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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Daniel Henrique Barboza 6b7f87d7f1 virhostdev: remove virHostdevReattachPCIDevice
virHostdevReattachPCIDevice() is a static that simply does
a wait loop with virPCIDeviceWaitForCleanup() before
calling virPCIDeviceReattach().

This loop traces back to commit d1e5676c0d, aiming to
solve a race condition between Libvirt returning the
device back to the host and QEMU trying to access it in
the meantime, which resulted in QEMU exiting on error
and killing the guest. This happens because device_del
is asynchronous, returning OK even if the guest didn't
release the device. Commit 01abc8a1b8 moved this code
to qemu_hostdev.c, 82e8dd4cf8 added the pci-stub conditional
for the loop, 899b261127 moved the code to virhostdev.c
where it stood until now.

The intent of this wait loop is still valid: device_del
is still not bullet proof into preventing the conditions
that commit d1e5676c0d aimed to fix, especially when considering
all the architectures we must support. However, this loop
is executed only in virHostdevReattachPCIDevice(), leaving
every other virPCIDeviceReattach() call prone to that error.

Let's move the wait loop code to virPCIDeviceReattach(). This
will:

-  make every reattach call safe from this race condition
with the pci-stub;

-  allow for a bit of code cleanup (virHostdevReattachPCIDevice()
can be erased, and virHostdevReAttachPCIDevices() can use
virPCIDeviceReattach() directly);

- make it easier to understand the overall reattach mechanisms in
Libvirt, without the risk of a newcomer wondering why reattach
is done slightly different in some instances.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-05 19:42:58 +02:00
.ctags.d maint: Add support for .ctags.d 2019-05-31 17:54:28 +02:00
.gnulib@8089c00979 maint: update gnulib for syntax-check on BSD 2019-01-07 13:54:07 -06:00
build-aux syntax check: update header guard check 2019-06-20 09:01:07 +02:00
docs virpci: Allow greater PCI domain value in virPCIDeviceAddressIsValid 2019-08-05 19:42:15 +02:00
examples examples: Group all C programs together 2019-06-03 17:27:43 +02:00
gnulib maint: Fix VPATH build 2019-01-07 21:56:16 -06:00
include/libvirt backup: Introduce virDomainCheckpoint APIs 2019-07-26 16:48:58 -05:00
m4 m4: Fix check for yajl.pc 2019-07-08 12:01:27 +02:00
po po: refresh translations from zanata 2019-07-30 12:43:31 +01:00
src virhostdev: remove virHostdevReattachPCIDevice 2019-08-05 19:42:58 +02:00
tests virpci: Allow greater PCI domain value in virPCIDeviceAddressIsValid 2019-08-05 19:42:15 +02:00
tools lib: Format PCI address differently 2019-08-05 19:42:15 +02:00
.color_coded.in
.ctags
.dir-locals.el
.gitignore examples: Group all C programs together 2019-06-03 17:27:43 +02:00
.gitlab-ci.yml gitlab: Perform some builds on Debian 10 2019-07-11 15:03:39 +02:00
.gitmodules
.gitpublish git: add config file telling git-publish how to send patches 2018-04-23 11:36:09 +01:00
.mailmap mailmap: Remove some duplicates 2019-06-07 13:18:08 +02:00
.travis.yml travis: put macOS script inline in the macOS matrix entry 2019-04-11 18:38:56 +01:00
.ycm_extra_conf.py.in
ABOUT-NLS
AUTHORS.in
autogen.sh
bootstrap maint: update gnulib for syntax-check on BSD 2019-01-07 13:54:07 -06:00
bootstrap.conf maint: Stop generating ChangeLog from git 2019-04-03 09:45:25 +02:00
cfg.mk remote: delete the avahi mDNS support 2019-06-21 12:59:42 +01:00
ChangeLog maint: Stop generating ChangeLog from git 2019-04-03 09:45:25 +02:00
config-post.h build: remove WITH_YAJL2 2019-04-03 13:30:47 +02:00
configure.ac maint: Post-release version bump to 5.7.0 2019-08-05 19:23:46 +02:00
COPYING
COPYING.LESSER
gitdm.config gitdm: Add gitdm configuration 2019-06-07 13:18:14 +02:00
libvirt-admin.pc.in
libvirt-lxc.pc.in
libvirt-qemu.pc.in
libvirt.pc.in
libvirt.spec.in backup: Introduce virDomainCheckpoint APIs 2019-07-26 16:48:58 -05:00
Makefile.am Don't include Makefile.ci in Makefile.am 2019-05-10 09:12:52 +02:00
Makefile.ci ci: Update image list 2019-07-11 15:03:37 +02:00
Makefile.nonreentrant
mingw-libvirt.spec.in backup: Introduce virDomainCheckpoint APIs 2019-07-26 16:48:58 -05:00
README
README-hacking
README.md README: fix license typo 2019-07-25 09:21:28 -06:00
run.in run: Don't export unnecessary paths 2019-03-15 11:50:23 +01:00

Build Status CII Best Practices

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

Libvirt uses the GNU Autotools build system, so in general can be built and installed with the usual commands. For example, to build in a manner that is suitable for installing as root, use:

$ ./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var
$ make
$ sudo make install

While to build & install as an unprivileged user

$ ./configure --prefix=$HOME/usr
$ make
$ make install

The libvirt code relies on a large number of 3rd party libraries. These will be detected during execution of the configure script and a summary printed which lists any missing (optional) dependencies.

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