NdisMSetVirtualFunctionBusData function

Description

A miniport driver calls the NdisMSetVirtualFunctionBusData function to write data to the PCI Express (PCIe) configuration space of a Virtual Function (VF) on the network adapter.

Note NdisMGetVirtualFunctionBusData must only be called by the miniport driver for the network adapter's PCIe Physical Function (PF).

Parameters

NdisMiniportHandle [in]

The network adapter handle that NDIS passed to the MiniportAdapterHandle parameter of MiniportInitializeEx.

VFId [in]

The identifier of the VF to which data is written to its PCI configuration space.

Buffer [in]

A pointer to a buffer that contains the data to be written to the PCI configuration space.

Offset [in]

The offset, in units of bytes, in the PCI configuration space to which data is written.

Length [in]

The length, in units of bytes, of the data to be written.

Return value

NdisMSetVirtualFunctionBusData returns the number of bytes written to the PCI configuration space. If the write operation fails, NdisMSetVirtualFunctionBusData returns zero.

Remarks

The PF miniport driver typically calls NdisMSetVirtualFunctionBusData when it handles an OID method request of OID_SRIOV_WRITE_VF_CONFIG_SPACE. However, the driver can call this function any time after virtualization has been enabled on the network adapter through a call to NdisMEnableVirtualization.

For more information about backchannel communication within the single root I/O virtualization (SR-IOV) interface, see SR-IOV PF/VF Backchannel Communication.

For more information about the SR-IOV interface, see Overview of Single Root I/O Virtualization (SR-IOV).

Interfacing to a Virtual Bus Driver

If an independent hardware vendor (IHV) provides a virtual bus driver (VBD) as part of its SR-IOV driver package, its miniport driver must not call NdisMSetVirtualFunctionBusData. Instead, the driver must interface with the VBD through a private communication channel, and request that the VBD call SetVirtualFunctionData. This function is exposed from the GUID_PCI_VIRTUALIZATION_INTERFACE interface that is supported by the underlying PCI bus driver.

The VBD that runs in the Hyper-V parent partition's management operating system can query the GUID_PCI_VIRTUALIZATION_INTERFACE interface by issuing an IRP_MN_QUERY_INTERFACE request to its physical device object (PDO) on the PCI bus. This request must be made from IRQL = PASSIVE_LEVEL. In this request, the driver must set the InterfaceType parameter to GUID_PCI_VIRTUALIZATION_INTERFACE.

See also

GUID_PCI_VIRTUALIZATION_INTERFACE

NdisMEnableVirtualization

OID_NIC_SWITCH_ALLOCATE_VF

OID_SRIOV_WRITE_VF_CONFIG_SPACE

SetVirtualFunctionData