EFI_GUID Alignment Mismatch

[dvdhrm]

Hi

There is currently a mismatch between the UEFI specification and EDK2 regarding alignment of EFI_GUID. The spec states about EFI_GUID:

128-bit buffer containing a unique identifier value. Unless otherwise specified, aligned on a 64-bit boundary.

However, EDK2 has no such alignment annotation and uses the native structure alignment (which in this case usually ends up as 32-bit aligned) (https://github.com/tianocore/edk2/blob/master/BaseTools/Source/C/Include/Common/UefiBaseTypes.h#L18)

While this is rather unproblematic for x86 C code, our Rust adaptation needs to know the alignment to avoid miscompilations. The obvious choice is to use 32-bit alignment and ignore the UEFI-specification. However, I wonder whether it is possible to get this mismatch fixed somehow? Is there a way to amend the specification to drop this requirement? I assume we cannot fix EDK2, since it would lead to alignment-mismatches when run against firmware compiled with 32-bit aligned GUIDs.

I also wonder what other implementations do, but have not investigated, yet.

Thanks
David