Re: [suspend/resume] Debugging via console

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Sun, May 04, 2008 at 05:08:42PM +0200, Jean-Yves Migeon wrote:
> Hi list,
> 
> Is there any way to have access to some debugging console through 
> hypervisor for a domU?
> 
> The goal is to have some kind of "failback" access for basic printk() 
> operations for debugging purposes, in case xencons device suspend/resume 
> goes horribly wrong in a domU.
> 
> There is still the HYPERVISOR_console_io hypercall, but I do not know if 
> it is the proper way to do it. BTW, it is restricted to dom0, except 
> when Xen is built with debug.

Yes, the proper way to do this is to use HYPERVISOR_console_io().
There are XENPRINTK macros that already do this in the sources
(or you can call printk directly). As you said, this requires a debug
hypervisor, and a serial console (the NetBSD xenkernel3 package provides
a debug hypervisor).

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--