获取 IRQL = PASSIVE_LEVEL 处的设备配置信息

若要访问 IRQL = PASSIVE_LEVEL 的设备配置空间，必须使用 IRP_MN_READ_CONFIG 和 IRP_MN_WRITE_CONFIG。 在 IRP 堆栈中指示要访问的配置空间以及 I/O 缓冲区的位置。 有关更多详细信息，请参阅 IO_STACK_LOCATION 结构的说明。

以下代码示例演示如何访问设备的配置空间。

NTSTATUS
ReadWriteConfigSpace(
    IN PDEVICE_OBJECT  DeviceObject,
    IN ULONG  ReadOrWrite,  // 0 for read, 1 for write
    IN PVOID  Buffer,
    IN ULONG  Offset,
    IN ULONG  Length
    )
{
    KEVENT event;
    NTSTATUS status;
    PIRP irp;
    IO_STATUS_BLOCK ioStatusBlock;
    PIO_STACK_LOCATION irpStack;
    PDEVICE_OBJECT targetObject;

    PAGED_CODE();
    KeInitializeEvent(&event, NotificationEvent, FALSE);
    targetObject = IoGetAttachedDeviceReference(DeviceObject);
    irp = IoBuildSynchronousFsdRequest(IRP_MJ_PNP,
                                       targetObject,
                                       NULL,
                                       0,
                                       NULL,
                                       &event,
                                       &ioStatusBlock);
    if (irp == NULL) {
        status = STATUS_INSUFFICIENT_RESOURCES;
        goto End;
    }
    irpStack = IoGetNextIrpStackLocation(irp);
    if (ReadOrWrite == 0) {
        irpStack->MinorFunction = IRP_MN_READ_CONFIG;
    } else {
        irpStack->MinorFunction = IRP_MN_WRITE_CONFIG;
    }
    irpStack->Parameters.ReadWriteConfig.WhichSpace = PCI_WHICHSPACE_CONFIG;
    irpStack->Parameters.ReadWriteConfig.Buffer = Buffer;
    irpStack->Parameters.ReadWriteConfig.Offset = Offset;
    irpStack->Parameters.ReadWriteConfig.Length = Length;

    // Initialize the status to error in case the bus driver does not 
    // set it correctly.
    irp->IoStatus.Status = STATUS_NOT_SUPPORTED;
    status = IoCallDriver(targetObject, irp);
    if (status == STATUS_PENDING) {
        KeWaitForSingleObject(&event, Executive, KernelMode, FALSE, NULL);
        status = ioStatusBlock.Status;
    }
End:
    // Done with reference
    ObDereferenceObject(targetObject);
    return status;
}