scenario-2.dot
:name: s5-scenario-2
Trigger the User VM's S5
========================
On the Service VM side, it uses the ``acrnctl`` tool to trigger the User VM's S5 flow:
``acrnctl stop user-vm-name``. Then, the Device Model sends a ``shutdown`` command
to the User VM through a channel. If the User VM receives the command, it will send an "ACK"
to the Device Model. It is the Service VM's responsibility to check if the User VMs
shutdown successfully or not, and decides when to power off itself.
User VM "life-cycle manager"
============================
As part of the current S5 reference design, a life-cycle manager daemon (life_mngr) runs in the
User VM to implement S5. It waits for the command from the Service VM on the
paired serial port. The simple protocol between the Service VM and User VM is as follows:
When the daemon receives ``shutdown``, it sends "acked" to the Service VM;
then it can power off the User VM. If the User VM is not ready to power off,
it can ignore the ``shutdown`` command.
.. _enable_s5:
Enable S5
*********
The procedure for enabling S5 is specific to the particular OS:
* For Linux (LaaG) or Windows (WaaG), refer to the following configurations in the
``devicemodel/samples/nuc/launch_uos.sh`` launch script for ``acrn-dm``.
.. literalinclude:: ../../../../devicemodel/samples/nuc/launch_uos.sh
:name: laag-waag-script
:caption: LaaG/WaaG launch script
:linenos:
:lines: 97-117
:emphasize-lines: 2-4,17
:language: bash
* For RT-Linux, refer to the ``devicemodel/samples/nuc/launch_hard_rt_vm.sh`` script:
.. literalinclude:: ../../../../devicemodel/samples/nuc/launch_hard_rt_vm.sh
:name: rt-script
:caption: RT-Linux launch script
:linenos:
:lines: 42-58
:emphasize-lines: 2-3,13
:language: bash
.. note:: For RT-Linux, the vUART is emulated in the hypervisor; expose the node as ``/dev/ttySn``.
#. For LaaG and RT-Linux VMs, run the life-cycle manager daemon:
a. Use these commands to build the life-cycle manager daemon, ``life_mngr``.
.. code-block:: none
$ cd acrn-hypervisor/misc/life_mngr
$ make life_mngr
#. Copy ``life_mngr`` and ``life_mngr.service`` into the User VM:
.. code-block:: none
$ scp life_mngr root@<test board address>:/usr/bin/life_mngr
$ scp life_mngr.service root@<test board address>:/lib/systemd/system/life_mngr.service
#. Use the below commands to enable ``life_mngr.service`` and restart the User VM.
.. code-block:: none
# chmod +x /usr/bin/life_mngr
# systemctl enable life_mngr.service
# reboot
#. For the WaaG VM, run the life-cycle manager daemon:
a) Build the ``life_mngr_win.exe`` application::
$ cd acrn-hypervisor/misc
$ make life_mngr
.. note:: If there is no ``x86_64-w64-mingw32-gcc`` compiler, you must run ``swupd bundle-add c-basic-mingw``
to install it.
#) Set up a Windows environment:
I) Download the :kbd:`Visual Studio 2019` tool from `<https://visualstudio.microsoft.com/downloads/>`_,
and choose the two options in the below screenshots to install "Microsoft Visual C++ Redistributable
for Visual Studio 2015, 2017 and 2019 (x86 or X64)" in WaaG:
.. figure:: images/Microsoft-Visual-C-install-option-1.png
.. figure:: images/Microsoft-Visual-C-install-option-2.png
#) In WaaG, use the :kbd:`WIN + R` shortcut key, input "shell:startup", click :kbd:`OK`
and then copy the ``life_mngr_win.exe`` application into this directory.
.. figure:: images/run-shell-startup.png
.. figure:: images/launch-startup.png
#) Restart the WaaG VM. The COM2 window will automatically open after reboot.
.. figure:: images/open-com-success.png
#. If the Service VM is being shut down (transitioning to the S5 state), it can call
``acrnctl stop vm-name`` to shut down the User VMs.
.. note:: S5 state is not automatically triggered by a Service VM shutdown; this needs
to be run before powering off the Service VM.
How to test
***********
.. note:: The :ref:`CBC <IOC_virtualization_hld>` tools and service installed by
the `software-defined-cockpit
<https://github.com/clearlinux/clr-bundles/blob/master/bundles/software-defined-cockpit>`_ bundle
will conflict with the vUART and hence need to be masked.
::
systemctl mask cbc_attach
systemctl mask cbc_thermal_fuse
systemctl mask cbc_thermald
systemctl mask cbc_lifecycle.service
Or::
ps -ef|grep cbc; kill -9 cbc_pid
#. Refer to the :ref:`enable_s5` section to set up the S5 environment for the User VMs.
.. note:: RT-Linux's UUID must use ``495ae2e5-2603-4d64-af76-d4bc5a8ec0e5``. Also, the
industry EFI image is required for launching the RT-Linux VM.
.. note:: Use the ``systemctl status life_mngr.service`` command to ensure the service is working on the LaaG or RT-Linux:
.. code-block:: console
* life_mngr.service - ACRN lifemngr daemon
Loaded: loaded (/usr/lib/systemd/system/life_mngr.service; enabled; vendor p>
Active: active (running) since Tue 2019-09-10 07:15:06 UTC; 1min 11s ago
Main PID: 840 (life_mngr)
.. note:: For WaaG, we need to close ``windbg`` by using the ``bcdedit /set debug off`` command
IF you executed the ``bcdedit /set debug on`` when you set up the WaaG, because it occupies the ``COM2``.
#. Use the``acrnctl stop`` command on the Service VM to trigger S5 to the User VMs:
.. code-block:: console
# acrnctl stop vm1
#. Use the ``acrnctl list`` command to check the User VM status.
.. code-block:: console
# acrnctl list
vm1 stopped