Libvirt-direct-network

= vNIC support using libvirt VIF Driver =

Hardware Based Virtual NICs (SR-IOV) can be achieved in via the following ways:
 * Direct Interface (Para-virtualized)
 * PCI Device (hostdev).

The interface can be assigned by using the interface name or PCI device address.

This approach has several limitations well documented in libvirt site here

It is possible to avoid these limitations by creating a libvirt network with a device pool containing all the VFs of an SR-IOV device. A network device is chosen from the interface pool and directly assigned to the guest VM.

This support is available using:
 * libvirt 0.9.4 - used for direct assignment
 * libvirt 0.10.0 - used for PCI device assignment.

Configuring the vNIC
In order to configure the vNIC the network pool name and the vnic_type should be provided to the VIF Driver. First phase: The network pool name will be provided by adding a configuration variable to the nova.conf named 'physical_network' and the vnic_type is set to 'direct'.

Next Phase: You should extend the data that is provided to the VIF Driver once the quantum port is created to provide the physical network name.

Creating the Network Pool
The creation of the Network Pool will be done according to Physical Network mapping to physical interface(s) either Manually (First phase) or by the Quantum Plugin Agent. An example for Network definition can be found here

Implementation

 * Additional vnic_type - 'direct' is defined.
 * The Implementation extends LibvirtGenericVIFDriver.
 * Initial support is for direct interface assignment
 * Next phase will add support for PCI device assignment.

Related Nova blueprint - Adding libvirt network interface to VIF Driver blueprint

Mellanox Quantum Plugin requires this functionality

You can watch the review process here: https://review.openstack.org/#/c/29048/