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Packet Flow over a Virtual Port

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The default NIC switch is a component of a network adapter that supports the single root I/O virtualization (SR-IOV) interface. The switch always attaches the default virtual port (VPort) to the PCI Express (PCIe) Physical Function (PF). The switch can attach one or more nondefault VPorts to the PF. For more information, see Creating a Virtual Port.

The following points apply to packets that are sent or received on a VPort that is attached to the PF:

  • Packets sent or received over the default VPort are specified with a VPort identifier value of DEFAULT_VPORT_ID.

    Packets sent or received over nondefault VPorts are specified with the VPort identifier that was returned when the VPort was created through an OID method request of OID_NIC_SWITCH_CREATE_VPORT. When the driver handles this OID request, it obtains the VPort identifier from the VPortId member of the NDIS_NIC_SWITCH_VPORT_PARAMETERS structure that is associated with the OID request.

    Note  When a VPort is deleted, it is possible for the miniport driver to receive an NBL that contains an invalid VPortId value. If this happens, the miniport should ignore the invalid VPort ID and use DEFAULT_VPORT_ID instead. The VPortId is found in the NetBufferListFilteringInfo portion of the NBL's OOB data, and is retrieved by using the NET_BUFFER_LIST_RECEIVE_FILTER_VPORT_ID macro.

  • The PF miniport driver calls NdisMIndicateReceiveNetBufferLists to indicate packets received from a VPort. Before the PF miniport driver calls NdisMIndicateReceiveNetBufferLists, it must set the VPort identifier in the out-of-band (OOB) data in the NET_BUFFER_LIST structure for the packet. The driver does this by using the NET_BUFFER_LIST_RECEIVE_FILTER_VPORT_ID macro.

  • The virtualization stack calls NdisSendNetBufferLists to transmit packets to a VPort. Before the virtualization stack calls NdisSendNetBufferLists, it sets the VPort identifier in the OOB data in the NET_BUFFER_LIST structure for the packet.

    The miniport driver obtains the VPort identifier by using the NET_BUFFER_LIST_RECEIVE_FILTER_VPORT_ID macro.

    The miniport driver must queue the transmit packet on the hardware transmit queue of the specified VPort.

Note  The miniport driver for the PCIe Virtual Function (VF) does not set or query the VPort identifier in the OOB data of the NET_BUFFER_LIST structure for a packet. When the VF miniport driver sends a packet, it queues the packet on the hardware transmit queue for the single nondefault VPort that is attached to the VF.