ACRN v2.5 (Jun 2021)¶
We are pleased to announce the release of the Project ACRN hypervisor version 2.5.
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
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 v2.5 GitHub release page) or
git clone https://github.com/projectacrn/acrn-hypervisor cd acrn-hypervisor git checkout v2.5
The project’s online technical documentation is also tagged to correspond with a specific release: generated v2.5 documents can be found at https://projectacrn.github.io/2.5/. Documentation for the latest under-development branch is found at https://projectacrn.github.io/latest/.
ACRN v2.5 requires Ubuntu 18.04. Follow the instructions in the Getting Started Guide to get started with ACRN.
What’s New in v2.5¶
- Nested Virtualization Technology Preview
A brand-new concept, nested virtualization, is introduced as a preview in this v2.5 release. Nested virtualization lets you run virtual machine instances inside of a guest VM that’s running on the ACRN hypervisor. It’s designed to leverage the KVM/QEMU community’s rich feature set while keeping ACRN’s unique advantages in partition mode and hybrid mode. Read more in the Enable Nested Virtualization advanced guide.
- Secure Boot Using EFI Stub
EFI stub, previously retired in favor of using direct boot, returns as an alternative to end-to-end secure boot with Grub. The hypervisor, Service VM kernel, and prelaunched VM kernel are packaged into a single
acrn.efiblob as an EFI application that can then be verified by the EFI BIOS. Read more in the Enable ACRN Secure Boot With EFI-Stub and Enable ACRN Secure Boot With GRUB advanced guides.
- Modularization Improvements
ACRN hypervisor modularization has been improved to be more scalable, including change to multiboot, interrupt handling, paging and memory management, and timers, with more to come in future releases.
- Configuration and Build Process Improvements
The ACRN configuration and build process continues to evolve from the changes made in the previous releases. For instructions using the build system, refer to Getting Started Guide. For an introduction on the concepts and workflow of the configuration tools and processes, refer to Introduction to ACRN Configuration.
Upgrading to v2.5 From Previous Releases¶
We highly recommended that you follow these instructions to upgrade to v2.5 from previous ACRN releases.
Generate New Board XML¶
Board XML files, generated by ACRN board inspector, contain board information that is essential to build ACRN. Compared to previous versions, ACRN v2.5 extends the schema of board XMLs to summarize board information more systematically. You must regenerate your board XML file using the new board inspector when you upgrade to ACRN v2.5 to get the additional information needed for configuration.
Before using the new board inspector, ensure you have Python >= 3.6 on the target
board and install the
lxml PyPI package. Refer to Additional Dependencies for
detailed steps to check and upgrade your Python version. The
lxml package can be
installed by executing the following command:
sudo pip3 install lxml
Refer to Getting Started Guide for a complete list of tools required to run the board inspector.
With the prerequisites done, copy the entire board inspector folder from
misc/config_tools/board_inspector to the target board,
cd to that
directory on the target, and run the board inspector tool using:
sudo python3 cli.py <my_board_name>
This will generate
<my_board_name>.xml in the current working directory.
You’ll need to copy that XML file back to the host system to continue
Add New Configuration Options¶
In v2.5, the following elements are added to scenario XML files:
The following element is renamed:
Constraints on values of the following element have changed:
vm.guest_flags.guest_flagno longer accepts an empty text. For VMs with no guest flag set, set the value to
With the changes to ACRN configuration, we made updates to the ACRN documentation around configuration, options, and parameters:
New capabilities are documented here:
We’ve also made edits throughout the documentation to improve clarity, formatting, and presentation throughout the ACRN documentation:
Fixed Issues Details¶
5626 - [CFL][industry] Host Call Trace once detected
5879 - hybrid_rt scenario does not work with large initrd in pre-launched VM
6015 - HV and DM: Obsolete terms cleanup for SSRAM
6024 - config-tools: generate board_info.h and pci_dev.c using xslt
6034 - dm: add allow_trigger_s5 mode to pm_notify_channel uart
6038 - [REG][RAMDISK] Fail to launch pre RTVM while config ramdisk
6056 - dm: a minor bug fix of unregister_mem_int
6072 - [WHL][WAAG]use config tool to passthru Audio,will not display GOP
6075 - [config_tools][regression][v2.5_rc1] config tool failed to save industry.xml with GuestFlagsOptionsType check
6078 - Make ACRN HV with hybrid_rt bootable without GRUB on UEFI BIOS
6100 - virtio_net_ping_rxq SEGV on read from NULL
6102 - Build failure for BOARD=qemu SCENARIO=sdc on release_2.5
6104 - [acrn-configuration-tool] Need update tgl-rvp.xml to the latest BIOS info
6113 - [config_tools][ADL-S]generated board xml parse error on ADL-S
6120 - [acrn-configuration-tool] shall we add CLOS_MASK elements into tgl scenario files as default configuration
6126 - TPM do not support dynamic GPA
6129 - virtio: NULL deref in hw/pci/virtio/virtio.c:664 in vq_endchains
6131 - guest/vlapic fatal assertion reachable from guest - DoS
6134 - [acrn-configuration-tool] lxml module not found when get board xml following doc
6138 - config-tools: support of launch script to generate the “allow_trigger_s5” automatically
6147 - ASAN reports UAF + SEGV when fuzzing exposed PIO with Hypercube guest VM.
6157 - coding style fix on v2.5 branch
6162 - [REG][EHL][SBL] Fail to boot sos
6168 - SOS failed to boot with nest enabled
6172 - member access within null pointer of type ‘struct xhci_trb’
6178 - config-tools: adding an empty node <pt_intx> for a pre-launched VM causing check_pt_intx throw out an error
6185 - [TGL][Industry]yaag can’t get ip after SRIVO VF passthru
6186 - [acrn-configuration-tool] CONFIG_MAX_MSIX_TABLE_NUM value is auto set as 64 when generate an new scenario xml
6199 - [doc][buildSource] can not pass SCENARIO parameter into hypervisor/build/.config with “make defconfig”