Xen3 DomU spins 100% busy during console access

Hi,

I was in vim in insert mode and just pasted a large
selection into the 
xenconsole - instant busy lockup. Once I figured out what
caused it I 
was able to repeat this 5 out of 5 times.

I tried this with small simple lines and was never able to
lockup the 
console. I have however managed to to cause this lockup by
pasting less 
than 1KB of data, and then pasting more in small pieces
until it exceeds 
1KB. I have no idea why 1KB might be a magic number but
perhaps its a hint.

lastly I also had a similar lockup by just connecting to the
console 
with 'xm console test1' no copy paste with the mouse at all.

this is an intel HT core, both Dom0 and DomU running 4.99.4
from Nov28 
daily builds.

xentools30-3.0.3nb1
xenkernel30-3.0.3

Simon