1432916983
qemuDomainDetachControllerDevice() calls
qemuDomainDetachExtensionDevice() when the controller type is
PCI. This is incorrect in multiple ways:
* Any code that tears down a device should be in the
qemuDomainRemove*Device() function (which is called after libvirt
gets a DEVICE_DELETED event from qemu indicating that the guest is
finished with the device on its end. The qemuDomainDetach*Device()
functions should only contain code that ensures the requested
operation is valid, and sends the command to qemu to initiate the
unplug.
* qemuDomainDetachExtensionDevice() is a function that applies to
devices that plug into a PCI slot, *not* necessarily PCI controllers
(which is what's being checked in the offending code). The proper
way to check for this would be to see if the DeviceInfo for the
controller device had a PCI address, not to check if the controller
is a PCI controller (the code being removed was doing the latter).
* According to commit 1d1e264f1 that added this code (and other
support for hotplugging zPCI devices on s390), it's not necessary to
explicitly detach the zPCI device when unplugging a PCI device. To
quote:
There's no need to implement hot unplug for zPCI as QEMU
implements an unplug callback which will unplug both PCI and
zPCI device in a cascaded way.
and the evidence bears this out - all the other uses of
qemuDomainDetachExtensionDevice() (except one, which I believe is
also in error, and is being removed in a separate patch) are only to
remove the zPCI extension device in cases where it was successfully
added, but there was some other failure later in the hotplug process
(so there was no regular PCI device to remove and trigger removal of
the zPCI extension device).
* PCI controllers are not hot pluggable, so this is dead code
anyway. (The only controllers that can currently be
hotplugged/unplugged are SCSI controllers).
Signed-off-by: Laine Stump <laine@laine.org>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
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:
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 2.1 (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:
- libvirt-users@redhat.com (for user discussions)
- libvir-list@redhat.com (for development only)
Further details on contacting the project are available on the website: