ACRN Configuration Tool

The ACRN configuration tool is designed for System Integrators / Tier 1s to customize ACRN to meet their own needs. It consists of two tools, the Kconfig tool and the acrn-config tool. The latter allows users to provision VMs via a web interface and configure the hypervisor from XML files at build time.


ACRN includes three types of configurations: Hypervisor, Board, and VM. Each are discussed in the following sections.

Hypervisor configuration

The hypervisor configuration selects a working scenario and target board by configuring the hypervisor image features and capabilities such as setting up the log and the serial port.

The hypervisor configuration uses the Kconfig make menuconfig mechanism. The configuration file is located in the acrn-hypervisor/hypervisor/arch/x86/configs/ folder.

The board-specific defconfig file, acrn-hypervisor/hypervisor/arch/x86/configs/$(BOARD).config is loaded first; it is the default Kconfig for the specified board.

Board configuration

The board configuration stores board-specific settings referenced by the ACRN hypervisor. This includes scenario-relevant information such as board settings, root device selection, and the kernel cmdline. It also includes scenario-irrelevant hardware-specific information such as ACPI/PCI and BDF information. The board configuration is organized as *.c/*.h files located in the acrn-hypervisor/hypervisor/arch/x86/configs/$(BOARD)/ folder.

VM configuration

VM configuration includes scenario-based VM configuration information that is used to describe the characteristics and attributes for VMs on each user scenario. It also includes launch script-based VM configuration information, where parameters are passed to the device model to launch post-launched User VMs.

Scenario based VM configurations are organized as *.c/*.h files located in the acrn-hypervisor/hypervisor/scenarios/$(SCENARIO)/ folder.

User VM launch script samples are located in the acrn-hypervisor/devicemodel/samples/ folder.

ACRN configuration XMLs

The ACRN configuration includes three kinds of XML files for acrn-config usage: board, scenario, and launch XML. All scenario-irrelevant hardware-specific information for the board configuration is stored in the board XML. The XML is generated by misc/acrn-config/target/, which runs on the target board. The scenario-relevant board and scenario-based VM configurations are stored in the scenario XML. The launch script-based VM configuration is stored in the launch XML. These two XMLs can be customized by using the web interface tool at misc/acrn-config/config_app/ End users can load their own configurations by importing customized XMLs or by saving the configurations by exporting XMLs.

Board XML format

The board XMLs are located in the acrn-hypervisor/misc/acrn-config/xmls/board-xmls/ folder. The board XML has an acrn-config root element and a board attribute:

<acrn-config board="BOARD">

As an input for the acrn-config tool, end users do not need to care about the format of board XML and should not modify it.

Scenario XML format

The scenario XMLs are located in the acrn-hypervisor/misc/acrn-config/xmls/config-xmls/ folder. The scenario XML has an acrn-config root element as well as board and scenario attributes:

<acrn-config board="BOARD" scenario="SCENARIO">

Additional scenario XML elements:

Specify the VM with VMID by its “id” attribute.
Specify the VM by its load order: PRE_LAUNCHED_VM, SOS_VM or POST_LAUNCHED_VM.
name (a child node of vm):
Specify the VM name which will be shown in the hypervisor console command: vm_list.
UUID of the VM. It is for internal use and is not configurable.

Select all applicable flags for the VM:

GUEST_FLAG_SECURE_WORLD_ENABLED specify whether secure world is enabled

GUEST_FLAG_LAPIC_PASSTHROUGH specify whether LAPIC is passed through

GUEST_FLAG_IO_COMPLETION_POLLING specify whether the hypervisor needs IO polling to completion

GUEST_FLAG_CLOS_REQUIRED specify whether CLOS is required

GUEST_FLAG_HIDE_MTRR specify whether to hide MTRR from the VM

GUEST_FLAG_RT specify whether the vm is RT-VM


Severity of the guest VM; the lower severity VM should not impact the higher severity VM.


