A subtle networking question - a bond/team over a qsfp+ virtual functions - can it be done?
Wrestling a day and over with an network configuration that may not make a sense at all - but not quite sure.
The situation: I want to use a VM as a routing gateway on a network, and did pass the 4 interfaces of an qsfp+ card ( Intel X520-Q1) as virtual function links to the VM. The card running in the host is "Intel Corporation Ethernet Converged Network Adapter X520-Q1", I want to make an bond over the 4 qsfp+ interfaces in the VM and use it as a gateway on the network. I currently use similar configuration, but with an Intel i350 card at 1Gb/s, with one interface and not 4.
The bonding driver in the VM definitely refuses to make an working bond on the 4 VF functions of the qsfp coming from the host. There is nothing in the logs - I am able to enslave the 4 interfaces, but the bond never comes up - and no error is given when I try 'ip link set bond0 up' - the link just stays down.
I am able to make a working bond on the host (and not in the guest) with the 4 PHYSICAL interfaces presented by the card, but not with the VF's. It actually may not make a sense at all to make an 802.3ad bond on virtual functions - what if I pass another virtual function from the same physical one as an separate interface to another VM?
Pretty much same result with the teaming driver - an 802.3ad team is formed, but never comes up - and nothing in the logs,
I think I need to pass the card as a pci device to the guest - but may there be be a way to use virtual functions presented by the card for bonding in the guest? I do not want to read the bonding / teaming driver code in order to understand this.
Any (qualified) suggestion is welcome.