Re: xen-backend (was: vifs not working?)

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

On Sun, May 25, 2008 at 05:56:33PM +0200, Christoph Egger wrote:
> 
> I think, it is best to start with a (stupid) question:
> 
> 
> When launching a PV guest with one disk and no vif,
> what is the successful code-path from "xm create"
> to the guest kernels boot message ?
> 
> Somewhere in between must be obviously the error.
> I turned on all dom0 xen debug messages and all
> what I get are debug messages from the xenbus_xs.c

From what I remeber, xm (or xend) creates the new domain's memory space
and loads it with the kernel, and create the new domain's entries (both
frontend and backend) in xenstore. Writing the backend values to xenstore
should trigger a call to *xenbus_create in backend drivers.
This will set a watch on the corresponding frontend entries, and switch the
backend state to XenbusStateInitWait. This should wakeup xenbackendd
which calls the scripts for the corresponding backends. The script
does whatever config is needed and writes to the store the informations for
the backend, and write the backend's "hotplug-status" entry to
"connected". I think writing hotplug-status is what cause xm or xend to
unpause the domU, which starts booting.

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