[libvir] Could not connect to xend

Hi. When I tried to run virsh to connect to xen, I have got an error --- libvirt failed to open connection to xend. Here is output with DEBUG enabled. What kind of additional information do you need? [root@localhost ~]# LIBVIRT_DEBUG=SPAM virsh DEBUG: libvirt.c: virInitialize (register drivers) DEBUG: libvirt.c: virConnectOpenAuth (name=(null), auth=0xb7ed79d8, flags=0) DEBUG: libvirt.c: do_open (Probed xen:///) DEBUG: libvirt.c: do_open (Using xen:/// as default URI, 1 hypervisor found) DEBUG: libvirt.c: do_open (name "xen:///" to URI components: scheme xen opaque (null) authority (null) server (null) user (null) port 0 path / ) DEBUG: libvirt.c: do_open (trying driver 0 (Test) ...) DEBUG: libvirt.c: do_open (driver 0 Test returned DECLINED) DEBUG: libvirt.c: do_open (trying driver 1 (QEMU) ...) DEBUG: libvirt.c: do_open (driver 1 QEMU returned DECLINED) DEBUG: libvirt.c: do_open (trying driver 2 (Xen) ...) DEBUG: xen_unified.c: xenUnifiedOpen (trying Xen sub-driver 0) DEBUG: xen_unified.c: xenUnifiedOpen (Xen sub-driver 0 open ok ) DEBUG: xen_unified.c: xenUnifiedOpen (trying Xen sub-driver 2) libvir: Xen Daemon error : internal error failed to connect to xend libvir: Xen Daemon error : internal error failed to connect to xend DEBUG: xen_unified.c: xenUnifiedOpen (Xen sub-driver 2 open failed ) DEBUG: libvirt.c: do_open (driver 2 Xen returned ERROR) DEBUG: hash.c: virUnrefConnect (unref connection 0x807bf88 xen:/// 1) DEBUG: hash.c: virReleaseConnect (release connection 0x807bf88 xen:///) error: failed to connect to the hypervisor