0276015325
virQEMUDriverConfigNew() always initializes the bitmap in its cgroupControllers member to -1 (i.e. all 1's). Prior to commit a9331394, if qemu.conf had a line with "cgroup_controllers", cgroupControllers would get reset to 0 before going through a loop setting a bit for each named cgroup controller. commit a9331394 left out the "reset to 0" part, so cgroupControllers would always be -1; if you didn't want a controller included, there was no longer a way to make that happen. This was discovered by users who were using qemu commandline passthrough to use the "input-linux" method of directing keyboard/mouse input to a virtual machine: https://www.redhat.com/archives/vfio-users/2016-April/msg00105.html Here's the first report I found of the problem encountered after upgrading libvirt beyond v2.0.0: https://www.redhat.com/archives/vfio-users/2016-August/msg00053.html Thanks to sL1pKn07 SpinFlo <sl1pkn07@gmail.com> for bringing the problem up in IRC, and then taking the time to do a git bisect and find the patch that started the problem.
LibVirt : simple API for virtualization
Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.
Daniel Veillard <veillard@redhat.com>