Security of Setup Variable

System can still boot to shell and OS successfully after EFI variable deletion/corruption.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Guo Mang <mang.guo@intel.com>

6 files changed, 465 insertions, 6 deletions

diff --git a/Platform/BroxtonPlatformPkg/BuildBios.bat b/Platform/BroxtonPlatformPkg/BuildBios.bat
index f656876c21..2ecc28d6bc 100644
--- a/Platform/BroxtonPlatformPkg/BuildBios.bat
+++ b/Platform/BroxtonPlatformPkg/BuildBios.bat
@@ -387,10 +387,15 @@ if not exist "%AutoGenPath%" (
 findstr /L "_PCD_VALUE_" %AutoGenPath% > %STITCH_PATH%\FlashMap.h

 

 echo Running FCE...

+copy /b %BUILD_PATH%\FV\FvIBBM.fv + /b %BUILD_PATH%\FV\Soc.fd /b %BUILD_PATH%\FV\Temp.fd

 :: Extract Hii data from build and store a copy in HiiDefaultData.txt

-fce.exe read -i %BUILD_PATH%\FV\Soc.fd > %BUILD_PATH%\FV\HiiDefaultData.txt 2>>EDK2.log

+:: UQI 0006 005C 0078 0030 0031 0030 0031 is for question prompt(STR_IPU_ENABLED)

+:: First 0006 is the length of string; Next six byte values are mapped to STR_IPU_ENABLED string value defined in Platform\BroxtonPlatformPkg\Common\PlatformSettings\PlatformSetupDxe\VfrStrings.uni.

+fce.exe read -i %BUILD_PATH%\FV\Temp.fd 0006 005C 0078 0030 0031 0030 0031 > %BUILD_PATH%\FV\HiiDefaultData.txt 2>>EDK2.log

 :: Generate the Setup variable and save changes to BxtXXX.fd

-fce.exe update -i %BUILD_PATH%\FV\Soc.fd -s %BUILD_PATH%\FV\HiiDefaultData.txt -o %BUILD_PATH%\FV\Bxt%Arch%.fd  1>>EDK2.log 2>&1

+:: B73FE497-B92E-416e-8326-45AD0D270091 is the GUID of IBBM FV

+fce.exe update -i %BUILD_PATH%\FV\Temp.fd -s %BUILD_PATH%\FV\HiiDefaultData.txt -o %BUILD_PATH%\FV\Bxt%Arch%.fd  -g B73FE497-B92E-416e-8326-45AD0D270091 -a 1>>EDK2.log 2>&1

+split -f %BUILD_PATH%\FV\Bxt%Arch%.fd -s 0x35000 -o %BUILD_PATH%\FV\FvIBBM.fv

 

 if ErrorLevel 1 goto BldFail

 

@@ -401,7 +406,7 @@ if "%BUILD_TYPE%"=="R" set BUILD_TYPE=R
 

 echo Copy BIOS...

 set BIOS_Name=%BOARD_ID%_%Arch%_%BUILD_TYPE%_%VERSION_MAJOR%_%VERSION_MINOR%

-copy /y/b %BUILD_PATH%\FV\Bxt%Arch%.fd  %STITCH_PATH%\%BIOS_Name%.ROM >nul

+copy /y/b %BUILD_PATH%\FV\Soc.fd          %STITCH_PATH%\%BIOS_Name%.ROM >nul

 copy /y   %STITCH_PATH%\FlashMap.h        %STITCH_PATH%\%BIOS_Name%.map >nul

 

 set Storage_Folder=%STITCH_PATH%\%BIOS_Name%

diff --git a/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformPreMemPei/MultiPlatSupport.h b/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformPreMemPei/MultiPlatSupport.h
new file mode 100644
index 0000000000..7f21da28ff
--- /dev/null
+++ b/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformPreMemPei/MultiPlatSupport.h
@@ -0,0 +1,201 @@
+/**@file

+

+Copyright (c) 2016 - 2017, Intel Corporation. All rights reserved.<BR>

+This program and the accompanying materials

+are licensed and made available under the terms and conditions of the BSD License

+which accompanies this distribution.  The full text of the license may be found at

+http://opensource.org/licenses/bsd-license.php

+

+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,

+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

+

+**/

+

+#ifndef __MULTI_PLATFORM_SUPPORT_H__

+#define __MULTI_PLATFORM_SUPPORT_H__

+

+extern EFI_GUID gDefaultDataOptSizeFileGuid;

+

+///

+/// Alignment of variable name and data, according to the architecture:

+/// * For IA-32 and Intel(R) 64 architectures: 1.

