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This patch simplifies (?) the of qemuDomainChangeNet() code while fixing some incorrect decisions about exactly when it's necessary to re-attach an interface's bridge device, or to fail the device update (needReconnect[*]) because the type of connection has changed (or within bridge and direct (macvtap) type because some attribute of the connection has changed that can't actually be modified after the tap/macvtap device of the interface is created). Example 1: it's pointless to require the bridge device to be reattached just because the interface has been switched to a different network (i.e. the name of the network is different), since the new network could be using the same bridge as the old network (very uncommon, but technically possible). Instead we should only care if the name of the *bridge device* changes (or if something in <virtualport> changes - see Example 3). Example 2: wrt changing the "type" of the interface, a change should be allowed if old and new type both used a bridge device (whether or not the name of the bridge changes), or if old and new type are both "direct" *and* the device being linked and macvtap mode remain the same. Any other change in interface type cannot be accommodated and should be a failure (i.e. needReconnect). Example 3: there is no valid reason to fail just because the interface has a <virtualport> element - the <virtualport> could just say "type='openvswitch'" in both the before and after cases (in which case it isn't a change by itself, and so is completely acceptable), and even if the interfaceid changes, or the <virtualport> disappears completely, that can still be reconciled by simply re-attaching the bridge device. (If, on the other hand, the modified <virtualport> is for a type='direct' interface, we can't domodify that, and so must fail (needReconnect).) (I tried splitting this into multiple patches, but they were so intertwined that the intermediate patches made no sense.) [*] "needReconnect" was a flag added to this function way back in 2012, when I still believed that QEMU might someday support connecting a new & different device backend (the way the virtual device connects to the host) to an already existing guest netdev (the virtual device as it appears to the guest). Sadly that has never happened, so for the purposes of qemuDOmainChangeNet() "needReconnect" is equivalent to "fail". 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