Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

On 9/11/11 2:38 AM, "Michael S. Tsirkin" [off-list ref] wrote:

On Fri, Sep 09, 2011 at 09:33:33AM -0700, Roopa Prabhu wrote:

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On 9/8/11 10:55 PM, "Michael S. Tsirkin" [off-list ref] wrote:

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On Thu, Sep 08, 2011 at 07:53:11PM -0700, Roopa Prabhu wrote:

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Phase 1: Goal: Enable hardware filtering for all macvlan modes
    - In macvlan passthru mode the single guest virtio-nic connected will
      receive traffic that he requested for
    - In macvlan non-passthru mode all guest virtio-nics sharing the
      physical nic will see all other guest traffic
      but the filtering at guest virtio-nic

I don't think guests currently filter anything.

I was referring to Qemu-kvm virtio-net in
virtion_net_receive->receive_filter. I think It only passes pkts that the
guest OS is interested. It uses the filter table that I am passing to
macvtap in this patch.

This happens after userspace thread gets woken up and data
is copied there. So relying on filtering at that level is
going to be very inefficient on a system with
multiple active guests. Further, and for that reason, vhost-net
doesn't do filtering at all, relying on the backends
to pass it correct packets.

Ok thanks for the info. So in which case, phase 1 is best for PASSTHRU mode
and for non-PASSTHRU when there is a single guest connected to a VF.
For non-PASSTHRU multi guest sharing the same VF, Phase 1 is definitely
better than putting the VF in promiscuous mode.
But to address the concern you mention above, in phase 2 when we have more
than one guest sharing the VF,

It's probably more interesting for a card without SRIOV support.

If its an SRIOV card I am assuming people likely using PASSTHRU mode.
Non-SRIOV cards will use any of the non-PASSTHRU mode.

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we will have to add filter lookup in macvlan
to filter pkts for each guest.

Any chance to enable hardware filters for that?

NAFAIK. Am not sure how you would do it too. Its still a single device from
where the host receives traffic from.

Thanks,
Roopa