XEN: Giving guest complete control over NIC(s).

[list user]

Gilboa Davara wrote:
> Hello all,
> 
> I'm installing Xen on a machine with multiple Gbps NICs that I'm using
> for driver development.
> Is there a way to give the guest complete control over a number of these
> NICs without having the host to route/bridge the traffic to the guest?

Yes.

1) use "lspci" to determine which PCI slots the network cards occupy
2) Hide them from dom0:  in dom0's grub.conf add "pciback.hide(xx:yy.z)"
    to the kernel boot parameters. e.g.
      "module /vmlinuz-2.6.16-xen ro root=/dev/vg0/fc4 \
      "pciback.hide=(aa:aa.a)(bb:bb.b)"
    Multiple slots may be hidden by adding additional parentheticized
    slot info.  *Don't use quotes* inside the parens.
3) give the selected pci slots to the domU by adding a corresponding
    line to its config file: e.g into /etc/xen/vm1 add:
      "pci = ['aa:aa.a','bb:bb.b']"
     Multiple slots are given within the brackets, *separated by commas*,
     *quotes are required* within the brackets.

As of 3.0.2 exported pci slots crash domUs when when trying to 
automagically save/restore domUs using xendomains or the other tools. 
They will require clean boots.

Hope that helps.


> If it's impossible, what's the expected performance hit in handling raw
> Ethernet traffic within the guest OS?
> 
> Gilboa
>