Xen Project 4.20 Release Notes
Overview
Xen Project 4.20.0 was released on 5th of March 2025.
Xen Project 4.20.0 is the work of 7 months of development.
New Feature Highlights
The list of new features can be found on the following page: Xen Project 4.20 Feature List
You can find information on support status (including security support) for various features in SUPPORT.md and Hypervisor Support Matrix.
Documentation is available online: Xen 4.20 Documentation
Build Requirements
Xen requires gcc v4.1.2 or later (x86), gcc 4.9 or later (arm32), or gcc 5.1 or later (arm64), gcc 12.2 or later (riscv64).
Build
First of all you will have to get the Xen 4.20 source code, which you can either download through our release tarball (including signature) from our download page. Alternatively, you can get the source in the following way:
- With a recent enough git (>= 1.7.8.2) just clone and checkout the proper tag (RELEASE-4.20.0) from the xen.git repo directly:
git clone -b RELEASE-4.20.0 https://xenbits.xenproject.org/git-http/xen.git
Build instructions can be found at Compiling Xen From Source or Compiling Xen From Source on NetBSD.
Changes affecting downstreams and users
- Reduce xenstore library dependencies.
- x86: Removed support for running on Xeon Phi processors.
- x86: Removed the `ucode=allow-same` command line option.
- x86: Removed x2APIC Cluster Mode for external interrupts. x2APIC Physical and Mixed Modes are still available.
- x86: Prefer ACPI reboot over UEFI ResetSystem() run time service call.
- x86: Prefer CMOS over EFI_GET_TIME as time source.
- x86: Add `wallclock` command line option to select time source.
- x86: xl suspend/resume subcommands.
Known issues
While we do the utmost to make the release perfect, there are always fixes which are not quite complete on time. We will add those here. So if you run into trouble, please check this section.
Currently known issues are: none