IVSHMEM Ethernet

.. zephyr:code-sample:: eth-ivshmem
   :name: Inter-VM Shared Memory (ivshmem) Ethernet
   :relevant-api: ivshmem ethernet

   Communicate with another "cell" in the Jailhouse hypervisor using IVSHMEM Ethernet.

Overview
********

This application demonstrates how to use IVSHMEM Ethernet to communicate with
another "cell" in the Jailhouse hypervisor. Currently only the qemu_cortex_a53
board is supported.

Building Jailhouse Linux for QEMU
*********************************

Clone Jailhouse yocto project. At the time of writing, the "next" branch has
some fixes that are not yet on the "master" branch:

.. code-block:: console

    git clone https://github.com/siemens/jailhouse-images.git
    cd jailhouse-images
    git checkout origin/next

Open the menu, select "QEMU ARM64 virtual target" then "Save & Build"
(this will take a while):

.. code-block:: console

    ./kas-container menu

Edit "start-qemu.sh":
 * change ``-cpu cortex-a57`` -> ``-cpu cortex-a53``
   under the ``arm64|aarch64`` case
 * Enable SSH access by appending ``,hostfwd=tcp::2222-:22`` to
   ``-netdev user,id=net`` in the QEMU process arguments
   (2222 can be replaced with any unused port)

Start QEMU:

.. code-block:: console

    ./start-qemu.sh arm64

This should boot Linux and drop into a shell.

Build the Zephyr sample
***********************

.. zephyr-app-commands::
   :zephyr-app: samples/drivers/ethernet/eth_ivshmem
   :board: qemu_cortex_a53
   :goals: build

Running the sample
******************

Copy the generated zephyr.bin to the Jailhouse Linux root cell:

.. code-block:: console

    scp -P 2222 path/to/zephyr.bin root@localhost:/root

Jailhouse has a prebuilt Zephyr cell configuration that works for
this sample "qemu-arm64-zephyr-demo".

Back in Jailhouse Linux shell, create the Zephyr cell:

.. code-block:: console

    jailhouse enable /etc/jailhouse/qemu-arm64.cell
    jailhouse console
    jailhouse cell create /etc/jailhouse/qemu-arm64-zephyr-demo.cell

You may see a quirk here where the Linux shell stops taking input...
If you get this, open a second shell via SSH:

.. code-block:: console

    ssh -p 2222 root@localhost

Load and start the Zephyr cell:

.. code-block:: console

    jailhouse cell load qemu-arm64-zephyr-demo zephyr.bin --address 0x70000000
    jailhouse cell start qemu-arm64-zephyr-demo

Now you can run Zephyr and Linux shell commands to communicate between
the cells.

Ping Linux from Zephyr
**********************

.. code-block:: console

    *** Booting Zephyr OS build v3.3.0-475-g45b9e84c6013 ***
    uart:~$ net ping 192.168.19.1
    PING 192.168.19.1
    28 bytes from 192.168.19.1 to 192.168.19.2: icmp_seq=1 ttl=64 time=5.06 ms
    28 bytes from 192.168.19.1 to 192.168.19.2: icmp_seq=2 ttl=64 time=7.99 ms
    28 bytes from 192.168.19.1 to 192.168.19.2: icmp_seq=3 ttl=64 time=1.77 ms

Ping Zephyr from Linux
**********************

.. code-block:: console

    root@demo:~# ping -c 3 192.168.19.2
    PING 192.168.19.2 (192.168.19.2) 56(84) bytes of data.
    64 bytes from 192.168.19.2: icmp_seq=1 ttl=64 time=0.646 ms
    64 bytes from 192.168.19.2: icmp_seq=2 ttl=64 time=1.45 ms
    64 bytes from 192.168.19.2: icmp_seq=3 ttl=64 time=1.28 ms

    --- 192.168.19.2 ping statistics ---
    3 packets transmitted, 3 received, 0% packet loss, time 2006ms
    rtt min/avg/max/mdev = 0.646/1.124/1.450/0.345 ms

Run zperf / iPerf
*****************

:ref:`zperf` / iPerf can be used to perform network throughput measurements.

In Zephyr:

.. code-block:: console

    # Start zperf TCP server
    zperf tcp download 5001

In Linux:

.. code-block:: console

    # Install iPerf 2.0.5
    apt install wget
    wget https://iperf.fr/download/ubuntu/iperf_2.0.5+dfsg1-2_arm64.deb
    apt install ./iperf_2.0.5+dfsg1-2_arm64.deb
    rm iperf_2.0.5+dfsg1-2_arm64.deb

    # Connect iPerf TCP client
    iperf -l 1K -V -c 192.168.19.2 -p 5001

Zephyr output:

.. code-block:: console

    TCP server started on port 5001
    New TCP session started.
    TCP session ended
     Duration:              10.01 s
     rate:                  57.72 Mbps

Linux output:

.. code-block:: console

    ------------------------------------------------------------
    Client connecting to 192.168.19.2, TCP port 5001
    TCP window size: 85.0 KByte (default)
    ------------------------------------------------------------
    [  3] local 192.168.19.1 port 58430 connected with 192.168.19.2 port 5001
    [ ID] Interval       Transfer     Bandwidth
    [  3]  0.0-10.0 sec  72.2 MBytes  60.6 Mbits/sec