On Thu, Dec 07, 2017 at 08:45:33AM -0800, Alexander Duyck wrote:

As far as indicating that the interfaces are meant to be enslaved I
wonder if we couldn't look at tweaking the PCI layout of the guest and
use that to indicate that a given set of interfaces are meant to be
bonded. For example the VFs are all meant to work as a part of a
multi-function device. What if we were to make virtio-net function 0
of a PCI/PCIe device, and then place any direct assigned VFs that are
meant to be a part of the bond in functions 1-7 of the device? Then it
isn't too far off from the model we have on the host where if the VF
goes away we would expect to see the traffic on the PF that is usually
occupying function 0 of a given device.

This pretty much precludes removing them with hotplug.

But as long as we are happy to limit this to pci devices,
maybe we should put them behind a pci bridge.

All devices behind a bridge would be assumed to have
the same backend.

QEMU has pci-bridge-seat which we could reuse for this -
just need to build a similar pci express bridge.

-- 
MST