[edk2-devel] [PATCH v1 0/5] EDK2 Code First: PI Specification: Update EFI_MM_COMMUNICATE_HEADER

[Marvin Häuser]

Good day,

May I ask about two small things?

1) Was there any rationale as to e.g. code compatibility with choosing 
UINT64 for the data length? I understand that this is the maximum of the 
two as of currently, but I wonder whether a message length that exceeds 
the UINT32 range (4 GB!) can possibly be considered sane or a good idea.

2) Is it feasible yet with the current set of supported compilers to 
support flexible arrays?

Thank you for your work!

Best regards,
Marvin

On 10.06.21 03:42, Kun Qin wrote:
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3430
>
> In PI Spec v1.7 Errata A, Vol.4, Sec 5.7 MM Communication Protocol, the
> MessageLength field of EFI_MM_COMMUNICATE_HEADER (also derived as
> EFI_SMM_COMMUNICATE_HEADER) is currently defined as type UINTN.
>
> But this structure, as a generic definition, could be used for both PEI
> and DXE MM communication. Thus for a system that supports PEI MM launch,
> but operates PEI in 32bit mode and MM foundation in 64bit, the current
> EFI_MM_COMMUNICATE_HEADER definition will cause structure parse error due
> to UINTN being used.
>
> The suggested change is to make the MessageLength field defined with
> definitive size as below:
> ```
> typedef struct {
> EFI_GUID  HeaderGuid;
> UINT64    MessageLength;
> UINT8     Data[ANYSIZE_ARRAY];
> } EFI_MM_COMMUNICATE_HEADER;
> ```
>
> Patch v1 branch: https://github.com/kuqin12/edk2/tree/BZ3398-MmCommunicate-Length
>
> Cc: Jian J Wang <jian.j.wang at intel.com>
> Cc: Hao A Wu <hao.a.wu at intel.com>
> Cc: Eric Dong <eric.dong at intel.com>
> Cc: Ray Ni <ray.ni at intel.com>
> Cc: Michael D Kinney <michael.d.kinney at intel.com>
> Cc: Liming Gao <gaoliming at byosoft.com.cn>
> Cc: Zhiguang Liu <zhiguang.liu at intel.com>
> Cc: Andrew Fish <afish at apple.com>
> Cc: Laszlo Ersek <lersek at redhat.com>
> Cc: Leif Lindholm <leif at nuviainc.com>
>
> Kun Qin (5):
>    EDK2 Code First: PI Specification: EFI_MM_COMMUNICATE_HEADER Update
>    MdeModulePkg: PiSmmIpl: Update MessageLength calculation for
>      MmCommunicate
>    MdeModulePkg: MemoryProfileInfo: Updated MessageLength calculation
>    MdeModulePkg: SmiHandlerProfileInfo: Updated MessageLength calculation
>    MdePkg: MmCommunication: Extend MessageLength field size to UINT64
>
>   MdeModulePkg/Application/MemoryProfileInfo/MemoryProfileInfo.c         | 20 +++--
>   MdeModulePkg/Application/SmiHandlerProfileInfo/SmiHandlerProfileInfo.c |  8 +-
>   MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c                                 | 13 ++-
>   BZ3430-SpecChange.md                                                   | 88 ++++++++++++++++++++
>   MdeModulePkg/Core/PiSmmCore/PiSmmIpl.inf                               |  1 +
>   MdePkg/Include/Protocol/MmCommunication.h                              |  3 +-
>   6 files changed, 124 insertions(+), 9 deletions(-)
>   create mode 100644 BZ3430-SpecChange.md
>



-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#76583): https://edk2.groups.io/g/devel/message/76583
Mute This Topic: https://groups.io/mt/83435921/1813853
Group Owner: devel+owner at edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [edk2-devel-archive at redhat.com]
-=-=-=-=-=-=-=-=-=-=-=-