Re: vifs not working?

[Sarton O'Brien <bsd-xen%roguewrt.org@localhost>]

On Wed, 21 May 2008 10:20:14 am der Mouse wrote:
> >> Okay, after a hand from two helpful listmembers, I've managed to get
> >> xen to start.  dom0 seems to work just fine.  But there's something
> >> wrong when trying to run domU machines: I can't make the network
> >> work.  [...]
> > I can't say that I've experimented much outside the standard
> > configuration but it's my understanding, due to the inability to
> > utilise pci devices within a domu, that a bridge interface is
> > required for a vif to materialise.
> 
> I'm fairly sure this is not the case.  When I "xm network-attach" a
> networkless domU, both the xennet and vif interfaces show up, and they
> work just fine as far as I've been able to tell (ping, ping -f - I have
> only a few minutes to play with them before xm errors and they go away
> again).  I'm giving serious thought to running xm network-attach and
> then stopping the xm process, in the hopes that it's where the timeout
> is happening and that that will make the interfaces stick around.
> 
> I may try a bridge, but if vifs _must_ be bridge members in order to
> work, something is cripplingly busted.  I suppose I could leave any I
> don't want bridged in one-member bridges, but that is quite definitely
> a workaround, not a fix.

I guess it's a matter of perspective, I'd be more inclined to say 'lacking in 
functionality' but that's me.

I guess my thought is, without an ethernet device nor a bridge, how is a vif 
to communicate? What exactly are you pinging? If you are able to ping 
anything other than localhost then I am a little surprised.

> I don't see what PCI access has to do with it; nothing says there's a
> PCI bus anywhere in sight.

No ... but if you were to opt out of a bridge, then you'd usually choose a 
physical interface. Unless there is some other way to emulate the physical 
layer that I'm unaware of (quite possibly).

The bridge is merely required to emulate the use of a physical interface. 
Obviously it can be utilised for more.

> I also wrote
> 
> >> Appended after my signature below is dmesg from the domU machine
> >> (taken after an attempt to use xm network-attach on it).
> 
> and then neglected to include it.  Fixed herewith.

I thought it was just me :)

Sarton