Hi, I was playing around with vcpupin and emulatorpin and managed to get into a strange state. From within python I get the following: (Pdb) dom = self._lookup_by_name(instance.name) (Pdb) dom.vcpus() ([(0, 1, 5970000000L, 2), (1, 1, 4580000000L, 3)], [(False, False, True, False), (False, False, True, False)]) The problem is that the cpuinfo for the second vcpu has it running on physical cpu 3, even though the affinity mask (within python and from taskset) says it can only run on physical cpu 2. The VM in question was originally started up running on pysical cpus 2 and 3, then I used the vcpupin/emulatorpin commands to only use physical cpu 2. Anyone got any ideas? I'm using libvirt-1.1.2 and libvirt-python-1.1.2 on a 3.4.82 kernel. Some more data: I have one VM running, taskset shows affinity as follows: root@compute-0:~# taskset -pac 7680 pid 7680's current affinity list: 2 pid 7681's current affinity list: 1-3 pid 7683's current affinity list: 2 pid 7684's current affinity list: 0 "virsh" has the following view: root@compute-0:~# virsh list Id Name State ---------------------------------------------------- 3 instance-0000001d running root@compute-0:~# virsh emulatorpin 3 emulator: CPU Affinity ---------------------------------- *: 2 root@compute-0:~# virsh vcpupin 3 VCPU: CPU Affinity ---------------------------------- 0: 2 1: 2 Thanks, Chris