[edk2-platforms][PATCH v2 1/1] MinPlatformPkg: Add FspNvsBuffer compression option

["Michael Kubacki" <mikuback@linux.microsoft.com>]

From: Michael Kubacki <michael.kubacki@microsoft.com>

Adds a PCD called "PcdEnableCompressedFspNvsBuffer" that allows the
"FspNvsBuffer" UEFI variable data to be saved as compressed data.

Especially due to the nature of the data saved in this variable, it
compresses well. For example, it has been found to reduce ~63KB
of data to ~13KB. Boot time impact has been found to be negligible.

The default value is FALSE to keep default behavior consistent.

Decompression can be performed on the variable data using the
standard UefiDecompressLib.

Cc: Chasel Chiu <chasel.chiu@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Isaac Oram <isaac.w.oram@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Eric Dong <eric.dong@intel.com>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
---

Notes:
    v2: Rebase onto 9769bf28d1fc

 Platform/Intel/MinPlatformPkg/FspWrapper/SaveMemoryConfig/SaveMemoryConfig.c   | 62 ++++++++++++++++----
 Platform/Intel/MinPlatformPkg/FspWrapper/SaveMemoryConfig/SaveMemoryConfig.inf |  4 ++
 Platform/Intel/MinPlatformPkg/MinPlatformPkg.dec                               |  6 ++
 Platform/Intel/MinPlatformPkg/MinPlatformPkg.dsc                               |  1 +
 4 files changed, 60 insertions(+), 13 deletions(-)

diff --git a/Platform/Intel/MinPlatformPkg/FspWrapper/SaveMemoryConfig/SaveMemoryConfig.c b/Platform/Intel/MinPlatformPkg/FspWrapper/SaveMemoryConfig/SaveMemoryConfig.c
index 0215e8eeddfb..95b8cef8b32b 100644
--- a/Platform/Intel/MinPlatformPkg/FspWrapper/SaveMemoryConfig/SaveMemoryConfig.c
+++ b/Platform/Intel/MinPlatformPkg/FspWrapper/SaveMemoryConfig/SaveMemoryConfig.c
@@ -3,6 +3,7 @@
   exists, and saves the data to nvRAM.
 
 Copyright (c) 2017 - 2022, Intel Corporation. All rights reserved.<BR>
+Copyright (c) Microsoft Corporation.<BR>
 SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
@@ -10,6 +11,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 #include <Base.h>
 #include <Uefi.h>
 #include <Library/BaseLib.h>
+#include <Library/CompressLib.h>
 #include <Library/UefiBootServicesTableLib.h>
 #include <Library/UefiRuntimeServicesTableLib.h>
 #include <Library/HobLib.h>
@@ -19,6 +21,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 #include <Library/BaseMemoryLib.h>
 #include <Library/LargeVariableReadLib.h>
 #include <Library/LargeVariableWriteLib.h>
+#include <Library/PcdLib.h>
 #include <Library/VariableWriteLib.h>
 #include <Guid/FspNonVolatileStorageHob2.h>
 
@@ -38,20 +41,26 @@ SaveMemoryConfigEntryPoint (
   IN EFI_SYSTEM_TABLE   *SystemTable
   )
 {
-  EFI_STATUS        Status;
-  EFI_HOB_GUID_TYPE *GuidHob;
-  VOID              *HobData;
-  VOID              *VariableData;
-  UINTN             DataSize;
-  UINTN             BufferSize;
-  BOOLEAN           DataIsIdentical;
+  EFI_STATUS         Status;
+  EFI_HOB_GUID_TYPE  *GuidHob;
+  VOID               *HobData;
+  VOID               *VariableData;
+  UINTN              DataSize;
+  UINTN              BufferSize;
+  BOOLEAN            DataIsIdentical;
+  VOID               *CompressedData;
+  UINT64             CompressedSize;
+  UINTN              CompressedAllocationPages;
 
-  DataSize        = 0;
-  BufferSize      = 0;
-  VariableData    = NULL;
-  GuidHob         = NULL;
-  HobData         = NULL;
-  DataIsIdentical = FALSE;
+  DataSize                  = 0;
+  BufferSize                = 0;
+  VariableData              = NULL;
+  GuidHob                   = NULL;
+  HobData                   = NULL;
+  DataIsIdentical           = FALSE;
+  CompressedData            = NULL;
+  CompressedSize            = 0;
+  CompressedAllocationPages = 0;
 
   //
   // Search for the Memory Configuration GUID HOB.  If it is not present, then
@@ -73,6 +82,29 @@ SaveMemoryConfigEntryPoint (
     }
   }
 