+/// * For IA-64 architecture: 8.

+///

+#if defined (MDE_CPU_IPF)

+#define ALIGNMENT         8

+#else

+#define ALIGNMENT         1

+#endif

+

+//

+// GET_PAD_SIZE calculates the miminal pad bytes needed to make the current pad size satisfy the alignment requirement.

+//

+#if (ALIGNMENT == 1)

+#define GET_PAD_SIZE(a) (0)

+#else

+#define GET_PAD_SIZE(a) (((~a) + 1) & (ALIGNMENT - 1))

+#endif

+

+///

+/// Alignment of Variable Data Header in Variable Store region.

+///

+#define HEADER_ALIGNMENT  4

+#define HEADER_ALIGN(Header)  (((UINTN) (Header) + HEADER_ALIGNMENT - 1) & (~(HEADER_ALIGNMENT - 1)))

+

+///

+/// Status of Variable Store Region.

+///

+/*typedef enum {

+  EfiRaw,

+  EfiValid,

+  EfiInvalid,

+  EfiUnknown

+} VARIABLE_STORE_STATUS;*/

+

+#pragma pack(1)

+

+///

+/// Variable Store Header Format and State.

+///

+#define VARIABLE_STORE_FORMATTED          0x5a

+#define VARIABLE_STORE_HEALTHY            0xfe

+

+///

+/// Variable Store region header.

+///

+/*typedef struct {

+  ///

+  /// Variable store region signature.

+  ///

+  EFI_GUID  Signature;

+  ///

+  /// Size of entire variable store, 

+  /// including size of variable store header but not including the size of FvHeader.

+  ///

+  UINT32  Size;

+  ///

+  /// Variable region format state.

+  ///

+  UINT8   Format;

+  ///

+  /// Variable region healthy state.

+  ///

+  UINT8   State;

+  UINT16  Reserved;

+  UINT32  Reserved1;

+} VARIABLE_STORE_HEADER;*/

+

+///

+/// Variable data start flag.

+///

+#define VARIABLE_DATA                     0x55AA

+

+///

+/// Variable State flags.

+///

+#define VAR_IN_DELETED_TRANSITION     0xfe  ///< Variable is in obsolete transition.

+#define VAR_DELETED                   0xfd  ///< Variable is obsolete.

+#define VAR_HEADER_VALID_ONLY         0x7f  ///< Variable header has been valid.

+#define VAR_ADDED                     0x3f  ///< Variable has been completely added.

+

+///

+/// Single Variable Data Header Structure.

+///

+/*typedef struct {

+  ///

+  /// Variable Data Start Flag.

+  ///

+  UINT16      StartId;

+  ///

+  /// Variable State defined above.

+  ///

+  UINT8       State;

+  UINT8       Reserved;

+  ///

+  /// Attributes of variable defined in UEFI specification.

+  ///

+  UINT32      Attributes;

+  ///

+  /// Size of variable null-terminated Unicode string name.

+  ///

+  UINT32      NameSize;

+  ///

+  /// Size of the variable data without this header.

+  ///

+  UINT32      DataSize;

+  ///

+  /// A unique identifier for the vendor that produces and consumes this varaible.

+  ///

+  EFI_GUID    VendorGuid;

+} VARIABLE_HEADER;*/

+

+///

+/// Single Variable Data Header Structure for Auth variable.

+///

+/*typedef struct {

+  ///

+  /// Variable Data Start Flag.

+  ///

+  UINT16      StartId;

+  ///

+  /// Variable State defined above.

+  ///

+  UINT8       State;

+  UINT8       Reserved;

+  ///

+  /// Attributes of variable defined in UEFI specification.

+  ///

+  UINT32      Attributes;

+  ///

+  /// Associated monotonic count value against replay attack.

