libvirt/NEWS.rst

libvirt 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.

v7.9.0 (unreleased)

• Security
• Removed features
• New features

  • Introduce virtio-mem <memory/> model

    New virtio-mem model is introduced for <memory/> device which is a paravirtualized mechanism of adding/removing memory to/from a VM. Use virDomainUpdateDeviceFlags() API to adjust amount of memory or virsh update-memory-device for convenience.

  • qemu: support disabling hotplug of devices on the pci-root controller

    the <target hotplug='on|off'/> option is now supported for the pci-root controller on i440fx-based (x86 "pc") machinetypes. This can be used to disable hotplug/unplug of devices from this controller. The default behavior is unchanged (hotplug is allowed).

• Improvements
• Bug fixes

v7.8.0 (2021-10-01)

• New features

  • nodedev: Add ability to automatically start mediated devices

    The autostart status of a persistent mediated devices can be managed with the new APIs virNodeDeviceSetAutostart() and virNodeDeviceGetAutostart(). The corresponding virsh command is nodedev-autostart. In addition, two new APIs were added to get additional information about node devices: virNodeDeviceIsPersistent() checks whether the device is persistently defined, and virNodeDeviceIsActive() checks whether the node device is currently active. This information can also be retrieved with the new virsh command nodedev-info.

v7.7.0 (2021-09-01)

• New features

  • Add support for Fibre Channel VMID

    New VM element <fibrechannel appid=''/> was added to allow users to set their appid for each VM which will be used by kernel to create Fibre Channel VMID. This allows various QoS levels, access control or collecting telemetry data per VM.

• Improvements

  • virsh: Allow XML validation for define of: storage pool, network, secret, nwfilter, interface

    • Add flag VIR_STORAGE_POOL_DEFINE_VALIDATE to validate storage pool input xml. For virsh, users can use it as virsh pool-define --validate.
    • Add flag VIR_NETWORK_DEFINE_VALIDATE to validate network input xml. For virsh, users can use it as net-define --validate.
    • Add flag VIR_SECRET_DEFINE_VALIDATE to validate secret input xml. For virsh, users can use it as secret-define --validate.
    • Add flag VIR_NWFILTER_DEFINE_VALIDATE to validate nwfilter input xml. For virsh, users can use it as nwfilter-define --validate.
    • Add flag VIR_INTERFACE_DEFINE_VALIDATE to validate interface input xml. For virsh, users can use it as iface-define --validate.

  • Add SecurityManager APIs for labeling network devices

    New virSecurityManagerSetNetdevLabel and virSecurityManagerSetNetdevLabel APIs are introduced and implemented in the Apparmor security driver. The qemu driver uses the APIs to label vhostuser ports on hotplug and restore labeling on unplug.

  • vmx: Parse vm.genid and support super wide SCSI bus

    The genid attribute is now reported for VMX guests. Libvirt can now properly process super wide SCSI bus (64 units).

  • qemu: Lifecycle action (on_poweroff/on_reboot) handling improvements

    The handling of lifecycle actions was fixed and improved in multiple ways:

    • restart-rename action was forbidden

      The action was never properly implemented in the qemu driver and didn't actually result in a restart of the VM but rather termination. The qemu driver now rejects such configurations.

    • preserve action was forbidden

      Similarly to the previous case this never worked as the intended semantics of the actions dictate. It's better to not allow it at all until there's a proper implementation

    • reboot action of on_poweroff now actually works

      The guest OS is now rebooted instead of terminating the VM when the reboot action is used and the guest OS powers down. Note that it's incompatible with on_reboot set to destroy.

    • Changes in action action of on_reboot are now updated with qemu

      Libvirtd can now properly update the on_reboot action in qemu which allows proper handling when changing between reboot and destroy actions. In addition, switching from reboot to destroy was forbidden for older qemus which don't support the update API as the guest could still reboot and execute some instructions until it was terminated.

• Bug fixes

  • qemu: Open chardev logfile on behalf of QEMU

    Guests with a logfile configured for their chardevs are now able to start even when no virtlogd is configured.

  • virhostmem: Handle numactl-less build in hugepages allocation/reporting

    Some architectures don't have notion of NUMA (e.g. s390x) but do support hugepages. Libvirt silently ignored requests to allocate/report hugepage pool when built without numactl. This is now fixed and the pool can be allocated/reported on properly.

  • qemu: Record proper backing format for overlays of qcow2+luks images

    Libvirt would record luks instead of qcow2 into the metadata. In practice this is a problem only when inspecting images manually via qemu-img as with libvirt users must use full specification of the backing chain in the domain XML which supersedes information recorded in the image metadata.

v7.6.0 (2021-08-02)

• Security

  • storage: Unlock pool objects on ACL check failures in storagePoolLookupByTargetPath (CVE-2021-3667)

    A logic bug in storagePoolLookupByTargetPath where the storage pool object was left locked after a failure of the ACL check could potentially deprive legitimate users access to a storage pool object by users who don't have access.

• New features

  • qemu: Incremental backup support via virDomainBackupBegin

    libvirt-7.6 along with the unreleased qemu-6.1 will fully support the change block tracking features (block-dirty-bitmaps) to be able to do incremental backups and management of the checkpoint states via the appropriate APIs.

  • qemu: Add support for launch security type s390-pv

    Specifying s390-pv as launch security type in an s390 domain prepares for running the guest in protected virtualization secure mode, also known as IBM Secure Execution. This simplifies the definition and reduces the risk of an incorrect definition, e.g. by forgetting to specify iommu=on on all virtio devices.

  • domstats: Add haltpolling time statistic interface

    Domstats now provide the data of cpu haltpolling time. This feature relies on statistics available after kernel version 5.8. This will allow the user to get more accurate CPU usage information if needed.

• Bug fixes

  • qemu: Fix migration with VIR_MIGRATE_NON_SHARED_INC

    libvirt 7.3.0 introduced a bug where VIR_MIGRATE_NON_SHARED_INC would not actually migrate the contents of the disk due to broken logic and at the same time could trigger migration of storage when VIR_MIGRATE_TUNNELLED is requested. This release fixes the bug.

  • qemu: Don't emit VIR_DOMAIN_EVENT_ID_BLOCK_THRESHOLD twice when registered with index

    When registering the threshold event with the index notation (e.g. vda[3]) libvirt would emit the event also for vda if the image is in the top layer. The intention was to emit two events only when the original registration was done without the index.

  • qemu: Pass discard requests for disks with copy_on_read='on'

    When a disk using the copy_on_read='on' option is configured also with discard='unmap' the discard requests will now be passed to the underlying image freeing up the space.

v7.5.0 (2021-07-01)

• Security

  • svirt: fix MCS label generation (CVE-2021-3631)

    A flaw in the way MCS labels were generated could result in a VM's resource not being fully protected from access by another VM were it to be compromised. https://gitlab.com/libvirt/libvirt/-/issues/153

• Removed features

  • xen: Remove support for Xen < 4.9

    In accordance with our platform support policy, the oldest supported Xen version is now bumped from 4.6 to 4.9.

• Improvements

  • docs: Document disk serial truncation status quo

    Disk <serial> is being truncated by QEMU before passed to the guest. Since it's impossible to fix it without running into further regressions the documentation was improved to document the intricacies.

• Bug fixes

  • qemu: Fixed validation of disk iothread configuration

    The validation of iothread config was previously moved to a place where it caused bogus errors when address wasn't allocated when hotplugging a disk. The check is now removed as it wasn't actually necessary at all.

v7.4.0 (2021-06-01)

• Removed features

  • qemu: Remove support for QEMU < 2.11

    In accordance with our platform support policy, the oldest supported QEMU version is now bumped from 1.5 to 2.11.

• New features

  • qemu: Add support for hotplugging <transient/> disks

    The disk hotplug code in the qemu driver now can handle hotplug of disks with automatically added overlay.

  • qemu: Add support for sharing base image of <transient/> disks

    Users can use <transient shareBacking='yes'/> to tell the qemu driver to never open the base image in write mode thus multiple VMs can share the same image. Note that the disk will be hotplugged during startup.

• Improvements

  • Add win-dmp crashdump format

    New win-dmp format for virDomainCoreDumpWithFormat API and/or virsh dump --format was introduced.

• Bug fixes

  • Allow 0 offset in XML schema for <slice type='storage' offset='0' size='321'/>

    Having a 0 offset so that the size of the image can be limited is a valid configuration so it was allowed in the XML schema.

v7.3.0 (2021-05-03)

• New features

  • xen: Support domains with more than 4TB

    The xen driver now supports domains with more than 4TB of memory with xen >= 4.13.

  • qemu: add socket for virtiofs filesystems

    Libvirt now supports filesystem devices that connect to a virtiofsd daemon launched outside of libvirtd, via the socket attribute of the source element.

  • nodedev: Add ability to manage persistent mediated devices

    Persistent mediated devices can now be managed with libvirt. virNodeDeviceDefineXML() defines a new device, virNodeDeviceUndefine() removes an existing definition, and virNodeDeviceCreate() starts a device definition that is currently inactive. Corresponding virsh commands nodedev-define, nodedev-undefine, and nodedev-start were also added. nodedev-list only lists active devices by default. Inactive device definitions can be shown with the new --inactive and --all flags.

  • qemu: Allow use of qemu's -compat option

    Curious developers or testers now can enable certain -compat modes which allow to notice use of deprecated commands and options as qemu will use the selected method to notify the user. The new behaviour can be requested using either the deprecation_behavior option in qemu.conf for all VMs or using <qemu:deprecation behavior='...'/> in the VM XML.

• Improvements

  • virsh: Improve errors with virsh snapshot-create-as

    The XML document constructed by virsh was forced through XML schema validation which yielded unintelligible error messages in cases such as when the path to the new image did not start with a slash. XML documents are no longer validated as the XML parser actually has better error messages which allow users to figure the problem out quickly.

  • qemu: Terminate backing store when doing a full-chain block pull

    When pulling everything into the overlay image the chain can be terminated since we know that it won't depend on any backing image and thus can prevent attempts to probe the backing chain.

  • qemu: Expose disk serial in virDomainGetGuestInfo()

    The virDomainGetGuestInfo() reports disk serial number among with other disk information.

• Bug fixes

  • qemu: Fix crash of libvirt on full block pull of a disk

    When the persistent definition contains a compatible disk (meaning the definition of the running and persistent config match) a block pull job would leave a dangling pointer in the config definition which resulted in a crash.

  • qemu: Use proper job cancelling command

    Libvirt's API contract for aborting a block copy job in 'ready' state declares that the destination image of the copy will contain a consistent image of the disk from the time when the block job was aborted. This requires that libvirt uses the proper cancelling qemu command to ensure that the data is consistent which was not the case.

  • qemu: Don't attempt storage migration when there are no migratable disks

    Due to a logic bug introduced in the previous release libvirt would attempt to migrate disks in case when no disks are selected/eligible for migration.

  • qemu: Fix very rare race when two block job 'ready' events are delivered

    In certain high-load scenarios, qemu might deliver the 'ready' event twice and if it's delivered when pivoting to the destination during a block copy job, libvirt would get confused and execute the code as if the job were aborted.

  • lxc: Fix container destroy with CGroupsV2

    When an LXC container was started and the host used CGroupsV2 it might have had created nested controllers under the container's scope. Libvirt was unaware and thus destroying the container failed with a cryptic error: failed to get cgroup backend for 'pathOfController'. The CGroup removal code was reworked and is now capable of dealing with such scenario.

  • bash-completion: Fix argument passing to $1

    Due to a bug in bash completion script, the auto completion did not work properly when a connection URI or read only flag were specified on virsh or virt-admin command line.

v7.2.0 (2021-04-01)

• New features

  • qemu: Implement domain memory dirty rate calculation API

    New API virDomainStartDirtyRateCalc() and virsh command domdirtyrate-calc are added to start calculating a live domain's memory dirty rate.

  • qemu: Support reporting memory dirty rate stats

    The memory dirty rate stats can be obtained through virsh domstats --dirtyrate via the virConnectGetAllDomainStats API.

  • qemu: Full disk backups via virDomainBackupBegin

    The qemu hypervisor driver now allows taking full disk backups via the virDomainBackupBegin API and the corresponding virsh wrapper.

    In future releases the feature will be extended to also support incremental backups (where only the difference since the last backup is copied) when qemu adds the required functionality.

  • Add support for audio backend specific settings

    With this release a new <audio/> element is introduced that allows users to configure audio output for their guests.

• Improvements

  • qemu: Compatibility with QEMU 6.0 for certain hot-(un)-plug operations

    Libvirt 7.2.0 is required for compatibility with the upcoming QEMU 6.0 release for hotplug and hotunplug of certain devices and helpers, such as iothreads, chardevs, RNG devices, disks with secret, ...

  • qemu: Various improvements to embedded mode

    Embedded mode for the QEMU driver, as well as the virt-qemu-run tool saw improvements in handling of domain life cycle, temporary directories creation (important when using disk secrets) and other minor fixes.

  • Documentation of split daemon related config files

    Split daemons read configuration files upon their start. These were never documented though.

• Bug fixes

  • Check host CPU for forbidden features

    CPU feature policy did not work as expected with host-passthrough and features supported by physical host. CPU features were not filtered out when @check was set to full.

  • Fix virNetworkUpdate() to work with split daemons

    Due to a bug in our code, virNetworkUpdate() did not work with split daemon unless management application connected to virtnetworkd directly.

  • qemu: increase locked memory limit when a vDPA device is present

    Just like VFIO devices, vDPA devices may need to have all guest memory pages locked/pinned in order to operate properly. These devices are now included when calculating the limit for memory lock.

  • Don't log error if SRIOV PF has no associated netdev

    Some SRIOV PFs don't have a netdev associated with them in which case libvirtd reported an error and refused to start. This is now fixed.

  • qemu: Only raise memlock limit if necessary

    Attempting to set the memlock limit might fail if we're running in a containerized environment where CAP_SYS_RESOURCE is not available, and if the limit is already high enough there's no point in trying to raise it anyway.

  • Restore security context of swtpm.log

    If a guest with emulated TPM was started and the daemon was restarted afterwards, the security context of the per-domain swtpm.log file was not restored on domain shutdown leaving it unable to be started again.

  • virtlogd|virtlockd: Fixed crash when upgrading the daemons in-place

    A bug preventing the in-place upgrade of virtlogd and virtlockd daemons was fixed, so they can again be upgraded without dropping the log file descriptors or locks on files.

v7.1.0 (2021-03-01)

• Portability

  • Implement Apple Silicon support

    libvirt now runs on the ARM-based Apple Silicon Macs.

• New features

  • Introduce virtio-pmem <memory/> model

    The virtio-pmem is a virtio variant of NVDIMM and just like NVDIMM virtio-pmem also allows accessing host pages bypassing guest page cache.

  • Introduce <boot order/> for <filesystem>

    Booting is possible from virtiofs filesystems. Introduce an option to control the boot order, like we do for other bootable devices.

  • hyperv: implement new APIs

    The virDomainUndefine(), virDomainUndefineFlags(), virDomainDefineXML(), virDomainAttachDevice(), and virDomainAttachDeviceFlags(), virConnectListAllNetworks(), virConnectNumOfNetworks(), virNetworkLookupByName(), virNetworkLookupByUUID(), virConnectNumOfDefinedNetworks(), virConnectListDefinedNetworks(), virNetworkGetAutostart(), virNetworkIsActive(), virNetworkIsPersistent(), virNetworkGetXMLDesc(), and virDomainScreenshot(), APIs have been implemented in the Hyper-V driver.

  • Support <teaming> element in plain <hostdev> devices

    This is useful when libvirt doesn't have the privileges necessary to set the hostdev device's MAC address (which is a necessary part of the alternate <interface type='hostdev'>).

  • Introduce <disk type='vhostuser'> support

    Introduces support for QEMU vhost-user-blk device that can be used to access storage exported via the vhost-user protocol by daemons such as the qemu-storage-daemon.

• Bug fixes

  • qemu: Fix disk quiescing rollback when creating external snapshots

  If the qemu guest agent call to freeze filesystems failed when creating an external snapshot with VIR_DOMAIN_SNAPSHOT_CREATE_QUIESCE flag the filesystems would be unconditionally thawed. This could cause problems when the filesystems were frozen by an explicit call to virDomainFSFreeze since the guest agent then rejects any further freeze attempts once are filesystems frozen, an explicit freeze followed by a quiesced snapshot would fail and thaw filesystems.

  Users are also encouraged to use virDomainFSFreeze/Thaw manually instead of relying on VIR_DOMAIN_SNAPSHOT_CREATE_QUIESCE if they need finer grained control.

  • cgroups: Fix how we setup and configure cgroups on hosts with systemd

    When libvirt is running on host with systemd we register every VM with machined which creates the VM root cgroup for us as well. Before this fix we were directly modifying files in the VM root cgroup which was incorrect because all the files are managed by systemd. The implication was that any change done by libvirt to cgroup attributes supported by systemd could be removed which happens for example by running systemctl daemon-reload.

    To fix the issue libvirt now uses DBus calls for some of the cgroup attributes that distribute the resources proportionally to the cgroup siblings and for the rest we have a new sub-cgroup that libvirt can managed directly.

    For more details why this is necessary see systemd cgroup documentation.

