Unable to start a Xen3 DOMU

["Steven M. Bellovin" <smb%cs.columbia.edu@localhost>]

I have a Xen3 DOM0 kernel running on a fairly recent -current (I'm not
certain of the exact date, but it's 4.99.3, from within the last week, I
believe -- I'm trying to run an absolutely up-to-date one, but I haven't
been able to build -current for the last day or so....)  I'm trying to run
a Xen3 DOMU now, but I can't get it to fire up.  When I do 'xm create -c',
I get

        Error: Device 0 (vif) could not be connected. Hotplug scripts not
working.

Tracing vif-bridge shows this:

 + PATH=/bin:/usr/bin:/usr/pkg/bin:/sbin:/usr/sbin:/usr/pkg/sbin
+ export PATH
+ xpath=/local/domain/0/backend/vif/5/0
+ xstatus=2
+ xenstore-read /local/domain/0/backend/vif/5/0/bridge
xenstore-read: couldn't read path /local/domain/0/backend/vif/5/0/bridge
+ xbridge=

I have xend and xenbackendd running (via rc.d); I haven't yet started
xendomains, since its purpose seems to be to start/stop DOMUs and I don't
have any yet.

(Btw, I've built a NetBSD DOMU image by manually untarring install sets in
the VND disk and doing other useful things, such as creating its /dev,
editing its rc.conf, etc -- that all seemed easier than running sysinst on
it.)

                --Steven M. Bellovin, http://www.cs.columbia.edu/~smb