5cd4606e38
The virHostdevPreparePCIDevices() function works in several
steps. In the very first one, it checks if devices we want to
detach from the host are not taken already by some other domain.
However, this piece of code returns different results depending
on the stub driver used (which is not wrong per se, but keep on
reading). If the stub driver is KVM then
virHostdevIsPCINodeDeviceUsed() is called which basically checks
if a PCI device from the detach list is not used by any domain
(including the one we are preparing the device for). If that is
the case, an error is reported ("device in use") and -1 is
returned.
However, that is not what happens if the stub driver is VFIO. If
the stub driver is VFIO, then we iterate over all PCI devices
from the same IOMMU group and check if they are taken by some
other domain (because a PCI device, well IOMMU group, can't be
shared between two or more qemu processes). But we fail to check,
if the device we are trying to detach from the host is not
already taken by a domain. That is, calling
virHostdevPreparePCIDevices() over a hostdev device twice
succeeds the first time and fails too late in the second run
(fortunately, virHostdevResetAllPCIDevices() will throw an error,
but this is already too late because the PCI device in question
was moved to the list of inactive PCI devices and now it appears
in both lists).
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Tested-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.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 2.0 (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:
- 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: