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NVME_CDW11_FEATURE_HOST_MEMORY_BUFFER union (nvme.h)

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Contains parameters for the Host Memory Buffer Feature that provides a mechanism for the host to allocate a portion of host memory for the controller to use exclusively.

After a successful completion of a Set Features command that enables the host memory buffer, the host will not write to the associated host memory region, buffer size, or descriptor list until the host memory buffer has been disabled.

After a successful completion of a Set Features command that disables the host memory buffer, the controller will not access any data in the host memory buffer until the host memory buffer has been enabled.

The values from this structure are used in the HostMemoryBuffer field of the NVME_CDW11_FEATURES structure.

Syntax

typedef union {
  struct {
    ULONG EHM : 1;
    ULONG MR : 1;
    ULONG Reserved : 30;
  } DUMMYSTRUCTNAME;
  ULONG  AsUlong;
} NVME_CDW11_FEATURE_HOST_MEMORY_BUFFER, *PNVME_CDW11_FEATURE_HOST_MEMORY_BUFFER;

Members

DUMMYSTRUCTNAME

DUMMYSTRUCTNAME.EHM

Enables the host memory buffer.

When this value is set to 1, the controller may use the host memory buffer. When this value is cleared to 0, the controller may not use the host memory buffer.

DUMMYSTRUCTNAME.MR

Indicates whether the host will return previously allocated memory to the controller.

When this value is set to 1, the host will return previously allocated memory the controller that was used prior to a reset or entering the Runtime D3 state. A returned host memory buffer will have the exact same size, descriptor list address, descriptor list contents, and host memory buffer contents as was last seen by the controller before the EHM field was cleared to 0. If cleared to 0, the host allocates host memory resources with undefined content.

DUMMYSTRUCTNAME.Reserved

AsUlong

Requirements

Requirement Value
Minimum supported client Windows 10
Header nvme.h

See also