Intel Extensible Firmware Interface - Page 70

Extensible Firmware Interface Specification
52 12/12/00 Version 1.02
The GetMemoryMap() function also returns the size and revision number of the
EFI_MEMORY_DESCRIPTOR. The DescriptorSize represents the size in bytes of an
EFI_MEMORY_DESCRIPTOR array element returned in MemoryMap. The size is returned to
allow for future expansion of the EFI_MEMORY_DESCRIPTOR in response to hardware
innovation. The structure of the EFI_MEMORY_DESCRIPTOR may be extended in the future but
it will remain backwards compatible with the current definition. Thus OS software must use the
DescriptorSize to find the start of each EFI_MEMORY_DESCRIPTOR in the MemoryMap
array.
Status Codes Returned
EFI_SUCCESS
The memory map was returned in the
MemoryMap buffer.
EFI_BUFFER_TOO_SMALL
The
MemoryMap buffer was too small. The current buffer size
needed to hold the memory map is returned in
MemoryMapSize.
EFI_INVALID_PARAMETER One of the parameters has an invalid value.