Re: [PATCH v4 10/13] MdeModulePkg/SmmLockBox(PEI): Remove an ASSERT in RestoreLockBox()

["Zeng, Star" <star.zeng@intel.com>]

Reviewed-by: Star Zeng <star.zeng@intel.com>

-----Original Message-----
From: Wu, Hao A 
Sent: Monday, February 11, 2019 3:58 PM
To: edk2-devel@lists.01.org
Cc: Wu, Hao A <hao.a.wu@intel.com>; Wang, Jian J <jian.j.wang@intel.com>; Zeng, Star <star.zeng@intel.com>
Subject: [PATCH v4 10/13] MdeModulePkg/SmmLockBox(PEI): Remove an ASSERT in RestoreLockBox()

This commit is out of the scope for BZ-1409. It is a refinement for the PEI library instance within SmmLockBoxLib.

For the below ASSERT statement within function RestoreLockBox():
  Status = SmmCommunicationPpi->Communicate (
                                  SmmCommunicationPpi,
                                  &CommBuffer[0],
                                  &CommSize
                                  );
  if (Status == EFI_NOT_STARTED) {
    //
    // Pei SMM communication not ready yet, so we access SMRAM directly
    //
    DEBUG ((DEBUG_INFO, "SmmLockBoxPeiLib Communicate - (%r)\n", Status));
    Status = InternalRestoreLockBoxFromSmram (Guid, Buffer, Length);
    LockBoxParameterRestore->Header.ReturnStatus = (UINT64)Status;
    if (Length != NULL) {
      LockBoxParameterRestore->Length = (UINT64)*Length;
    }
  }
  ASSERT_EFI_ERROR (Status);

It is possible for previous codes to return an error status that is possible for happen. One example is that, when the 'if' statement 'if (Status == EFI_NOT_STARTED) {' is entered, function
InternalRestoreLockBoxFromSmram() is possible to return 'BUFFER_TOO_SMALL'
if the caller of RestoreLockBox() provides a buffer that is too small to hold the content of LockBox.

Thus, this commit will remove the ASSERT here.

Please note that the current implementation of RestoreLockBox() is handling the above-mentioned error case properly, so no additional error handling codes are needed here.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
---
 MdeModulePkg/Library/SmmLockBoxLib/SmmLockBoxPeiLib.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/MdeModulePkg/Library/SmmLockBoxLib/SmmLockBoxPeiLib.c b/MdeModulePkg/Library/SmmLockBoxLib/SmmLockBoxPeiLib.c
index 9f73480070..8c3e65bc96 100644
--- a/MdeModulePkg/Library/SmmLockBoxLib/SmmLockBoxPeiLib.c
+++ b/MdeModulePkg/Library/SmmLockBoxLib/SmmLockBoxPeiLib.c
@@ -623,7 +623,6 @@ RestoreLockBox (
       LockBoxParameterRestore->Length = (UINT64)*Length;
     }
   }
-  ASSERT_EFI_ERROR (Status);
 
   if (Length != NULL) {
     *Length = (UINTN)LockBoxParameterRestore->Length;
--
2.12.0.windows.1