Release of libvirt-8.5.0

[Jiri Denemark]

The 8.5.0 release of both libvirt and libvirt-python is tagged and
signed tarballs and source RPMs are available at

    https://libvirt.org/sources/
    https://libvirt.org/sources/python/

Thanks everybody who helped with this release by sending patches,
reviewing, testing, or providing feedback. Your work is greatly
appreciated.

* New features

  * qemu: Introduce support for network backed NVRAM

    Users can now use remote store NVRAM image by specifying newly introduced
    attribute `type='network'` with `<nvram>` element.

  * qemu: Add support for post-copy migration recovery

    A new ``VIR_MIGRATE_POSTCOPY_RESUME`` flag (``virsh migrate --postcopy-resume``)
    was introduced for recovering from a failed post-copy migration.

  * Introduce thread_pool_min and thread_pool_max attributes to IOThread

    New attributes ``thread_pool_min`` and ``thread_pool_max`` were introduced
    to ``<iothread/>`` as well as new ``<defaultiothread/>`` element with the
    same attributes. This way it's possible to instruct QEMU to spawn enough
    worker threads for an IOThread upfront, resulting in predictable time
    needed to process an I/O request.

* Improvements

  * Define a TFTP server without a DHCP server in network configuration

    It's now possible to define a network with no DHCP server but with a TFTP
    server. This may be useful when DHCP service is provided by other entity on
    the network than libvirt spawned dnsmasq.

* Bug fixes

  * qemu: Restore label to temp file in qemuDomainScreenshot()

    When virDomainScreenshot() is called, libvirt instructs QEMU to save the
    screenshot into a temporary file. This file needs to be labelled correctly,
    so that QEMU can access it. And since the file is temporary (it's deleted
    after the screenshot was taken) the corresponding label restore was
    missing. This proven to be problematic for profile based models, like
    AppArmor, where the temporary files were added into the profile but never
    removed, which resulted in longer profile recalculation times.

  * qemuBuildInterfaceConnect: Initialize @tapfd array

    Due to an uninitialized array, unsuccessful attempt to start a guest with
    an ``<interface/>`` might have resulted in closing of a random FD and thus
    sudden disconnect of a client or other random failures.

  * qemu: Fix hotplug of network interfaces

    A logic bug introduced in a recent refactor was fixed. The bug caused a
    problem when hot-adding a network interface, which failed with the
    following error::

      error: internal error: unable to execute QEMU command 'netdev_add': File descriptor named '(null)' has not been found

  * Fix ``startupPolicy`` validation for ``block`` disks

    Setting of ``startupPolicy`` for a block disk would result in an error due
    to a logic bug in a recent refactor.

  * qemu: Fix crash when overriding device properties via ``<qemu:override>`` element

    Adding an override for a device property would result in a crash of the qemu
    driver.

Enjoy.

Jirka