VM guest bridging issue with i40e

There's some trouble with a kvm guest that is bridged to the host networks i40e (X710) NIC. The guest no longer receives DHCP replies and probably other traffic as well.
I bisected this back to the following commit.
commit 79c21a827e98081895a8b9650f1b0a8b37b16125

Author: Anjali Singhai Jain <[email protected]>
Date:   Thu Nov 13 03:06:14 2014 +0000

i40e: Add new update VSI flow to accommodate FW fix with VSI Loopback mode

All VSIs on a VEB should either have loopback enabled or disabled, a mixed mode is not supported for a VEB. Since our driver supports multiple VSIs per PF that need to talk to each other make sure to enable Loopback for the PF and FDIR VSI as well.

Also, we now have to explicitly enable Loopback mode otherwise we fail VSI creation for VMDq and VF VSIs.

Reproducer:
Adding bridge on the host

# brctl addbr br0
# brctl addif br0 eth6
virt XML for bridging
    <interface type='bridge'>
      <source bridge='br0'/>
    </interface>
Now request IP via DHCP from the kvm guest.

The problem appears as soon as loopback gets enabled on the main VSI. From the XL710 spec:
7.4.9.5.4.1.1 Add VSI Settings Recommendations
Table 7-86. Add VSI Recommended settings
Allow Loopback 0 for PF

Is it correct that the main VSI represents the PF? If so shouldn't loopback stay disabled for the main VSI?

Stefan