I had this error today. It was on a 20.04 development test server, upon which I was trying to start a freshly installed 20.04 server guest. The error occurred because I had this on my grub command line:
cgroup_no_v1=all Once I removed it, the VM started fine. Note that I do not use virt-manager, I was using "virsh start serv-dev". Why did I originally have "cgroup_no_v1=all"? Well, I forgot to get rid of it, after debugging problems with the schedutil governor for either the intel_cpufreq (intel_pstate in passive mode) or acpi-cpufreq CPU frequency scaling drivers for mainline kernel 5.4, where it gets busted due to "UCLAMP_TASK_GROUP=Y"in the Ubuntu kernel configuration. I was using kernel 5.3.0-18-generic today. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1845562 Title: libvirt error Invalid value '+cpu' for 'cgroup.subtree_control' To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1845562/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