+  ///

+  UINT64      MonotonicCount;

+  ///

+  /// Associated TimeStamp value against replay attack. 

+  ///

+  EFI_TIME    TimeStamp;

+  ///

+  /// Index of associated public key in database.

+  ///

+  UINT32      PubKeyIndex;

+  ///

+  /// Size of variable null-terminated Unicode string name.

+  ///

+  UINT32      NameSize;

+  ///

+  /// Size of the variable data without this header.

+  ///

+  UINT32      DataSize;

+  ///

+  /// A unique identifier for the vendor that produces and consumes this varaible.

+  ///

+  EFI_GUID    VendorGuid;

+} AUTHENTICATED_VARIABLE_HEADER;*/

+

+typedef struct {

+  UINT16 DefaultId;

+  UINT16 BoardId;

+} DEFAULT_INFO;

+

+typedef struct {

+  UINT16 Offset;

+  UINT8  Value;

+} DATA_DELTA;

+

+typedef struct {

+  //

+  // HeaderSize includes HeaderSize fields and DefaultInfo arrays

+  //

+  UINT16 HeaderSize;

+  //

+  // DefaultInfo arrays those have the same default setting.

+  //

+  DEFAULT_INFO DefaultInfo[1];

+  //

+  // Default data is stored as variable storage or the array of DATA_DELTA. 

+  //

+} DEFAULT_DATA;

+

+#pragma pack()

+

+#endif

diff --git a/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformPreMemPei/PlatformInitPreMem.c b/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformPreMemPei/PlatformInitPreMem.c
index fe454bf89f..49121aed7d 100644
--- a/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformPreMemPei/PlatformInitPreMem.c
+++ b/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformPreMemPei/PlatformInitPreMem.c
@@ -75,6 +75,15 @@
 #include <Library/PlatformSecLib.h>

 #include <Library/TimerLib.h>

 

+#include <PiPei.h>

+#include <Library/PeiServicesTablePointerLib.h>

+#include <MultiPlatSupport.h>

+

+//

+// GUID used in FCE. FCE generate ffs file with this GUID.

+//

+EFI_GUID gDefaultDataOptSizeFileGuid = { 0x003e7b41, 0x98a2, 0x4be2, { 0xb2, 0x7a, 0x6c, 0x30, 0xc7, 0x65, 0x52, 0x25 }};

+

 #if (ENBDT_PF_ENABLE == 1)

 //

 //SSC

@@ -913,6 +922,7 @@ PlatformInitPreMemEntryPoint (
   PEI_BOARD_PRE_MEM_INIT_PPI       *BoardPreMemInitPpi;

   UINTN                            Instance;

   UINT64                           AcpiVariableSetCompatibility;

+  UINTN                            VarSize;

 

   Status = (*PeiServices)->RegisterForShadow (FileHandle);

 

@@ -1116,6 +1126,29 @@ PlatformInitPreMemEntryPoint (
     Tick = CarMap->IbblPerfRecord4;

     PERF_END_EX (NULL, "IBBMVer", "IBBL", Tick, 0x1041);

 

+

+    VarSize = sizeof (SYSTEM_CONFIGURATION);

+    Status = VariableServices->GetVariable (

+                    VariableServices,

+                    L"Setup",

+                    &gEfiSetupVariableGuid,

+                    NULL,

+                    &VarSize,

+                    &SystemConfiguration

+                    );

+    if (EFI_ERROR (Status) || VarSize != sizeof(SYSTEM_CONFIGURATION)) {

+      Status = PlatformCreateDefaultVariableHob (EFI_HII_DEFAULT_CLASS_STANDARD);

+      ASSERT_EFI_ERROR (Status);

+    }

+    Status = VariableServices->GetVariable (

+                    VariableServices,

+                    L"Setup",

+                    &gEfiSetupVariableGuid,

+                    NULL,

+                    &VarSize,

+                    &SystemConfiguration

+                    );

+    ASSERT_EFI_ERROR (Status);

     //

     // Normal boot - build Hob for SEC performance data.

     //

@@ -1372,3 +1405,177 @@ ReadBxtIPlatformIds (
   return EFI_SUCCESS;

 }

 

+

+/**

+Description:

+

+  This function finds the matched default data and create GUID hob for it. 

