Xen 3.3: unknown type console at xenbus0 id0 not configured

[Juan RP <xtraeme%gmail.com@localhost>]

Hey,

I've just installed Xen-3.3 on -current/amd64, seems to work
fine all the time except for some issues that I will report
later. One of them is that I see some of these lines reported
in domUs:

$ dmesg|grep unknown
unknown type console at xenbus0 id 0 not configured
unknown type console at xenbus0 id 0 not configured
unknown type console at xenbus0 id 0 not configured
$

What do they mean? perhaps it's new in Xen 3.1 or up, but
I'd like to know if they are useful or not.