  • qemu: Fix swtpm device with aarch64

    The TPM TIS device name for x86 is tpm-tis, whereas for aarch64 it is tpm-tis-device. Fix the use of TPM TIS device with aarch64 by using the proper device name when building the QEMU command line.

  • libxl: Fix domain shutdown

    Commit fa30ee04a2 introduced the possibility of a race between the shutdown and death threads used to process domain shutdown and death events from libxl. On normal domain shutdown the shutdown thread handles all aspects of shutting down and cleaning up the domain. The death thread is only used to handle out-of-band domain destruction and is inhibited when domain shutdown is under libvirt's control. The race is avoided by also inhibiting the death thread when libvirt starts the shutdown thread.

v7.0.0 (2021-01-15)

• Project governance

  • Formal handover of release tarball signing

    Starting from libvirt-6.6 the release tarballs are signed by Jiří Denemark. Releases starting with 7.0 contain a note from the previous maintainer Daniel Veillard officially handing over the signing of packages so that the transition can be verified.

• New features

  • nodedev: Add node device driver support for AP devices

    Add support for detecting and listing Adjunct Processor(AP) cards, AP queues and AP matrix devices (which are capable of MDEV) of a KVM host system in libvirt node device driver with correct object relationships.

  • qemu: Allow control of qcow2 metadata cache

    In specific usecases such as when massive storage images are used it's possible to achieve better performance by increasing the metadata cache size. The new knob allows advanced users setting the size according to qemu's documentation to suit their image.

  • conf: Add support for keeping TPM emulator state

    Currently, swtpm TPM state file is removed when a transient domain is powered off or undefined. Add per-TPM emulator option persistent_state for keeping TPM state.

• Improvements

  • qemu: Discourage users from polling virDomainGetBlockJobInfo for block job completion

    Document that waiting for events is a more robust solution.

  • secret: Relax XML schema for the usage name of a secret

    Various bits of documentation of how to use libvirt with RBD volumes used an usage name which would not pass the XML validation. Relax the requirement to make such XMLs valid.

  • virnetdevopenvswitch: Various improvements

    The code that handles <interface type='vhostuser'/> was given various improvements. So far, libvirt assumed vhostuser interfaces are handled exclusively by OpenVSwitch and refused to start a guest if it was not so. Now a guest can be started successfully even if the interface is created by some other tool (e.g. dpdk-testpmd). Also, the code that detects the interface name was adapted to new versions of OpenVSwitch and thus can detect name more reliably.

  • qemu: Report guest disks information in virDomainGetGuestInfo

    Libvirt is now able to report disks and filesystems from the guest's perspective (using guest agent). And with sufficiently new guest agent (5.3.0 or newer) the API also handles disks on CCW bus.

• Bug fixes

  • qemu: Fix logic bug in inactive snapshot deletion

    This release fixes a bug introduced in libvirt-6.9 where libvirt's snapshot metadata would not be deleted on successful snapshot deletion.

  • qemu: Fix VMs with <iotune> on an empty cdrom

    Specifying <iotune> for an empty cdrom would prevent the VM from starting as qemu doesn't accept the tuning for an empty drive. We now postpone setting the parameters until a new media is inserted.

  • Avoid taking extra host memory when launching pSeries guests

    Under certain conditions, pSeries guests were being launched with more RAM than it was specified in the domain XML by the user. New pSeries domains created with libvirt 7.0.0 will always launch with the right amount of initial memory. Existing guests that migrate from an older libvirt version to 7.0.0 will not be affected by this change.

  • qemu: Don't cache NUMA caps

    virsh capabilities contains <topology/> section which reports NUMA topology among with amount of free hugepages per each NUMA node. However, these amounts were not updated between calls.

  • networkGetDHCPLeases: Handle leases with infinite expiry time

    Since libvirt-6.3.0 it is possible to configure expiry time for DHCP leases. If the expiry time was infinite then virsh net-dhcp-leases and NSS plugins refused to work.

  • qemu: Don't prealloc mem for real NVDIMMs

    If a real life NVDIMM is assigned to a guest via <memory model='nvdimm'/> then QEMU is no longer instructed to preallocate memory for it. This prevents unnecessary wear on the NVDIMM.

  • network: Introduce mutex for bridge name generation

    When new libvirt network is defined or created and the input XML does not contain any bridge name, libvirt generates one. However, it might have happened that the same name would be generated for different networks if two or more networks were defined/created at once.

v6.10.0 (2020-12-01)

• Security

  • qemu: Enable client TLS certificate validation by default for chardev, migration, and backup servers.

  The default value if qemu.conf options chardev_tls_x509_verify, migrate_tls_x509_verify, or backup_tls_x509_verify are not specified explicitly in the config file and also the default_tls_x509_verify config option is missing are now '1'. This ensures that only legitimate clients access servers, which don't have any additional form of authentication.

• New features

  • qemu: Implement OpenSSH authorized key file management APIs

    New APIs (virDomainAuthorizedSSHKeysGet() and virDomainAuthorizedSSHKeysSet()) and virsh commands (get-user-sshkeys and set-user-sshkeys) are added to manage authorized_keys SSH file for user.

  • hyperv: implement new APIs

    The virDomainGetMaxMemory(), virDomainSetMaxMemory(), virDomainGetSchedulerType(), virDomainGetSchedulerParameters(), virDomainGetSchedulerParametersFlags(), virDomainGetVcpus(), virDomainGetVcpusFlags(), virDomainGetMaxVcpus(), virDomainSetVcpus(), and virDomainSetVcpusFlags() APIs have been implemented in the Hyper-V driver.

• Improvements

  • virsh: Support network disks in virsh attach-disk

    The virsh attach-disk helper command which simplifies attaching of disks without the need for the user to formulate the disk XML manually now supports network-backed images. Users can specify the protocol and host specification with new command line arguments. Please refer to the man page of virsh for further information.

• Bug fixes

  • remote: fixed performance regression in SSH tunnelling

    The virt-ssh-helper binary introduced in 6.8.0 had very poor scalability which impacted libvirt tunnelled migration and storage volume upload/download in particular. It has been updated and now has performance on par with netcat.

• Removed features

  • hyperv: removed support for the Hyper-V V1 WMI API

    This drops support for Windows Server 2008R2 and 2012. The earliest supported version is now Windows 2012R2.

v6.9.0 (2020-11-02)

• New features

  • nodedev: Add support for channel subsystem (CSS) devices on S390

    A CSS device is represented as a parent device of a CCW device. This support allows to create vfio-ccw mediated devices with virNodeDeviceCreateXML().

  • qemu: Implement memory failure event

    New event is implemented that is emitted whenever a guest encounters a memory failure.

  • qemu: Implement support for <transient/> disks

    VMs based on the QEMU hypervisor now can use <transient/> option for local file-backed disks to configure a disk which discards changes made to it while the VM was active.

  • hyperv: implement new APIs

    The virConnectGetCapabilities(), virConnectGetMaxVcpus(), virConnectGetVersion(), virDomainGetAutostart(), virDomainSetAutostart(), virNodeGetFreeMemory(), virDomainReboot(), virDomainReset(), virDomainShutdown(), and virDomainShutdownFlags() APIs have been implemented in the Hyper-V driver.

  • bhyve: implement virtio-9p filesystem support

    Implement virito-9p shared filesystem using the <filesystem/> element.

  • qemu: Add support for vDPA network devices.

    VMs using the QEMU hypervisor can now specify vDPA network devices using <interface type='vdpa'>. The node device APIs also now list and provide XML descriptions for vDPA devices.

• Bug fixes

  • hyperv: ensure WQL queries work in all locales

    Relying on the "Description" field caused queries to fail on non-"en-US" systems. The queries have been updated to avoid using localized strings.

  • rpc: Fix virt-ssh-helper detection

    libvirt 6.8.0 failed to correctly detect the availability of the new virt-ssh-helper command on the remote host, and thus always used the fallback instead; this has now been fixed.

v6.8.0 (2020-10-01)

• Security

  • qemu: double free in qemuAgentGetInterfaces() in qemu_agent.c

    Clients connecting to the read-write socket with limited ACL permissions may be able to crash the libvirt daemon, resulting in a denial of service, or potentially escalate their privileges on the system. CVE-2020-25637.

• New features

  • xen: Add writeFiltering attribute for PCI devices

    By default Xen filters guest writes to the PCI configuration space of a PCI hostdev, which may cause problems for some devices. The writeFiltering attribute of the device's <source> element can be used to disable the filtering and allow all guest writes to the configuration space.

  • bhyve: Support setting the framebuffer resolution

    Libvirt can now set the framebuffer's "w" and "h" parameters using the resolution element.

  • bhyve: Support VNC password authentication

    Libvirt can now probe whether the bhyve binary supports VNC password authentication. In case it does, a VNC password can now be passed using the passwd attribute on the <graphics> element.

  • remote: virt-ssh-helper replaces nc for SSH tunnelling

    Libvirt now provides a virt-ssh-helper binary on the server side. The libvirt remote client will use this binary for setting up an SSH tunnelled connection to hosts. If not present, it will transparently fallback to the traditional nc tunnel. The new binary makes it possible for libvirt to transparently connect across hosts even if libvirt is built with a different installation prefix on the client vs server. It also enables remote access to the unprivileged per-user libvirt daemons (e.g. using a URI such as qemu+ssh://hostname/session). The only requirement is that virt-ssh-helper is present in $PATH of the remote host.

  • esx: implement few APIs

    The virConnectListAllNetworks(), virDomainGetHostname(), and virDomainInterfaceAddresses() (only for VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_AGENT source) APIs were implemented in the esx driver.

• Improvements

  • qemu: Allow migration over UNIX sockets

    QEMU migration can now be performed completely over UNIX sockets. This is useful for containerised scenarios and can be used in both peer2peer and direct migrations.

  • dbus: Use GLib implementation instead of libdbus

    Adopting GLib DBus implementation simplifies our code as libdbus provides low-level APIs where we had to have a lot of helper functions. With this change we also remove dependency on libdbus and possibly fix all the DBus related libvirtd crashes seen over the time.

  • Re-introduce NVDIMM auto-alignment for pSeries Guests

    The auto-alignment logic was removed in v6.7.0 in favor of requiring the size provided by the user to be already aligned; however, this had the unintended consequence of breaking some existing guests. v6.8.0 restores the previous behavior with an improvement: it also reflects the auto-aligned value in the domain XML.

  • qemu: Preserve qcow2 cluster size after external snapshots

    The new overlay image which is installed on top of the current chain when taking an external snapshot now preserves the cluster size of the original top image to preserve any performance tuning done on the original image.

• Bug fixes

  • qemu: Various (i)SCSI backed hostdev fixes

    (i)SCSI backed hostdevs now work again with an arbitrarily long user-specified device alias and also honor the 'readonly' property after a recent rewrite.

• Removed features

  • node_device: Remove HAL node device backend

    HAL is deprecated on all supported OS so there is no need to keep it in libvirt. udev backend is used on Linux OSes and devd can be eventually implemented as replacement for FreeBSD.

v6.7.0 (2020-09-01)

• Packaging changes

  • Libvirt switch to Meson build system

    Libvirt abandoned autotools and switched to Meson build system.

• New features

  • qemu: Add support for initiator IQN configuration for iSCSI hostdevs

    Similarly to iSCSI <disk> users can use an <initiator> element inside <hostdev> with the same format to configure the IQN value used by the qemu initiator when connecting to an iSCSI target.

  • xen: Add support for device model command-line passthrough

    Xen supports passing arbitrary arguments to the QEMU device model using the device_model_args setting in xl.cfg(5). The libvirt xen driver now supports this using <xen:commandline/> XML extensions.

  • shmem: Add support for shmem-{plain, doorbell} role option

    The role attribute controls how the domain behaves on migration. With role=master, the guest will copy the shared memory on migration to the destination host. With role=peer, the migration is disabled.

  • bhyve: Sound device support

    This feature allows to configure guest sound device using the <sound> element, and map it to the host sound device using the <audio> element.

• Improvements

  • Allow sparse streams for block devices

    Sparse streams (e.g. virsh vol-download --sparse or virsh vol-upload --sparse) now handle if one of the stream ends is a block device.

  • Remove NVDIMM auto-alignment for pSeries Guests

    This feature was introduced in libvirt v6.2.0 as part of the overall NVDIMM support for pSeries guests. The idea was to relieve the user from knowing ppc64 alignment details, but the end result is that we ended up with inconsistencies between domain XML and actual NVDIMM size the guest is using. To promote consistency between domain XML and the guest, unaligned NVDIMM sizes for pSeries guests will now be forbidden and no size auto-alignment will be made. Instead, libvirt will suggest an aligned round up size for the user.

  • apparmor: Several improvements

    Add support for virtiofs filesystem and allow QEMU to load old shared objects after upgrade.

• Bug fixes

  • virdevmapper: Deal with kernels without DM support

    In the previous release libvirt dropped libdevmapper in favor of its own implementation. However, it failed to deal correctly with kernels that either don't have device mapper enabled or where the dm-mod module is not loaded yet. This is now fixed.

  • resctrl: Use exclusive lock for /sys/fs/resctrl

    When two or more domains were attempted to start at once, due to a bug in implementation, resctrl was not locked properly and thus threads did not mutually exclude with each other resulting in not setting requested limitations.

  • mdev: Fix daemon crash when reattaching mdevs on assignment conflict

    If there's a list of mdevs to be assigned to a domain, but one of them (NOT the first) is already assigned to a different domain then libvirtd would crash. This is now fixed.

  • Fix logic in setting COW flag on btrfs

    When COW is not explicitly requested to be disabled or enabled, then libvirt should do nothing on non-BTRFS file systems.

  • Avoid crash due to race in glib event loop code

    Libvirt switched to glib event loop in 6.1.0 but it was also tickling a bug in glib code leading to the daemon crash. Libvirt way of calling glib was changed so the daemon crashes no more.

  • virdevmapper: Handle kernel without device-mapper support

    In the previous release, Libvirt dropped libdevmapper in favor of its own implementation. But the implementation did not handle kernels without device-mapper support. This is now fixed.

  • remove autogenerated macvtap names from migration XML

    Autogenerated macvtap device names were being left in the migration XML, which could result in libvirt erroneously deleting the macvtap device of a different guest in the aftermath of failing to restart the guest on the destination host. Removing the autogenerated names avoids this.

v6.6.0 (2020-08-02)

• New features

  • Allow configuring of ACPI NUMA HMAT

    Libvirt allows configuring ACPI Heterogeneous Memory Attribute Table to hint software running inside the guest on optimization.

  • esx: Add a type attribute for mac addresses.

    This attribute allows (when set to static) ignoring VMWare checks of the MAC addresses that would generate a new one if they were in its OUI (00:0c:29).

  • conf: add control over COW for storage pool directories

    The storage pool code now attempts to disable COW by default on btrfs, but management applications may wish to override this behaviour. This is now possible via new cow element.

• Improvements

  • esx: Change the NIC limit for recent virtualHW versions

    Specifying a virtualHW version greater or equal to 7 (ESXi 4.0) will allow you to use up to 10 NICs instead of 4 as it was previously.

  • qemu: Support encrypted TLS keys for NBD disks

    The secret key used for disks can now be encrypted similarly to TLS keys used for migration, chardev and others.

  • qemu: VIR_DOMAIN_EVENT_ID_BLOCK_THRESHOLD can now be registered for <mirror>

    The event can now be used also for block copy destinations by using the index of the <mirror> image.

  • qemu: consider available CPUs in vcpupin/emulatorpin output

    This patch changes the default bitmap of vcpupin and emulatorpin, in the case of domains with static vcpu placement, all available CPUs instead of all possible CPUs are returned making these APIs consistent with the behavior of vcpuinfo.

• Bug fixes

  • virdevmapper: Don't use libdevmapper to obtain dependencies

    When building domain's private /dev in a namespace, libdevmapper was consulted for getting full dependency tree of domain's disks. However, this meant that libdevmapper opened /dev/mapper/control which wasn't closed and was leaked to QEMU. CVE-2020-14339

  • qemu: Report correct index in VIR_DOMAIN_EVENT_ID_BLOCK_THRESHOLD

    Starting from libvirt 5.10 with QEMU 4.2 the VIR_DOMAIN_EVENT_ID_BLOCK_THRESHOLD event would report incorrect device index when reported for an image from the backing chain of a disk.

  • qemu: Don't fail active layer block commit or block copy in certain cases

    Starting from libvirt-6.5 an active layer block commit or a block copy could fail if the same destination was used more than once.

  • qemu: Don't change ownership of restore file

    When restoring a domain from a file, Libvirt no longer changes its ownership.

  • qemu: Set SPAPR TPM default to 2.0 and prevent 1.2 choice

    The firmware (SLOF) on QEMU for ppc64 does not support TPM 1.2, so prevent the choice of TPM 1.2 when the SPAPR device model is chosen and use a default of '2.0' (TPM 2) for the backend.

  • qemu: Do not set //cpu/@migratable for running domains

    Libvirt release of 6.4.0 started to fill the default value for //cpu/@migratable attribute according to QEMU support. However, active domains either have the migratable attribute already set or they were started with older Libvirt which doesn't support the attribute.

v6.5.0 (2020-07-03)

• New features

  • Allow firmware blobs configuration

    QEMU offers a way to tweak how firmware configures itself and/or provide new configuration blobs. New <sysinfo/> type is introduced that will hold these new blobs. It's possible to either specify new value as a string or provide a filename which contents then serve as the value.

