ACRN v2.7 (Dec 2021)¶
We are pleased to announce the release of the Project ACRN hypervisor version 2.7.
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 download this source code either as a zip or
tar.gz file (see the ACRN v2.7 GitHub release page) or
git clone https://github.com/projectacrn/acrn-hypervisor cd acrn-hypervisor git checkout v2.7
The project’s online technical documentation is also tagged to correspond with a specific release: generated v2.7 documents can be found at https://projectacrn.github.io/2.7/. Documentation for the latest development branch is found at https://projectacrn.github.io/latest/.
ACRN v2.7 requires Ubuntu 18.04. Follow the instructions in the Getting Started Guide to get started with ACRN.
What’s New in v2.7¶
- API and Documentation Updates for User VM and Service VM Terminology
More often than not, the terms “UOS” and “SOS” referred to the User VM and Service VM components of an ACRN Hypervisor system and not to the VM’s OS. We’ve updated the hypervisor APIs and documentation to properly reflect these names and removed uses of UOS and SOS.
In the code, uses of
sosin names were changed to
service_vmrespectively. When specifically referring to the OS of these VMs, we now use
service_vm_os. These changes appear throughout the C files, as well as in the
For example, here are examples of old and new names:
#define SOS_SOCKET_PORT 0x2000
#define SERVICE_VM_SOCKET_PORT 0x2000
static uint16_t get_uos_count(void)
static uint16_t get_user_vm_count(void)
static uint16_t get_phy_addr(uint8_t uos_id, uint16_t vaddr)
static uint16_t get_phy_addr(uint8_t user_vmid, uint16_t vaddr)
- Update Scenario Names
The pre-defined scenario names were changed to be indicative of their properties instead of an example use. The “industry” scenario is now called “shared”, the “logical partitioning” scenario is now called “partitioned”, and the “hybrid” scenario name remains the same.
Here are the three configuration scenarios:
Shared: The physical hardware resources can be shared among post-launched User VMs. The Service VM (Device Model) provides device emulation for the shared virtual devices.
Partitioned: The physical resources are strictly dedicated to individual pre-launched User VMs and there is no Service VM needed.
Hybrid: The physical resource are dedicated to pre-launched User VMs and the Service VM provides resource emulation and sharing for post-launched User VMs, all in the same system configuration.
- User-Friendly VM names
Instead of using a UUID as the User VM identifier, we’re now using a user-friendly VM name.
- Extend Use of CAT Cache Tuning to VMs
In previous releases, Cache Allocation Technology (CAT) was available only at the hypervisor level and with per-pCPU granularity. In this v2.7 release, each VM with exclusive cache resources can partition them with per-thread granularity and allocate cache resources to prioritized tasks.
- Expand Passthrough Device Use Cases
We now allow pre-launched VMs (in partitioned or hybrid scenarios) to use graphics device passthrough for improved performance, a feature previously available to only post-launched VMs.
Trusted Platform Module (TPM) 2.0 and its associated resource can now be passthrough to post-launched VMs, a feature previously available to only pre-launched VMs..
Upgrading to v2.7 From Previous Releases¶
We highly recommended that you follow these instructions to upgrade to v2.7 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 v2.7 adds the following hardware information to board XMLs to support new features and fixes.
The new board XML can be generated using the ACRN board inspector in the same way as ACRN v2.6. Refer to Using ACRN Configuration Toolset for a complete list of steps to deploy and run the tool.
Update Configuration Options¶
In v2.7, the following elements are added to scenario XML files.
vm.name(This is a required element. Names must be unique, up to 15 characters long, and contain no space characters.)
hv.CAPACITIES.MAX_VM_NUM(Default value is
hv.FEATURES.RDT.VCAT_ENABLED(Default value is
The following elements were removed.
hv.MEMORY.HV_RAM_SIZE(Hypervisor RAM size is now computed by the linker)
As part of using consistent names for UOS and SOS, we also change configuration option names or values using these obsolete terms:
In v2.7, the
acrn-dm command line parameter
--cpu_affinity is now mandatory
when launching a User VM. If the launch XML settings, used to generate the launch
scripts, do not specify a
cpu_affinity value, the ACRN Configurator will look for
it from the scenario XML settings. Verify that your existing launch scripts
--cpu_affinity parameter as
acrn-dm will now complain if it’s
We’ve updated references throughout the documentation to use “Service VM” and “User VM” instead of “SOS” and “UOS” respectively.
