Xen Project 4.19 Feature List

From Xen

Notable Features

This release has seen the increase in hardware support for both x86 and Arm, together with the addition of other improvements and features:

  • ARM: FF-A notification support.
  • ARM: Introduction of dynamic node programming using overlay dtbo.
  • x86: HVM PIRQs are disabled by default.
  • x86: Reduce IOMMU setup time for hardware domain.
  • x86: Allow HVM/PVH domains to map foreign pages.
  • x86: Declare PVH dom0 supported with caveats.
  • x86: Introduce a new x2APIC driver that uses Cluster Logical addressing mode for IPIs and Physical addressing mode for external interrupts.
  • Changed flexible array definitions in public I/O interface headers to not use "1" as the number of array elements.
  • The minimum supported OCaml toolchain version is now 4.05.
  • xl/libxl configures vkb=[] for HVM domains with priority over vkb_device.
  • Increase the maximum number of CPUs Xen can be built for from 4095 to 16383.
  • When building with Systemd support (./configure --enable-systemd), remove libsystemd as a build dependency. Systemd Notify support is retained, now using a standalone library implementation.
  • xenalyze no longer requires --svm-mode when analyzing traces generated on AMD CPUs.
  • Add a new 9pfs backend running as a daemon in dom0. First user is Xenstore-stubdom now being able to support full Xenstore trace capability.
  • libxl support for backendtype=tap with tapback.

Ongoing activities

The Xen community has several interesting initiatives, where work is ongoing and is expected to bear fruit in forthcoming releases. Some of the highlights:

  • Code symbol annotations and MISRA compliance improvements.

ARM

On Arm, PCI-passthrough work is ongoing, including some refactoring and improvements of the existing code. The work will be included in the next few releases.

RISC-V

On RISC-V, identity mapping was introduced and also some architecture specific headers. In the next few releases full Xen build, and trap handling will be introduced.

POWER

On PowerPC, basic exception handler implementation was introduced and also some minor fixes and improvements.