  • nodedev: Add ability to create mediated devices

    Mediated devices can now be created with virNodeDeviceCreateXML(). This functionality requires the mdevctl utility to be installed. The XML schema for node devices was expanded to support attributes for mediated devices.

  • QEMU: add TPM Proxy device support

    libvirt can now create guests using a new device type called "TPM Proxy". The TPM Proxy connects to a TPM Resource Manager present in the host, enabling the guest to run in secure virtual machine mode with the help of an Ultravisor. Adding a TPM Proxy to a pSeries guest brings no security benefits unless the guest is running on a PPC64 host that has Ultravisor and TPM Resource Manager support. Only one TPM Proxy is allowed per guest. A guest using a TPM Proxy device can instantiate another TPM device at the same time. This device is supported only for pSeries guests via the new 'spapr-tpm-proxy' model of the TPM 'passthrough' backend.

  • virhook: Support hooks placed in several files

    Running all scripts from directory /etc/libvirt/hooks/<driver>.d in alphabetical order. Hook script in old place will be executed as first for backward compatibility.

  • qemu: Add support for migratable host-passthrough CPU

    QEMU 2.12 made it possible for guests to use a migration-friendly version of the host-passthrough CPU. This feature is now exposed by libvirt.

• Improvements

  • network: Support NAT with IPv6

    It's now possible to use <nat ipv6="yes"/> in a libvirt network.

  • qemu: Auto-fill NUMA information for incomplete topologies

    If the NUMA topology is not fully described in the guest XML, libvirt will complete it by putting all unspecified CPUs in the first NUMA node. This is only done in the QEMU binary itself supports disjointed CPU ranges for NUMA nodes.

  • qemu: Assign hostdev-backed interfaces to PCIe slots

    All SR-IOV capable devices are PCIe, so when their VFs are assigned to guests they should end up in PCIe slots rather than conventional PCI ones.

• Bug fixes

  • qemu: fixed crash in qemuDomainBlockCommit

    This release fixes a regression which was introduced in libvirt v6.4.0 where libvirtd always crashes when a block commit of a disk is requested.

  • qemu: fixed zPCI address auto generation on s390

    Removes the correlation between the zPCI address attributes uid and fid. Fixes the validation and autogeneration of zPCI address attributes.

  • qemu: Skip pre-creation of NVMe disks during migration

    libvirt has no way to create NVMe devices on the target host, so it now just makes sure they exist and let the migration proceed in that case.

v6.4.0 (2020-06-02)

• New features

  • qemu: Add support for pvscsi controllers

    pvscsi is the VMware paravirtualized SCSI controller, which has been supported in QEMU for a number of years.

  • cpu: Report model information for ARM CPUs

    virsh capabilities will now include information about the host CPU when run on ARM machines.

  • qemu: support network interface downscript

    QEMU has the ability to run a script when a NIC is brought up and down. Libvirt only enables use of the up script. Now add support for postscript when NIC is down/detached.

• Improvements

  • qemu: stricter validation for disk type='lun'

    The 'lun' type is meant for SCSI command passthrough, which can't be achieved if qemu's block layer features are used. Disk type='lun' is now allowed only when the format is 'raw' and no other block layer features are requested.

  • qemu: auto-fill of incomplete NUMA topologies

    Domains with incomplete NUMA topologies, where the sum of vCPUs in all NUMA cells is less than the total of vCPUs, will get their first NUMA cell to be auto-filled with the remaining vCPUs. This behavior reproduces what QEMU already does in these cases. Users are encouraged to provide complete NUMA topologies to avoid unexpected changes in the domain XML.

  • Cooperlake x86 CPU model is added

• Bug fixes

  • qemu: fixed regression in network device hotplug with new qemu versions

    Starting from QEMU-5.0 it's required to conform to strict schema when hotplugging network devices. Libvirt didn't conform to the schema so in versions prior to 6.4.0 network device hotplug fails in certain cases. This version fixes it and adds stricter testing to prevent further issues.

  • remote: Look up libxl driver correctly

    This makes xen:// connection URIs usable in split daemon mode.

  • systemd: Start libvirtd after firewalld/iptables services

    This solves an issue where iptables rules and chains created by libvirtd would get removed by a service started after it.

  • network: Re-create iptables chains on firewalld restart

    firewalld resets all iptables rules and chains on restart, and this includes deleting those created by libvirt.

  • qemu: reject readonly attribute for virtiofs

    virtiofs does not yet support read-only shares.

v6.3.0 (2020-05-05)

• New features

  • qemu: support disabling hotplug/unplug of PCIe devices

    libvirt can now set the "hotplug" option for pcie-root-ports and pcie-switch-downstream-ports, which can be used to disable hotplug/unplug of devices from these ports (default behavior is for these controllers to accept all hotplug/unplug attempts, but this is often undesirable).

  • vbox: added support for version 6.0 and 6.1 APIs

    libvirt can now support use of the VirtualBox 6.0 and 6.1 APIs. This is compile tested only, so we are looking for feedback from users on how well it works in practice.

  • xen: Add support for 'e820_host' hypervisor feature

    e820_host is a Xen-specific option only available for PV guests. When enabled it provides the guest with a virtual e820 memory map based on the host one. It must be enabled to allow hotplugging PCI devices to PV guests, particularly when memory ballooning is enabled.

  • xen: Add support for 'passthrough' hypervisor feature

    passthrough is a Xen-specific option new to Xen 4.13 that enables PCI passthrough for guests. It must be enabled to allow hotplugging PCI devices.

  • qemu: support async IO mode 'io_uring'

    Linux 5.1 introduces a fast and efficient async IO interface io_uring, then qemu implements that in version 5.0. It could be used in file, host device and host cdrom backend by io='io_uring' of disk XML.

  • Lease time option included for network DHCP settings

    Users can now configure expiry time for leases for networks where libvirt manages DHCP. The time can be specified for whole range and/or fine tuned per individual host.

  • qemu: Implement pSeries Spectre mitigation features

    Users can now setup the following capabilities of pSeries guests: CFPC (Cache Flush on Privilege Change), SBBC (Speculation Barrier Bounds Checking) and IBS (Indirect Branch Speculation).

  • qemu: Add support for virtio packed option

    The packed attribute controls if QEMU should try to use packed virtqueues. Possible values are on or off.

• Improvements

  • qemu: Allow checkpoint redefine for offline VMs

    Skip the liveness and capability checks when redefining checkpoints as we don't need QEMU interactions to update the metadata.

  • daemons: Improve timeout handling

    Daemons now support --timeout 0 which suppresses daemon killing after given time of inactivity.

  • qemu: Add support for 'multidevs' option

    This option prevents misbehaviours on guest if a QEMU 9pfs export contains multiple devices, due to the potential file ID collisions this otherwise may cause.

• Bug fixes

  • qemu: Various embed driver fixes

    When using shared resources from embed driver (e.g. hugepages, machined, etc.) libvirt now generates an unique handler that is not conflicting with other embed drivers or system or session daemons.

  • cpu: Distinguish Cascadelake-Server from Skylake-Server

    Libvirt now properly detects Cascadelake-Server and Skylake-Server processors which differ only in stepping.

  • qemu: Fix domain restore from a block device

    When using namespaces, libvirt was unable to restore a domain from a block device because libvirt tried to relabel the device inside the namespace while QEMU was given FD to the block device in the host.

  • node_device_udev: Handle move events

    Libvirt now handles move event which is emitted on a NIC rename.

  • qemu: Fix capabilities probing with TCG

    Libvirt no long assumes TCG is always available. It now detects whether QEMU supports TCG and reports it accordingly.

• Removed features

  • vbox: removed support for version 5.0 and 5.1 APIs

    libvirt no longer supports use of VirtualBox 5.0 and 5.1 since these versions reached their end of life on 2017/05 and 2018/04 respectively.

v6.2.0 (2020-04-02)

• New features

  • qemu: NVDIMM support for pSeries guests

    QEMU 5.0 implements NVDIMM memory support for pSeries guests. This is done by adding an 'uuid' element in the memory XML, which can either be provided in the XML or, if omitted, generated automatically.

  • qemu: Add virtiofs support

    This feature, introduced in QEMU 4.2, is a more modern alternative to virtio-9p, which is exposed through the same <filesystem/> element.

  • admin: Support reloading TLS certificates

    After renewing TLS certificates, it was usually necessary to restart libvirtd for the new ones to be loaded: now the same result can be obtained without restarting the daemon by using virt-admin server-update-tls .

• Removed features

  • Removed support for INI style of comments

    With switching of our internal code to GLib, parsing of client authentication config files is handed over to GLib which does not support INI style of comments starting with a semicolon ( ; ). Use number sign ( # ) instead.

• Improvements

  • qemu: Don't compare local and remote hostnames on migration

    This check was introduced to prevent same-host migration, but did not work as expected when multiple libvirtd instances were running on the same host but in different containers. With this release, the host UUID (which should be unique to the container) is checked instead.

  • qemu: Use per-VM event loops

    Instead of using a single even loop to process communication with the QEMU monitor and guest agent, create a separate one for each VM. This helps with scalability and prevents scenarios where a single malfunctioning VM could affect all those running on the same host.

  • qemu: Support migration with SLIRP helper interface

    With QEMU 5.0, a new D-Bus backend allows migration of external processes. When needed, libvirt will start a per-vm D-Bus bus, and migrate the slirp-helper along with QEMU.

• Bug fixes

  • qemu: Open backing chain late for shallow block copy reusing external images

    With introduction of -blockdev for QEMU storage configuration in libvirt-5.10 we've started opening the backing chain of the destination/mirror of a virDomainBlockcopy started with VIR_DOMAIN_BLOCK_COPY_REUSE_EXT | VIR_DOMAIN_BLOCK_COPY_SHALLOW flags when starting the job rather than when virDomainBlockJobAbort with VIR_DOMAIN_BLOCK_JOB_ABORT_PIVOT is issued. For users depending on this undocumented quirky pre-blockdev behaviour this caused a regression as the backing chain could not be modified while the copy of the top image was progressing due to QEMU image locking. Note that this fix also requires qemu-5.0 while -blockdev is used starting from QEMU-4.2.

  • Don't generate machine names containing dots

    Even though the guest name containing dots is not a problem for libvirt itself, we need to strip them out when registering with machined because of the latter's requirements.

v6.1.0 (2020-03-03)

• New features

  • qemu: new rng backend type: builtin

    It implements qemu builtin rng backend. That uses getrandom syscall to generate random, no external rng source needed. Available since QEMU 4.2.

  • support for virtio+hostdev NIC <teaming>

    QEMU 4.2.0 and later, combined with a sufficiently recent guest virtio-net driver (e.g. the driver included in Linux kernel 4.18 and later), supports setting up a simple network bond device comprised of one virtio emulated NIC and one hostdev NIC (which must be an SRIOV VF). (in QEMU, this is known as the "virtio failover" feature). The allure of this setup is that the bond will always favor the hostdev device, providing better performance, until the guest is migrated - at that time QEMU will automatically unplug the hostdev NIC and the bond will send all traffic via the virtio NIC until migration is completed, then QEMU on the destination side will hotplug a new hostdev NIC and the bond will switch back to using the hostdev for network traffic. The result is that guests desiring the extra performance of a hostdev NIC are now migratable without network downtime (performance is just degraded during migration) and without requiring a complicated bonding configuration in the guest OS network config and complicated unplug/replug logic in the management application on the host - it can instead all be accomplished in libvirt with the interface <teaming> subelement "type" and "persistent" attributes.

  • support BR_ISOLATED flag for guest interfaces attached to a Linux host bridge

    Since Linux kernel 4.18, the Linux host bridge has had a flag BR_ISOLATED that can be applied to individual ports. When this flag is set for a port, traffic is blocked between that port and any other port that also has the BR_ISOLATED flag set. libvirt domain interface config now supports setting this flag via the <port isolated='yes'/> setting. It can also be set for all connections to a particular libvirt network by setting the same option in the network config - since the port for the host itself does not have BR_ISOLATED set, the guests can communicate with the host and the outside world, but guests on that network can't communicate with each other. This feature works for QEMU and LXC guests with interfaces attached to a Linux host bridge.

  • qemu: Introduce the 'armvtimer' timer type

    QEMU 5.0 introduces the ability to control the behavior of the virtual timer for KVM ARM/virt guests, and this new timer type exposes the same capability to libvirt users.

  • qemu: Storage configuration improvements

    Libvirt now accepts <backingStore type='volume'> and allows specifying the offset and size of the image format container inside the storage source via the <slices> subelement.

  • qemu: Introduce the 'tpm-spapr' TPM model

    This device, available starting from QEMU 5.0, is limited to pSeries guests.

  • qemu: support Panic Crashloaded event handling

    The pvpanic device now supports a 'crashloaded' event, which is emitted when a guest panic has occurred but has already been handled by the guest itself.

  • qemu: Implement virDomainGetHostnameFlags

    The --source argument to virsh domhostname can be used to specify what data source to use for the domain hostnames. Currently, in addition to the 'agent', libvirt can also use 'lease' information from dnsmasq to get the hostname.

• Improvements

  • qemu: Image format probing is allowed in certain cases

    To resolve regressions when users didn't specify the backing image format in the overlay, libvirt now probes the format in certain secure scenarios which fixes a few common existing cases. Additionally the knowledge base was extended to provide more information on how to rectify the problem.

  • qemu: Support "dies" in CPU topology

    This CPU topology concept, new in QEMU 4.1.0, sits between the existing "socket" and "core".

  • libxl: Add support for Credit2 scheduler parameters

  • lxc: Add support LXC 3 network configuration format

• Bug fixes

  • conf: Do not generate machine names ending with a dash

    Recent systemd versions do not allow them.

• Packaging changes

  • use of gnulib has been completely eliminated

    Historically libvirt has embedded gnulib to provide fixes for various platform portability problems. This usage has now been eliminated and alternative approaches for platform portability problems adopted where required. This has been validated on the set of platforms covered by automated CI build testing. Other modern Linux distros using glibc are expected to work. Linux distros using non-glibc packages, and other non-Linux platforms may encounter regressions when building this release. Please report any build problems encountered back to the project maintainers for evaluation.

v6.0.0 (2020-01-15)

• Packaging changes

  • support for python2 is removed

    Libvirt is no longer able to be built using the Python 2 binary. Python 3 must be used instead.

  • docs: the python docutils toolset is now required

    The use of rst2html has been introduced for the website build process since docs are now being written in the RST as an alternative to HTML.

• New features

  • new PCI hostdev address type: unassigned

    A new PCI hostdev address type 'unassigned' is introduced. An unassigned PCI hostdev behaves like any regular PCI hostdev inside Libvirt, but it is not usable by the guest. This gives the user a new option to manage the binding of PCI devices via Libvirt, declaring PCI hostdevs in the domain XML but allowing just a subset of them to be assigned to the guest.

  • Provide init scripts for sub-deaemons

    So far libvirt shipped systemd unit files for sub-daemons. With this release, init scripts are available too. Package maintainers can choose which one to install via --with-init-script configure option.

  • qemu: Support cold-unplug of sound devices

  • qemu: Implement VIR_MIGRATE_PARAM_TLS_DESTINATION

    This flag, which can be enabled using virsh 's --tls-destination option, allows migration to succeed in situations where there is a mismatch between the destination's hostname and the information stored in its TLS certificate.

  • qemu: Support reporting memory bandwidth usage stats

    Implement Intel RDT-MBM in libvirt. The stats can be obtained via virsh domstats --memory .

  • qemu: Allow accessing NVMe disks directly

    Before this release there were two ways to configure a NVMe disk for a domain. The first was using <disk/> with the <source/> pointing to the /dev/nvmeXXXX . The other was using PCI assignment via <hostdev/> element. Both have their disadvantages: the former adds latency of file system and block layers of the host kernel, the latter prohibits domain migration. In this release the third way of configuring NVMe disk is added which combines the advantages and drops disadvantages of the previous two ways. It's accessible via <disk type='nvme'/>.

• Removed features

  • 'phyp' Power Hypervisor driver removed

    The 'phyp' Power Hypervisor driver has not seen active development since 2011 and does not seem to have any real world usage. It has now been removed.

• Improvements

  • qemu: xz save image compression is faster

    When using the xz format to compressed virtual machine saved state images, the "-3" compression level preset is now used. This results in slightly larger files, but with a massively reduced time to compress. The xz format offers the best compression level for saved state images, albeit still with the slowest running time. For the fastest possible running time, at cost of the larest compressed size, lzop should be used.

  • domain: Improve job stat handling

    It is now possible to retrieve stats for completed and failed jobs.

  • qemu: Don't hold monitor and agent job at the same time

    Before this change, a malicious (or buggy) qemu-guest-agent running in the guest could make other libvirt APIs unavailable for an unbounded amount of time.

• Bug fixes

  • qemu: Report error if backing image format is not specified explicitly

    For a long time libvirt was assuming that a backing file is RAW when the format was not specified. This didn't pose a problem until blockdev support was enabled in last release. Libvirt now requires that the format is specified in the image metadata or domain XML and the VM will refuse to start otherwise. Additionally the error message now links to the knowledge base which summarizes how to fix the images.

