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.
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Laine Stump c7ea694f7d qemu: rework needBridgeChange/needReconnect decisions in qemuDomainChangeNet()
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>
2024-09-19 13:56:39 -04:00
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.github/workflows github: Update lockdown message when opening a PR 2024-05-15 12:31:23 +02:00
.gitlab/issue_templates gitlab: issue_template: Remove labelling commands 2022-06-01 12:27:10 +02:00
build-aux virshtest: Prepare for testing against output files 2024-04-02 14:24:30 +02:00
ci ci: update OpenSUSE Leap to 15.6 2024-08-16 13:11:57 +02:00
docs docs: Document memory bandwidth allocation limits more clearly 2024-09-13 12:55:39 +02:00
examples examples: Define _GNU_SOURCE for more examples 2024-02-07 18:01:03 +01:00
include Include support for Vfio stats during Migration 2024-07-10 12:28:55 +02:00
po Translated using Weblate (English (United Kingdom)) 2024-09-18 11:17:56 +02:00
scripts scripts/rpcgen: skip tests if tirpc is not present 2024-05-08 15:57:13 +01:00
src qemu: rework needBridgeChange/needReconnect decisions in qemuDomainChangeNet() 2024-09-19 13:56:39 -04:00
subprojects Move src/keycodemapdb -> subprojects/keycodemapdb 2023-04-17 15:02:38 +02:00
tests qemu: Reject unsupported chardev backend protocols 2024-09-19 10:30:15 +02:00
tools virsh: cmdList: Revert to script-friendly output for 'virsh list --uuid' 2024-09-05 15:24:55 +02:00
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.gitattributes Add .gitattributes file 2022-03-17 14:33:12 +01:00
.gitignore Revert ".gitignore: Ignore cscope and other *tags files" 2023-02-08 17:24:31 +01:00
.gitlab_pages_redirects docs: gitlab redirects: Drop '/libvirt' prefix for hosting the web through gitlab pages 2024-02-13 16:56:49 +01:00
.gitlab-ci.yml gitlab: add missing job inheritance for codestyle 2024-06-17 11:36:00 +01:00
.gitmodules Move src/keycodemapdb -> subprojects/keycodemapdb 2023-04-17 15:02:38 +02:00
.gitpublish gitpublish: Tweak prefix 2023-12-05 11:48:28 +01:00
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AUTHORS.rst.in AUTHORS: change my (Nikolay Shirokovskiy) email 2022-04-06 11:00:53 +03:00
config.h
configmake.h.in
CONTRIBUTING.rst meson: adjust our documentation to mention meson instead of autoconf 2020-08-03 09:27:09 +02:00
COPYING
COPYING.LESSER
gitdm.config
libvirt-admin.pc.in
libvirt-lxc.pc.in
libvirt-qemu.pc.in
libvirt.pc.in
libvirt.spec.in rpm: Add riscv64 to arches_qemu_kvm 2024-09-18 11:26:55 +02:00
meson_options.txt network: introduce a "none" firewall backend type 2024-06-17 15:55:14 +01:00
meson.build util/virutil: Use readpassphrase when libbsd is available 2024-09-12 13:12:47 +02:00
NEWS.rst NEWS: Mention breakage of scrip-friendly virsh output 2024-09-05 15:24:55 +02:00
README.rst docs: update docs pointing to old mailing list addrs 2023-10-31 10:04:27 +00:00
run.in run.in: Detect binaries in builddir properly 2024-06-04 14:39:00 +02:00

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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:

Further details on contacting the project are available on the website:

https://libvirt.org/contact.html