Xen: Connecting and Disconnecting Device

# xm block-list domain
Vdev  BE handle state evt-ch ring-ref BE-path
768    0    0     1      -1     -1    /local/domain/0/backend/vbd/20/768
5632   0    0     1      -1     -1    /local/domain/0/backend/vbd/20/5632
# xenstore-read /local/domain/0/backend/vbd/20/5632/params
/mnt/w7.iso
# xm block-detach domain 5632 -f
# xm block-attach domain file:/path/to/device /dev/hdc r