We’ve also made edits throughout the documentation to improve clarity, formatting, and presentation:
Fixed Issues Details¶
5112 - ACRN debug shell help output behavior, line length, and misspellings
5626 - [CFL][industry] Host Call Trace once detected
5692 - Update config option documentation in schema definition files
6012 - [Mainline][PTCM] [ConfigTool]Obsolete terms cleanup for SSRAM
6024 - [TGL][Master][IVSHMEM] Only one share memory device in SOS while enabled two from the scenario xml
6270 - [ADL-S][Industry][Yocto] WaaG boot up but no UI display with more than 1G memory
6284 - [v2.6] vulnerable coding style in hypervisor and DM
6340 - [EF]Invalid LPC entry prevents GOP driver from working properly in WaaG for DP3
6360 - ACRN Makefile missing dependencies
6366 - TPM pass-thru shall be able to support start method 6, not only support Start Method of 7
6387 - enable GVT-d for pre-launched linux guest
6405 - [ADL-S][Industry][Yocto] WaaG BSOD in startup when run reboot or create/destroy stability test.
6417 - ACRN ConfigTool improvement from DX view
6428 - [acrn-configuration-tool] Fail to generate launch script when disable CPU sharing
6431 - virtio_console use-after-free
6434 - HV panic when SOS VM boot 5.4 kernel
6442 - [EF]Post-launched VMs do not boot with “EFI Network” enabled
6461 - [config_tools] kernel load addr/entry addr should not be configurable for kernel type KERNEL_ELF
6473 - [HV]HV can’t be used after dumpreg rtvm vcpu
6476 - [hypercube][TGL][ADL]pci_xhci_insert_event SEGV on read from NULL
6481 - ACRN on QEMU can’t boot up with v2.6 branch
6482 - [ADL-S][RTVM]rtvm poweroff causes sos to crash
6494 - acrn_trace build failure with latest e2fsprogs v1.46.2 version
6502 - [ADL][HV][UC lock] SoS kernel panic when #GP for UC lock enabled
6508 - [HV]Refine pass-thru device PIO BAR handling
6518 - [hypercube][ADL]acrn-dm program crash during hypercube testing
6528 - [TGL][HV][hybrid_rt] dmidecode Fail on pre-launched RTVM
6530 - [ADL-S][EHL][Hybrid]Path of sos rootfs in hybrid.xml is wrong
6533 - [hypercube][tgl][ADL] mem leak while poweroff in guest
6542 - [hypercube][tgl][ADL] mem leak while poweroff in guest
6562 - [ADL-S][Config tool] fail to tpm_getcap -l
6565 - [acrn-configuration-tool] “modprobe pci_stub” should be executed before unbinding passthru devices
6572 - [ADL-S][Acrntrace]failed to run acrntrace test
6584 - HV:check vmx capability
6592 - [doc] failed to make hvdiffconfig
6610 - [config tool vUART] IRQ of vUART of pnp 8250 is not generated correctly
6620 - acrn-config: pass-thru device PIO BAR identical mapping
6663 - Current HV_RAM_SIZE calculation algorithm sometimes cause build failure
6674 - [TGL][HV][hybrid] (v2.7 only) during boot zephyr64.elf find HV error: “Unable to copy HPA 0x100000 to GPA 0x7fe00000 in VM0”
6677 - Service VM shall not have capability to access IOMMU
6704 - [ADL-S][Partitioned]Kernel panic when boot Pre-launched RTVM with 8 pci devices passthru
6709 - Issues for platform ICX-D HCC enabling
6719 - Board Inspector tool crashes if cpuid is not installed
6724 - (v2.7 only) Remove the GET_PLATFORM_INFO support in ACRN
6736 - Improved readability desirable for the Board Inspector tool
6743 - acrn-crashlog/acrnprobe compilation failure with OpenSSL 3.0
6752 - ACRN HV shows multiple PCIe devices with “out of mmio window” warnings - false alert
6755 - [icx-d lcc]CAT_capability enable RDT fail
6767 - [acrn-configuration-tool] Getting duplicate PT_SLOT value If generate launch script continuously through the UI
6769 - [v2.7] vulnerable coding style in hypervisor and DM
6778 - [ADL][SSRAM][Master]Error messages output during RTCM unit test
6780 - [ADL][SSRAM][Master]ACRN boot crash with SSRAM enabled
6799 - [REG][ADL-S][VxWorks] SOS force reboot while launching vxworks
6834 - [Acrn-hypervisor][Debug release]Failed to build hypervisor with hv_debug_release enable
6848 - [ADL][RTVM]ACPI error while launching rtvm
6851 - [DM] segfault on virtio_console_control_tx()
6877 - [DM][ASAN] UAF in mevent_handle()
6885 - adl-s-shared sos can’t get in
6888 - [ADL-S]Yaag reboots too slowly
6899 - [ADL-S][shared] Core type error when launch RTVM use atom core.
6907 - [ADL-S][ICX-D][shared][Regression]Multi RT launch failed with V2.7_RC3 build.
6908 - [ADL-S][Multi_RT]Shutdown one RT and others will hang when launch multi RT.
6919 - [hypercube][ADL] mem leak while power off in guest (phase-II)
6931 - [ADL][CPUID] RTVM CPUID 0x2 EBX value is not equal to HV cpuid 0x2 EBX