ACRN v3.0 (Jun 2022)

We are pleased to announce the release of the Project ACRN hypervisor version 3.0.

ACRN is a flexible, lightweight reference hypervisor that is built with real-time and safety-criticality in mind. It is optimized to streamline embedded development through an open-source platform. See the What Is ACRN introduction for more information.

All project ACRN source code is maintained in the repository and includes folders for the ACRN hypervisor, the ACRN device model, tools, and documentation. You can download this source code either as a zip or tar.gz file (see the ACRN v3.0 GitHub release page) or use Git clone and checkout commands:

git clone
cd acrn-hypervisor
git checkout v3.0

The project’s online technical documentation is also tagged to correspond with a specific release: generated v3.0 documents can be found at Documentation for the latest development branch is found at

ACRN v3.0 requires Ubuntu 20.04. Follow the instructions in the Getting Started Guide to get started with ACRN.

What’s New in v3.0

Redesigned ACRN Configuration

We heard your feedback: ACRN configuration is difficult, confusing, and had too many parameters that were not easy to understand. Release v3.0 features a new ACRN Configurator UI tool with a more intuitive design and workflow that simplifies getting the setup for the ACRN hypervisor right. You’ll also see changes for configuring individual VMs. We’ve greatly reduced the number of parameters needing your attention, organized them into basic and advanced categories, provided practical defaults, and added error checking so you can be much more confident in your configuration before building ACRN. We’ve also integrated the previously separated scenario and launch options into a merged scenario XML configuration file managed by the new Configurator. Read more in the ACRN Configurator Tool page.

This is our first major step of continued ACRN user experience improvements. If you have feedback on this, or other aspects of ACRN, please share them on the ACRN users mailing list.

We’ve also simplified installation of the Configurator by providing a Debian package that you can download from the ACRN v3.0 tag assets and install. See the Getting Started Guide for more information.

Improved Board Inspector Collection and Reporting

You run the ACRN Board Inspector tool to collect information about your target system’s processors, memory, devices, and more. The generated board XML file is used by the ACRN Configurator to determine which ACRN configuration options are possible, as well as possible values for target system resources. The v3.0 Board Inspector has improved scanning and provides more messages about potential issues or limitations of your target system that could impact ACRN configuration options. Read more in Board Inspector Tool.

Commercial off-the-shelf Tiger Lake machine support

The Vecow SPC-7100 system is validated and supported by ACRN. This is a commercially available 11th Generation Intel® Core™ Processor (codenamed Tiger Lake) from Vecow. Read more in the Supported Hardware documentation.

Refined shutdown & reset sequence

A Windows User VM can now shut down or reset the system gracefully. This supports a user model where a Windows-based VM provides a system management interface. This shutdown capability is achieved by lifecycle managers in each VM that talk to each other via a virtual UART channel.

Hypervisor Real Time Clock (RTC)

Each VM now has its own PC/AT-compatible RTC/CMOS device emulated by the hypervisor. With this, we can avoid any sudden jump in a VM’s system clock that may confuse certain applications.

ACRN Debianization

We appreciate a big contribution from the ACRN community! Helmut Buchsbaum from TTTech Industrial submitted a “debianization” feature that lets developers build and package ACRN into several Debian packages, install them on the target Ubuntu or Debian OS, and reboot the machine with ACRN running. Read more in debian/README.rst.

Upgrading to v3.0 from Previous Releases

With the introduction of the Configurator UI tool, the need for manually editing XML files is gone. While working on this improved Configurator, we’ve also made many adjustments to available options in the underlying XML files, including merging the previous scenario and launch XML files into a combined scenario XML file. The board XML file generated by the v3.0 Board Inspector tool includes more information about the target system that is needed by the v3.0 Configurator.

We recommend you generate a new board XML for your target system with the v3.0 Board Inspector. You should also use the v3.0 Configurator to generate a new scenario XML file and launch scripts. Scenario XML files and launch scripts created by previous ACRN versions will not work with the v3.0 ACRN hypervisor build process and could produce unexpected errors during the build.