  • qemu: Fix non-shared storage migration over NBD

  • qemu: Generate a single MAC address for hotplugged network devices

    Since libvirt 4.6.0, when hotplugging a network device that didn't have a MAC address already assigned by the user, two separate addresses would be generated: one for the live configuration, which would show up immediately, and one for the inactive configuration, which would show up after the first reboot. This situation was clearly undesirable, so a single MAC address is now generated and used both for the live configuration and the inactive one.

v5.10.0 (2019-12-02)

• New features

  • qemu: Introduce support for ARM CPU features

    The only features supported at the moment are SVE vector lengths, which were introduced in QEMU 4.2.0.

  • qemu: Support boot display for GPU mediated devices

    Until now, GPU mediated devices generally did not show any output until the guest OS had initialized the vGPU. By specifying the ramfb attribute, QEMU can be configured to use ramfb as a boot display for the device: this allows for display of firmware messages, boot loader menu, and other output before the guest OS has initialized the vGPU.

  • Add API to change the response timeout for guest agent commands

    By default, when a command is sent to the guest agent, libvirt waits forever for a response from the guest agent. If the guest is unresponsive for any reason, this can block the calling thread indefinitely. By setting a custom timeout using virDomainAgentSetResponseTimeout() , API users can change this behavior.

• Improvements

  • Devices CGroup v2 support

    Libvirt supported all controllers of CGroup v2 but the devices controller which is implemented in this release.

  • Cold plug of sound device

    The QEMU driver now can handle cold plug of <sound/> devices.

  • Probe for default CPU types

    With QEMU 4.2.0 we can probe for the default CPU model used by QEMU for a particular machine type and store it in the domain XML. This way the chosen CPU model is more visible to users and libvirt will make sure the guest will see the exact same CPU after migration.

  • Adaptation to qemu's blockdev

    QEMU introduced a new way of specifying disks on the command line which enables fine-grained control over the block stack. Libvirt has adapted to this.

• Refactors

  • More GLib integration

    More patches were merged that replace our internal functions with GLib ones. Also some effort was invested in replacing gnulib modules with GLib functions.

  • Rewrite of Perl scripts into Python

    Libvirt used Perl scripts to check for coding style, generate some code and things like that. To bring the number of languages used down, these scripts were rewritten into Python.

• Bug fixes

  • Warn verbosely if using old loader:nvram pairs

    Some distributions still use --with-loader-nvram or nvram variable in qemu.conf. This is now discouraged in favour of FW descriptors. However, instead of silently ignoring user's config, libvirt warns if outdated config is detected.

  • Drop pconfig from Icelake-Server CPU model

    The pconfig feature was enabled in QEMU by accident in 3.1.0. All other newer versions do not support it and it was removed from the Icelake-Server CPU model in QEMU.

  • Wait longer for device removal confirmation on PPC64

    After sending device hot unplug request to QEMU, libvirt waits up to 5 seconds for qemu to confirm the device removal. On some architectures (like PPC64) this can take longer time and libvirt now reflects that.

  • Forcibly create nodes in domain's namespace

    The QEMU driver starts a domain in a namespace with private /dev and creates only those nodes there which the domain is configured to have. However, it may have happened that if a node changed its minor number this change wasn't propagated to the namespace.

  • Various AppArmor bugfixes

    The AppArmor driver now knows how to handle <shmem/> devices and also snapshotting more disks at once.

  • Improved video model autoselection

    If a graphics device was added to XML that had no video device, libvirt automatically added a video device which was always of type 'cirrus' on x86_64, even if the underlying qemu didn't support cirrus. Libvirt now bases the decision on qemu's capabilities.

v5.9.0 (2019-11-05)

• Packaging changes

  • Start linking against GLib and using its features

    Up until now, libvirt has been dealing with platform portability and the lack of certain features in libc by using gnulib and implementing its own functions and data structures respectively; going forward, it will prefer the facilities offered by GLib instead.

  • Stop distributing generated documentation

    Most downstreams already patch the libvirt source to some extent, so this change will probably not affect them.

  • Rewrite several Perl scripts in Python

    Phasing out Perl usage is part of the project strategy.

• New features

  • qemu: Introduce a new video model of type 'ramfb'

    Introduce a new video model type to the domain XML that supports the ramfb standalone device in qemu.

  • qemu: Implement the ccf-assist pSeries feature

    Users can now decide whether ccf-assist (Count Cache Flush Assist) support should be available to pSeries guests.

  • Xen: Support specifying ACPI firmware path

    The libxl driver now supports specifying an ACPI firmware path using the acpi element.

  • qemu: Support specifying resolution for video devices

• Removed features

  • logging: Drop support for including stack traces

    This feature was intended to aid debugging, but in practice it resulted in logs that were too verbose to be useful and also resulted in a significant performance penalty.

• Improvements

  • qemu: Implement CPU comparison/baseline on s390x

    This functionality has been historically limited to x86_64, but it's now available on s390x too.

• Bug fixes

  • lib: autostart objects exactly once

    If libvirtd or any of the sub-daemons is started with socket activation then objects might be autostarted more than once. For instance, if a domain under qemu:///session URI is mark as autostarted and the session daemon is started then the domain is started with it. If user shuts the domain down and the session daemon is started again, the user's wish to keep the domain shut off is ignored and the domain is autostarted again. This is now fixed.

  • qemu: Properly advertise bochs-display availability

    Support for bochs-display was introduced in libvirt 5.6.0, but until now the model was not listed in the domain capabilities.

  • security: Don't remember labels for TPM devices

    Due to the way they're implemented in the kernel, trying to remember labels for TPM devices makes it impossible to use them.

  • security: Properly rollback after failure in a stacked driver

    When multiple security drivers are involved, failure in one of them would result in only the corresponding changes being rolled back, leaving the ones performed by drivers that had been activated earlier in place. All changes are rolled back now.

  • Fix build with musl libc

  • Improve compatibility with non-bash shells

v5.8.0 (2019-10-05)

• New features

  • qemu: Support use of precreated tap/macvtap devices by unprivileged libvirtd

    It is now possible for an unprivileged libvirtd to make use of tap and macvtap devices that were previously created by some other entity. This is done by setting managed='no' along with the device name in the target subelement of <interface type='ethernet'> .

  • qemu: Support vhost-user-gpu

    Support for running virtio GPUs in separate processes with vhost-user backend. It requires QEMU newer than 4.1.

  • Introduce virConnectSetIdentity API

    When split daemons are in use, this API is used to forward uid, gid and SELinux info from virproxyd to other driver daemons such as virtqemud .

• Improvements

  • qemu: Support running SLIRP networking in a separate process

    User can configure the slirp-helper path in qemu.conf . It will start a slirp-helper process to provide SLIRP networking when the VM is started with network interface "user". That will allow stricter security policies for QEMU SLIRP network.

• Removed features

  • Remove xenapi driver

    The xenapi driver is removed since it has not received any significant development since its initial contribution nine years ago and has no known user base.

v5.7.0 (2019-09-03)

• New features

  • qemu: Support Direct Mode for Hyper-V Synthetic timers

    The QEMU driver now supports Direct Mode for Hyper-V Synthetic timers for Hyper-V guests.

  • lib: Add virDomainGetGuestInfo()

    This API is intended to aggregate several guest agent information queries and is inspired by stats API virDomainListGetStats() . It is anticipated that this information will be provided by a guest agent running within the domain. It's exposed as virsh guestinfo .

  • Experimental split of libvirtd into separate daemons

    The big monolithic libvirtd daemon can now be replaced by smaller per-driver daemons. The new split daemons are considered experimental at this time and distributions are encouraged to continue using the traditional libvirtd by default.

  • qemu: Support kvm-hint-dedicated performance hint

    With <hint-dedicated state='on'/> and <cpu mode='host-passthrough'/> , it allows a guest to enable optimizations when running on dedicated vCPUs. QEMU newer than 2.12.0 and kernel newer than 4.17 are required.

• Removed features

  • Remove KVM assignment support

    The KVM style of PCI device assignment was removed from the kernel in version 4.12.0 after being deprecated since 4.2.0. Libvirt defaults to VFIO for a long time. Remove support for KVM device assignment from libvirt too.

  • libxml: min required libxml is now 2.9.1

    Support for building with libxml versions older than 2.9.1 has been dropped.

• Improvements

  • virsh: Support setting bandwidth in migrate subcommand

    In addition to postcopy bandwidth, the virsh migrate subcommand now supports specifying precopy bandwidth with the --bandwidth parameter.

  • libxl: Implement domain metadata getter/setter

    The libxl driver now supports virDomainGetMetadata() and virDomainSetMetadata() APIs.

  • test driver: Expand API coverage

    Additional APIs have been implemented in the test driver.

  • Report RNG device in domain capabilities XML

    Libvirt now reports if RNG devices are supported by the underlying hypervisor in the domain capabilities XML.

  • Stop linking NSS plugins with libvirt.so

    This reduces the amount of code and 3rd party libraries are that loaded into all processes.

  • Split the setuid virt-login-shell binary into two pieces

    The setuid virt-login-shell binary is now a tiny shim that sanitizes the process execution environment variables and arguments, before launching the trusted virt-login-shell-helper binary.

  • qemu: Allow migration with disk cache on

    When QEMU supports flushing caches at the end of migration, we can safely allow migration even if disk/driver/@cache is neither none nor directsync .

• Bug fixes

  • Various security label remembering fixes

    In the previous release libvirt introduced remembering of original owners and SELinux labels on files. However, the feature did not work properly with snapshots, on migrations or on network filesystems. This is now fixed.

  • Allow greater PCI domain numbers

    Libvirt used to require PCI domain number to be not greater than 0xFFFF. The code was changed to allow 32 bits long numbers.

  • Various D-Bus fixes

    When D-Bus is not available, libvirt was reporting random errors. These are now gone.

  • Prefer read-only opening of PCI config files

    When enumerating PCI bus, libvirt opens config files under sysfs mount and parses them to learn various aspects of the device (e.g. its capabilities). Only in a very limited number of cases it is actually writing into the file. However, it used to open the file also for writing even if it was only reading from it.

  • Fix AppArmor profile

    Since the 5.6.0 release, libvirt uses procfs to learn the list of opened file descriptors when spawning a command. However, our AppArmor profile was not allowing such access.

  • Don't block storage driver when starting or building a pool

    Starting or building a storage pool can take a long time to finish. During this time the storage driver was blocked and thus no other API involving the storage driver could run. This is now fixed.

v5.6.0 (2019-08-05)

• New features

  • qemu: Introduce a new video model of type 'bochs'

    Introduce a new video model type that supports the bochs-display device that was added in qemu version 3.0.

  • api: new virDomainCheckpoint APIs

    Introduce several new APIs for creating and managing checkpoints in the test and qemu drivers (the latter requires qcow2 images). Checkpoints serve as a way to tell which portions of a disk have changed since a point in time.

  • qemu: Add support for overriding max threads per process limit

    systemd-based systems impose a limit on the number of threads a process can spawn, which in some cases can be exceeded by QEMU processes running VMs. Add a max_threads_per_process option to qemu.conf to override the system default.

  • Remember original owners and SELinux labels of files

    When a domain is starting up libvirt changes DAC and SELinux labels so that domain can access it. However, it never remembered the original labels and therefore the file was returned back to root:root . With this release, the original labels are remembered and restored properly.

  • network: Allow passing arbitrary options to dnsmasq

    This works similarly to the existing support for passing arbitrary options to QEMU, and just like that feature it comes with no support guarantees.

• Removed features

  • xen: Remove sxpr config support

    Remove the sxpr style config parser and formatter a year after the xend driver was removed.

• Improvements

  • qemu: Allow XML validation for snapshot creation

    Add flag VIR_DOMAIN_SNAPSHOT_CREATE_VALIDATE to validate snapshot input XML. For virsh, users can use it as virsh snapshot-create --validate .

  • Support encrypted soft TPM

    A soft TPM backend could be encrypted with passphrase. Now libvirt supports using a secret object to hold the passphrase, and referring to it via the encryption element of the TPM device.

  • test driver: Expand API coverage

    Additional APIs have been implemented in the test driver.

  • Implement per-driver locking

    Drivers now acquire a lock when they're loaded, ensuring that there can never be two instances of the same driver active at a time.

  • nss: Report newer addresses first

    In some cases, a guest might be assigned a new IP address by DHCP before the previous lease has expired, in which case the NSS plugin will correctly report both addresses; many applications, however, ignore all addresses but the first, and may thus end up trying to connect using a stale address. To prevent that from happening, the NSS plugin will now always report the newest address first.

  • util: Optimize mass closing of FDs when spawning child processes

    When the limit on the number of FDs is very high, closing all unwanted FDs after calling fork() can take a lot of time and delay the start of the child process. libvirt will now use an optimized algorithm that minimizes such delays.

• Bug fixes

  • logging: Ensure virtlogd rollover takes priority over logrotate

    virtlogd implements its own rollover mechanism, but until now logrotate could end up acting on the logs before virtlogd had a chance to do so itself.

v5.5.0 (2019-07-02)

• Security

  • api: Prevent access to several APIs over read-only connections

    Certain APIs give root-equivalent access to the host, and as such should be limited to privileged users. CVE-2019-10161, CVE-2019-10166, CVE-2019-10167, CVE-2019-10168.

• New features

  • qemu: Support SMMUv3 IOMMU

    SMMUv3 is an IOMMU implementation for ARM virt guests.

  • network: Introduce the network port API

    This new public API can be used by virtualization drivers to manage network resources associated with guests, and is a further step towards splitting libvirtd into multiple daemons.

• Removed features

  • qemu: Remove support for virDomainQemuAttach and virConnectDomainXMLFromNative APIs

    The qemu implementations for the APIs mentioned above were removed and the APIs now return an error. The implementation was stale for a long time and did not work with modern QEMU command lines, generated from libvirt or otherwise.

  • Stop supporting migration of config files from pre-XDG layout

    The new layout was introduced with libvirt 0.9.13 (Jul 2012).

  • Remove Avahi mDNS support

    This feature was never used outside of virt-manager, which has itself stopped using it a while ago.

• Improvements

  • sysinfo: Report SMBIOS information on aarch64

    While SMBIOS support has historically been limited to x86_64, modern aarch64 machines often offer access to the same information as well, and libvirt now exposes it to the user when that's the case.

  • test driver: Expand API coverage

    Even more APIs that were missing from the test driver have now been implemented.

  • virt-xml-validate: Allow input to be read from stdin

  • qemu: Validate spapr-vio addresses as 32-bit

    libvirt has always considered these addresses (used for pSeries guests) as 64-bit, but the sPAPR specification says that they're 32-bit instead.

• Bug fixes

  • qemu: Set process affinity correctly when using <numatune>

    libvirt would mistakenly interpret the nodeset attribute as a list of CPUs instead of as a list of NUMA node, and the process affinity would be set incorrectly as a result; this has now been fixed.

v5.4.0 (2019-06-03)

• Security

  • cpu: Introduce support for the md-clear CPUID bit

    This bit is set when microcode provides the mechanism to invoke a flush of various exploitable CPU buffers by invoking the x86 VERW instruction. CVE-2018-12126, CVE-2018-12127, CVE-2018-12130, CVE-2019-11091.

  • Restrict user access to virt-admin, virtlogd and virtlockd

    The intended users for these facilities are the root user and the libvirtd service respectively, but these restrictions were not enforced correctly. CVE-2019-10132.

• Improvements

  • test driver: Expand API coverage

    Several APIs that were missing from the test driver have now been implemented.

  • Avoid unnecessary static linking

    Most binaries shipped as part of libvirt, for example virtlogd and libvirt_iohelper , were embedding parts of the library even though they also linked against the libvirt.so dynamic library. This is no longer the case, which results in both the disk and memory footprint being reduced.

  • qemu: Report stat-htlb-pgalloc and stat-htlb-pgfail balloon stats

    These stats have been introduced in QEMU 3.0.

• Bug fixes

  • qemu: Fix emulator scheduler support

    Setting the scheduler for QEMU's main thread before QEMU had a chance to start up other threads was misleading as it would affect other threads (vCPU and I/O) as well. In some particular situations this could also lead to an error when the thread for vCPU #0 was being moved to its cpu,cpuacct cgroup. This was fixed so that the scheduler for the main thread is set after QEMU starts.

  • apparmor: Allow hotplug of vhost-scsi devices

v5.3.0 (2019-05-04)

• New features

  • qemu: Add support for setting the emulator scheduler parameters

    I/O threads and vCPU threads already support setting schedulers, but until now it was impossible to do so for the main QEMU thread (emulator thread in the libvirt naming). This is, however, requested for some very specific scenarios, for example when vCPU threads are running at such priority that could starve the main thread.

• Removed features

  • vbox: Drop support for VirtualBox 4.x releases

    Support for all the 4.x releases was ended by VirtualBox maintainers in December 2015. Therefore, libvirt support for these releases is dropped.

• Improvements

  • qemu: Use PCI by default for RISC-V guests

    PCI support for RISC-V guests was already available in libvirt 5.1.0, but it required the user to opt-in by manually assigning PCI addresses: with this release, RISC-V guests will use PCI automatically when running against a recent enough (4.0.0+) QEMU release.

