error: Unable to initialize /machine cgroup: Invalid argument

with this in libvirtd.log

virCgroupDetect:373 : Failed to detect mounts for /machine
qemuInitCgroup:425 : Unable to initialize /machine cgroup: Invalid argument

and the error goes away if I unmount /sys/fs/cgroup.

Reverting to 1.0.4 fixes this, but this exposes another thing that I report even if I'm not sure it's an error: if I create a domain with 1.0.5.1 (I use the latest virt-manager to do this), in the xml of the domain there's a line that doesn't seem to have the close tag

<controller type='pci' index='0' model='pci-root'/>

If I revert to 1.0.4 the domain with this line in the xml doesn't even get listed between the available domains and I got this in libvirtd.log

virDomainControllerDefParseXML:4838 : internal error Unknown controller type 'pci'

deleting the interested line make it available again.

Please let me know if you need further informations on the matters.

Matteo