[libvirt-users] error: unsupported configuration: block I/O throttling not supported with this QEMU binary

Hi, guys. I want to change block I/O throttle using 'virsh blkdeviotune' with vm not running, it reported an error: # virsh blkdeviotune instance-000000dc /dev/loop0 --total-bytes-sec 20000000 --total-iops-sec 20 --config error: Unable to change block I/O throttle error: unsupported configuration: block I/O throttling not supported with this QEMU binary I can do this when the vm is running. Is it a bug? How can I fix this problem. BTW,My libvirt version is 0.9.13: # virsh version Compiled against library: libvir 0.9.13 Using library: libvir 0.9.13 Using API: QEMU 0.9.13 Running hypervisor: QEMU 1.1.2 Thanks. 2012-11-28 hzguanqiang