  • qemu: Advertise firmware autoselection in domain capabilities

    The firmware autoselection feature is now exposed in domain capabilities and management applications can query for accepted values, i.e. values that are accepted and for which libvirt found firmware descriptor files. Firmware Secure Boot support is also advertised.

  • Drop YAJL 1 support

    YAJL 2 is widely adopted and maintaining side by side support for two versions is unnecessary.

• Bug fixes

  • rpc: cleanup in virNetTLSContextNew

    Failed new gnutls context allocations in virNetTLSContextNew function results in double free and segfault. Occasional memory leaks may also occur.

  • virsh: various completers fixes

    There were some possible crashers, memory leaks, etc. which are now fixed.

  • qemu: Make hugepages work with memfd backend

    Due to a bug in command line generation libvirt did not honor hugepages setting with memfd backend.

  • Enforce ACL write permission for getting guest time & hostname

    Getting the guest time and hostname both require use of guest agent commands. These must not be allowed for read-only users, so the permissions check must validate "write" permission not "read".

v5.2.0 (2019-04-03)

• New features

  • Add Storage Pool Capabilities output

    Add support to list an enumerated list of supported Storage Pools via the virConnectGetCapabilities API when connected via a Storage Driver. Add support to get a more detailed list XML output Storage Pool Capabilities vis the virConnectGetStoragePoolCapabilites API.

  • qemu: Support virtio-{non-}transitional device models

    virtio-transitional and virtio-non-transitional model values were added to the QEMU driver for the following devices: disk , interface , filesystem , rng , vsock , memballoon , controller type scsi , controller type virtio-serial , input bus virtio type passthrough , hostdev type scsi_host . These new models can be used to give fine grained control over what virtio device version is presented to the guest.

  • qemu: Enable firmware autoselection

    Libvirt allows users to provide loader path for some time now. However, this puts some burden on users because they need to know what firmware meets their requirements. Now that QEMU ships firmware description files this burden can be moved onto libvirt. It is as easy as setting the firmware attribute in the os element (accepted values are bios and efi ). Moreover, libvirt automatically enables domain features needed for firmware it chooses.

  • snapshots: Add support for topological listings

    A new flag VIR_DOMAIN_SNAPSHOT_LIST_TOPOLOGICAL is available for the various snapshot listing APIs such as virDomainListAllSnapshots(). For drivers that support the flag, the listed snapshots are guaranteed to be sorted such that parents occur before children.

  • Xen: Add support for max grant frames setting

    Add support for Xen's max_grant_frames setting by adding a new xenbus controller type with a maxGrantFrames attribute. E.g. <controller type='xenbus' maxGrantFrames='64'/>

  • qemu: Add support for parallel migration

    With QEMU 4.0.0 libvirt can enable parallel migration which causes the memory pages to be processed in parallel by several threads and sent to the destination host using several connections at the same time. This may increase migration speed in case a single thread is unable to saturate the network link.

• Removed features

  • Drop support for Upstart and "Red Hat" init scripts

    Not a single one of the platforms we target still uses Upstart, and the Upstart project itself has been abandoned for several years now; the same is true for the "Red Hat" (really System V) init scripts, since RHEL 7 and later releases use systemd.

• Improvements

  • Report class information for PCI node device capability.

  • Split setup of IPv4 and IPv6 top level chain

    The requirement resulting from private chains improvement done in v5.1.0 was refined so that only tables from corresponding IP version are required. This means that if a network doesn't have IPv6 enabled then those tables are not required.

  • Don't default to building the QEMU driver

    Historically, the QEMU driver has been special in that it was enabled by default, with the option to explicitly opt-out of it; starting now, we're enabling it opportunistically if we detect that all requirements are available, just like we do with other drivers.

• Bug fixes

  • virt-host-validate: Fix IOMMU check on s390x

  • qemu: Allow creating pSeries guests with graphics and no USB mouse

    It's now possible to prevent libvirt from automatically adding a USB mouse to pSeries guests by including a USB tablet in the input XML: doing so is desiderable as using a tablet results in a much better user experience when working with GUIs.

  • qemu: Set $HOME and XGD variables for qemu:///system guests

    This avoids files being accidentally created under / or the guests not being able to start because they lack the necessary permissions to write to that location.

v5.1.0 (2019-03-04)

• New features

  • bhyve: Add support for additional command-line arguments

    The bhyve driver now supports passing additional command-line arguments to the bhyve process using the new <bhyve:commandline> element in domain configuration.

  • network: Support setting a firewalld "zone" for virtual network bridges

    All libvirt virtual networks with bridges managed by libvirt (i.e. those with forward mode of "nat", "route", "open", or no forward mode) will now be placed in a special firewalld zone called "libvirt" by default. The zone of any network bridge can be changed using the zone attribute of the network's bridge element.

  • bhyve: Support for ignoring unknown MSRs reads and writes

    A new <features> element <msrs unknown='ignore'/> was introduced and the bhyve driver supports it to control unknown Model Specific Registers (MSRs) reads and writes.

  • qemu: Add support for encrypted VNC TLS keys

    Use the password stored in the secret driver under the uuid specified by the vnc_tls_x509_secret_uuid option in qemu.conf.

  • Add storage pool namespace options

    Allow for adjustment of RBD configuration options via Storage Pool XML Namespace adjustments.

  • qemu: Add support for setting post-copy migration bandwidth

    Users can now limit the bandwidth of post-copy migration, e.g. via virsh migrate --postcopy-bandwidth .

• Improvements

  • Create private chains for virtual network firewall rules

    Historically firewall rules for virtual networks were added straight into the base chains. This works but has a number of bugs and design limitations. To address them, libvirt now puts firewall rules into its own chains. Note that with this change the filter , nat and mangle tables are required for both IPv4 and IPv6 .

  • Detect CEPH and GPFS as shared FS

    When starting a migration libvirt performs some sanity checks to make sure domain will be able to run on the destination. One of the requirements is that the disk has to either be migrated too or be accessible from a network filesystem. CEPH and GPFS weren't detected as a network filesystem.

  • Advertise network MTU via DHCP when specified

    If network MTU is set and the network has DHCP enabled, advertise the MTU in DHCP transaction too so that clients can adjust their link accordingly.

  • qemu: Allocate memory at the configured NUMA nodes from start

    Libvirt used to just start QEMU, let it allocate memory for the guest, and then use CGroups to move the memory to configured NUMA nodes. This is suboptimal as huge chunks of memory have to be moved. Moreover, this relies on ability to move memory later which is not always true. A change was made to set process affinity correctly from the start so that memory is allocated on the configured nodes from the beginning.

  • Support for newer Wireshark

    Adapt libvirt to use the more recent release requiring a source build configuration of libvirt --with-wireshark to upgrade to the more recent version.

  • Batch mode virsh and virt-admin parsing improvements

    When parsing a single-argument command_string in batch mode, virsh and virt-admin now permit newlines in addition to semicolons for splitting commands, and backslash-newline for splitting long lines, to be more like shell parsing.

• Bug fixes

  • qemu: Use CAP_DAC_OVERRIDE during QEMU capabilities probing

    By default, libvirt runs the QEMU process as qemu:qemu which could cause issues during probing as some features like AMD SEV might be inaccessible to QEMU because of file system permissions. Therefore, CAP_DAC_OVERRIDE is granted to overcome these for the purposes of probing.

  • storage: Add default mount options for fs/netfs storage pools

    Altered the command line generation for fs/netfs storage pools to add some default options. For Linux based systems, the options added are "nodev, nosuid, noexec". For FreeBSD based systems, the options added are "nosuid, noexec".

  • qemu: Allow use of PCI for RISC-V guests

    This works with QEMU 4.0.0+ only and is opt-in at the moment, since it requires users to manually assign PCI addresses, but is otherwise fully functional.

  • network: Fix virtual networks on systems using firewalld+nftables

    Because of the transitional state of firewalld's new support for nftables, not all iptables features required by libvirt are yet available, so libvirt must continue to use iptables for its own packet filtering rules even when the firewalld backend is set to use nftables. However, due to the way iptables support is implemented in kernels using nftables (iptables rules are converted to nftables rules and processed in a separate hook from the native nftables rules), guest networking was broken on hosts with firewalld configured to use nftables as the backend. This has been fixed by putting libvirt-managed bridges in their own firewalld zone, so that guest traffic can be forwarded beyond the host and host services can be exposed to guests on the virtual network without opening up those same services to the rest of the physical network. This means that host access from virtual machines is no longer controlled by the firewalld default zone (usually "public"), but rather by the new firewalld zone called "libvirt" (unless configured otherwise using the new zone attribute of the network bridge element).

  • qemu: Fix i6300esb watchdog hotplug on Q35

    Ensure that libvirt allocates a PCI address for the device so that QEMU did not default to an address that would not allow for device hotplug.

  • lxc: Don't reboot host on virDomainReboot

    If the container is really a simple one (init is just bash and the whole root is passed through) then virDomainReboot and virDomainShutdown would reboot or shutdown the host. The solution is to use different method to reboot or shutdown the container in that case (e.g. signal).

  • rpc: Various stream fixes

    One particular race was fixed, one locking problem and error reporting from streams was made better.

  • qemu: Fix guestfwd hotplug/hotunplug

    Fixed the generation of the guestfwd hotplug/unplug command sent to QEMU to match the syntax used when creating the initial command line.

  • qemu: Forbid CDROMs on virtio bus

    Attempting to create an empty virtio-blk drive or attempting to eject it results into an error. Forbid configurations where users would attempt to use CDROMs in virtio bus.

  • qemu: Use 'raw' for 'volume' disks without format

    Storage pools might want to specify format of the image when translating the volume thus libvirt can't add any default format when parsing the XML. Add an explicit format when starting the VM and format is not present neither by user specifying it nor by the storage pool translation function.

  • qemu: Assume 'raw' default storage format also for network storage

    Post parse callback adds the 'raw' type only for local files. Remote files can also have backing store (even local) so we should do this also for network backed storage.

  • qemu: Fix block job progress reporting and advocate for READY event

    In some cases QEMU can get to 100% and still not reach the synchronised phase. Initiating a pivot in that case will fail. Therefore it is strongly advised to wait for VIR_DOMAIN_BLOCK_JOB_READY event which does not suffer from this problem.

  • qemu: Don't format image properties for empty drive

    If a -drive has no image, then formatting attributes such as cache, readonly, etc. would cause errors to be reported from QEMU. This was fixed by not supplying the attributes for devices without an image.

  • External snapshot metadata redefinition is fixed

    Attempting to use VIR_DOMAIN_SNAPSHOT_CREATE_REDEFINE to reinstate the metadata describing an external snapshot created earlier for an offline domain no longer fails.

v5.0.0 (2019-01-15)

• New features

  • Xen: Add support for openvswitch

    The libxl driver now supports virtual interfaces that connect to an openvswitch bridge, including interfaces with VLAN tagging and trunking configuration.

  • qemu: Report whether KVM nesting is available

    Running nested KVM guests requires specific configuration steps to be performed on the host; libvirt will now report in the host capabilities whether KVM nesting support is available.

• Removed features

  • Drop UML driver

    The UML driver was unmaintained and not tested for quite some time now. Worse, there is a bug that causes it to deadlock on some very basic operations (e.g. dumping domain XML). These facts make us believe no one uses it.

• Improvements

  • qemu: Add support for ARMv6l guests

  • Support more NVDIMM configuration options

    Introduce more configuration options. For the source element, add the 'alignsize' and 'pmem' subelements. For the target element, add the 'readonly' subelement.

  • cpu: Add support for "stibp" x86_64 feature

    Add cpu flag stibp (Single Thread Indirect Branch Predictors) to prevent indirect branch predictions from being controlled by the sibling Hyperthread.

  • libxl: Handle external domain destroy

    Historically, if a domain was destroyed using xl rather than through libvirt APIs, libvirt would not be aware of the fact and keep considering it as running. This is no longer the case.

  • Start selecting the first available DRI device for OpenGL operations

    If OpenGL support is needed (either with SPICE gl enabled or with egl-headless), libvirt is now able to pick the first available DRI device for the job. At the same time, this improvement is also a bugfix as it prevents permission-related issues with regards to our mount namespaces and the default DRI render node's permissions which would normally prevent QEMU from accessing such a device.

  • qemu: Add support for postcopy-requests migration statistics

    The virDomainJobInfo can get number page requests received from the destination host during post-copy migration.

• Bug fixes

  • lxc: Don't forbid interfaces with type=direct

    Such interfaces are supported by lxc and should be allowed.

  • qemu: Fully clean up RNG devices on detach

    Some RNG device types, such as those using EGD, might need extra clean up on the host in addition to removing the guest-side device.

v4.10.0 (2018-12-03)

• New features

  • qemu: Add Hyper-V PV IPI and Enlightened VMCS support

    The QEMU driver now has support for Hyper-V PV IPI and Enlightened VMCS for Windows and Hyper-V guests.

  • qemu: Added support for PCI devices on S390

    PCI addresses can now include the new zpci element which contains uid (user-defined identifier) and fid (PCI function identifier) attributes and makes the corresponding devices usable by S390 guests.

  • Support changing IOThread polling parameters for a live guest

    Introduced virDomainSetIOThreadParams which allows dynamically setting the IOThread polling parameters used by QEMU to manage the thread polling interval and the algorithm for growth or shrink of the polling time. The values only affect a running guest with IOThreads. The guest's IOThread polling values can be viewed via the domain statistics.

  • Xen: Add support for PVH

    The libxl driver now supports Xen's PVH virtual machine type. PVH machines are enabled with the new "xenpvh" OS type, e.g. <os><type>xenpvh</type></os>

  • qemu: Added support for CMT (Cache Monitoring Technology)

    Introduced cache monitoring using the monitor element in cachetune for vCPU threads. Added interfaces to get and display the cache utilization statistics through the command 'virsh domstats' via the virConnectGetAllDomainStats API.

  • qemu: Add support for nested HV for pSeries guests

    Nested HV support makes it possible to run nested (L2) guests with minimal performance penalty when compared to regular (L1) guests on ppc64 hardware.

• Bug fixes

  • Xen: Handle soft reset shutdown event

    The pvops Linux kernel uses soft reset to handle the crash machine operation. The libxl driver now supports the soft reset shutdown event, allowing proper crash handling of pvops-based HVM domains.

v4.9.0 (2018-11-04)

• New features

  • util: Add cgroup v2 support

    cgroup v2 support has been implemented in libvirt, with both "unified" (v2 only) and "hybrid" (v2 + v1) setups being usable; existing "legacy" (v1 only) setups will keep working.

  • qemu: Add vfio AP support

    The QEMU driver now has support to passthrough adjunct processors into QEMU guests on S390.

• Improvements

  • rpc: Make 'genprotocol' output reproducible

    This is another step towards making libvirt builds fully reproducible.

• Bug fixes

  • security: Fix permissions for UNIX sockets

    Since 4.5.0, libvirt is using FD passing to hand sockets over to QEMU, which in theory removes the need for them to be accessible by the user under which the QEMU process is running; however, other processes such as vdsm need to access the sockets as well, which means adjusting permissions is still necessary.

  • cpu_map: Add Icelake model definitions

    These CPU models will be available in the upcoming 3.1.0 QEMU release.

  • util: Properly parse URIs with missing trailing slash

    Some storage URIs were not parsed correctly, in which case libvirt ended up emitting XML that it would then refuse to parse back.

v4.8.0 (2018-10-01)

• New features

  • Xen: Support PM Suspend and Wakeup

    The libxl driver now supports the virDomainPMSuspendForDuration and virDomainPMWakeup APIs.

• Removed features

  • Xen: Drop support for Xen 4.4 and 4.5

    Xen 4.4 and 4.5 are no longer supported by the Xen community. Drop support for these older versions and require Xen >= 4.6.

  • nwfilter: Disallow binding creation in session mode

    Ensure that a filter binding creation is not attempted in session mode and generates a proper error message.

• Improvements

  • qemu: Retrieve guest hostname through QEMU Guest Agent command

    QEMU is now able to retrieve the guest hostname using a new QEMU-GA command called 'guest-get-host-name'. Virsh users can execute 'domhostname' for QEMU driver for domains configured to use the Guest Agent.

  • virsh: Implement vsh-table in virsh and virsh-admin

    The new API fixes problems with table-alignment, making the tables more readable and deals with unicode.

• Bug fixes

  • storage: Allow inputvol to be encrypted

    When creating a storage volume based on another volume, the base input volume is allowed to be encrypted.

  • virsh: Require explicit --domain for domxml-to-native

    The --domain option for domxml-to-native virsh command has always been documented as required, but commit v4.3.0-127-gd86531daf2 accidentally made it optional.

  • lxc_monitor: Avoid AB / BA lock race

    A deadlock situation could occur when autostarting a LXC domain 'guest' due to two threads attempting to take opposing locks while holding opposing locks (AB BA problem).

v4.7.0 (2018-09-03)

• New features

  • storage: add storage pool iscsi-direct

    Introduce a new storage pool backend that uses libiscsi instead of iscsiadm. It support basic pool operations: checkPool and refreshPool.

  • Add support for MBA (Memory Bandwidth Allocation technology)

    Domain vCPU threads can now have allocated some parts of host memory bandwidth by using the memorytune element in cputune .

  • qemu: Add support for RISC-V guests

    riscv32 and riscv64 guest architectures are now supported.

