[libvirt] virsh nodedev-dempxml is not supported by the connection driver

Hi, I meet a problem when I use the command "virsh nodedev-dumpxml pci_0000_00_19_0",it shows as follows: root@shahe26:~# virsh nodedev-list error: Failed to count node devices error: this function is not supported by the connection driver: virNodeNumOfDevices root@shahe26:~# virsh nodedev-dumpxml pci_0000_00_19_0 error: Could not find matching device 'pci_0000_00_19_0' error: this function is not supported by the connection driver: virNodeDeviceLookupByName root@shahe26:~# virsh -version 0.9.0 root@shahe26:~# virsh net-list Name State Autostart ----------------------------------------- default active yes root@shahe26:~# virsh list Id Name State ---------------------------------- root@shahe26:~# I find that only the command "virsh nodedev-? ***" can't work . How can I solve this problem ? thanks. best regards, qinguan