# Changelog

Notable changes to Xen will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)

## [Unreleased](https://xenbits.xen.org/gitweb/?p=xen.git;a=shortlog)

### Added
 - This file and MAINTAINERS entry.
 - Use x2APIC mode whenever available, regardless of interrupt remapping
   support.
 - Performance improvements to guest assisted TLB flushes, either when using
   the Xen hypercall interface or the viridian one.
 - Assorted pvshim performance and scalability improvements plus some bug
   fixes.
 - Hypervisor framework to ease porting Xen to run on hypervisors.
 - Initial support to run on Hyper-V.
 - Initial hypervisor file system (hypfs) support.
 - libxl support for running qemu-xen device model in a linux stubdomain.
 - New 'domid_policy', allowing domain-ids to be randomly chosen.
 - Option to preserve domain-id across migrate or save+restore.
 - Support in kdd for initial KD protocol handshake for Win 7, 8 and 10 (64 bit).
 - Tech preview support for Control-flow Execution Technology, with Xen using
   Supervisor Shadow Stacks for its own protection.

### Changed
 - The CPUID data seen by a guest on boot is now moved in the migration
   stream.  A guest migrating between non-identical hardware will now no
   longer observe details such as Family/Model/Stepping, Cache, etc changing.
   An administrator still needs to take care to ensure the features visible to
   the guest at boot are compatible with anywhere it might migrate.

## [4.13.0](https://xenbits.xen.org/gitweb/?p=xen.git;a=shortlog;h=RELEASE-4.13.0) - 2019-12-17

> Pointer to release from which CHANGELOG tracking starts