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NVME_CDW10_CREATE_IO_QUEUE union (nvme.h)

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Contains parameters that are used in the Create I/O Completion Queue and Create IO Submission Queue commands. The Create I/O Completion Queue command is used to create all I/O Completion Queues with the exception of the Admin Completion Queue and the Create I/O Submission Queue command is used to create I/O Submission Queues.

The NVME_CDW10_CREATE_IO_QUEUE structure is used in the CDW10 field of the CREATEIOCQ and CREATEIOSQ parameters of the Command structure.

Syntax

typedef union {
  struct {
    ULONG QID : 16;
    ULONG QSIZE : 16;
  } DUMMYSTRUCTNAME;
  ULONG  AsUlong;
} NVME_CDW10_CREATE_IO_QUEUE, *PNVME_CDW10_CREATE_IO_QUEUE;

Members

DUMMYSTRUCTNAME

DUMMYSTRUCTNAME.QID

The Queue Identifier (QID) field indicates the identifier to assign to the Completion Queue or Submission Queue to be created.

This identifier corresponds to either the Completion Queue Head Doorbell used for the Completion Queue command or the Submission Queue Tail Doorbell used for the Submission Queue command.

This 16-bit ID value should not exceed the value reported in the NVME_FEATURE_NUMBER_OF_QUEUES feature for I/O Completion Queues or I/O Submission Queues. If the value specified is 0h, exceeds the Number of Queues reported, or corresponds to an identifier already in use, the controller should return an error of NVME_STATUS_INVALID_QUEUE_IDENTIFIER.

DUMMYSTRUCTNAME.QSIZE

The Queue Size (QSIZE) field indicates the size of the Completion Queue or Submission Queue to be created. The Queue Size is indicated in a 16-bit 0’s based field that specifies the number of entries in the queue.

The minimum size for a queue is two entries. The maximum size for either an I/O Submission Queue or an I/O Completion Queue is 64K entries, limited by the maximum queue size supported by the controller that is reported in the Maximum Queue Entries Supported (MQES) field of the NVME_CONTROLLER_CAPABILITIES structure.

The maximum size for the Admin Submission and Admin Completion Queue is defined as 4K entries. One entry in each queue is not available for use due to Head and Tail entry pointer definition.

If the size is 0h or larger than the controller supports, the controller should return an error of Invalid Queue Size.

AsUlong

Requirements

Requirement Value
Minimum supported client Windows 10
Header nvme.h

See also