+  if (PcdGetBool (PcdEnableCompressedFspNvsBuffer)) {
+    if (DataSize > 0) {
+      CompressedAllocationPages = EFI_SIZE_TO_PAGES (DataSize);
+      CompressedData            = AllocatePages (CompressedAllocationPages);
+      if (CompressedData == NULL) {
+        DEBUG ((DEBUG_ERROR, "[%a] - Failed to allocate compressed data buffer.\n", __FUNCTION__));
+        ASSERT_EFI_ERROR (EFI_OUT_OF_RESOURCES);
+        return EFI_OUT_OF_RESOURCES;
+      }
+
+      CompressedSize = EFI_PAGES_TO_SIZE (CompressedAllocationPages);
+      Status         = Compress (HobData, DataSize, CompressedData, &CompressedSize);
+      if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_ERROR, "[%a] - failed to compress data. Status = %r\n", __FUNCTION__, Status));
+        ASSERT_EFI_ERROR (Status);
+        return Status;
+      }
+    }
+
+    HobData  = CompressedData;
+    DataSize = (UINTN)CompressedSize;
+  }
+
   if (HobData != NULL) {
     DEBUG ((DEBUG_INFO, "FspNvsHob.NvsDataLength:%d\n", DataSize));
     DEBUG ((DEBUG_INFO, "FspNvsHob.NvsDataPtr   : 0x%x\n", HobData));
@@ -136,6 +168,10 @@ SaveMemoryConfigEntryPoint (
     DEBUG((DEBUG_ERROR, "Memory S3 Data HOB was not found\n"));
   }
 
+  if (CompressedData != NULL) {
+    FreePages (CompressedData, CompressedAllocationPages);
+  }
+
   //
   // This driver does not produce any protocol services, so always unload it.
   //
diff --git a/Platform/Intel/MinPlatformPkg/FspWrapper/SaveMemoryConfig/SaveMemoryConfig.inf b/Platform/Intel/MinPlatformPkg/FspWrapper/SaveMemoryConfig/SaveMemoryConfig.inf
index 61e85a658693..0f12deb131ca 100644
--- a/Platform/Intel/MinPlatformPkg/FspWrapper/SaveMemoryConfig/SaveMemoryConfig.inf
+++ b/Platform/Intel/MinPlatformPkg/FspWrapper/SaveMemoryConfig/SaveMemoryConfig.inf
@@ -26,6 +26,7 @@ [LibraryClasses]
   LargeVariableReadLib
   LargeVariableWriteLib
   BaseLib
+  CompressLib
 
 [Packages]
   MdePkg/MdePkg.dec
@@ -45,6 +46,9 @@ [Guids]
   gFspNonVolatileStorageHob2Guid                ## CONSUMES
   gFspNvsBufferVariableGuid                     ## PRODUCES
 
+[Pcd]
+  gMinPlatformPkgTokenSpaceGuid.PcdEnableCompressedFspNvsBuffer
+
 [Depex]
   gEfiVariableArchProtocolGuid        AND
   gEfiVariableWriteArchProtocolGuid
\ No newline at end of file
diff --git a/Platform/Intel/MinPlatformPkg/MinPlatformPkg.dec b/Platform/Intel/MinPlatformPkg/MinPlatformPkg.dec
index 8e603b7bf94b..94353cb76824 100644
--- a/Platform/Intel/MinPlatformPkg/MinPlatformPkg.dec
+++ b/Platform/Intel/MinPlatformPkg/MinPlatformPkg.dec
@@ -306,6 +306,12 @@ [PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
 
   gMinPlatformPkgTokenSpaceGuid.PcdPlatformMemoryCheckLevel|0|UINT32|0x30000009
 
+  ## Controls whether the FSP NVS buffer is saved as compressed data.
+  # Data compression can significantly reduce variable storage usage for FSP NVS buffer data.
+  # Platforms that choose to compress the data will need to decompress the variable data upon
+  # extraction.
+  gMinPlatformPkgTokenSpaceGuid.PcdEnableCompressedFspNvsBuffer|FALSE|BOOLEAN|0x30000010
+
   ## This PCD is to control which device is the potential trusted console input device.<BR><BR>
   # For example:<BR>
   # USB Short Form: UsbHID(0xFFFF,0xFFFF,0x1,0x1)<BR>
diff --git a/Platform/Intel/MinPlatformPkg/MinPlatformPkg.dsc b/Platform/Intel/MinPlatformPkg/MinPlatformPkg.dsc
index 09aa6fe4d51c..ae170f87d548 100644
--- a/Platform/Intel/MinPlatformPkg/MinPlatformPkg.dsc
+++ b/Platform/Intel/MinPlatformPkg/MinPlatformPkg.dsc
@@ -106,6 +106,7 @@ [LibraryClasses.common.DXE_DRIVER]
   FspWrapperPlatformLib|MinPlatformPkg/FspWrapper/Library/DxeFspWrapperPlatformLib/DxeFspWrapperPlatformLib.inf
   TestPointCheckLib|MinPlatformPkg/Test/Library/TestPointCheckLib/DxeTestPointCheckLib.inf
   TestPointLib|MinPlatformPkg/Test/Library/TestPointLib/DxeTestPointLib.inf
+  CompressLib|MinPlatformPkg/Library/CompressLib/CompressLib.inf
 
 [LibraryClasses.common.DXE_SMM_DRIVER]
   TestPointCheckLib|MinPlatformPkg/Test/Library/TestPointCheckLib/SmmTestPointCheckLib.inf
-- 
2.28.0.windows.1