General information may be found here https://wiki.openstack.org/wiki/SR-IO...

OpenStack Juno adds inbox support to request VM access to virtual network via SR-IOV NIC. With the introduction of SR-IOV based NICs, the traditional virtual bridge is no longer required. Each SR-IOV port is associated with a virtual function (VF). SR-IOV ports may be provided by Hardware-based Virtual Ethernet Bridging (HW VEB); or they may be extended to an upstream physical switch (IEEE 802.1br). There are two ways that SR-IOV port may be connected:

    directly connected to its VF
    connected with a macvtap device that resides on the host, which is then connected to the corresponding VF

Neutron
Using ML2 Neutron plugin modify /etc/neutron/plugins/ml2/ml2_conf.ini:

[ml2]
tenant_network_types = vlan
type_drivers = vlan
mechanism_drivers = openvswitch,sriovnicswitch
[ml2_type_vlan]
network_vlan_ranges = physnet1:2:100

If SRIOV network adapters support VF link state setting and admin state management is desired, make sure to add /etc/neutron/plugins/ml2/ml2_conf_sriov.ini with following section:

[ml2_sriov]
agent_required = True

Neutron server should be run with the two configuration files /etc/neutron/plugins/ml2/ml2_conf.in and /etc/neutron/plugins/ml2/ml2_conf_sriov.ini

neutron-server --config-file /etc/neutron/neutron.conf --config-file /etc/neutron/plugins/ml2/ml2_conf.ini --config-file /etc/neutron/plugins/ml2/ml2_conf_sriov.ini