+

+Arguments:

+

+  DefaultId - Specifies the type of defaults to retrieve.

+

+Returns:

+

+  EFI_SUCCESS - The matched default data is found.

+  EFI_NOT_FOUND - The matched default data is not found.

+  EFI_OUT_OF_RESOURCES - No enough resource to create HOB.

+

+**/

+EFI_STATUS

+PlatformCreateDefaultVariableHob (

+  IN UINT16  DefaultId

+  )

+

+{

+  UINTN                      FvInstance;

+  EFI_FIRMWARE_VOLUME_HEADER *FvHeader;

+  EFI_FFS_FILE_HEADER        *FfsHeader;

+  UINT32                     FileSize;

+  EFI_COMMON_SECTION_HEADER  *Section;

+  UINT32                     SectionLength;

+  BOOLEAN                    DefaultSettingIsFound;

+  DEFAULT_DATA               *DefaultData;

+  DEFAULT_INFO               *DefaultInfo;

+  VARIABLE_STORE_HEADER      *VarStoreHeader;

+  VARIABLE_STORE_HEADER      *VarStoreHeaderHob;

+  UINT8                      *VarHobPtr;

+  UINT8                      *VarPtr;

+  UINT32                     VarDataOffset;

+  UINT32                     VarHobDataOffset;

+  BOOLEAN                    IsFirstSection;

+  DATA_DELTA                 *DataDelta;

+  UINTN                      DataDeltaSize;

+  UINTN                      Index;

+  CONST EFI_PEI_SERVICES     **PeiServices;

+

+  //

+  // Get PeiService pointer

+  //

+  PeiServices = GetPeiServicesTablePointer ();

+

+  //

+  // Find the FFS file that stores all default data.

+  //

+  DefaultSettingIsFound = FALSE;

+  FvInstance            = 0;

+  FfsHeader             = NULL;

+  while (((*PeiServices)->FfsFindNextVolume (PeiServices, FvInstance, (VOID **) &FvHeader) == EFI_SUCCESS) &&

+         (!DefaultSettingIsFound)) {

+    FfsHeader = NULL;

+    while ((*PeiServices)->FfsFindNextFile (PeiServices, EFI_FV_FILETYPE_FREEFORM, FvHeader, (VOID **) &FfsHeader) == EFI_SUCCESS) {

+      if (CompareGuid ((EFI_GUID *) FfsHeader, &gDefaultDataOptSizeFileGuid)) {

+        DefaultSettingIsFound = TRUE;

+        break;

+      }

+    }

+    FvInstance ++;

+  }

+

+  //

+  // FFS file is not found.

+  //

+  if (!DefaultSettingIsFound) {

+    return EFI_NOT_FOUND;

+  }

+

+  //

+  // Find the matched default data for the input default ID and plat ID.

+  //

+  DefaultSettingIsFound = FALSE;

+  VarStoreHeaderHob     = NULL;

+  VarHobPtr      = NULL;

+  DataDelta      = NULL;

+  DataDeltaSize  = 0;

+  IsFirstSection = TRUE;

+  VarStoreHeader = NULL;

+  Section  = (EFI_COMMON_SECTION_HEADER *)(FfsHeader + 1);

+  FileSize = *(UINT32 *)(FfsHeader->Size) & 0x00FFFFFF;

+  while (((UINTN) Section < (UINTN) FfsHeader + FileSize) && !DefaultSettingIsFound) {

+    DefaultData = (DEFAULT_DATA *) (Section + 1);

+    DefaultInfo   = &(DefaultData->DefaultInfo[0]);

+    SectionLength = *(UINT32 *)Section->Size & 0x00FFFFFF;

+

+    if (IsFirstSection) {

+      //

+      // Create HOB to store default data so that Variable driver can use it.

+      // Allocate more data for header alignment.

+      //

+      VarStoreHeader = (VARIABLE_STORE_HEADER *) ((UINT8 *) DefaultData + DefaultData->HeaderSize);

+      VarStoreHeaderHob = (VARIABLE_STORE_HEADER *) BuildGuidHob (&VarStoreHeader->Signature, VarStoreHeader->Size + HEADER_ALIGNMENT - 1);

+      if (VarStoreHeaderHob == NULL) {

+        //

+        // No enough hob resource.

