Re: no udev events in netback domU driver domain 2.6.32.14

[philip tricca <flihp@twobit.us>]

Konrad Rzeszutek Wilk wrote:
> On Tue, Jul 06, 2010 at 10:04:03PM -0400, philip tricca wrote:
>> I've spent a bit trying to configure and unprivileged network driver
>> domain using the current 2.6.32.14 pvops kernel (haven't up'd to .15
>> due to incompatibility with 4.0.0 release).  I've been partially
>> successful but am failing in what I'd think would be the last step:
>> getting udev rules to fire when attaching network devices using
>> xen-netback & xen-netfront drivers.  From my reading of the pvops
>> wiki page there's a possibility that the wiring between the drivers
>> and the udev events may not have been forward ported completely.  In
>> fact, using 'udevadm monitor' I don't see any events at all when the
>> vif is created in the driver domain and when eth0 is created in the
>> client (both are created when xm network-attach is run).
> 
> You won't see the 'eth0' being created from Dom0 side. But you should
> see the rest:

Correct.  I don't see any udev events from dom0: the nic is passed to a 
domU (call it a driver domain) through pciback so all of the vif events 
happen there.  Another domU is getting its eth0 through the netback 
offered up by the driver domain

>> Is anyone familiar enough with these portions of the driver to
>> comment on this?  If this "should" be working I can post the details
>> of my setup and debug information if necessary but I don't want to
>> flood the list with a huge email if it isn't necessary.
> 
> This is what I get:
> 
> [root@phenom ~]#  udevadm monitor --kernel --env --property
> monitor will print the received events for:
> KERNEL - the kernel uevent

<snip\>

I am now getting the right udev events (the same ones Konrad shows) in 
both my driver domain and in the client.  The problem I am still having 
is related to the xenstore.

The network scripts run by udev access data in the xen store and use it 
to return status information to dom0:
/local/domain/X/backend/vif/Y/Z/hotplug-status
The xenstore is completely inaccessible from my driver domain however. 
I've installed the xenstored daemon in the driver domain which requires 
running it with the --no-domain-init option to keep it from trying to 
execute privileged operations (it's not dom0).

Even with the xenstored daemon running though I (and the networking 
scripts) still can't access then xenstore.

I'm making progress but I could use a hint if someone's got one.

Cheers,
- Philip