SR-IOV-Passthrough-For-Networking-Liberty

SR-IOV Networking in OpenStack Juno/Kilo/Liberty

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

Nova

Nova support for SR-IOV enables scheduling an instance with SR-IOV ports based on their network connectivity. The neutron ports' associated physical networks have to be considered in making the scheduling decision. PCI Whitelist has been enhanced to allow tags to be associated with PCI devices. PCI devices available for SR-IOV networking should be tagged with physical_network label.

For SR-IOV networking, a pre-defined tag "physical_network" is used to define the physical network to which the devices are attached. A whitelist entry is defined as:

   ["vendor_id": "<id>",] ["product_id": "<id>",]
   ["address": "[[[[<domain>]:]<bus>]:][<slot>][.[<function>]]" |
   "devname": "Ethernet Interface Name",]  
   "physical_network":"name string of the physical network"

<id> can be an asterisk (*) or a valid vendor/product ID as displayed by the Linux utility lspci. The address uses the same syntax as in lspci. The devname can be a valid PCI device name. The only device names that are supported are those displayed by the Linux utility ifconfig -a and correspond to either a PF or a VF on a vNIC.

If the device defined by the address or devname corresponds to a SR-IOV PF, all VFs under the PF will match the entry.

Multiple whitelist entries per host are supported.

Neutron

Neutron support for SR-IOV requires ML2 Plugin with SR-IOV supporting mechanism driver. Currently there is ML2 Mechanism Driver for SR-IOV capable NIC based switching (HW VEB). There are network adapters from different vendors that vary by supporting various functionality. If VF link state update is supported by vendor network adapter, the SR-IOV NIC L2 agent should be deployed to leverage this functionality .

VM creation flow with SR-IOV vNIC

• Create one or more neutron ports. Run:

  neutron port-create <net-id> --binding:vnic-type <direct | macvtap | normal>

• Boot VM with one or more neutron ports. Run:

  nova boot --flavor m1.large --image <image>
         --nic port-id=<port1> --nic port-id=<port2> <vm name>

Note that in the nova boot API, users can specify either a port-ID or a net-ID. If a net-ID is specified, it is assumed that the user is requesting a normal virtual port (which is not an SR-IOV port).