vCPU affinity map. Each vCPU will be mapped to the selected pCPU ID. A different vCPU in the same VM cannot be mapped to the same pCPU. If the pCPU is mapped by different VMs, cpu_sharing of the VM must be set to Enabled in the launch XML.
base (a child node of epc_section):
SGX EPC section base; must be page aligned.
size (a child node of epc_section):
SGX EPC section size in bytes; must be page aligned.
Class of Service for Cache Allocation Technology settings. Refer to RDT Allocation Feature Supported by Hypervisor for details.
start_hpa (a child node of memory):
The start physical address in host for the VM.
size (a child node of memory):
The memory size in bytes for the VM.
name (a child node of os_config):
Specify the OS name of VM; currently, it is not referenced by the hypervisor code.
kern_type (a child node of os_config):
Specify the kernel image type so that the hypervisor can load it correctly. Currently supports KERNEL_BZIMAGE and KERNEL_ZEPHYR.
kern_mod (a child node of os_config):
The tag for the kernel image that acts as a multiboot module; it must exactly match the module tag in the GRUB multiboot cmdline.
ramdisk_mod (a child node of os_config):
The tag for the ramdisk image which acts as a multiboot module; it must exactly match the module tag in the GRUB multiboot cmdline.
bootargs (a child node of os_config):
For internal use and is not configurable. Specify the kernel boot arguments in bootargs under the parent of board_private.
kern_load_addr (a child node of os_config):
The loading address in host memory for the VM kernel.
kern_entry_addr (a child node of os_config):
The entry address in host memory for the VM kernel.
Specify the vuart (A.K.A COM) with the vUART ID by its “id” attribute. Refer to vUART Configuration for detailed vUART settings.
type (a child node of vuart):
vUART (A.K.A COM) type, currently only supports the legacy PIO mode.
base (a child node of vuart):
vUART (A.K.A COM) enabling switch. Enable by exposing its COM_BASE (SOS_COM_BASE for Service VM); disable by returning INVALID_COM_BASE.
irq (a child node of vuart):
vCOM irq.
target_vm_id (a child node of vuart1):
COM2 is used for VM communications. When it is enabled, specify which target VM the current VM connects to.
target_uart_id (a child node of vuart1):
Target vUART ID that vCOM2 connects to.
PCI devices number of the VM; it is hard-coded for each scenario so it is not configurable for now.
PCI devices list of the VM; it is hard-coded for each scenario so it is not configurable for now.
Stores scenario-relevant board configuration.
rootfs for the Linux kernel.
ttyS console for the Linux kernel.
bootargs (a child node of board_private):
Specify kernel boot arguments.

Launch XML format

The launch XMLs are located in the acrn-hypervisor/misc/acrn-config/xmls/config-xmls/ folder. The launch XML has an acrn-config root element as well as board, scenario and uos_launcher attributes:

<acrn-config board="BOARD" scenario="SCENARIO" uos_launcher="UOS_NUMBER">

Attributes of the uos_launcher specify the number of User VMs that the current scenario has:

Specify the User VM with its relative ID to Service VM by the “id” attribute.
Specify the User VM Realtime capability: Soft RT, Hard RT, or none of them.
Specify the User VM memory size in Mbyte.
GVT arguments for the VM. Input format: low_gm_size high_gm_size fence_sz. Recommendation is: 64 448 8. Leave it blank to disable the GVT.
Virtual bootloader type; currently only supports OVMF.
Specify whether the pCPUs listed can be shared with other VMs.
Specify whether the device model emulates the vUART0(vCOM1); refer to vUART Configuration for details. If set to Enable, the vUART0 is emulated by the device model; if set to Disable, the vUART0 is emulated by the hypervisor if it is configured in the scenario XML.
Specify whether the User VM power off channel is through the IOC, Powerbutton, or vUART.
USB xHCI mediator configuration. Input format: bus#-port#[:bus#-port#: ...]. e.g.: 1-2:2-4. refer to USB Virtualization for details.
Select the passthrough device from the lspci list; currently we support: usb_xdci, audio, audio_codec, ipu, ipu_i2c, cse, wifi, Bluetooth, sd_card, ethernet, wifi, sata, and nvme.
network (a child node of virtio_devices):
The virtio network device setting. Input format: tap_name,[vhost],[mac=XX:XX:XX:XX:XX:XX].
block (a child node of virtio_devices):
The virtio block device setting. Input format: [blk partition:][img path] e.g.: /dev/sda3:./a/b.img.
console (a child node of virtio_devices):
The virtio console device setting. Input format: [@]stdio|tty|pty|sock:portname[=portpath][,[@]stdio|tty|pty:portname[=portpath]].


The configurable and readonly attributes are used to mark whether the items is configurable for users. When configurable="0" and readonly="true", the item is not configurable from the web interface. When configurable="0". the item does not appear on the interface.

Configuration tool workflow

Hypervisor configuration workflow

The hypervisor configuration is based on the Kconfig make menuconfig mechanism. Begin by creating a board-specific defconfig file to set up the default Kconfig values for the specified board. Next, configure the hypervisor build options using the make menuconfig graphical interface. The resulting .config file is used by the ACRN build process to create a configured scenario- and board-specific hypervisor image.


Figure 23 defconfig file sample


Figure 24 menuconfig interface sample

Refer to Step 4: Build the hypervisor configuration for detailed configuration steps.

Board and VM configuration workflow

Python offline tools are provided to configure Board and VM configurations. The tool source folder is acrn-hypervisor/misc/acrn-config/.

Here is the offline configuration tool workflow:

  1. Get the board info.

    1. Set up a native Linux environment on the target board.

    2. Copy the target folder into the target file system and then run the sudo python3 $(BOARD) command.

    3. A $(BOARD).xml that includes all needed hardware-specific information is generated in the ./out/ folder. (Here $(BOARD) is the specified board name)

      Native Linux requirement:
      Release: Ubuntu 18.04+ or Clear Linux 30210+
      Tools: cpuid, rdmsr, lspci, dmidecode (optional)
      Kernel cmdline: “idle=nomwait intel_idle.max_cstate=0 intel_pstate=disable”
  2. Customize your needs.

