Changelog & Release Notes

Release 4.0 - Xen

New Features

  • Added ability to boot one Linux and one Zephyr domain on Xen in dom0less mode

  • Added ability to boot three Zephyr sample applications

  • Added basic Linux test suite using BATS


  • A new Yocto layer has been created called meta-armv8r64-extras, which extends meta-arm-bsp with additional use cases

  • Moved documentation to the new repository and expanded to cover new use cases. It is now published on ReadTheDocs

  • Upgraded to FVP version 11.18.16

  • Upgraded to U-Boot 2022.01 and enabled support for applying device tree overlays

  • Upgraded to Linux kernel 5.15

  • Added support to boot-wrapper-aarch64 for S-EL2 SMP payloads such as Xen

  • Amended the device tree to support the virtio random number generator

  • Added ssh-pregen-hostkeys to the default image to improve boot times

  • Amended the default model parameters to support enabling cache_state_modelled

  • Removed support for PREEMPT_RT Linux kernel builds

  • Third-party Yocto layers used to build the software stack:

    layers: meta, meta-poky
    branch: kirkstone
    revision: 0c3b92901cedab926f313a2b783ff2e8833c95cf
    layers: meta-filesystems, meta-networking, meta-oe, meta-python
    branch: kirkstone
    revision: fcc7d7eae82be4c180f2e8fa3db90a8ab3be07b7
    layers: meta-virtualization
    branch: kirkstone
    revision: 0d35c194351a9672d18bff52a8f2fbabcd5b0f3d
    layers: meta-arm, meta-arm-bsp, meta-arm-toolchain
    branch: kirkstone
    revision: 32ca791aaa6634e90a7c6ea3994189ef10a7ac90

Known Issues and Limitations

  • The bp.refcounter.use_real_time model parameter is not supported for the hypervisor and baremetal Zephyr use cases

  • “Dom0less” is a new set of features for Xen, some of which are still being developed in the Xen community. In this case, a “dom0less” domain running Linux cannot enable the CONFIG_XEN option, which will cause some limitations. For example, Linux can’t detect that it is running inside a Xen domain, so some Xen domain platform-specific Power Management control paths will not be invoked. One of the specific cases is that using the command echo 0 > /sys/devices/system/cpu/cpu0/online to power off the Linux domain’s vcpu0 is invalid.

  • Issues and limitations mentioned in Known Issues and Limitations of Release 2

Release 3 - UEFI

Release Note—uefi

New Features

  • Added U-Boot v2021.07 for UEFI support

  • Updated boot-wrapper-aarch64 revision and added support for booting U-Boot

  • Included boot-wrapper-aarch64 PSCI services in /memreserve/ region


  • Configured the FVP to use the default RAM size of 4 Gb

  • Added virtio_net User Networking mode by default and removed instructions about tap networking setup

  • Updated Linux kernel version from 5.10 to 5.14 for both standard and Real-Time (PREEMPT_RT) builds

  • Fixed the counter frequency initialization in boot-wrapper-aarch64

  • Fixed PL011 and SP805 register sizes in the device tree

Known Issues and Limitations

  • Device DMA memory cache-coherence issue: the FVP cache_state_modelled parameter will affect the cache coherence behavior of peripherals’ DMA. When users set cache_state_modelled=1, they also have to set cci400.force_on_from_start=1 to force the FVP to enable snooping on upstream ports

  • Issues and limitations mentioned in Known Issues and Limitations of Release 2

Release 2 - SMP

Release Note—smp

New Features

  • Enabled SMP support via boot-wrapper-aarch64 providing the PSCI CPU_ON and CPU_OFF functions

  • Introduced Armv8-R64 compiler flags

  • Added Linux PREEMPT_RT support via linux-yocto-rt-5.10

  • Added support for file sharing with the host machine using Virtio P9

  • Added support for runfvp

  • Added performance event support (PMU) in the Linux device tree



Known Issues and Limitations

  • Only PSCI CPU_ON and CPU_OFF functions are supported

  • Linux kernel does not support booting from secure EL2 on Armv8-R AArch64

  • Linux KVM does not support Armv8-R AArch64

Release 1 - Single Core

Release Note

New Features

Introduced fvp-baser-aemv8r64 as a Yocto machine support the following BSP components on the Yocto hardknott release branch, where a standard Linux kernel can be built and run:

  • boot-wrapper-aarch64

  • Linux kernel: linux-yocto-5.10


Initial version.

Known Issues and Limitations

  • Only support one CPU since SMP is not functional in boot-wrapper-aarch64 yet