+        //

+        return EFI_OUT_OF_RESOURCES;

+      }

+

+      //

+      // Copy variable storage header.

+      //

+      CopyMem (VarStoreHeaderHob, VarStoreHeader, sizeof (VARIABLE_STORE_HEADER));

+      //

+      // Copy variable data.

+      //

+      VarPtr           = (UINT8 *) HEADER_ALIGN ((UINTN) (VarStoreHeader + 1));

+      VarDataOffset    = (UINT32) ((UINTN) VarPtr - (UINTN) VarStoreHeader);

+      VarHobPtr        = (UINT8 *) HEADER_ALIGN ((UINTN) (VarStoreHeaderHob + 1));

+      VarHobDataOffset = (UINT32) ((UINTN) VarHobPtr - (UINTN) VarStoreHeaderHob);

+      CopyMem (VarHobPtr, VarPtr, VarStoreHeader->Size - VarDataOffset);

+      //

+      // Update variable size.

+      //

+      VarStoreHeaderHob->Size = VarStoreHeader->Size - VarDataOffset + VarHobDataOffset;

+

+      //

+      // Update Delta Data

+      //

+      VarHobPtr = (UINT8 *) VarStoreHeaderHob - VarDataOffset + VarHobDataOffset;

+    } else {

+      //

+      // Apply delta setting

+      //

+      DataDelta     = (DATA_DELTA *) ((UINT8 *) DefaultData + DefaultData->HeaderSize);

+      DataDeltaSize = SectionLength - sizeof (EFI_COMMON_SECTION_HEADER) - DefaultData->HeaderSize;

+      for (Index = 0; Index < DataDeltaSize / sizeof (DATA_DELTA); Index ++) {

+        *((UINT8 *) VarHobPtr + DataDelta[Index].Offset) = DataDelta[Index].Value;

+      }

+    }

+

+    //

+    // Find the matched DefaultId

+    //

+    while ((UINTN) DefaultInfo < (UINTN) DefaultData + DefaultData->HeaderSize) {

+      if (DefaultInfo->DefaultId == DefaultId) {

+        DefaultSettingIsFound = TRUE;

+        break;

+      }

+      DefaultInfo ++;

+    }

+    //

+    // Size is 24 bits wide so mask upper 8 bits. 

+    // SectionLength is adjusted it is 4 byte aligned.

+    // Go to the next section

+    //

+    SectionLength = (SectionLength + 3) & (~3);

+    ASSERT (SectionLength != 0);

+    Section = (EFI_COMMON_SECTION_HEADER *)((UINT8 *)Section + SectionLength);

+    IsFirstSection = FALSE;

+  }

+  //

+  // Matched default data is not found.

+  //

+  if (!DefaultSettingIsFound) {

+    //

+    // Change created HOB type to be unused.

+    //

+    if (VarStoreHeaderHob != NULL) {

+      ((EFI_HOB_GUID_TYPE *)((UINT8 *) VarStoreHeaderHob - sizeof (EFI_HOB_GUID_TYPE)))->Header.HobType = EFI_HOB_TYPE_UNUSED;

+    }

+    return EFI_NOT_FOUND;

+  }

+

+

+  return EFI_SUCCESS;

+}

+

diff --git a/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformPreMemPei/PlatformInitPreMem.h b/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformPreMemPei/PlatformInitPreMem.h
index 17b4dad36d..3aa5033e08 100644
--- a/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformPreMemPei/PlatformInitPreMem.h
+++ b/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformPreMemPei/PlatformInitPreMem.h
@@ -139,5 +139,9 @@ InstallMonoStatusCode (
   IN CONST EFI_PEI_SERVICES    **PeiServices

   );

 

+EFI_STATUS 

+PlatformCreateDefaultVariableHob (

+IN UINT16  DefaultId

+);

 #endif

 

diff --git a/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformSetupDxe/PlatformSetupDxe.c b/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformSetupDxe/PlatformSetupDxe.c
index 54c751faaf..ff594965f2 100644
--- a/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformSetupDxe/PlatformSetupDxe.c
+++ b/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformSetupDxe/PlatformSetupDxe.c
@@ -402,6 +402,8 @@ SystemConfigCallback (
   CHAR16                                     *StringBuffer2;

