Notable changes to Xen will be documented in this file.
The format is based on Keep a Changelog
unstable UNRELEASED - TBD
- dropped support for the (x86-only) "vesa-mtrr" and "vesa-remap" command line options
4.16.0 - 2021-12-02
- XENSTORED_ROOTDIR environment variable from configuartion files and initscripts, due to being unused.
- Quarantining of passed-through PCI devices no longer defaults to directing I/O to a scratch page, matching original post-XSA-302 behavior (albeit the change was also backported, first appearing in 4.12.2 and 4.11.4). Prior (4.13...4.15-like) behavior can be arranged for either by enabling the IOMMU_QUARANTINE_SCRATCH_PAGE setting at build (configuration) time or by passing "iommu=quarantine=scratch-page" on the hypervisor command line.
- pv-grub stubdoms will no longer be built per default. In order to be able to use pv-grub configure needs to be called with "--enable-pv-grub" as parameter.
- qemu-traditional based device models (both, qemu-traditional and ioemu-stubdom) will no longer be built per default. In order to be able to use those, configure needs to be called with "--enable-qemu-traditional" as parameter.
- Fixes for credit2 scheduler stability in corner case conditions.
- Ongoing improvements in the hypervisor build system.
- vtpmmgr miscellaneous fixes in preparation for TPM 2.0 support.
- 32bit PV guests only supported in shim mode.
- Improved PVH dom0 debug key handling.
- Fix booting on some Intel systems without a PIT (i8254).
- Cleanup of the xenstore library interface.
- Fix truncation of return value from xencall2 by introducing a new helper that returns a long instead.
- Fix system register accesses on Arm to use the proper 32/64bit access size.
- Various fixes for Arm OP-TEE mediator.
- Switch to domheap for Xen page tables.
- 32bit Arm builds to the gitlab-ci automated tests.
- x86 full system tests to the gitlab-ci automated tests.
- Arm limited vPMU support for guests.
- Static physical memory allocation for dom0less on arm64.
- dom0less EFI support on arm64.
- GICD_ICPENDR register handling in vGIC emulation to support Zephyr OS.
- CPU feature leveling on arm64 platform with heterogeneous cores.
- Report unpopulated memory regions safe to use for external mappings, Arm and device tree only.
- Support of generic DT IOMMU bindings for Arm SMMU v2.
- Limit grant table version on a per-domain basis.
4.15.0 - 2021-04-08
- ARM IOREQ servers (device emulation etc.) (Tech Preview)
- Renesas IPMMU-VMSA (Supported, not security supported; was Tech Preview)
- ARM SMMUv3 (Tech Preview)
- Switched MSR accesses to deny by default policy.
- Intel Processor Trace support (Tech Preview)
- Named PCI devices for xl/libxl
- Improved documentation for xl PCI configuration format
- Support for zstd-compressed dom0 (x86) and domU kernels
- EFI: Enable booting unified hypervisor/kernel/initrd/DT images
- Reduce ACPI verbosity by default
- Add ucode=allow-same option to test late microcode loading path
- Library improvements from NetBSD ports upstreamed
- CI loop: Add Alpine Linux, Ubuntu Focal targets; drop CentOS 6
- CI loop: Add qemu-based dom0 / domU test for ARM
- CI loop: Add dom0less aarch64 smoke test
- x86: Allow domains to use AVX-VNNI instructions
- Factored out HVM-specific shadow code, improving code clarity and reducing the size of PV-only hypervisor builds
- Added XEN_SCRIPT_DIR configuration option to specify location for Xen scripts, rather than hard-coding /etc/xen/scripts
- xennet: Documented a way for the backend (or toolstack) to specify MTU to the frontend
- xenstore can now be live-updated on a running system. (Tech preview)
- Some additional affordances in various xl subcommands.
- Added workarounds for the following ARM errata: Cortex A53 #843419, Cortex A55 #1530923, Cortex A72 #853709, Cortex A73 #858921, Cortex A76 #1286807, Neoverse-N1 #1165522
- On detecting a host crash, some debug key handlers can automatically triggered to aid in debugging
- Increase the maximum number of guests which can share a single IRQ from 7 to 16, and make this configurable with irq-max-guests
- qemu-xen-traditional as host process device model, now "No security support, not recommended". (Use as stub domain device model is still supported - see SUPPORT.md.)
4.14.0 - 2020-07-23
- 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.
- 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 - 2019-12-17
Pointer to release from which CHANGELOG tracking starts