[Announce] ACRN Open Source Ver2.2 Release Notes

Zou, Terry

Hi all,


We are very pleased to announce Version 2.2 release of ACRN. You can see the release blog from https://projectacrn.org/blog/ and detailed Release Notes in website https://projectacrn.github.io/latest/release_notes/release_notes_2.2.html

What’s New in v2.2

·       Elkhart Lake and Tiger Lake processor support

At Intel Industrial iSummit 2020, Intel announced the latest additions to their enhanced-for-IoT Edge portfolio: the Intel® Atom® x6000E Series, Intel® Pentium® and Intel® Celeron® N and J Series (all code named Elkhart Lake), and 11th Gen Intel® Core™ processors (code named Tiger Lake-UP3). The ACRN team is pleased to announce that this ACRN v2.2 release already supports these processors.

  • Support for time deterministic applications with new features e.g., Time Coordinated Computing and Time Sensitive Networking
  • Support for functional safety with new features e.g., Intel Safety Island

·       On Elkhart Lake, ACRN can boot using Slim Bootloader

Slim Bootloader is an alternative bootloader to UEFI BIOS.

·       Shared memory based inter-VM communication (ivshmem) is extended

ivshmem now supports all kinds of VMs including pre-launched VM, Service VM, and other User VMs. (See ACRN Shared Memory Based Inter-VM Communication)

·       CPU sharing supports pre-launched VM

·       RTLinux with preempt-RT linux kernel 5.4 is validated both as a pre-launched and post-launched VM

·       ACRN hypervisor can emulate MSI-X based on physical MSI with multiple vectors

·       Staged removal of deprivileged boot mode support

ACRN has supported deprivileged boot mode to ease the integration of Linux distributions such as Clear Linux. Unfortunately, deprivileged boot mode limits ACRN’s scalability and is unsuitable for ACRN’s hybrid hypervisor mode. In ACRN v2.2, deprivileged boot mode is no longer the default and will be complete removed in ACRN v2.3. We’re focusing instead on using multiboot2 boot (via Grub). Multiboot2 is not supported in Clearlinux though, so we have chosen Ubuntu (and Yocto Project) as the preferred Service VM OSs moving forward.


See the v2.2 full release notes and documentation for more information about this release including fixed and known issues.

Improvements, updates, and corrections have been made throughout our documentation as well, including these documents:

Because we’re dropping deprivileged boot mode support in the next v2.3 release, we’re also switching our Service VM of choice away from Clear Linux. We’ve begun this transition in the v2.2 documentation and removed some Clear Linux-specific tutorials. Deleted documents are still available in the version-specific v2.1 documentation.


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. Check out What is ACRN introduction for more information. All project ACRN source code is maintained in the https://github.com/projectacrn/acrn-hypervisor repository and includes folders for the ACRN hypervisor, the ACRN device model, tools, and documentation. You can either download this source code as a zip or tar.gz file (see the ACRN v2.2 GitHub release page) or use Git clone and checkout commands:


git clone https://github.com/projectacrn/acrn-hypervisor
cd acrn-hypervisor
git checkout v2.2


The project’s online technical documentation is also tagged to correspond with a specific release: generated v2.2 documents can be found at https://projectacrn.github.io/2.2/. Documentation for the latest under-development branch is found at https://projectacrn.github.io/latest/.


ACRN v2.2 requires Ubuntu 18.04. Follow the instructions in the Getting Started Guide for ACRN Industry Scenario with Ubuntu Service VM to get started with ACRN. We recommend that all developers upgrade to ACRN release v2.2.


Best & Regards


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