• Improvements

  • qemu: Add ccw support for vhost-vsock

    Support the vhost-vsock-ccw device on S390.

  • qemu: Make default machine type independent of QEMU

    We can't control whether or not QEMU will change its default machine type in the future, or whether downstream distributions will decide to compile out some machine types, so our only option to provide a predictable behavior is taking care of the default ourselves; management applications and users are encouraged to explicitly pick a machine type when creating new guests.

  • apparmor: Various improvements

    Rules have been added to deal with a number of scenarios that didn't work correctly.

• Bug fixes

  • esx: Truncate CPU model name

    Some CPU model names are too long to be stored into the corresponding property, and should be explicitly truncated to avoid unexpected behavior in users of the virNodeGetInfo() API such as virsh nodeinfo .

  • utils: Remove arbitrary limit on socket_id/core_id

    Both values were assumed to be smaller than 4096, but in fact they are entirely hardware-dependent and there have been reports of machines presenting much bigger values, preventing libvirt from working correctly; all such limits have now been removed.

v4.6.0 (2018-08-06)

• New features

  • qemu: Implement the HTM pSeries feature

    Users can now decide whether HTM (Hardware Transactional Memory) support should be available to the guest.

  • qemu: Enable VNC console for mediated devices

    Host devices now support a new attribute 'display' which can be used to turn on frame buffer rendering on a vgpu mediated device instead of on an emulated GPU, like QXL.

• Improvements

  • qemu: Introduce a new video model of type 'none'

    Introduce a new video model type that disables the automatic addition of a video device to domains with 'graphics' specified in their XML. This can be useful with GPU mediated devices which can serve as the only rendering devices within the guest.

  • virsh: Add --alias to attach-disk and attach-interface commands

    Add option --alias to set customized device alias name when using attach-disk or attach-interface commands.

  • virsh: Support usb and sata address to attach-disk

    Usb or sata address could be used when attach-disk with --address. For example, use usb address as usb:<bus>.<port>, use sata address as <controller>.<bus>.<unit>.

v4.5.0 (2018-07-02)

• New features

  • qemu: Provide TPM emulator support

    Support QEMU's TPM emulator based on swtpm. Each QEMU guest gets its own virtual TPM.

  • bhyve: Support specifying guest CPU topology

    Bhyve's guest CPU topology could be specified using the <cpu><topology ../></cpu> element.

  • qemu: Add support for extended TSEG size

    Support specifying extended TSEG size for SMM in QEMU.

  • qemu: Add support for SEV guests

    SEV (Secure Encrypted Virtualization) is a feature available on AMD CPUs that encrypts the guest memory and makes it inaccessible even to the host OS.

• Removed features

  • Remove support for qcow/default encrypted volumes

    Disallow using a qcow encrypted volume for the guest and disallow creation of the qcow or default encrypted volume from the storage driver. Support for qcow encrypted volumes has been phasing out since QEMU 2.3 and by QEMU 2.9 creation of a qcow encrypted volume via qemu-img required usage of secret objects, but that support was never added to libvirt.

  • Make GnuTLS mandatory

    Building without GnuTLS is no longer possible.

  • qemu: Remove allow_disk_format_probing configuration option

    The option represented a security risk when used with malicious disk images, so users were recommended against enabling it; with this release, it's been removed altogether.

• Improvements

  • capabilities: Provide info about host IOMMU support

    Capabilities XML now provide information about host IOMMU support.

  • virsh: Add --all to domblkinfo command

    Alter the domblkinfo command to add the option --all in order to display the size details of each domain block device from one command in a output table.

  • qemu: Allow concurrent access to monitor and guest agent

    Historically libvirt prevented concurrent accesses to the qemu monitor and the guest agent. Therefore two independent calls (one querying the monitor and the other querying guest agent) would serialize which hurts performance. The code was reworked to allow two independent calls run at the same time.

  • qemu: Allow configuring the page size for HPT pSeries guests

    For HPT pSeries guests, the size of the host pages used to back guest memory and the usable guest page sizes are connected; the new setting can be used to request that a certain page size is available in the guest.

  • Add support to use an raw input volume for encryption

    It is now possible to provide a raw input volume as input for to generate a luks encrypted volume via either virsh vol-create-from or virStorageVolCreateXMLFrom.

  • qemu: Add support for vsock hot (un)plug and cold (un)plug

  • qemu: Add support for NBD over TLS

    NBD volumes can now be accessed securely.

  • qemu: Implement FD passing for Unix sockets

    Instead of having QEMU open the socket and then connecting to it, which is inherently racy, starting with QEMU 2.12 we can open the socket ourselves and pass it to QEMU, avoiding race conditions.

  • virsh: Introduce --nowait option for domstat command

    When this option is specified, virsh will try to fetch the guest stats but abort instead of stalling if they can't be retrieved right away.

• Bug fixes

  • qemu: Fix a potential libvirtd crash on VM reconnect

    Initialization of the driver worker pool needs to come before libvirtd trying to reconnect to all machines, since one of the QEMU processes migh have already emitted events which need to be handled prior to us getting to the worker pool initialization.

  • qemu: Fix domain resume after failed migration

    Recent versions of QEMU activate block devices before the guest CPU has been started, which makes it impossible to roll back a failed migration. Use the late-block-activate migration capability if supported to avoid the issue.

  • vmx: Permit guests to have an odd number of vCPUs

    An odd number of vCPUs greater than 1 was forbidden in the past, but current versions of ESXi have lifted that restriction.

v4.4.0 (2018-06-04)

• New features

  • bhyve: Support locking guest memory

    Bhyve's guest memory may be wired using the <memoryBacking><locked/></memoryBacking> element.

  • qemu: Provide VFIO channel I/O passthrough support

    Support passthrough devices that use channel I/O based mechanism in a QEMU virtual machine.

  • qemu: Add support for migration of VMs with non-shared storage over TLS

    It's now possible to use the VIR_MIGRATE_TLS flag together with VIR_MIGRATE_NON_SHARED_DISK. The connection is then secured using the TLS environment which is setup for the migration connection.

  • Add support for VM Generation ID

    The VM Generatation ID exposes a 128-bit, cryptographically random, integer value identifier, referred to as a Globally Unique Identifier (GUID) to the guest in order to notify the guest operating system when the virtual machine is executed with a different configuration. Add a new domain XML processing and a domain capabilities feature.

  • Introduce virDomainDetachDeviceAlias

    This new API enables users to detach device using only its alias.

  • Introduce new virConnectCompareHypervisorCPU and virConnectBaselineHypervisorCPU APIs

    Unlike the old virConnectCompareCPU and virConnectBaselineCPU APIs, both new APIs consider capabilities of a specific hypervisor.

  • Introduce SCSI persistent reservations support

    The QEMU driver gained support for qemu-pr-helper which enables guests to issue SCSI commands for persistent reservation.

  • qemu: Implement multiple screen support for virDomainScreenshot

    While the virDomainScreenshot API supported multihead video cards, the implementation was missing. But now that QEMU implemented it libvirt has done as well.

  • qemu: add support for vhost-vsock-device

    A new vsock device was introduced, allowing communication between the guest and the host via the AF_VSOCK family.

• Improvements

  • qemu: Add support for OpenGL rendering with SDL

    Domains using SDL as a graphics backend will now be able to use OpenGL accelerated rendering.

  • qemu: Add support for 'output' audio codec

    Support QEMU's 'hda-output' codec advertising only a line-out for ich6 and ich9 sound devices.

  • virsh: Enhance event name completion

    Implement event name completion for some commands (e.g. event, secret-event, pool-event and nodedev-event)

v4.3.0 (2018-05-02)

• New features

  • qemu: Add support for the pcie-to-pci-bridge controller

    Pure PCIe guests such as x86_64/q35 and aarch64/virt will now add this controller when traditional PCI devices are in use.

  • Xen: Support setting CPU features for host-passthrough model

    The CPU model presented to Xen HVM domains is equivalent to libvirt's host-passthrough model, although individual features can be enabled and disabled via the cpuid setting. The libvirt libxl driver now supports enabling and disabling individual features of the host-passthrough CPU model.

• Removed features

  • Xen: Drop the legacy xend-based driver

    The xm/xend toolstack was deprecated in Xen 4.2 and removed from the Xen sources in the 4.5 development cycle. The libvirt driver based on xend is now removed from the libvirt sources.

• Improvements

  • qemu: Support hot plug and hot unplug of mediated devices

    Libvirt now allows mediated devices to be hot plugged and hot unplugged from a guest rather than reporting an error that this isn't supported. In fact, kernel has been supporting this since 4.10.

• Bug fixes

  • Improve handling of device mapper targets

    When starting a domain with a disk backed by a device mapper volume libvirt also needs to allow the storage backing the device mapper in CGroups. In the past kernel did not care, but starting from 4.16 CGroups are consulted on each access to the device mapper target.

v4.2.0 (2018-04-01)

• New features

  • Support building with Python 3

    Python is required to build libvirt, and up until now only Python 2 could be used as an interpreter. All scripts used during build have now been made compatible with Python 3, which means both major releases of the language are fully supported.

  • qemu: Provide ccw address support for graphics and input devices

    Support the virtio-gpu-ccw device as a video device and virtio-{keyboard, mouse, tablet}-ccw devices as input devices on S390.

• Improvements

  • qemu: Add logging of guest crash information on S390

    On S390, when the guest crashes and QEMU exposes the guest crash information, log the relevant data to the domain log file.

  • qemu: use arp table of host to get the IP address of guests

    Find IP address of a VM by arp table on hosts. If someone customizing IP address inside VM, it will be helpful.

  • Xen: Remove hard-coded scheduler weight

    The libxl driver was accidentally hard-coding the per-domain scheduler weight to 1000, silently ignoring any user-provided <shares> in <cputune> . The driver now honors <shares> , and defers setting a default value to Xen. Note that the Xen default is 256, so any domains started after this improvement will have one fourth the shares of previously started domains. If all domains must have equal CPU shares, administrators must manually set the weight of previously started domains to 256, or restart them.

• Bug fixes

  • qemu: TLS migration now enforces use of TLS for the NBD connection

    When the VIR_MIGRATE_TLS flag was used with the migration API libvirt did not ensure that the NBD connection was using TLS as well. The code now rejects such migration as the TLS transport for NBD is not ready yet, but prevents a false sense of security that TLS would be used. The support TLS for NBD will be added soon.

v4.1.0 (2018-03-05)

• New features

  • Added support for CAT (Cache allocation Technology)

    Domain vCPU threads can now have allocated some parts of host cache using the cachetune element in cputune .

  • Allow opening secondary drivers

    Up until now it was possible to connect to only hypervisor drivers (e.g. qemu:///system, lxc:///, vbox:///system, and so on). The internal drivers (like network driver, node device driver, etc.) were hidden from users and users could use them only indirectly. Starting with this release new connection URIs are accepted. For instance network:///system, storage:///system and so on.

  • virtlogd, virtlockd: Add support for admin protocol

    These two daemons now support admin protocol through which some admin info can be gathered or some configuration tweaked on the fly.

• Improvements

  • virsh: Enhance bash completion

    Implement more bash completions so that basic libvirt objects can be auto-completed (e.g. networks, interfaces, NWFilters, and so on).

  • qemu: Use VIR_ERR_DEVICE_MISSING for various hotplug/detach messages

  • qemu: Allow showing the dump progress for memory only dump

    Alter the QEMU dump-guest-memory command processing to check for and allow asynchronous completion which then allows for the virsh dump --memory-only --verbose command to display percent completion data.

  • conf: add support for setting Chassis SMBIOS data fields

  • libxl: add support for setting clock offset and adjustment

  • Make port allocator global

    Up until now each driver had their own port allocator module. This meant that info on port usage was not shared. Starting with this release, the port allocator module is made global and therefore drivers allocate ports from global pool.

  • Fixed some compiler warnings that appear with GCC 8

• Bug fixes

  • qemu: Check for unsafe migration more thoroughly

    If a domain disk is stored on local filesystem (e.g. ext4) but is not being migrated it is very likely that domain is not able to run on destination. Regardless of share/cache mode.

  • qemu: Fix updating device with boot order

    Starting with 3.7.0 release updating any device with boot order would fail with 'boot order X is already used by another device' while in fact it was the very same device.

  • virlog: determine the hostname on startup CVE-2018-6764

    At later point it might not be possible or even safe to use getaddrinfo(). It can in turn result in a load of NSS module which can even be loaded from unsage guest filesystem and thus escape the confinment of its container.

  • qemu: Rework vCPU statistics fetching

    Fetching vCPU statistics was very expensive because it lead to waking up vCPU threads in QEMU and thus it degraded performance. The code was reworked so that fetching statistics does not wake up halted vCPUs.

  • qemu: unlink memory backing file on domain shutdown

    Depending on the filesystem where domain memory is stored, some files might have been left behind. This is not a problem on hugetlbfs, but it is a problem on regular filesystems like ext4.

  • qemu: Fix shutting down domains in parallel

    If multiple domains were being shut down in parallel, libvirtd might have deadlocked.

  • nodedev: Update PCI mdev capabilities dynamically

    PCI devices may have other nested capabilities, like SRIOV and mdev which depend on the device being plugged into the native vendor driver. However, in case such a device is directly assigned to a guest using VFIO driver, the device will naturally lose these capabilities and libvirt needs to reflect that.

v4.0.0 (2018-01-19)

• New features

  • tools: Provide bash completion support

    Both virsh and virt-admin now implement basic bash completion support.

  • qemu: Refresh capabilities on host microcode update

    A microcode update can cause the CPUID bits to change; therefore, the capabilities cache should be rebuilt when such an update is detected on the host.

  • lxc: Set hostname based on container name

• Improvements

  • CPU frequency reporting improvements

    The CPU frequency will now be reported by virsh nodeinfo and other tools for s390 hosts; at the same time; CPU frequency has been disabled on aarch64 hosts because there's no way to detect it reliably.

  • libxl: Mark domain0 as persistent

  • Xen: Add support for multiple IP addresses on interface devices

  • qemu: Add support for hot unplugging redirdev device

• Bug fixes

  • qemu: Enforce vCPU hotplug granularity constraints

    QEMU 2.7 and newer don't allow guests to start unless the initial vCPUs count is a multiple of the vCPU hotplug granularity, so validate it and report an error if needed.

v3.10.0 (2017-12-04)

• New features

  • conf: Support defining distances between virtual NUMA cells

    A NUMA hardware architecture supports the notion of distances between NUMA cells. This can now be specified using the <distances> element within the NUMA cell configuration. Drivers which support this include Xen and QEMU.

  • Xen: Support defining vNUMA topology

    Xen now supports defining a virtual NUMA topology for VMs, including specifying distances between NUMA cells.

  • qemu: Add the ability to configure HPT resizing for pSeries guests

    The user can now decide whether HPT (Hash Page Table) resizing should be enabled, disabled or required instead of leaving it up to hypervisor defaults and negotiation between the guest and the host.

  • qemu: Add vmcoreinfo feature

    Starting with QEMU 2.11, the guest can save kernel debug details when this feature is enabled and the kernel supports it. It is useful to process kernel dump with KASLR enabled, and also provides various kernel details to crash tools.

  • conf: Move the auth and encryption definitions to disk source

    Allow parsing and formatting of the auth and encryption sub-elements to be a child of the source element. This will allow adding an auth sub-element to a backingStore or mirror elements as a means to track specific authentication and/or encryption needs.

• Improvements

  • vbox: Add VirtualBox 5.2 support

  • vbox: Add support for configuring storage controllers

    The VirtualBox driver now supports the <controller> element in the domain XML for configuring storage controllers in VBOX VMs. Additionally, libvirt's domain XML schema was updated to allow optional model attribute for <controller type='ide'> which is used by the VBOX driver to set the IDE controller model to be one of 'piix4', 'piix4' (default), or 'ich6'. Finally, with this change dumpxml generates <controller> elements that correspond to current VBOX VM storage controller configuration.

  • vbox: Add support for attaching empty removable disks

    The VirutalBox driver now supports adding CD-ROM and floppy disk devices that do not have the disk source specified. Previously such devices were silently ignored.

  • vbox: Add support for attaching SAS storage controllers

    In VirtualBox, SCSI and SAS are distinct controller types whereas libvirt does not make such distinction. Therefore, the VBOX driver was updated to allow attaching SAS controllers via <controller type='scsi' model='lsisas1068'> element. If there are both SCSI and SAS controllers present in the VBOX VM, the domain XML can associate the disk device using the <address> element with the controller attribute, and optionally, set the port via unit attribute.

  • qemu: Generate predictable paths for qemu memory backends

    In some cases management applications need to know paths passed to memory-backend-file objects upfront. Libvirt now generates predictable paths so applications can prepare the files if they need to do so.

  • Shareable disks work properly with recent qemu

    Recent qemu versions added image locking to avoid potential corruption of disk images. This broke shareable disks with libvirt since the feature was turned on by default in qemu. Libvirt now enables sharing of those disks in qemu so that the image locking is not applied in that case. Additionally libvirt now checks that shareable disks have supported format (raw) to avoid metadata corruption.

  • Improve serial console behavior on non-x86 architectures

    ppc64, aarch64 and s390x guests were treating the <serial> and <console> elements differently from x86, in some cases presenting misleading information to the user. The behavior is now consistent across all architectures and the information reported is always accurate.

