Re: [Xen-users] "XENBUS: Device with no driver" errors on Debian

[Mark Williamson <mark.williamson@xxxxxxxxxxxx>]

On Tuesday 15 July 2008, Ben Firshman wrote:
> I understand these kernel versions use paravirt_ops or something. Does
> this mean there is no PCI passthrough support? Can these kernels even
> run with a 2.6.18 dom0? I have tried upgrading to 2.6.25-2 with no luck.

You don't need a matching domU and dom0 kernel, so the kernel should work.

The paravirt_ops kernel doesn't supported PCI passthrough currently; it only 
supports unprivileged domU functionality.  If it's a paravirt_ops kernel 
you're using then you can't pass a PCI device to it.

You really need a dom0-capable kernel to successfully control a PCI device.  
Is there any reason not to just use the same kernel as dom0?  Is it a driver 
support issue?

> Can someone fill me in? I can't find any documentation about it
> anywhere. The debian package descriptions even fail to mention which
> kernels will and won't work as a dom0 - it's a matter of trial and
> error for new users it seems!

That's a bit unfortunate.  You basically need something that is capable of 
being a dom0 in order to accept a PCI passthrough.  If the domU's kernel is 
paravirt_ops then it doesn't meet this requirement.

Does the description given by apt-cache show <pkgname> mention anything about 
whether something is paravirt_ops or not?

Cheers,
Mark

>
> Ben
>
> On 15 Jul 2008, at 18:05, Ben Firshman wrote:
> > I have fixed the console by adding hvc0 to inittab, but still no
> > luck with the PCI. Both errors still show in dmesg.
> >
> > Ben
> >
> > On 14 Jul 2008, at 14:43, Ben Firshman wrote:
> >> I am running debian lenny, with the standard Xen 3.2 packages, with
> >> the 2.6.18-6-xen-686 kernel as dom0, and 2.6.24-1-xen-686 as domU.
> >> Everything is working fine apart from the console and the PCI
> >> passthrough. I am getting these errors in the domU on startup:
> >>
> >> XENBUS: Device with no driver: device/pci/0
> >> XENBUS: Device with no driver: device/console/0
> >>
> >> Does this mean the modules are missing? I have the linux-
> >> modules-2.6.24-1-xen-686 package installed in the domU, I can't
> >> understand what could be wrong. Do they need to built into the
> >> kernel or something?
> >>
> >> pciback is working fine on the dom0:
> >>
> >> pciback 0000:04:00.0: seizing device
> >> pciback 0000:01:00.0: seizing device
> >> pciback 0000:01:00.1: seizing device
> >> pciback 0000:01:00.2: seizing device
> >> pciback 0000:01:01.0: seizing device
> >> pciback 0000:01:02.0: seizing device
> >>
> >> Thanks
> >>
> >> Ben
> >>
> >> _______________________________________________
> >> Xen-users mailing list
> >> Xen-users@xxxxxxxxxxxxxxxxxxx
> >> http://lists.xensource.com/xen-users
> >
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> > http://lists.xensource.com/xen-users
>
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