Hi Ard,

No worries. Liming has helped to merge these patches here: MM 
communicate functionality in variable policy by lgao4 · Pull Request 
#2443 · tianocore/edk2 (github.com) 
<https://github.com/tianocore/edk2/pull/2443>. Thanks for checking back.

Regards,
Kun

On 9/7/2022 1:27 AM, Ard Biesheuvel wrote:
> On Mon, 13 Dec 2021 at 19:23, Kun Qin<kuqin12@gmail.com>  wrote:
>> Hi ArmPkg and MdeModulePkg maintainers,
>>
>> Now that the hard freeze is lifted, could you please provide some
>> feedback on these patches when you have a chance?
>>
> My apologies for not responding to these changes.
>
> If these patches are still relevant, please rebase and resend them.
>
>
>> On 12/06/2021 10:41, Ard Biesheuvel wrote:
>>> On Mon, 6 Dec 2021 at 19:35, Kun Qin<kuqin12@gmail.com>  wrote:
>>>> Hi ArmPkg and MdeModulePkg maintainers,
>>>>
>>>> It has been a week since the patches were sent. Could you please review
>>>> the changes and let me know if there is any feedback? Any input is
>>>> appreciated.
>>>>
>>> As far as I know, we are still in hard freeze for the upcoming stable tag.
>>>
>>>> On 11/29/2021 16:39, Kun Qin via groups.io wrote:
>>>>> REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3709
>>>>> REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3751
>>>>>
>>>>> Currently, setups with variable policy operations used together with MM
>>>>> communicate from ArmPkg could fail with `EFI_INVALID_PARAMETER`. This was
>>>>> due to the errors from 2 following aspects:
>>>>>
>>>>> 1. For variable policy implementations in MdeModulePkg, the DXE runtime
>>>>> agent would communicate to MM to disable, register or query policies.
>>>>> However, during these operations, the MessageLength calculation is
>>>>> including MM communicate header. This could lead to MM agent read data
>>>>> across the given buffer boundary and/or trigger other errors.
>>>>>
>>>>> 2. On the other hand, current MM communicate routine from ArmPkg would
>>>>> fail the function if the input message length does not equal to input
>>>>> buffer size.
>>>>>
>>>>> As defined in PI specification, the `CommSize`, when as input, should
>>>>> stand for "The size of the data buffer being passed in", which would mean
>>>>> the maximal number of bytes `CommBuffer` can hold. In turn, the value of
>>>>> this input parameter can be used for MM handlers to determine whether the
>>>>> output data is too large to fit in this buffer. Enforcing the incoming
>>>>> buffer to hold exactly the number of used bytes mismatches with the PI
>>>>> spec description.
>>>>>
>>>>> This change fix MessageLength field calculation from variable policy and
>>>>> updated input argument inspections from MM communicate routine in ArmPkg
>>>>> to match PI spec descriptions.
>>>>>
>>>>> Patch v1 branch:https://github.com/kuqin12/edk2/tree/mm_communicate_check
>>>>>
>>>>> Cc: Jian J Wang<jian.j.wang@intel.com>
>>>>> Cc: Liming Gao<gaoliming@byosoft.com.cn>
>>>>> Cc: Hao A Wu<hao.a.wu@intel.com>
>>>>> Cc: Leif Lindholm<leif@nuviainc.com>
>>>>> Cc: Ard Biesheuvel<ardb+tianocore@kernel.org>
>>>>> Cc: Bret Barkelew<Bret.Barkelew@microsoft.com>
>>>>> Cc: Michael Kubacki<michael.kubacki@microsoft.com>
>>>>>
>>>>> Kun Qin (2):
>>>>>      MdeModulePkg: VariableSmmRuntimeDxe: Fix Variable Policy Message
>>>>>        Length
>>>>>      ArmPkg: MmCommunicationDxe: Update MM communicate input arguments
>>>>>        checks
>>>>>
>>>>>     ArmPkg/Drivers/MmCommunicationDxe/MmCommunication.c               | 44 ++++++++++++--------
>>>>>     MdeModulePkg/Universal/Variable/RuntimeDxe/VariablePolicySmmDxe.c | 10 ++---
>>>>>     2 files changed, 32 insertions(+), 22 deletions(-)
>>>>>