[libvirt] network down lead vm been shutdown

hi,all the connection between remote-viewer and guest is good, now unplug Network Cable, wait several minutes, then kill virt-viewer. now guest will be shutdwn. ---winxp.log of libvirt---------- handle_dev_display_connect: connect handle_new_display_channel: add display channel client handle_new_display_channel: New display (client 0x7f1cbf9f6ed0) dcc 0x7f1c584db2b0 stream 0x7f1cbfd61560 handle_new_display_channel: jpeg disabled handle_new_display_channel: zlib-over-glz disabled listen_to_new_client_channel: NEW ID = 0 display_channel_client_wait_for_init: creating encoder with id == 0 reds_handle_read_link_done: spice channels 3 should be encrypted reds_handle_auth_mechanism: Auth method: 1 reds_show_new_channel: channel 3:0, connected successfully, over Secure link inputs_connect: inputs channel client create flush_display_commands: update timeout red_channel_client_disconnect: 0x7f1c584db2b0 (channel 0x7f1c580458d0 type 2 id 0) display_channel_client_on_disconnect: validate_surface: failed on 13 validate_surface: panic !worker->surfaces[surface_id].context.canvas 2013-05-02 09:00:16.717+0000: shutting down