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Deleting a NIC Switch

Last Updated: 9/2/2016

A network adapter that supports single root I/O virtualization (SR-IOV) must be able to delete a NIC switch. Only the miniport driver for the PCI Express (PCIe) Physical Function (PF) of the SR-IOV adapter can delete a NIC switch on the adapter.

Note Starting with NDIS 6.30 in Windows Server 2012, the SR-IOV interface supports only one NIC switch on the network adapter. This switch is known as the default NIC switch, and is referenced by the NDIS_DEFAULT_SWITCH_ID identifier.

Prior to halting the PF miniport driver, NDIS deletes the NIC switch by issuing an object identifier (OID) set request of OID_NIC_SWITCH_DELETE_SWITCH. The InformationBuffer member of the NDIS_OID_REQUEST structure contains a pointer to an NDIS_NIC_SWITCH_DELETE_SWITCH_PARAMETERS structure that specifies the identifier of the switch being deleted.

NDIS enforces the following policies before issuing the OID set request of OID_NIC_SWITCH_DELETE_SWITCH to the PF miniport driver:

  • NDIS guarantees that all receive filters have been cleared from the default and nondefault virtual ports (VPorts) on the NIC switch. Receive filters are cleared through an OID set request of OID_RECEIVE_FILTER_CLEAR_FILTER.

  • NDIS guarantees that all nondefault virtual ports (VPorts) created on the switch have been previously deleted. VPorts are deleted through an OID set request of OID_NIC_SWITCH_DELETE_VPORT.

  • NDIS guarantees that all the resources for PCIe Virtual Functions (VFs) attached to the NIC switch have been previously freed. VFs are freed through an OID set request of OID_NIC_SWITCH_FREE_VF.

When it receives the OID method request of OID_NIC_SWITCH_DELETE_SWITCH, the PF miniport driver must do the following:

  1. If the PF miniport driver supports static creation and configuration of NIC switches, it must free the software resources associated with the specified NIC switch. However, the driver can only free the hardware resources for the NIC switch when MiniportHaltEx is called.

    For more information about static NIC switch creation, see Static Creation of a NIC Switch.

  2. If the PF miniport driver supports the dynamic creation and configuration of NIC switches, it must free the hardware and software resources associated with the specified NIC switch.

    For more information about dynamic NIC switch creation, see Dynamic Creation of a NIC Switch.

  3. If the PF miniport driver supports the dynamic creation of NIC switches and all the NIC switches have been deleted on the network adapter, the driver must disable virtualization on the adapter by calling NdisMEnableVirtualization. To disable virtualization, the network adapter must set the EnableVirtualization parameter to FALSE and the NumVFs parameter to zero.

    NdisMEnableVirtualization clears the NumVFs member and the VF Enable bit in the SR-IOV Extended Capability structure in the PCIe configuration space of the network adapter's PF.

    Note If the PF miniport driver supports static creation and configuration of NIC switches, it must only call NdisMEnableVirtualization when MiniportHaltEx is called.

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