Given the scope of changes for the v3.0 release, we have recommendations for how to upgrade from prior ACRN versions:

  1. Start fresh from our Getting Started Guide. This is the best way to ensure you have a v3.0-ready board XML file from your target system and generate a new scenario XML and launch scripts from the new ACRN Configurator that are consistent and will work for the v3.0 build system.

  2. Use the upgrade tool to attempt upgrading configuration files that worked with a release before v3.0. You’ll need the matched pair of scenario XML and launch XML files from a prior configuration, and use them to create a new merged scenario XML file. See Upgrading ACRN Configurations to Recent Releases for details.

  3. Manually edit your prior scenario XML and launch XML files to make them compatible with v3.0. This is not our recommended approach.

Here are some additional details about upgrading to the v3.0 release.

Generate New Board XML

Board XML files, generated by ACRN board inspector, contain board information that is essential for building the ACRN hypervisor and setting up User VMs. Compared to previous versions, ACRN v3.0 adds the following information to the board XML file for supporting new features and fixes:

  • Add --add-llc-cat to Board Inspector command line options to manually provide Cache Allocation Technology (CAT) to the generated board XML when the target hardware does not report availability of this feature. See Board Inspector Command-Line Options and PR #7331.

  • Collect all information about SR-IOV devices: see PR #7302.

  • Extract all serial TTYs and virtio input devices: see PR #7219.

  • Extract common ioapic information such as ioapic id, address, gsi base, and gsi num: see PR #6987.

  • Add another level of die node even though the hardware reports die topology in CPUID: see PR #7080.

  • Bring up all cores online so Board Inspector can run cpuid to extract all available cores’ information: see PR #7120.

  • Add CPU capability and BIOS invalid setting checks: see PR #7216.

  • Improve Board Inspector summary and logging based on log levels option: see PR #7429.

See the Board Inspector Tool documentation for a complete list of steps to install and run the tool.

Update Configuration Options

In v3.0, data in a launch XML are now merged into the scenario XML for the new Configurator. When practical, we recommend generating a new scenario and launch scripts by using the Configurator.

As explained in this Upgrading ACRN Configurations to Recent Releases document, we do provide a tool that can assist upgrading your existing pre-v3.0 scenario and launch XML files in the new merged v3.0 format. From there, you can use the v3.0 ACRN Configurator to open upgraded scenario file for viewing and further editing if the upgrader tool lost meaningful data during the conversion.

As part of the developer experience improvements to ACRN configuration, the following XML elements were refined in the scenario XML file:

  • RDT

  • vUART


  • Memory

  • virtio devices

The following elements are added to scenario XML files.

  • vm.lapic_passthrough

  • vm.io_completion_polling

  • vm.nested_virtualization_support

  • vm.virtual_cat_support

  • vm.secure_world_support

  • vm.hide_mtrr_support

  • vm.security_vm

The following elements were removed.







  • vm.guest_flags

  • vm.board_private

See the Scenario Configuration Options documentation for details about all the available configuration options in the new Configurator.

In v3.0, we refine the structure of the generated scripts so that PCI functions are identified only by their BDF. This change serves as a mandatory step to align how passthrough devices are configured for pre-launched and post-launched VMs. This allows us to present a unified view in the ACRN Configurator for assigning passthrough device. We removed some obsolete dynamic parameters and updated the usage of the Device Model (acrn-dm) --cpu_affinity parameter in launch script generation logic to use the lapic ID instead of pCPU ID. See Device Model Parameters and Launch Script for details.

Document Updates

With the introduction of the improved Configurator, we could improve our Getting Started Guide documentation and let you quickly build a simple ACRN hypervisor and User VM configuration from scratch instead of using a contrived pre-defined scenario configuration. That also let us reorganize and change configuration option documentation to use the newly defined developer-friendly names for configuration options.

