Running Ubuntu in the Service VM

This document builds on the Getting Started series and explains how to use Ubuntu instead of Clear Linux OS as the Service VM with the ACRN hypervisor. (Note that different OSs can be used for the Service and User VM.) In the following instructions, we will build on material described in Using SDC Mode on the NUC.

Install Ubuntu (natively)

Ubuntu 18.04.1 LTS is used throughout this document; other older versions such as 16.04 also work.

  • Download Ubuntu 18.04 from the Ubuntu 18.04.1 LTS (Bionic Beaver) page and select the ubuntu-18.04.1-desktop-amd64.iso image.

  • Follow Ubuntu’s online instructions to install it on your device.


    Configure your device’s proxy settings to have full internet access.

  • While not strictly required, enabling SSH gives the user a very useful mechanism for accessing the Service VM remotely or when running one or more User VM. Follow these steps to enable it on the Ubuntu Service VM:

    sudo apt-get install openssh-server
    sudo service ssh status
    sudo service ssh start
  • If you plan to SSH Ubuntu as root, you must also modify /etc/ssh/sshd_config:

    PermitRootLogin yes

Install ACRN

ACRN components are distributed in source form, so you must download the source code, build it, and install it on your device.

  1. Install the build tools and dependencies.

    Follow the instructions found in Build ACRN from Source to install all the build tools and dependencies on your system.

  2. Clone the Project ACRN code repository.

    Enter the following:

    cd ~
    git clone
    git checkout acrn-2019w47.1-140000p


    We clone the git repository above but it is also possible to download the tarball for any specific tag or release from the Project ACRN Github release page.

  3. Build and install ACRN.

    Here is the short version on how to build and install ACRN from source:

    cd ~/acrn-hypervisor
    sudo make install

    For more details, refer to Build ACRN from Source.

  4. Install the hypervisor.

    The ACRN device model and tools are installed as part of the previous step. However, make install does not install the hypervisor (acrn.efi) on your EFI System Partition (ESP), nor does it configure your EFI firmware to boot it automatically. Therefore, follow the steps below to perform these operations and complete the ACRN installation.

    1. Add the ACRN hypervisor and Service VM kernel to it (as root):

      ls /boot/efi/EFI/ubuntu/

      You should see the following output:

      fw  fwupx64.efi  grub.cfg  grubx64.efi  MokManager.efi  shimx64.efi
    2. Install the hypervisor (acrn.efi):

      sudo mkdir /boot/efi/EFI/acrn/
      sudo cp ~/acrn-hypervisor/build/hypervisor/acrn.efi /boot/efi/EFI/acrn/
    3. Configure the EFI firmware to boot the ACRN hypervisor by default:

      # For SATA
      sudo efibootmgr -c -l "\EFI\acrn\acrn.efi" -d /dev/sda -p 1 \
             -L "ACRN Hypervisor" -u "bootloader=\EFI\ubuntu\grubx64.efi "
      # For NVMe
      sudo efibootmgr -c -l "\EFI\acrn\acrn.efi" -d /dev/nvme0n1 -p 1 \
             -L "ACRN Hypervisor" -u "bootloader=\EFI\ubuntu\grubx64.efi "


    Note the extra space at the end of the EFI command-line options strings above. This is a workaround for a current efi-stub bootloader name issue. It ensures that the end of the string is properly detected.

    1. Verify that “ACRN Hypervisor” is added and that it will boot first:

      sudo efibootmgr -v

      You can also verify it by entering the EFI firmware at boot (using F10).

    2. Change the boot order at any time using efibootmgr -o XXX,XXX,XXX:

    sudo efibootmgr -o xxx,xxx,xxx

Install the Service VM kernel

Download the latest Service VM kernel.

  1. The latest Service VM kernel from the latest Clear Linux OS release is located here: Look for the following .rpm file: linux-iot-lts2018-sos-<kernel-version>-<build-version>.x86_64.rpm.

    While we recommend using the current (latest) Clear Linux OS release, you can download a specific Clear Linux release from an area with that release number, such as the following:

  2. Download and extract the latest Service VM kernel (this guide uses 31670 as the current example):

    sudo mkdir ~/sos-kernel-build
    cd ~/sos-kernel-build
    sudo apt-get install rpm2cpio
    rpm2cpio linux-iot-lts2018-sos-4.19.78-98.x86_64.rpm | cpio -idmv
  3. Install the Service VM kernel and its drivers (modules):

    sudo cp -r ~/sos-kernel-build/usr/lib/modules/4.19.78-98.iot-lts2018-sos/ /lib/modules/
    sudo mkdir /boot/acrn/
    sudo cp ~/sos-kernel-build/usr/lib/kernel/org.clearlinux.iot-lts2018-sos.4.19.78-98  /boot/acrn/
  4. Configure Grub to load the Service VM kernel:

    • Modify the /etc/grub.d/40_custom file to create a new Grub entry that will boot the Service VM kernel.

      menuentry 'ACRN Ubuntu Service VM' --id ubuntu-service-vm {
              insmod gzio
              insmod part_gpt
              insmod ext2
              linux  /boot/acrn/org.clearlinux.iot-lts2018-sos.4.19.78-98  pci_devices_ignore=(0:18:1) console=tty0 console=ttyS0 root=PARTUUID=<UUID of rootfs partition> rw rootwait ignore_loglevel no_timer_check consoleblank=0 i915.nuclear_pageflip=1 i915.avail_planes_per_pipe=0x01010F i915.domain_plane_owners=0x011111110000 i915.enable_gvt=1 i915.enable_guc=0 hvlog=2M@0x1FE00000


      Adjust this to use your partition UUID (PARTUUID) for the root= parameter (or use the device node directly).

      Adjust the kernel name if you used a different RPM file as the source of your Service VM kernel.

      The command line for the kernel in /etc/grub.d/40_custom should be entered as a single line, not as multiple lines. Otherwise, the kernel will fail to boot.

    • Modify the /etc/default/grub file to make the grub menu visible when booting and make it load the Service VM kernel by default. Modify the lines shown below:

    • Update Grub on your system:

      sudo update-grub
  5. Reboot the system.

    Reboot the system. You should see the Grub menu with the new ACRN ubuntu-service-vm entry. Select it and proceed to booting the platform. The system will start the Ubuntu Desktop and you can now log in (as before).


    If you don’t see the Grub menu after rebooting the system (and you are not booting into the ACRN hypervisor), enter the EFI firmware at boot (using F10) and manually select ACRN Hypervisor.

    If you see a black screen on the first-time reboot after installing the ACRN Hypervisor, wait a few moments and the Ubuntu desktop will display.

    To verify that the hypervisor is effectively running, check dmesg. The typical output of a successful installation resembles the following:

    dmesg | grep ACRN
    [    0.000000] Hypervisor detected: ACRN
    [    0.862942] ACRN HVLog: acrn_hvlog_init

Prepare the User VM

For the User VM, we are using the same Clear Linux OS release version as for the Service VM.

  • Download the Clear Linux OS image from

    cd ~
    unxz clear-31670-kvm.img.xz
  • Download the “linux-iot-lts2018” kernel:

    sudo mkdir ~/uos-kernel-build
    cd ~/uos-kernel-build
    rpm2cpio linux-iot-lts2018-4.19.78-98.x86_64.rpm | cpio -idmv
  • Update the User VM kernel modules:

    sudo losetup -f -P --show ~/clear-31670-kvm.img
    sudo mount /dev/loop0p3 /mnt
    sudo cp -r ~/uos-kernel-build/usr/lib/modules/4.19.78-98.iot-lts2018/ /mnt/lib/modules/
    sudo cp -r ~/uos-kernel-build/usr/lib/kernel /lib/modules/
    sudo umount /mnt

    If you encounter a permission issue, follow these steps:

    sudo chmod 777 /dev/acrn_vhm
  • Add the following package:

    sudo apt update
    sudo apt install m4 bison flex zlib1g-dev
    cd ~
    tar zxvf acpica-unix-20191018.tar.gz
    cd acpica-unix-20191018
    make clean && make iasl
    sudo cp ./generate/unix/bin/iasl /usr/sbin/
  • Adjust the script:

    You need to adjust the /usr/share/acrn/samples/nuc/ script to match your installation. Modify the following lines:

    -s 3,virtio-blk,/root/clear-31670-kvm.img \


    The User VM image can be stored in other directories instead of ~/. Remember to also modify the image directory in

Start the User VM

You are now all set to start the User VM:

sudo /usr/share/acrn/samples/nuc/

Congratulations, you are now watching the User VM booting up!

Enable network sharing

After booting up the Service VM and User VM, network sharing must be enabled to give network access to the Service VM by enabling the TAP and networking bridge in the Service VM. The following script example shows how to set this up (verified in Ubuntu 16.04 and 18.04 as the Service VM).

#setup bridge for uos network
br=$(brctl show | grep acrn-br0)
ip tuntap add dev tap0 mode tap

# if bridge not existed
if [ "$br"x != "acrn-br0"x ]; then
#setup bridge for uos network
brctl addbr acrn-br0
brctl addif acrn-br0 enp3s0
ifconfig enp3s0 0
dhclient acrn-br0

# Add TAP device to the bridge
brctl addif acrn-br0 tap0
ip link set dev tap0 up


The Service VM network interface is called enp3s0 in the script above. Adjust the script if your system uses a different name (e.g. eno1).

Enable the USB keyboard and mouse

Refer to Using SDC Mode on the NUC for instructions on enabling the USB keyboard and mouse for the User VM.