• Bug fixes

  • vbox: Do not ignore failures to attach disk devices when defining

    The define now fails and reports an error if any of the controller or disk devices specified in the domain XML fail to attach to the VirtualBox VM.

  • vbox: Fix dumpxml to always output disk devices

    The VirtualBox driver was ignoring any disk devices in dumpxml output if there was a SAS storage controller attached to the VM.

  • vbox: Fix dumpxml to always generate valid domain XML

    When a VirtualBox VM has multiple disks attached, each to a different storage controller that uses 'sd' prefix for block device names e.g. one disk attached to SATA and one to SCSI controller, it no longer generates XML where both would have 'sda' device name assigned. Instead it properly assigns 'sda' and 'sdb' to those disks in the order of appearance.

  • Securely pass iSCSI authentication data

    Rather than supplying the authentication data as part of the iSCSI URL for a disk or host device, utilize the encrypted secret object to securely pass the authentication data.

v3.9.0 (2017-11-02)

• New features

  • Add capability to allow hot (un)plug of a domain watchdog device

  • Allow users to set device aliases

    Users can set aliases to domain devices and thus identify them easily.

  • qemu: Support multiqueue for virtio-blk

    Multiqueue support for virtio-blk has been available in QEMU ever since 2.7.0, and now libvirt guests can enable it.

  • Add virDomainSetLifecycleAction API

    Provided a new API to allow dynamic guest lifecycle control for guest reactions to poweroff, restart, or crash type events related to the domain XML on_poweroff , on_reboot , and on_crash elements. The virsh set-lifecycle-action command was created to control the actions.

  • qemu: Allow cold(un)plugging and hot(un)plugging input devices

  • net: Implement QoS for vhostuser

• Improvements

  • Allow a logical volume to be create using LUKS

    A logical volume may be created using an encryption element using "luks" format. This does require a previously created secret to store the passphrase used to encrypt the volume Adding the volume to a domain can then either provide the secret or allow the consumer in the guest to provide the passphrase in order to decrypt the volume.

  • net: Ignore auto-generated MAC address when detaching an interface

    If the MAC address has not been specified by the user, libvirt will try and fill in the gaps by generating one; however, for some error paths that led to some confusing error messages, so when an auto-generated MAC address is specified the error message will not include the auto-generated MAC.

  • net: Enable MAC address lookup for virDomainInterfaceStats

  • apparmor: Several improvements

    Changes include permitting access to data about USB devices and dnsmasq instances, allowing spaces in guest names and many more.

  • cpu: Use CPU information obtained from QEMU when possible

    Recent QEMU versions can expose information about which CPU models are available and usable on the host; libvirt will now make use of such information whenever possible.

  • hyperv: Various improvements

    The error reported when clients can't connect to Hyper-V has been made more descriptive, and memory limits for guests are now mapped to more appropriate libvirt equivalents.

  • qemu: Report QEMU error on failed migration

    Instead of reporting a generic error, ask QEMU for a more detailed and thus hopefully more helpful one.

  • vbox: Implement autoport for RDP

    libvirt will now obtain the (dynamically allocated) RDP port number from VirtualBox itself, avoiding conflicts between multiple guests wanting to use RDP at the same time.

  • qemu: Allow rotation of small logs

    On a host where numerous unique instances are executed per day, it's quite possible that, even though each of the single log files are fairly small, collectively the quantity and volume may add tens of thousands of log files to the /var/log/libvirt/qemu/ directory. Removing the constraints that log have to be bigger than 100 KiB before they can be rotated solves the issue.

• Bug fixes

  • Fix swapped interface statistics and QoS

    Due to internal implementation, reported statistics for some types of interfaces were swapped (RX appeared in TX and vice versa). Similarly, QoS was set in reversed way.

  • Properly resize local LUKS encrypted volume

    Resizing of a local LUKS encrypted volume will now use qemu-img to resize the volume. This will require configuring a secret for the LUKS encrypted volume.

  • qemu: Reserve PCI addresses for implicit i440fx devices

    Failing to do so causes the addresses to be considered usable by libvirt, which means they could be assigned to more than one device resulting in the guest failing to start.

  • spec: Restart libvirtd only at the end of the upgrade process

    Use %posttrans to make sure libvirtd is not restarted before all other components, such as the library itself and storage / hypervisor drivers, have already been upgraded.

• Security

  • qemu: Ensure TLS clients always verify the server certificate

    While it's reasonable to turn off client certificate validation, as setting it up can be non-trivial, clients should always verify the server certificate to avoid MITM attacks. However, libvirt was using the same knob to control both checks, leading to CVE-2017-1000256 / LSN-2017-0002.

v3.8.0 (2017-10-04)

• New features
  • qemu: Added support for cold-(un)plug of watchdog devices
  • qemu: Added support for setting IP address os usernet interfaces
  • qemu: Added support for Veritas Hyperscale (VxHS) block devices
  • storage: Added new events for pool-build and pool-delete
• Improvements

  • qemu: Set DAC permissions properly for spice rendernode

    When a rendernode path is set for SPICE GL on qemu:///system , we now correctly set DAC permissions on the device at VM startup. This is the last remaining hurdle to let SPICE GL work for qemu:///system without any external host changes.

  • nodedev: Add switchdev offload query to NIC capabilities

    Allow querying the NIC interface capabilities for the availability of switchdev offloading (also known as kernel-forward-plane-offload).

  • New CPU models for AMD and Intel

    AMD EPYC and Intel Skylake-Server CPU models were added together with their features

  • Improve long waiting when saving a domain

    While waiting for a write to disk to be finished, e.g. during save, even simple operations like virsh list would be blocking due to domain lock. This is now resolved by unlocking the domain in places where it is not needed.

• Bug fixes

  • Proper units are now used in virsh manpage for dom(mem)stats

    Previously the documentation used multiples of 1000, but now it is fixed to use multiples of 1024.

  • qemu: Fix error reporting when disk attachment fails

    There was a possibility for the actual error to be overridden or cleared during the rollback.

  • qemu: Fix assignment of graphics ports after daemon restart

    This could be seen with newer kernels that have bug regarding SO_REUSEADDR. After libvirtd was restarted it could assign already used address to new guests which would make them fail to start. This is fixed by marking used ports unavailable when reconnecting to running QEMU domains.

  • Fix message decoding which was causing a very strange bug

    When parsing an RPC message with file descriptors was interrupted and had to restart, the offset of the payload was calculated badly causing strange issues like not being able to find a domain that was not requested.

v3.7.0 (2017-09-04)

• New features

  • qemu: Add managedsave-edit commands

    Using managedsave-dumpxml, managedsave-define and managedsave-edit commands, now we can dump and edit the XML configuration of domain which has managedsave image.

  • qemu: Add migrate-getmaxdowntime command

    Currently, the maximum tolerable downtime for a domain being migrated is write-only from libvirt, via migrate-setmaxdowntime. This implements a complementary migrate-getmaxdowntime command

  • bhyve: Support autoport for VNC ports

    It's no longer necessary to explicitly specify VNC port for the bhyve guests. With the autoport feature it will be allocated automatically. Please refer to the bhyve driver documentation for examples.

  • qemu: Added support for setting heads of virtio GPU

  • qemu: Added support to configure reconnect timeout for chardev devices

    When you have a TCP or UNIX chardev device and it's connected somewhere you can configure reconnect timeout if the connection is closed.

• Improvements

  • qemu: Report a clear error when dropping a VM during startup

    "Failed to load config for domain 'DOMNAME'" is now reported if a VM config can't be parsed for some reason, and thus provides a clear indication for users (and devs).

  • apparmor: Update for QEMU 2.10 compatibility

    Starting with QEMU 2.10, disk images and NVRAM files get automatically locked to prevent them from being corrupted; however, file locking needs to be explicitly allowed through virt-aa-helper or AppArmor will reject the requests and the guest will not be able to run.

  • virsh: List Unix sockets in 'domdisplay' output

    VNC and SPICE graphics can use Unix sockets instead of TCP/IP sockets as connection endpoints, but such a configuration was not handled correctly by virsh domdisplay , causing the respective endpoints to be missing from the output.

  • qemu: Don't check whether offline migration is safe

    Since offline migration only copies the guest definition to the destination host, data corruption is not a concern and the operation can always be performed safely.

  • virt-host-validate: Fix IOMMU detection on ppc64

• Bug fixes

  • qemu: Better support for international domain names (with wide characters)

    There were some issues with multi-byte domains getting lost on daemon restart due to truncation, so the code now handles multi-byte names a bit better.

  • qemu: Support long domain names with namespaces

    Domains with extremely long names would fail to start due to temporary namespace paths being created with the whole name. The path is now generated with shortened name instead.

  • qemu: Tolerate missing emulator binary during libvirtd restart

    For some time libvirt required qemu capabilities being present when parsing VM configs during startup. As a side effect VM configs would fail to parse and thus vanish, if the emulator binary would be uninstalled or broken. Libvirt now tolerates when capabilities are missing during startup.

  • qemu: Prevent pSeries guests from disappearing in some situations

    pSeries guest would disappear if any of the host devices they were configured to use was not available during libvirtd startup, which could easily happen for SR-IOV Virtual Functions. This scenario is now handled correctly.

  • qemu: Honor <on_reboot/> setting

    The setting was accepted by the parser, but not actually implemented.

  • Fix --verbose option for all daemons

    Since v3.0.0, the option had been ignored by all libvirt daemons ( libvirtd , virtlogd and virtlockd ); it's now working as intended once again.

v3.6.0 (2017-08-02)

• New features

  • hyperv: Implement virDomainSetMemory and virDomainSendKey APIs

  • qemu: Support multiple PHBs for pSeries guests

    pSeries guests can now have multiple PHBs (PCI Host Bridges), which show up as separate PCI domains in the guest. To create additional PHBs, simply add PCI controllers with model pci-root to the guest configuration.

  • qemu: Isolate hostdevs on pSeries guests

    To enable better error reporting and recovery, unrelated hostdevs will now be automatically isolated on pSeries guests by placing them on separate PHBs (PCI Host Bridges).

• Improvements

  • qemu: platform serial devices can now use chardev features

    QEMU VMs that depend on platform serial devices can now use QEMU's -chardev option, which enables access to advanced features like log file configuration. This applies to the default serial devices for arm, aarch64, and some ppc configurations.

  • Require use of GCC 4.4 or Clang compilers

    We only ever test libvirt with GCC or Clang (which provides a GCC compatible compilation environment). Between them, these compilers cover every supported operating system platform, including Windows.

  • qemu: shared disks with directsync cache should be safe for migration

    At present shared disks can be migrated with either readonly or cache=none . But cache=directsync should be safe for migration, because both cache=directsync and cache=none don't use the host page cache, and cache=direct write through qemu block layer cache.

  • Handle hotplug change on VLAN configuration using OVS

    Libvirt was taught to handle VLAN change for running OVS interface.

• Bug fixes

  • qemu: Use vCPU 'node-id' property and pass it back to qemu

    vCPU properties gathered from query-hotpluggable-cpus need to be passed back to QEMU. As QEMU did not use the node-id property until now and libvirt forgot to pass it back properly (it was parsed but not passed around) we did not honor this.

  • Miscellaneous stream fixes

    After introducing sparse stream features there were still some known bugs left. Those are fixed in this release.

  • qemu: Miscellaneous domain NS fixes

    Libvirt starts qemu domains in separate Linux namespaces for a while now. However, there were still some bugs lingering. For instance libvirt did not know how to handle file based bind mounts.

  • Various CPU driver improvements

    There were some minor bugs when using 'host-model' CPU.

v3.5.0 (2017-07-04)

• New features

  • qemu: Add support for loadparm for a boot device

    Add an optional boot parameter 'loadparm' for a boot device. Loadparm is an 8 byte parameter that, when present, is queried by S390 guests via sclp or diag 308. Linux guests on S390 use it to select a boot entry.

  • Support controlling how video devices are exposed to the bhyve guests

    The vgaconf attribute was added to video 's driver element. Possible values are: on , off , and io . It controls the way how bhyve exposes video devices to its guests; various guest OSes might require different settings to boot properly.

  • qemu: Add support for live updates of coalesce settings

    Users can now use virsh update-device to change the coalesce settings of an interfaces while the domain is running.

  • qemu: Allow VirtIO devices to use vIOMMU

    It is now possible to turn on IOTBL for the vIOMMU and have VirtIO devices use it, provided they have been configured appropriately.

• Improvements

  • qemu: block copy job can be used with persistent domains

    Until now it was not possible to use block copy with persistent VMs. In use cases where it's not required to recover the job after VM shutdown, it's possible to specify VIR_DOMAIN_BLOCK_COPY_TRANSIENT_JOB flag to start the copy job.

  • JSON pseudo-protocol backing store parser supports new format of qemu 2.9

    QEMU 2.9 modified a few structures corresponding to the JSON format of specifying a backing store for a disk image. Libvirt now implements the new format.

  • Capabilities now include info about host's CAT settings

    Various information about resource control from the host is gathered and presented in capabilities if available.

  • apparmor: Several improvements

    Allow access to Ceph config, EFI firmware on both x86_64 and aarch64, device tree on ppc64 and more.

  • qemu: Support host-model on POWER9 machines

• Bug fixes

  • qemu: snapshot: retrieve image metadata from user provided files

    Disk images of an external snapshot created with VIR_DOMAIN_SNAPSHOT_CREATE_REUSE_EXT flag specified would not be scanned for metadata after recent changes. The metadata is necessary to allow keeping relative paths between images when doing a block-commit.

  • Parse decimal numbers in a locale-independent way

    Some locales, such as de_DE and pt_BR , use comma rather than dot to separate the integer part from the fractional part of a decimal number; however, several data sources such as the kernel use a locale-independent representation and need to be treated accordingly.

  • Support compilation with newer compiler and libc versions

    Several fixes have been included to make compilation with Clang 4.0.0, GCC 7.1 and glibc >= 2.25.90 possible.

  • qemu: Query name for vhost-user interfaces at runtime

    This makes it possible to use virsh subcommands such as domiflist and domifstat on vhost-user interfaces.

  • qemu: Set MTU for hotplugged interfaces correctly

    When hotplugging a network interface, the MTU was only set on the guest side. Set it on the host side as well.

  • qemu: Forbid updating MTU for interfaces of running guests

    The MTU setting can't be modified while the guest is running, so any attempt to alter it at runtime will now result in an error rather than being silently ignored.

  • qemu: Fix specifying QXL heads with older QEMU releases

    Specifying the number of QXL heads was not working correctly for QEMU releases older than 1.6.

  • qemu: Fix migration to older libvirt/QEMU versions

    When the guest is started, libvirt updates the CPU definition to reflect the actual CPU features to enforce ABI. We need to send original and updated CPU definition in order to support migration to older libvirt/QEMU versions. Only the updated CPU definition was sent to destination.

v3.4.0 (2017-06-02)

• New features

  • Improved streams to efficiently transfer sparseness

    New extension to virStream was implemented so that virStorageVolDownload and virStorageVolUpload can preserve file sparseness.

  • I/O APIC type can be specified for QEMU/KVM domains

    The ioapic tag was added to domain features , so the type of the I/O APIC can now be specified (e.g. putting it in userspace for KVM domains).

  • The reason for VM shutdown is reported, if known

    QEMU 2.10 will be able to report the reason for shutting down (whether that was caused by the guest or not), and libvirt is prepared for that and reports that information in its shutdown event as well, if it is known.

• Improvements

  • Repository now has new README.md file

    The new file uses markdown syntax, so it looks better on github and possibly other web pages, but it has also more useful information. The old README is now symlink to the new file.

  • qemu: Use GICv2 by default for aarch64/virt TCG guests

    The emulated GICv3 has some limitations that make it unusable as a default; use GICv2 until they're sorted out. This change makes it once again possible to run aarch64/virt guests on a x86_64 host without having to tweak their configuration.

  • Additional capabilities for the node_device module

    Introduce two new capabilities to the node_device module. The first is for CCW devices, most common on the S390 architecture. The second is for fibre channel-backed SCSI devices and exposes the fc_remote_port sub-capability to SCSI target devices.

  • Node devices now report Mediated device capabilities

    Endpoint devices support new mdev capability and their parents now report the supported types in new mdev_types capability.

  • Capabilities now report information about host caches

    If supported in the kernel, host capabilities will now list L3 caches. The code for other levels was added as well, but only L3 caches are reported currently.

  • POWER9 CPU model was added

    It is now properly reported in host capabilities.

  • libxl: NUMA sibling distances are now reported in host capabilities

  • VMDK version 3 files are now properly detected

  • Interrupt remapping and Extended interrupt mode for IOMMU devices

    These two new features can now be controlled with new <driver intremap='on/off' eim='on/off'/> tag for iommu devices.

  • Graphics in libxl domains now have default addresses

    Even though there were default addresses before this change, they were not saved in the XML. It is now possible to see and control the listen addresses properly.

  • Default USB controllers are now added for devices in libxl domains

    Even though they were added automatically when USB device was attached, they could've been missing in some other cases. The logic is now fixed so there are always USB controllers, even if there was none of them in the specified XML.

