The following reply was made to PR port-xen/29999; it has been noted by GNATS.

From: Manuel Bouyer <bouyer@antioche.lip6.fr>
To: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Cc: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>, gnats-bugs@NetBSD.org,
	port-xen-maintainer@NetBSD.org, gnats-admin@NetBSD.org,
	netbsd-bugs@NetBSD.org
Subject: Re: port-xen/29999: ctrl_if_interrupt IPL problem
Date: Tue, 19 Apr 2005 09:06:54 +0200

 On Tue, Apr 19, 2005 at 02:51:22AM +0100, Christian Limpach wrote:
 > >if there's a way to poll events (i couldn't find any),
 > >i think it's better to use it because ddb needs to do busy-loop anyway.
 > 
 > I think it should work to do HYPERVISOR_block calls in the loop. 
 > HYPERVISOR_block will return as soon as there are any (unmasked) events 
 > pending and then one could call the control message handler from the loop 
 
 Ha, I didn't know HYPERVISOR_block(). I'll experiment with that.
 Thanks !
 
 > --  you might have entered the debugger at a bad moment where the control 
 > message handling is in an inconsistent state, but there's not much you can 
 > do about that.
 
 There is also the issue that we may receive control message for something
 else than the console. As all but console use CALLBACK_IN_BLOCKING_CONTEXT
 they will be queued up, but eventually the ring will overflow.
 
 > At some point, we will move the console I/O into a seperate 
 > shared page, having it shared with the control messages is just too 
 > inconvenient.
 
 Sure ! :)
 
 -- 
 Manuel Bouyer <bouyer@antioche.eu.org>
      NetBSD: 26 ans d'experience feront toujours la difference
 --