# Releases

This is the list of official releases for libvirt, along with an overview of the changes introduced by each of them.

For a more fine-grained view, use the git log.

### v3.0.0 (2017-01-17)

- New features
  - Domain events for metadata content changes
    The domain events framework has a new event ID that can be used to get notifications when domain metadata content changes.
  - Event notifications for the secret object
    The secret object now supports event notifications, covering lifcycle changes and secret value changes.
  - New localPtr attribute for "ip" element in network XML
  - qemu: Support QEMU group I/O throttling
    Add the capability to allow group I/O throttling via a new domain <disk> <iotune> subelement "group_name" to allow sharing I/O throttling quota between multiple drives.
  - nss: Introduce `libvirt_guest`
    New `libvirt_guest` nss module that translates libvirt guest names into IP addresses.
  - daemon: Add support for runtime logging settings adjustment
    Logging-related settings like log outputs and filters can now be adjusted during runtime using the admin interface without the necessity of the daemon's restart.
  - storage: Add virStorageVolInfoFlags API
    Add the API to support using the VIR_STORAGE_VOL_GET_PHYSICAL flag in order to return the host physical size in bytes of the image container in the allocation field of the _virStorageVolInfo structure. The --physical flag has been added to the virsh vol-info command to access the data.
  - libxl: Implement virDomainGetMaxVcpus API
  - storage: Add overwrite flag checking for logical pool
    Add support for the OVERWRITE flags for the logical storage backend including checking for existing data on the target volumes when building a new logical pool on target volume(s).
  - qemu: Add support for guest CPU configuration on s390(x)
- Improvements
  - perf: Add more perf statistics
    Add support to get the count of branch instructions executed, branch misses, bus cycles, stalled frontend cpu cycles, stalled backend cpu cycles, and ref cpu cycles by applications running on the platform.
  - conf: Display <physical> for volume xml
    Add a display of the <physical> size of a disk volume in the output of the volume XML.
  - qemu: Use virtio-pci by default for aarch64 mach-virt guests
    virtio-pci provides several advantages over virtio-mmio, such as the ability to hotplug devices and improved performance. While opting in to virtio-pci has been possible for a while, newly-defined guests will now use it automatically.
  - vbox: remove support for VirtualBox 3.x and older
    Those old VirtualBox versions have been unsupported by upstream for a long time and the API of 4.0 and newer has diverged enough to require code abstractions to handle differences. Removing support for those old versions drops lots of code from the driver and simplifies the logic to ease implementation of new features going forward.
  - virsh: pool-info: introduce option --bytes
    Add option --bytes to virsh pool-info in order ti allow display of units in bytes rather than default of human readable output.
  - scsi: Add parent wwnn/wwpn or fabric capability for createVport
    Improve the algorithm searching for the parent scsi_host device for vHBA/NPIV scsi_host creation. Rather than supplying the "parent" by name, it's now possible to define the parent by it's wwnn/wwpn or fabric_wwn in the node device create XML or the storage pool XML.
  - qemu: aggregate pcie-root-ports onto multiple functions of a slot
    When pcie-root-ports are added to pcie-root in order to provide a place to connect PCI Express endpoint devices, libvirt now aggregates multiple root ports together onto the same slot (up to 8 per slot) in order to conserve slots. Using this method, it's possible to connect more than 200 endpoint devices to a guest that uses PCIe without requiring setup of any PCIe switches.
- Bug fixes
  - lxc: fix accidental killing of containers during libvirtd restart
    The libvirt_lxc process was previously not moved into the container scope. As a result, if systemd reloads its config after a container is started, when libvirtd is later restarted it will accidentally kill the containers.
  - qemu: Correct GetBlockInfo values
    For an active domain, correct the physical value provided for a raw sparse file backed storage and the allocation value provided for a qcow2 file backed storage that hasn't yet been opened on the domain.
  - qemu: Make virtio console usable on ppc64 guests
    The chardev detection code has been improved and can now handle this configuration properly.
  - qemu: Enable mount namespace
    To avoid funny races with udev relabelling devices under our hands and to enhance security, libvirt now spawns each qemu process with its own `/dev`.
  - storage: Fix implementation of no-overwrite for file system backend
    Fix file system storage backend implementation of the OVERWRITE flags to be consistent between code and documentation. Add checks to ensure that when building a new file system on a target volume that there is not something already on the disk in a format that libvirt can recognize.
  - qemu: Create hugepage path on per domain basis
    Historically, all hugepage enabled domains shared the same path under hugetlbfs. This left libvirt unable to correctly set security labels on it. With this release, however, each domain is put into a separate path which is also correctly labeled.
  - conf: Reject domains with duplicate drive addresses
    Reject duplicate drive addresses for disks and hostdevs at domain definition.
  - libxl: reverse defaults on HVM net device attach
    Fixes network interface attach for HVM domains when no model is specified. Emulated hotplug isn't yet supported and hence we should default to the general working scenario.
  - libxl: always enable pae for x86_64 HVM
    By default pae is disabled in libxl. Without an explicit <pae/> setting in the domain <features> configuration, an x86_64 HVM domain would be get an i686 environment. pae should always be enabled for x86_64 HVM domains.

### v2.5.0 (2016-12-04)

- New features
  - shmem: Add support for additional models
    The shmem device can now utilize QEMU's ivshmem-plain and ivshmem-doorbell, more modern versions of ivshmem.
  - vbox: Add VirtualBox 5.1 support
  - libssh: New transport
    The new libssh transport allows one to connect to a running libvirtd via SSH, using the libssh library; for example: `qemu+libssh://server/system`.
  - vhost-scsi: Add support scsi_host hostdev passthrough
    Add the capability to pass through a scsi_host HBA and the associated LUNs to the guest.
  - qemu: Users can now enable debug logging for native gluster volumes in qemu using the "gluster_debug_level" option in qemu.conf
  - memory hotplug: Slot numbers for memory devices are now automatically allocated and thus persistent. In addition slot numbers can be specified without providing a base address, which simplifies user configuration
  - qemu: Express devices will be placed on PCIe bus by default
    For machine types that use a PCI Express root bus (e.g. x86_64/Q35 and aarch64/virt), any unaddressed PCI device that is an Express device (all virtio-1.0 devices, e1000e, nec-xhci, vfio assigned devices) will be placed on an Express controller (i.e. a pcie-root-port) instead of a legacy PCI controller (i.e. pci-bridge) with the root ports added as needed.
- Improvements
  - docs: Better documentation for migration APIs and flags
  - vbox: Address thread safety issues
  - virsh: Add support for passing an alternative persistent XML to migrate command
  - vhostuser: Allow hotplug of multiqueue devices
  - NEWS: Switch to an improved format
    List user-visible changes instead of single commits for a better high-level overview of differences between libvirt releases.
  - website: Modernize layout and branding
    The libvirt website looked very cluttered and outdated; it has now been completely overhauled, resulting in a design that's better organized and more pleasant to look at.
- Bug fixes
  - vz: Fix migration in P2P mode
  - Forbid newline character in names of some libvirt objects
  - Fix compilation on macOS

Older libvirt releases didn't have proper release notes, and as such are not included in this page: if you're looking for information about them, start from those made in 2016 and work your way back.