  • Limits for RPC messages were increased

    Hitting the RPC limits we have is easier every day, so they were increased once again and some guessing logic was improved as well. It is now possible to get more stats than ever using the virConnectGetAllDomainStats() call and push through even bigger requests and replies for all APIs.

• Bug fixes

  • qemu: Create memory_backing_dir on startup

    Libvirt's policy is that directories are created on startup if they don't exist. We've missed this one.

  • PCIe 4.0 cards now report proper link speeds

    It could happen that the link speed for PCIe devices was not properly reported or the nodedev-dumpxml just failed. That was due to mistake in the field width, but should now work properly.

  • qemu: Do not report errors on shutdown

    For some users, in some rare cases, it could happen that there was an error message "internal error: End of file from qemu monitor" in the logs even though no problem happened. The detection of these false positives was improved and such errors should not show any more.

  • User-specified UNIX socket paths for virtio channels should not be reset

    It could happen, in some cases, that libvirt would mistake a user-specified path for its own generated one and thus remove it from the XML. The detection of such addresses was improved now.

  • Fix address reservation during RNG hot-plug

    When error occurred in a specific point in time during the hot-plug of an RNG device, it could happen that an address was released even though another device was already using it, making it possible to hot-plug another device with that address, effectively having duplicated addresses in the XML.

v3.3.0 (2017-05-05)

• New features

  • net: Add support for coalesce settings

    Enabling data batching through these settings can improve network performance for guests.

  • qemu: Add support for guest CPU cache specification

    This features allows fine-grained control of the cache behavior of the guest CPU.

  • qemu: Add support for the qemu-xhci USB controller

• Improvements

  • hyperv: Support Hyper-V 2012 and newer

    Starting with Hyper-V 2012 the API has changed causing the existing driver to be unable to send and process requests properly. This has been resolved by adding abstractions to handle the differences and ease handling such breaks if they happen in the future.

  • libxl: Add support for nested HVM domains

    Xen has supported nested HVM domains since version 4.4. The libvirt libxl driver now supports nested HVM domains by specifying the host-passthrough CPU mode when defining a domain.

  • qemu: Implement ACPI support for aarch64 guests

    Up until this point, ACPI support was only advertised for x86_64 guests and disabling it for aarch64 guests was not possible at all.

  • vz: Add support for changing the number of vCPUs

  • qemu: Automatically choose the best USB controller for guests

    The recently introduced qemu-xhci USB controller is the best choice for both ppc64 and aarch64 guests, so use it by default on those architectures if available.

  • daemon: Increase default task limit for libvirtd

    The default number of tasks for the pids cgroup controller is 512, which libvirtd can quickly bump into when starting lots of guests. Raise the limit to a more reasonable 32768.

  • docs: Include man pages describing key code names and values

  • virsh: Report initialization errors

    Sometimes virsh might be unable to start: when that happens, report useful diagnostics instead of failing silently.

• Bug fixes

  • nss: Don't require a network restart for libvirt_guest

    Previously, the libvirt_guest NSS module would only work properly after the corresponding network had been restarted; now newly started guests will be reported correctly right away.

  • storage: Remove unavailable transient pools after restart

    Solve an issue where transient storage pools would be stuck in an unmanageable state if the source disappeared and libvirtd was subsequently restarted.

  • storage: Fix capacity value for LUKS encrypted volumes

    The 'capacity' value (e.g. guest logical size) for a LUKS volume is smaller than the 'physical' value of the file in the file system, so we need to account for that.

  • qemu: Fix regression when hyperv/vendor_id feature is used

    Guests using the feature would not be started at all; it is now possible to start them as expected.

  • qemu: Do not crash on USB address with no port and invalid bus

  • crypto: Always pad data before encrypting it

    If this step is not performed, when the data length matches the chunk size the decryption routines will misinterpret the last byte of data as the padding length and fail to decode it correctly.

v3.2.0 (2017-04-02)

• New features

  • The virt-host-validate tool now supports bhyve hypervisor

  • Introduce NVDIMM memory model

    NVDIMM is new type of memory introduced into QEMU 2.6. The idea is that we have a non-volatile memory module that keeps the data persistent across domain reboots and offers much faster data accesses. However, due to a bug in QEMU, this feature is not enabled for QEMUs older than 2.9.0.

  • qemu: Introduce support for generic PCIe Root Ports

    For new controllers, a generic device (pcie-root-port) will be used by default instead of the Intel-specific device (ioh3420), provided the QEMU binary supports it.

  • qemu: Add support for checking guest CPU ABI compatibility

    When migrating a domain to a different host, restoring a domain from a file or reverting a snapshot libvirt will make sure the guest CPU QEMU presents to the guest OS exactly matches the one provided on the source host (or before the domain's state was saved). This enhanced check may also be requested when starting a new domain to ensure the virtual CPU exactly matches the one specified in the XML.

  • qemu: Add support to migrate using TLS

    Add the ability to migrate QEMU guests using TLS via a new flag VIR_MIGRATE_TLS or virsh migrate '--tls' option. Requires using at least QEMU 2.9.0 in order to work properly.

  • qemu: add mediated devices framework support

    Recent kernel version introduced new mediated device framework, so provide an initial support of this framework for libvirt, mainly by introducing a new host device type in the XML.

  • qemu: Add support for setting TSC frequency

    Setting TSC frequency is required to enable migration for domains with 'invtsc' CPU feature turned on.

  • Add support for block device threshold event

    When using thin provisioning, management tools need to resize the disk in certain cases. To avoid having them to poll disk usage this version introduces an event which will be fired when a given offset of the storage is written by the hypervisor. Together with the API it allows registering thresholds for given storage backing volumes and this event will then notify management if the threshold is exceeded. Currently only the qemu driver supports this.

  • bhyve: Add support for UEFI boot ROM, VNC, and USB tablet

    The bhyve driver now supports booting using the UEFI boot ROM, so non-FreeBSD guests that support UEFI could be booted without using an external boot loader like grub-bhyve. Video is also supported now, allowing to connect to guests via VNC and use an USB tablet as an input device. Please refer to the driver page for domain XML examples.

• Improvements

  • qemu: Detect host CPU model by asking QEMU on x86_64

    Previously, libvirt detected the host CPU model using CPUID instruction, which caused libvirt to detect a lot of CPU features that are not supported by QEMU/KVM. Asking QEMU makes sure we don't start it with unsupported features.

  • perf: Add more perf statistics

    Add support to get the count of cpu clock time, task clock time, page faults, context switches, cpu migrations, minor page faults, major page faults, alignment faults, emulation faults by applications running on the platform.

  • Write hyperv crash information into vm log

    qemu's implementation of the hyperv panic notifier now reports information about the crash from the guest os. Starting with this version, libvirt logs the information to the vm log file for possible debugging.

• Bug fixes

  • QEMU: Use adaptive timeout for connecting to monitor

    When starting qemu, libvirt waits for qemu to create the monitor socket which libvirt connects to. Historically, there was sharp 30 second timeout after which the qemu process was killed. This approach is suboptimal as in some scenarios with huge amounts of guest RAM it can take a minute or more for kernel to allocate and zero out pages for qemu. The timeout is now flexible and computed by libvirt at domain startup.

  • Overwrite (clear) 2 KB instead of just 512 bytes when initializing logical device

  • Describe the logical backend requirements better for pool-create-as

v3.1.0 (2017-03-03)

• New features

  • storage: Add Virtuozzo storage backend storage pool

    Add new storage backend to support pool and volume management within the Virtuozzo Storage environment. Virtuozzo Storage is a highly available distributed software defined storage with built-in replication and disaster recovery.

  • qemu: Add support for memory backing with file source

    Add support in numa topology for file source inside memory backing (hugepages are not needed) Three new elements <source/>,<access/> and <allocation/> were added to <memoryBacking/> element. Also new configuration parameter memory_backing_dir was added to qemu.conf.

  • network: make openvswitch call timeout configurable

    Adding the ability to specify the timeout value in seconds for openvswitch calls in the libvirtd configuration file.

  • bhyve: add e1000 NIC support

    Add support for e1000 NIC. Previously, the only available option was virtio-net .

  • libxl: add tunneled migration support

    Add tunneled migration to libxl driver, which is always capable of strong encryption and doesn't require any extra network connection other than what's required for remote access of libvirtd.

  • qemu: add rendernode argument

    Add a new attribute 'rendernode' to <gl> spice element.

  • nodedev: add drm capability

    Add a new 'drm' capability for Direct Rendering Manager (DRM) devices, providing device type information.

  • Add API for individual/specific vCPU hotplug

    The new API allows selecting specific vCPUs to be added/removed from the VM. The existing APIs allowed only adding/removing from the end which did not play well with NUMA.

• Improvements

  • virsh: pool-list: allow both --uuid and --name in one command

    Adjust the virsh-pool command to support the --uuid and/or --name options in order to print just the --name and/or --uuid of pools.

  • Introduce MTU to domain <interface/> and <network>

    Allow setting MTU size for some types of domain interface and network.

  • libxl: improve support for <timer> configurations

    Add support for multiple timers. Extend the tsc timer to support the emulate mode. Improve conversion of timer XML to/from xl.cfg.

  • storage: modularize the storage driver

    Split up the storage driver backends into loadable modules so that binary distributions don't have to compromise on shipping the storage driver with all backends which may pull in too many dependencies.

• Bug fixes

  • nodedev: Fabric name must not be required for fc_host capability

    fabric_name is one of many fc_host attributes in Linux that is optional and left to the low-level driver to decide if it is implemented. For example the zfcp device driver does not provide a fabric name for an fcp host. The requirement for the existence of a fabric name has been removed by making it optional.

  • bhyve: change address allocation schema for SATA disks

    Previously, the bhyve driver assigned PCI addresses to SATA disks directly rather than assigning that to a controller and using SATA addresses for disks. It was implemented this way because bhyve has no notion of an explicit SATA controller. However, as this doesn't match libvirt's understanding of disk addresses, the bhyve driver was changed to follow the common schema and have PCI addresses for SATA controllers and SATA addresses for disks. If you're having issues because of this, it's recommended to edit the domain's XML and remove <address type='pci'> from the <disk> elements with <target bus='sata'/> and let libvirt regenerate it properly.

  • libxl: maximum memory fixes

    Fix reporting of domain maximum memory. Fix setting dom0 maximum memory.

  • libxl: fix disk detach when <driver> not specified

  • libxl: fix dom0 autoballooning with Xen 4.8

  • qemu: Allow empty script path to <interface/>

    Historically, this was always allowed. Unfortunately, due to some rework done for 1.3.2 release a bug was dragged in which suddenly stop allowing domain with such configuration to start.

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.

  • qemu: Fix XML dump of autogenerated websocket

    As a result autogenerated websocket port is regenerated on domain restore, migration and such as it should be.

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.

  • Allow debugging of gluster volumes in qemu

    Users can now enable debug logging for native gluster volumes in qemu using the "gluster_debug_level" option in qemu.conf

  • Pre-allocate memory slots for 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

v2.4.0 (2016-11-01)

No release notes.

v2.3.0 (2016-10-04)

No release notes.

v2.2.0 (2016-09-02)

No release notes.

v2.1.0 (2016-08-02)

No release notes.

v2.0.0 (2016-07-01)

No release notes.

v1.3.5 (2016-06-04)

No release notes.

v1.3.4 (2016-05-01)

No release notes.

v1.3.3 (2016-04-06)

No release notes.

v1.3.2 (2016-03-01)

No release notes.

v1.3.1 (2016-01-17)

No release notes.

v1.3.0 (2015-12-09)

No release notes.

v1.2.21 (2015-11-04)

No release notes.

v1.2.20 (2015-10-02)

No release notes.

v1.2.19 (2015-09-02)

No release notes.

v1.2.18 (2015-08-03)

No release notes.

v1.2.17 (2015-07-02)

No release notes.

v1.2.16 (2015-06-01)

No release notes.

v1.2.15 (2015-05-04)

No release notes.

v1.2.14 (2015-04-02)

No release notes.

v1.2.13 (2015-03-02)

No release notes.

v1.2.12 (2015-01-27)

No release notes.

v1.2.11 (2014-12-13)

No release notes.

v1.2.10 (2014-11-03)

No release notes.

v1.2.9 (2014-10-01)

No release notes.

v1.2.8 (2014-09-02)

No release notes.

v1.2.7 (2014-08-02)

No release notes.

v1.2.6 (2014-07-02)

No release notes.

v1.2.5 (2014-06-02)

No release notes.

v1.2.4 (2014-05-04)

No release notes.

v1.2.3 (2014-04-01)

No release notes.

v1.2.2 (2014-03-02)

No release notes.

v1.2.1 (2014-01-16)

No release notes.

v1.2.0 (2013-12-02)

No release notes.

v1.1.4 (2013-11-04)

No release notes.

v1.1.3 (2013-10-01)

No release notes.

v1.1.2 (2013-09-02)

No release notes.

v1.1.1 (2013-07-30)

No release notes.

v1.1.0 (2013-07-01)

No release notes.

v1.0.6 (2013-06-03)

No release notes.

v1.0.5 (2013-05-02)

No release notes.

v1.0.4 (2013-04-01)

No release notes.

v1.0.3 (2013-03-05)

No release notes.

v1.0.2 (2013-01-30)

No release notes.

v1.0.1 (2012-12-17)

No release notes.

v1.0.0 (2012-11-02)

No release notes.

v0.10.2 (2012-09-24)

No release notes.

v0.10.1 (2012-08-31)

No release notes.

v0.10.0 (2012-08-29)

No release notes.

v0.9.13 (2012-08-02)

No release notes.

v0.9.12 (2012-05-14)

No release notes.

v0.9.11 (2012-04-03)

No release notes.

v0.9.10 (2012-02-13)

No release notes.

v0.9.9 (2012-01-07)

No release notes.

v0.9.8 (2011-12-08)

No release notes.

v0.9.7 (2011-11-08)

No release notes.

v0.9.6 (2011-09-22)

No release notes.

v0.9.5 (2011-09-20)

No release notes.

v0.9.4 (2011-08-03)

No release notes.

v0.9.3 (2011-07-04)

No release notes.

v0.9.2 (2011-06-06)

No release notes.

v0.9.1 (2011-05-05)

No release notes.

v0.9.0 (2011-04-04)

No release notes.

v0.8.8 (2011-02-17)

No release notes.

v0.8.7 (2011-01-04)

No release notes.

v0.8.6 (2010-11-30)

No release notes.

v0.8.5 (2010-10-29)

No release notes.

v0.8.4 (2010-09-10)

No release notes.

v0.8.3 (2010-08-04)

No release notes.

v0.8.2 (2010-07-05)

No release notes.

v0.8.1 (2010-04-30)

No release notes.

v0.8.0 (2010-04-12)

No release notes.

v0.7.7 (2010-03-05)

No release notes.

v0.7.6 (2010-02-03)

No release notes.

v0.7.5 (2009-12-23)

No release notes.

v0.7.4 (2009-11-20)

No release notes.

v0.7.3 (2009-11-20)

No release notes.

v0.7.2 (2009-10-14)

No release notes.

v0.7.1 (2009-09-15)

No release notes.

v0.7.0 (2009-08-05)

No release notes.

v0.6.5 (2009-07-03)

No release notes.

v0.6.4 (2009-05-29)

No release notes.

v0.6.3 (2009-04-24)

No release notes.

v0.6.2 (2009-04-03)

No release notes.

v0.6.1 (2009-03-03)

No release notes.

v0.6.0 (2009-01-31)

No release notes.

v0.5.1 (2008-12-04)

No release notes.

v0.5.0 (2008-11-25)

No release notes.

v0.4.6 (2008-09-23)

No release notes.

v0.4.5 (2008-09-08)

No release notes.

v0.4.4 (2008-06-25)

No release notes.

v0.4.3 (2008-06-12)

No release notes.

v0.4.2 (2008-04-08)

No release notes.

v0.4.1 (2008-03-03)

No release notes.

v0.4.0 (2007-12-18)

No release notes.

v0.3.3 (2007-09-30)

No release notes.

v0.3.2 (2007-08-21)

No release notes.

v0.3.1 (2007-07-24)

No release notes.

v0.3.0 (2007-07-09)

No release notes.

v0.2.3 (2007-06-08)

No release notes.

v0.2.2 (2007-04-17)

No release notes.

v0.2.1 (2007-03-16)

No release notes.

v0.2.0 (2007-02-14)

No release notes.

v0.1.11 (2007-01-22)

No release notes.

v0.1.10 (2006-12-20)

No release notes.

v0.1.9 (2006-11-29)

No release notes.

v0.1.8 (2006-10-16)

No release notes.

v0.1.7 (2006-09-29)

No release notes.

v0.1.6 (2006-09-22)

No release notes.

v0.1.5 (2006-09-05)

No release notes.

v0.1.4 (2006-08-16)

No release notes.

v0.1.3 (2006-07-11)

No release notes.

v0.1.2 (2006-07-03)

No release notes.

v0.1.1 (2006-06-21)

No release notes.

v0.1.0 (2006-04-10)

No release notes.

v0.0.6 (2006-02-28)

No release notes.

v0.0.5 (2006-02-23)

No release notes.

v0.0.4 (2006-02-10)

No release notes.

v0.0.3 (2006-02-09)

No release notes.

v0.0.2 (2006-01-29)

No release notes.

v0.0.1 (2005-12-19)

No release notes.