Intel Extensible Firmware Interface - Manual (Page 196)

Extensible Firmware Interface Specification
6-4 12/01/02 Version 1.10
Description
Each vendor may create and manage its own variables without the risk of name conflicts by using a
unique
VendorGuid . When a variable is set its Attributes are supplied to indicate how the
data variable should be stored and maintained by the system. The attributes affect when the
variable may be accessed and volatility of the data. Any attempts to access a variable that does not
have the attribute set for runtime access will yield the
EFI_NOT_FOUND error.
If the Data buffer is too small to hold the contents of the variable, the error
EFI_BUFFER_TOO_SMALL is returned and DataSize is set to the required buffer size to obtain
the data.
Status Codes Returned
EFI_SUCCESS The function completed successfully.
EFI_NOT_FOUND The variable was not found.
EFI_BUFFER_TOO_SMALL The DataSize is too small for the result. DataSize has
been updated with the size needed to complete the request.
EFI_INVALID_PARAMETER VariableName is NULL .
EFI_INVALID_PARAMETER VendorGuid is NULL .
EFI_INVALID_PARAMETER DataSize is NULL .
EFI_INVALID_PARAMETER Data is NULL .
EFI_DEVICE_ERROR The variable could not be retrieved due to a hardware error.