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Windows Driver Kit DDI reference (nc-pcivirt-sriov_read_block)

SRIOV_READ_BLOCK callback

Description

Reads data from the specified configuration block of a PCI Express SR-IOV Virtual Function (VF).

Parameters

`Context` [in]

A pointer to a driver-defined context.

`VfIndex` [in]

A zero-based index of the VF to which this read operation applies.

`BlockId` [in]

A number identifying the block to be read. This is defined by the provider of the PF driver.

`Buffer` [out]

A pointer to a buffer that receives the data read from the VF's configuration space.

`Length` [in]

The length in bytes of this read operation. Must not be greater than VPCI_MAX_READ_WRITE_BLOCK_SIZE defined in Pcivirt.h.

Return value

Return STATUS_SUCCESS if the operation succeeds. Otherwise, return an appropriate NTSTATUS error code.

Prototype

SRIOV_READ_BLOCK SriovReadBlock;

NTSTATUS SriovReadBlock(
  _In_  PVOID  Context,
  _In_  USHORT VfIndex,
  _In_  ULONG  BlockId,
  _Out_ PVOID  Buffer,
  _In_  ULONG  Length
)
{ ... }

typedef SRIOV_READ_BLOCK *PSRIOV_READ_BLOCK;

Remarks

This callback function is implemented by the physical function (PF) driver. It is invoked when the system wants to read a configuration block for one of its VFs.

The PF driver registers its implementation by setting the ReadVfConfigBlock member of the SRIOV_DEVICE_INTERFACE_STANDARD, configuring a WDF_QUERY_INTERFACE_CONFIG structure, and calling WdfDeviceAddQueryInterface.

View the official Windows Driver Kit DDI reference