## Software environment - Operating system: CentOS 9 Stream - Architecture: x86_64 - kernel version: kernel-5.14.0-105.el9.x86_64 - libvirt version: libvirt-daemon-8.3.0-1.el9.x86_64 - Hypervisor and version: qemu-kvm-core-7.0.0-4.el9.x86_64 ## Description of problem On recent kernels it is not possible to set vCPU quota to `-1`. Libvirt fails with: ``` Traceback (most recent call last): File "/usr/lib/python3.9/site-packages/vdsm/virt/vm.py", line 5572, in setCpuTuneQuota self._dom.setSchedulerParameters({'vcpu_quota': int(quota)}) File "/usr/lib/python3.9/site-packages/vdsm/virt/virdomain.py", line 121, in f ret = attr(*args, **kwargs) File "/usr/lib/python3.9/site-packages/vdsm/common/libvirtconnection.py", line 131, in wrapper ret = f(*args, **kwargs) File "/usr/lib/python3.9/site-packages/vdsm/common/function.py", line 94, in wrapper return func(inst, *args, **kwargs) File "/usr/lib64/python3.9/site-packages/libvirt.py", line 2818, in setSchedulerParameters raise libvirtError('virDomainSetSchedulerParameters() failed') libvirt.libvirtError: Invalid value '-1' for 'cpu.max': Invalid argument ``` This seems to be caused by some change in cgroups v2 which does not consider negative value as valid anymore: ``` # echo -1 > cpu.max -bash: echo: write error: Invalid argument ``` But this is also a libvirt problem because documentation clearly says: ``` A domain with quota as any negative value indicates that the domain has infinite bandwidth for vCPU threads, which means that it is not bandwidth controlled. ```