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NVME_COMPLETION_ENTRY structure (nvme.h)

  • Article

Specifies an entry in the Completion Queue that is 16 bytes in size.

Syntax

typedef struct {
  ULONG DW0;
  ULONG DW1;
  union {
    struct {
      USHORT SQHD;
      USHORT SQID;
    } DUMMYSTRUCTNAME;
    ULONG AsUlong;
  } DW2;
  union {
    struct {
      USHORT              CID;
      NVME_COMMAND_STATUS Status;
    } DUMMYSTRUCTNAME;
    ULONG AsUlong;
  } DW3;
} NVME_COMPLETION_ENTRY, *PNVME_COMPLETION_ENTRY;

Members

DW0

The contents of Dword 0 contain command specific information.

If a command uses Dword 0, then the definition of this Dword is contained within the associated command definition. If a command does not use Dword 0, then this field is reserved.

DW1

DW2

A union that contains the information in Dword 2.

DW2.DUMMYSTRUCTNAME

DW2.DUMMYSTRUCTNAME.SQHD

Indicates the current Submission Queue Head pointer for the Submission Queue indicated in the SQ Identifier (SQID) field. This is used to indicate to the host the Submission Queue entries that have been consumed and may be re-used for new entries.

Note

The value returned is the value of the Submission Queue Head pointer when the completion queue entry was created. By the time host software consumes the completion queue entry, the controller may have an SQ Head pointer that has advanced beyond the value indicated.

DW2.DUMMYSTRUCTNAME.SQID

Specifies the Submission Queue to which the associated command was issued to. The SQID field is used in combination with the Command Identifier (CID) by the host software to uniquely determine the completed command when more than one Submission Queue shares a single Completion Queue.

DW2.AsUlong

DW3

A union that contains the information in Dword 3.

DW3.DUMMYSTRUCTNAME

DW3.DUMMYSTRUCTNAME.CID

Indicates the identifier of the command that is being completed.

This identifier is assigned by host software when the command is submitted to the Submission Queue. The combination of the SQ Identifier SQID and Command Identifier CID uniquely identifies the command that is being completed. The maximum number of requests outstanding at one time is 64K.

DW3.DUMMYSTRUCTNAME.Status

A NVME_COMMAND_STATUS structure that indicates the status for the command that is being completed.

A value of 0h for this Field indicates a successful command completion with no fatal or non-fatal error conditions. Unless otherwise noted, if a command fails to complete successfully for multiple reasons, then the particular status code returned is chosen by the vendor.

DW3.AsUlong

Requirements

Requirement Value
Minimum supported client Windows 10
Header nvme.h