   EFI_STATUS                                 Status;

   SEC_OPERATION_PROTOCOL                     *SeCOp;

+  UINTN                        VariableSize;

+  UINT32                       VariableAttributes;

 

   StringBuffer1 = AllocateZeroPool (200 * sizeof (CHAR16));

   ASSERT (StringBuffer1 != NULL);

@@ -412,7 +414,43 @@ SystemConfigCallback (
     return EFI_OUT_OF_RESOURCES;

   }

 

+  Private = EFI_CALLBACK_INFO_FROM_THIS (This);

+  FakeNvData = &Private->FakeNvData;

+

   switch (Action) {

+    case EFI_BROWSER_ACTION_FORM_OPEN:

+    {

+      if (KeyValue == 0x1003) {

+        if (!HiiGetBrowserData (&mSystemConfigGuid, mVariableName, sizeof (SYSTEM_CONFIGURATION), (UINT8 *) FakeNvData)) {

+           return EFI_NOT_FOUND;

+        }

+

+        CheckSystemConfigLoad (FakeNvData);

+

+        //

+        // Pass changed uncommitted data back to Form Browser

+        //

+        HiiSetBrowserData (&mSystemConfigGuid, mVariableName, sizeof (SYSTEM_CONFIGURATION), (UINT8 *) FakeNvData, NULL);

+      }

+      break;

+    }

+    case EFI_BROWSER_ACTION_SUBMITTED:

+    {

+      if (KeyValue == 0x1002) {

+        VariableSize = sizeof (SYSTEM_CONFIGURATION);

+        Status = gRT->GetVariable (

+                        L"Setup",

+                        &gEfiSetupVariableGuid,

+                        &VariableAttributes,

+                        &VariableSize,

+                        FakeNvData

+                        );

+        if (!EFI_ERROR (Status)) {

+          CheckSystemConfigSave (FakeNvData);

+        }

+      }

+      break;

+    }

     case EFI_BROWSER_ACTION_CHANGING:

     case EFI_BROWSER_ACTION_CHANGED:

     {

diff --git a/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformSetupDxe/Vfr.vfr b/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformSetupDxe/Vfr.vfr
index 4b10a49bfe..5e5b4facb6 100644
--- a/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformSetupDxe/Vfr.vfr
+++ b/Platform/BroxtonPlatformPkg/Common/PlatformSettings/PlatformSetupDxe/Vfr.vfr
@@ -16,6 +16,9 @@
 #include "PlatformSetupDxeStrDefs.h"

 #include "Guid/SetupVariable.h"

 

+#define EFI_VARIABLE_NON_VOLATILE       0x00000001

+#define EFI_VARIABLE_BOOTSERVICE_ACCESS 0x00000002

+#define EFI_VARIABLE_RUNTIME_ACCESS     0x00000004

 

 formset

   guid     = SYSTEM_CONFIGURATION_GUID,

@@ -24,8 +27,7 @@ formset
   class    = 1,

   subclass = 0,

 

-

-  varstore SYSTEM_CONFIGURATION, name = Setup, guid = SYSTEM_CONFIGURATION_GUID;

+  efivarstore SYSTEM_CONFIGURATION, attribute = EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_RUNTIME_ACCESS, name = Setup, guid = SYSTEM_CONFIGURATION_GUID;

   form formid = ROOT_FORM_ID,

     title    = STRING_TOKEN(STR_SYSTEM_SETUP_TITLE);

 

@@ -34,7 +36,9 @@ formset
     //

     goto ROOT_MAIN_FORM_ID,

       prompt = STRING_TOKEN(STR_MAIN_TITLE),

-      help   = STRING_TOKEN(STR_MAIN_HELP);

+      help   = STRING_TOKEN(STR_MAIN_HELP),

+      flags  = INTERACTIVE,                      // INTERACTIVE indicate it's marked with EFI_IFR_FLAG_CALLBACK

+      key    = 0x1003;                           // Question ID which will be passed-in in COnfigAccess.Callback()

 

     //

     // Jump to  2)CPU Configuration Form