Check out our improved Getting Started and Configuration documents:

Here are some of the high-level design documents that were updated since the v2.7 release:

We’ve also made edits throughout the documentation to improve clarity, formatting, and presentation. We started updating feature enabling tutorials based on the new Configurator, and will continue updating them after the v3.0 release (in the latest documentation).

Some obsolete documents were removed from the v3.0 documentation, but can still be found in the archived versions of previous release documentation, such as for v2.7.

Fixed Issues Details

  • 7712 - [config_tool] Make Basic tab the default view

  • 7657 - [acrn-configuration-tool] Failed to build acrn with make BOARD=xx SCENARIO=shared RELEASE=y

  • 7641 - config-tools: No launch scripts is generated when clicking save

  • 7637 - config-tools: vsock refine

  • 7634 - [DX][TeamFooding][ADL-S] Failed to build acrn when disable multiboot2 in configurator

  • 7623 - [config_tool] igd-vf para is no longer needed in launch script

  • 7609 - [Config-Tool][UI]build acrn failed after delete VMs via UI

  • 7606 - uninitialized variables are used in hpet.c

  • 7597 - [config_tool] Use Different Board - delete old board file

  • 7592 - [acrn-configuration-tool] Hide PCI option for Console virtual UART type

  • 7581 - [ADL-S][shared]The SOS cmdline parameter shouldn’t be added manually and should be changed in Debian package.

  • 7571 - [config_tool] Working folder with my_board.xml behavior

  • 7563 - [ADL-S][SSRAM]RTCM Unit run failed with 2G memory size

  • 7556 - [config_tool] VUART is configured to PCI and generate launch script without relevant parameters

  • 7546 - [acrn-configuration-tool]Scenario files generated with acrn-configurator for boards without serial ports ACRN debug build fails

  • 7540 - [config_tool]: rename virtio console as virtio serial port(as console)

  • 7538 - configurator: CPU Affinity should be hidden from service vm

  • 7535 - config-tools: add vhost vsock in v3.0

  • 7532 - [config_tool] dialog box and deleting VM related issues

  • 7530 - [configurator] Maximum Virtual CLOS configuration value should not allow negative numbers

  • 7526 - [configurator] Assigning one cpu to multiple Pre-launched VMs is not reported as error

  • 7519 - [config_tool] Duplicate VM name

  • 7514 - fix FEATURES to restore basic view

  • 7506 - config-tools: configurator widget vuart connection needs validation

  • 7500 - [config_tool] Failed to delete post-launched VM due to IVSHMEM

  • 7498 - fails to run on target with clean Ubuntu installation

  • 7495 - [config_tool] Starting new configuration deletes all files in existing working folder

  • 7492 - configurator: fix configurator build issue

  • 7488 - Configurator version confusion

  • 7486 - [config_tool] Duplicate VM name

  • 7484 - configurator: User-input working directory not working

  • 7481 - [config_tool] No validation for required fields in widgets

  • 7470 - [config_tool][UI] scenario.xml is still generated even though there are setting errors

  • 7469 - [config_tool][UI] No promption on save button if there are wrong settings

  • 7455 - configurator: vUART widget not working

  • 7450 - config-tools: bugfix for file related issues in UI

  • 7445 - [Config-Tool][UI]The shared VMs_name for IVSHMEM is not consistent with the VM_name modification

  • 7442 - [config_tool] Tooltip runs off screen

  • 7435 - configurator: Steps should be inactive until prior step complete

  • 7425 - Cache was not locked after post-RTVM power off and restart

  • 7424 - [config_tool] Virtual USB HCI should be a dropdown menu

  • 7421 - configurator: Unable to display PCI devices droplist

  • 7420 - configurator: Unable to set physical CPU affinity

  • 7419 - configurator: prelaunched VM assigned wrong VMID

  • 7418 - configurator: open folder path incorrect

  • 7413 - config-tools: bugfix for UI

  • 7402 - [acrn-deb] install board_inspector overwrites grub cmdline

  • 7401 - Post-RTVM boot failure with SSRAM enabled

  • 7400 - [acrn-configuration-tool][acrn-deb] grub is not update correctly after install the acrn-deb

