+ uses this interrupt to get information about link status and errors
+ in the fast path.
+
+.. _enic-flow-director:
+
+Flow director support
+---------------------
+
+Advanced filtering support was added to 1300 series VIC firmware starting
+with version 2.0.13 for C-series UCS servers and version 3.1.2 for UCSM
+managed blade servers. In order to enable advanced filtering the 'Advanced
+filter' radio button should be enabled via CIMC or UCSM followed by a reboot
+of the server.
+
+With advanced filters, perfect matching of all fields of IPv4, IPv6 headers
+as well as TCP, UDP and SCTP L4 headers is available through flow director.
+Masking of these fields for partial match is also supported.
+
+Without advanced filter support, the flow director is limited to IPv4
+perfect filtering of the 5-tuple with no masking of fields supported.
+
+SR-IOV mode utilization
+-----------------------
+
+UCS blade servers configured with dynamic vNIC connection policies in UCS
+manager are capable of supporting assigned devices on virtual machines (VMs)
+through a KVM hypervisor. Assigned devices, also known as 'passthrough'
+devices, are SR-IOV virtual functions (VFs) on the host which are exposed
+to VM instances.
+
+The Cisco Virtual Machine Fabric Extender (VM-FEX) gives the VM a dedicated
+interface on the Fabric Interconnect (FI). Layer 2 switching is done at
+the FI. This may eliminate the requirement for software switching on the
+host to route intra-host VM traffic.
+
+Please refer to `Creating a Dynamic vNIC Connection Policy
+<http://www.cisco.com/c/en/us/td/docs/unified_computing/ucs/sw/vm_fex/vmware/gui/config_guide/b_GUI_VMware_VM-FEX_UCSM_Configuration_Guide/b_GUI_VMware_VM-FEX_UCSM_Configuration_Guide_chapter_010.html#task_433E01651F69464783A68E66DA8A47A5>`_
+for information on configuring SR-IOV Adapter policies using UCS manager.
+
+Once the policies are in place and the host OS is rebooted, VFs should be
+visible on the host, E.g.:
+
+.. code-block:: console
+
+ # lspci | grep Cisco | grep Ethernet
+ 0d:00.0 Ethernet controller: Cisco Systems Inc VIC Ethernet NIC (rev a2)
+ 0d:00.1 Ethernet controller: Cisco Systems Inc VIC SR-IOV VF (rev a2)
+ 0d:00.2 Ethernet controller: Cisco Systems Inc VIC SR-IOV VF (rev a2)
+ 0d:00.3 Ethernet controller: Cisco Systems Inc VIC SR-IOV VF (rev a2)
+ 0d:00.4 Ethernet controller: Cisco Systems Inc VIC SR-IOV VF (rev a2)
+ 0d:00.5 Ethernet controller: Cisco Systems Inc VIC SR-IOV VF (rev a2)
+ 0d:00.6 Ethernet controller: Cisco Systems Inc VIC SR-IOV VF (rev a2)
+ 0d:00.7 Ethernet controller: Cisco Systems Inc VIC SR-IOV VF (rev a2)
+
+Enable Intel IOMMU on the host and install KVM and libvirt. A VM instance should
+be created with an assigned device. When using libvirt, this configuration can
+be done within the domain (i.e. VM) config file. For example this entry maps
+host VF 0d:00:01 into the VM.
+
+.. code-block:: console
+
+ <interface type='hostdev' managed='yes'>
+ <mac address='52:54:00:ac:ff:b6'/>
+ <source>
+ <address type='pci' domain='0x0000' bus='0x0d' slot='0x00' function='0x1'/>
+ </source>
+
+Alternatively, the configuration can be done in a separate file using the
+``network`` keyword. These methods are described in the libvirt documentation for
+`Network XML format <https://libvirt.org/formatnetwork.html>`_.
+
+When the VM instance is started, the ENIC KVM driver will bind the host VF to
+vfio, complete provisioning on the FI and bring up the link.
+
+.. note::
+
+ It is not possible to use a VF directly from the host because it is not
+ fully provisioned until the hypervisor brings up the VM that it is assigned
+ to.
+
+In the VM instance, the VF will now be visible. E.g., here the VF 00:04.0 is
+seen on the VM instance and should be available for binding to a DPDK.
+
+.. code-block:: console
+
+ # lspci | grep Ether
+ 00:04.0 Ethernet controller: Cisco Systems Inc VIC SR-IOV VF (rev a2)
+
+Follow the normal DPDK install procedure, binding the VF to either ``igb_uio``
+or ``vfio`` in non-IOMMU mode.
+
+Please see :ref:`Limitations <enic_limitations>` for limitations in
+the use of SR-IOV.
+
+.. _enic-genic-flow-api:
+
+Generic Flow API support
+------------------------
+
+Generic Flow API is supported. The baseline support is:
+
+- **1200 series VICs**
+
+ 5-tuple exact Flow support for 1200 series adapters. This allows:
+
+ - Attributes: ingress
+ - Items: ipv4, ipv6, udp, tcp (must exactly match src/dst IP
+ addresses and ports and all must be specified).
+ - Actions: queue and void
+ - Selectors: 'is'
+
+- **1300 series VICS with Advanced filters disabled**
+
+ With advanced filters disabled, an IPv4 or IPv6 item must be specified
+ in the pattern.
+
+ - Attributes: ingress
+ - Items: eth, ipv4, ipv6, udp, tcp, vxlan, inner eth, ipv4, ipv6, udp, tcp
+ - Actions: queue and void
+ - Selectors: 'is', 'spec' and 'mask'. 'last' is not supported
+ - In total, up to 64 bytes of mask is allowed across all haeders
+
+- **1300 series VICS with Advanced filters enabled**
+
+ - Attributes: ingress
+ - Items: eth, ipv4, ipv6, udp, tcp, vxlan, inner eth, ipv4, ipv6, udp, tcp
+ - Actions: queue, mark, flag and void
+ - Selectors: 'is', 'spec' and 'mask'. 'last' is not supported
+ - In total, up to 64 bytes of mask is allowed across all haeders
+
+More features may be added in future firmware and new versions of the VIC.
+Please refer to the release notes.
+
+Ingress VLAN Rewrite
+--------------------
+
+VIC adapters can tag, untag, or modify the VLAN headers of ingress
+packets. The ingress VLAN rewrite mode controls this behavior. By
+default, it is set to pass-through, where the NIC does not modify the
+VLAN header in any way so that the application can see the original
+header. This mode is sufficient for many applications, but may not be
+suitable for others. Such applications may change the mode by setting
+``devargs`` parameter ``ig-vlan-rewrite`` to one of the following.
+
+- ``pass``: Pass-through mode. The NIC does not modify the VLAN
+ header. This is the default mode.
+
+- ``priority``: Priority-tag default VLAN mode. If the ingress packet
+ is tagged with the default VLAN, the NIC replaces its VLAN header
+ with the priority tag (VLAN ID 0).
+
+- ``trunk``: Default trunk mode. The NIC tags untagged ingress packets
+ with the default VLAN. Tagged ingress packets are not modified. To
+ the application, every packet appears as tagged.
+
+- ``untag``: Untag default VLAN mode. If the ingress packet is tagged
+ with the default VLAN, the NIC removes or untags its VLAN header so
+ that the application sees an untagged packet. As a result, the
+ default VLAN becomes `untagged`. This mode can be useful for
+ applications such as OVS-DPDK performance benchmarks that utilize
+ only the default VLAN and want to see only untagged packets.
+
+.. _enic_limitations: