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Hi,

I would just like to share my idea on somehow managing sr-iov networking
attributes in neutron (e.g. mac addr, ip addr, vlan).  I've had experience
implementing this and that was before pci-passthrough feature in nova
existed.  Basically, nova still did the plugging and the unplugging of vifs
and neutron did all the provisioning of networking attributes.  At that
time, the best hack I can do was to treat sr-iov nics as ordinary vifs that
were distinguishable by nova and neutron.  So to implement that, when
booting an instance in nova, a certain sr-iov-vf-specific extra_spec was
used (e.g. vfs := 1) indicating the number of sr-iov vfs to create and
eventually represented as mere vif objects in nova.  In nova, the sr-iov
vfs were represented as vifs but a special exception was made wherein
sr-iov vfs aren't really plugged, because of course it isn't necessary.  In
effect, the vifs that represent the vfs were accounted in the db including
its ip and mac addresses, and vlan tags.  With respect to l2 isolation, the
vlan tags were retrieved when booting the instance through neutron api and
were applied in libvirt xml.  To summarize, the networking attributes such
as ip and mac addresses and vlan tags were applied normally to vfs and thus
preserved the normal "OS way" of managing these like ordinary vifs.
 However, since its just a hack, some consequences and issues surfaced such
as, proper migration of these networking attributes weren't tested,
 libvirt seems to mistakenly swap the mac addresses when rebooting the
instances, and most importantly the vifs that represented the vfs lack
passthrough-specific information.  Since today OS already has this concept
of PCI-passthrough, I'm thinking this could be combined with the idea of a
vf that is represented by a vif to have a complete abstraction of a
manageable sr-iov vf.  I have not read thoroughly the preceeding replies,
so this idea might be redundant or irrelevant already.

Cheers,
Pepe


On Thu, Oct 17, 2013 at 4:32 AM, Irena Berezovsky <irenab at mellanox.com>wrote:

>  Hi,
>
> As one of the next steps for PCI pass-through I would like to discuss is
> the support for PCI pass-through vNIC.
>
> While nova takes care of PCI pass-through device resources  management and
> VIF settings, neutron should manage their networking configuration.
>
> I would like to register a summit proposal to discuss the support for PCI
> pass-through networking.
>
> I am not sure what would be the right topic to discuss the PCI
> pass-through networking, since it involve both nova and neutron.
>
> There is already a session registered by Yongli on nova topic to discuss
> the PCI pass-through next steps.
>
> I think PCI pass-through networking is quite a big topic and it worth to
> have a separate discussion.
>
> Is there any other people who are interested to discuss it and share their
> thoughts and experience?
>
>
>
> Regards,
>
> Irena
>
>
>
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>
>


-- 
To stop learning is like to stop loving.
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