    1. Copy $(BOARD).xml to the host development machine.
    2. Run the misc/acrn-config/config_app/ tool on the host machine and import the $(BOARD).xml. Select your working scenario under Scenario Setting and input the desired scenario settings. The tool will do a sanity check on the input based on the $(BOARD).xml. The customized settings can be exported to your own $(SCENARIO).xml.
    3. In the configuration tool UI, input the launch script parameters for the post-launched User VM under Launch Setting. The tool will sanity check the input based on both the $(BOARD).xml and $(SCENARIO).xml and then export settings to your $(LAUNCH).xml.
    4. The user defined XMLs can be imported by acrn-config for modification.


    Refer to Use the ACRN configuration app for more details on the configuration tool UI.

  1. Auto generate the code.

    Python tools are used to generate configurations in patch format. The patches are applied to your local acrn-hypervisor git tree automatically.

    1. Generate a patch for the board-related configuration:

      cd misc/acrn-config/board_config
      python3 --board $(BOARD).xml --scenario $(SCENARIO).xml

      Note that this can also be done by clicking Generate Board SRC in the acrn-config UI.

    2. Generate a patch for scenario-based VM configuration:

      cd misc/acrn-config/scenario_config
      python3 --board $(BOARD).xml --scenario $(SCENARIO).xml

      Note that this can also be done by clicking Generate Scenario SRC in the acrn-config UI.

    3. Generate the launch script for the specified post-launched User VM:

      cd misc/acrn-config/launch_config
      python3 --board $(BOARD).xml --scenario $(SCENARIO).xml --launch $(LAUNCH).xml --uosid xx

      Note that this can also be done by clicking Generate Launch Script in the acrn-config UI.

  2. Re-build the ACRN hypervisor. Refer to Build ACRN from Source to re-build the ACRN hypervisor on the host machine.

  3. Deploy VMs and run ACRN hypervisor on the target board.


Figure 25 Offline tool workflow

Use the ACRN configuration app

The ACRN configuration app is a web user interface application that performs the following:

  • reads board info
  • configures and validates scenario settings
  • automatically generates patches for board-related configurations and scenario-based VM configurations
  • configures and validates launch settings
  • generates launch scripts for the specified post-launched User VMs.


  • Clone acrn-hypervisor:

    $git clone
  • Install ACRN configuration app dependencies:

    $ cd ~/acrn-hypervisor/misc/acrn-config/config_app
    $ sudo pip3 install -r requirements


  1. Launch the ACRN configuration app:

    $ python3
  2. Open a browser and navigate to the website automatically, or you may need to visit this website manually. Make sure you can connect to open network from browser because the app needs to download some JavaScript files.


    The ACRN configuration app is supported on Chrome, Firefox, and MS Edge. Do not use IE.

    The website is shown below:

  3. Set the board info:

    1. Click Import Board info.

    2. Upload the board info you have generated from the ACRN config tool.

    3. After board info is uploaded, you will see the board name from the Board info list. Select the board name to be configured.

  4. Choose a scenario from the Scenario Setting menu which lists all the scenarios, including the default scenarios and the user-defined scenarios for the board you selected in the previous step. The scenario configuration xmls are located at acrn-hypervisor/misc/acrn-config/xmls/config-xmls/[board]/.


    Note that you can also use a customized scenario xml by clicking Import. The configuration app automatically directs to the new scenario xml once the import is complete.

  5. The configurable items display after one scenario is selected. Here is the example of “SDC” scenario:

    • You can edit these items directly in the text boxes, cor you can choose single or even multiple items from the drop down list.
    • Read-only items are marked as grey.
    • Hover the mouse pointer over the item to display the description.
  6. Click Export to save the scenario xml; you can rename it in the pop-up modal.


    All customized scenario xmls will be in user-defined groups which located in acrn-hypervisor/misc/acrn-config/xmls/config-xmls/[board]/user_defined/.

    Before saving the scenario xml, the configuration app will validate the configurable items. If errors exist, the configuration app lists all wrong configurable items and shows the errors as below:


    After the scenario is saved, the page automatically directs to the saved scenario xmls. You can delete the configured scenario by clicking Export -> Remove.

  7. Click Generate Board SRC to save the current scenario setting and then generate a patch for the board-related configuration source codes in acrn-hypervisor/hypervisor/arch/x86/configs/[board]/.

  8. Click Generate Scenario SRC to save the current scenario setting and then generate a patch for the scenario-based VM configuration scenario source codes in acrn-hypervisor/hypervisor/scenarios/[scenario]/.

The Launch Setting is quite similar to the Scenario Setting:

  1. Upload board info or select one board as the current board.

  2. Import your local launch setting xml by clicking Import or selecting one launch setting xml from the menu.

  3. Select one scenario for the current launch setting from the Select Scenario drop down box.

  4. Configure the items for the current launch setting.

  5. Save the current launch setting to the user-defined xml files by clicking Export. The configuration app validates the current configuration and lists all wrong configurable items and shows errors.

  6. Click Generate Launch Script to save the current launch setting and then generate the launch script.