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Attempts to use update-device to modify just the link state of a guest interface were failing due to a supposed attempt to modify something in the interface that can't be modified live (even though the only thing that was changing was the link state, which *can* be modified live). It turned out that this failure happened because the guest interface in question was type='network', and the network in question was a 'direct' network that provides each guest interface with one device from a pool of network devices. As a part of qemuDomainChangeNet() we would always allocate a new port from the network driver for the updated interface definition (by way of calling virDomainNetAllocateActualDevice(newdev)), and this new port (ie the ActualNetDef in newdev) would of course be allocated a new host device from the pool (which would of course be different from the one currently in use by the guest interface (in olddev)). Because direct interfaces don't support changing the host device in a live update, this would cause the update to fail. The solution to this is to realize that as long as the interface doesn't get switched to a different network as a part of the update, the network port information (ie the ActualNetDef) will not change as a part of updating the guest interface itself. So for sake of comparison we can just point the newdev at the ActualNetDef of olddev, and then clear out one or the other when we're done (to avoid a double free or, more likely, attempt to reference freed memory). (If, on the other hand, the name of the network has changed, or if the interface type has changed to type='network' from something else, then we *do* need to allocate a new port (actual device) from the network driver (as we used to do in all cases when the new type was 'network'), and also indicate that we'll need to replace olddev in the domain with newdev (because either of these changes is major enough that we shouldn't just try to fix up olddev) Partially-Resolves: https://issues.redhat.com/browse/RHEL-7036 Signed-off-by: Laine Stump <laine@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
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==============================
Libvirt API for virtualization
==============================
Libvirt provides a portable, long term stable C API for managing the
virtualization technologies provided by many operating systems. It
includes support for QEMU, KVM, Xen, LXC, bhyve, Virtuozzo, VMware
vCenter and ESX, VMware Desktop, Hyper-V, VirtualBox and the POWER
Hypervisor.
For some of these hypervisors, it provides a stateful management
daemon which runs on the virtualization host allowing access to the
API both by non-privileged local users and remote users.
Layered packages provide bindings of the libvirt C API into other
languages including Python, Perl, PHP, Go, Java, OCaml, as well as
mappings into object systems such as GObject, CIM and SNMP.
Further information about the libvirt project can be found on the
website:
https://libvirt.org
License
=======
The libvirt C API is distributed under the terms of GNU Lesser General
Public License, version 2.1 (or later). Some parts of the code that are
not part of the C library may have the more restrictive GNU General
Public License, version 2.0 (or later). See the files ``COPYING.LESSER``
and ``COPYING`` for full license terms & conditions.
Installation
============
Instructions on building and installing libvirt can be found on the website:
https://libvirt.org/compiling.html
Contributing
============
The libvirt project welcomes contributions in many ways. For most components
the best way to contribute is to send patches to the primary development
mailing list. Further guidance on this can be found on the website:
https://libvirt.org/contribute.html
Contact
=======
The libvirt project has two primary mailing lists:
* users@lists.libvirt.org (**for user discussions**)
* devel@lists.libvirt.org (**for development only**)
Further details on contacting the project are available on the website:
https://libvirt.org/contact.html