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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Jiri Denemark a396f76f70 qemu: Enable removing features from CPU models
Features removed from a CPU model are marked with "removed='yes'"
attribute in the CPU map. Such features will always be present in a CPU
definition produced by libvirt regardless on their state. In other words
a running domain (even saved in a file) will always explicitly contain
states of all features removed from the specified CPU model. This
enables migration to older libvirt which would otherwise think the
affected features should be enabled as they are still included in the
CPU model in the older version of CPU map. Migration from an old libvirt
to a new one would be broken as the new libvirt would think the removed
features should be disabled (because they are not included in the CPU
model anymore), which might not be the case on the source host. Thus we
were refusing to remove CPU features unless they were never working and
no domain could even be running with those features enabled.

This patch removes the limitation. When handling CPU definitions with
missing features marked as removed in the specified CPU model, we know
whether it comes from a running domain, in which case it must have been
created by older libvirt where the missing CPU features were not removed
yet. This means the features must have been enabled on the source and we
can automatically fix the definition by adding the missing features with
correct states.

We can safely remove any CPU feature from our CPU models now, but it
should only be used for features removed from all versions of a given
CPU model in QEMU because unversioned models correspond to v1.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2024-05-02 19:56:45 +02:00
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build-aux virshtest: Prepare for testing against output files 2024-04-02 14:24:30 +02:00
ci ci: drop CentOS 8 Stream and refresh 2024-05-02 13:52:30 +01:00
docs conf: Introduce support for virtio-sound devices 2024-05-02 15:38:32 +02:00
examples examples: Define _GNU_SOURCE for more examples 2024-02-07 18:01:03 +01:00
include libvirt: Introduce virDomainGraphicsReload API 2024-03-08 17:00:15 +01:00
po Translated using Weblate (Swedish) 2024-05-02 08:13:07 +02:00
scripts scripts/meson-dist.py: Get builddir from env too 2024-05-02 14:33:20 +02:00
src qemu: Enable removing features from CPU models 2024-05-02 19:56:45 +02:00
subprojects
tests cpu: Add removedPolicy parameter to virCPUUpdate 2024-05-02 19:56:45 +02:00
tools vsh: Refactor logic in vshCommandParse 2024-04-25 14:13:20 +02:00
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.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 docs: Add redirects configuration for gitlab pages 2024-01-19 15:51:47 +01:00
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.gitpublish gitpublish: Tweak prefix 2023-12-05 11:48:28 +01:00
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AUTHORS.rst.in
config.h
configmake.h.in
CONTRIBUTING.rst
COPYING
COPYING.LESSER
gitdm.config
libvirt-admin.pc.in
libvirt-lxc.pc.in
libvirt-qemu.pc.in
libvirt.pc.in
libvirt.spec.in spec: Handle new location of bash-completion .pc file 2024-02-27 12:05:38 +00:00
meson_options.txt build: Add userfaultfd_sysctl build option 2024-02-13 17:44:26 +01:00
meson.build scripts/meson-dist.py: Get builddir from env too 2024-05-02 14:33:20 +02:00
NEWS.rst Post-release version bump to 10.4.0 2024-05-02 11:10:01 +02:00
README.rst docs: update docs pointing to old mailing list addrs 2023-10-31 10:04:27 +00:00
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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