  • 7392 - There is no virtio_devices node in generic scenario xml

  • 7383 - [acrn-configuration tool] make scenario shared file error cp error

  • 7376 - Virtio-GPU in guest_vm fails to get the EDID

  • 7370 - [acrn-deb] install_compile_package function is not consistent with gsg

  • 7366 - [acrn-configuration tool] make scenario shared file error cp error

  • 7365 - [config_tool] Get errors running board_inspector

  • 7361 - config_tool: Add check for RTVM pCPU assignment

  • 7356 - [UI] Board info not updated when user changed the board XML

  • 7349 - [UI]Not delete all VMs while delete Service_VM on UI

  • 7345 - Build will fail when using absolute path

  • 7337 - Memory leak after creating udmabuf for virtio-gpu zero_copy

  • 7330 - [PCI UART] Fail to build hypervisor without pci uart bdf value

  • 7327 - refine pgentry_present field in struct pgtable

  • 7301 - [Virtio-GPU]Not enough free memory reserved in SOS

  • 7298 - boot time issue for acrn-dm

  • 7297 - update parameter in schema

  • 7296 - Segment fault is triggered in course of Virtio-gpu rebooting test

  • 7270 - combined cpu_affinity warning for service vm

  • 7267 - service vm cpu affinity issue

  • 7265 - About 20s after booting uaag with usb mediator,usb disk isn’t recognized

  • 7261 - Hide PTM in Configurator UI

  • 7256 - Remove SCHED_IORR and KERNEL_RAWIMAGE

  • 7249 - doc: Exception in Sphinx processing doesn’t display error message

  • 7248 - restore copyright notice of original author of some files.

  • 7246 - Can’t fully parse the xml content that was saved by the same version configurator

  • 7241 - need copyright notice and license in virtio_gpu.c

  • 7212 - Exception”not enough space in guest VE820 SSRAM area” showed when built ACRN with RTCT table

  • 7208 - iasl segfault when reboot user VM with virtio-i2c devices

  • 7197 - The error message is found after adding the specific mac address in the launch script

  • 7172 - [acrn-configuration-tool] offline_cpus won’t be executed in NOOP mode

  • 7171 - Link to instead of including old release notes in the current release

  • 7159 - acrn-config: config tool get_node apic_id failed

  • 7136 - [acrn-configuration-tool] Share memory should never support 512M since the HV_RAM_SIZE_MAX is limited to 0x40000000 but not a platform specific problem

  • 7133 - Guest VM system reset may fail and ACRN DM program hang

  • 7127 - config-tools: remove SERIAL_CONSOLE extracion for bootargs of SOS

  • 7124 - [DM]: Fail to boot the Laag guest if the boot option of “pci=nomsi” is added for Guest kernel

  • 7119 - config-tools: bring all cores online

  • 7109 - Python traceback if the ‘dpkg’ tool is not available

  • 7098 - Memory leakage bug induced by opendir() in ACRN applications

  • 7084 - config_tools: append passthrough gpu bdf in hexadecimal format

  • 7077 - config-tools: find pci hole based on all pci hostbridge

  • 7058 - config_tools: board_inspector cannot generate compliable xml for Qemu

  • 7045 - Segmentation fault when passthrough TSN to post_launched VM with enable_ptm option

  • 7022 - ACRN debian package not complete when source is not cloned to standard folder

  • 7018 - No expected exception generated on some platform.

Known Issues

  • 6631 - [KATA] Kata support is broken since v2.7

  • 6978 - openstack failed since ACRN v2.7

  • 7827 - [Configurator] Pre_launched standard VMs cannot share CPU with Service VM

  • 7831 - [Configurator] Need to save twice to generate vUART and IVSHMEM addresses