Re: [net-next,1/2] add iovnl netlink support

[Chris Wright <chrisw@redhat.com>]

* Arnd Bergmann (arnd@arndb.de) wrote:
> On Wednesday 21 April 2010, Chris Wright wrote:
> > * Arnd Bergmann (arnd@arndb.de) wrote:
> > > On Wednesday 21 April 2010, Chris Wright wrote:
> > > > * Arnd Bergmann (arnd@arndb.de) wrote:
> > > > > Since it seems what you really want to do is to do the exchange with the
> > > > > switch from here, maybe the hardware configuration part should be moved
> > > > > the DCB interface?
> > > > 
> > > > I suppose this would work  (although it's a bit odd being out of scope
> > > > of DCB spec).
> > > 
> > > It could be anywhere, it doesn't have to be the DCB interface, but could
> > > be anything ranging from ethtool to iplink I guess. And we should define
> > > it in a way that works for any SR-IOV card, whether it's using Cisco's
> > > protocol in firmware, 802.1Qbg VDP in firmware, lldpad to do VDP or
> > > none of the above and just provides an internal switch like all the
> > > existing NICs.
> > 
> > Heh, that's exactly what iovnl does ;-)
> 
> No, according to what you write below, it's exactly what iovnl does *not* do,
> i.e. part 1 in my list.

OK, I see...in this case to me hw setup was the port profile for the
enic to initiate host<->switch negotiation, sorry for confusion.

> > > 1. Setting up the slave device
> > >  a) create an SR-IOV VF to assign to a guest
> > >  b) create a macvtap device to pass to qemu or vhost
> > >  c) attach a tap device to a bridge
> > >  d) create a macvlan device and put it into a container
> > >  e) create a virtual interface for a VMDq adapter
> > 
> > OK, but iovnl isn't doing this.
> 
> The set_mac_vlan that Scott's patch adds seems to implement 1a), as far
> as I can tell. Interestingly, this is not actually implemented in
> the enic driver in patch 2/2. So if we all agree that this is out of the
> scope of iovnl, let's just remove it from the interface and find another
> way for it (ethtool, iplink, ..., as listed above).

Scott, any objection?  At least a way to keep moving forward on the port
profile bit.

> Note that we still need to pass the MAC address and VLAN ID (or a list
> of these) to the external switch, my point is just that this should be
> separate from enforcing it in the hypervisor.

Yup, we should focus on reconciling the diff of enic vs vpd port profile
needs.

> > > 2) Registering the slave with the switch
> > >  a) use Cisco protocol in enic firmware (see patch 2/2)
> > >  b) use standard VDP in lldpad
> > >  c) use reverse-engineered cisco protocol in some user tool for
> > >     non-enic adapters.
> > >  d) use standard VDP in firmware (hopefully this never happens)
> > >  e) do nothing at all (as we do today)
> > 
> > And this is the step that is the main purpose of iovnl.
> > 
> > Here's the simplest snippet of libvirt to show this.  It sends
> > set_port_profile netlink messages and then creates macvtap.  As simple
> > as it gets...
> > 
> > --- a/src/qemu/qemu_conf.c
> > +++ b/src/qemu/qemu_conf.c
> > @@ -1470,6 +1470,11 @@ qemudPhysIfaceConnect(virConnectPtr conn,
> >          net->model && STREQ(net->model, "virtio"))
> >          vnet_hdr = 1;
> >  
> > +    setPortProfileId(net->data.direct.linkdev,
> > +                      net->data.direct.mode,
> > +                      net->data.direct.profileid,
> > +                      net->mac);
> > +
> >      rc = openMacvtapTap(net->ifname, net->mac, linkdev, brmode,
> >                          &res_ifname, vnet_hdr);
> 
> Ok. In case of VDP, I guess this needs to be extended with the vlan ID
> that has been configured, and possibly with a UUID, because we need to
> pass the same one on the target machine if we migrate it.
> 
> Alternatively, the setPortProfileId could figure out the MAC address and
> VLAN ID from the device itself, but then we don't need to pass either of
> them.