OvmfPkg/EmuVariableFvbRuntimeDxe/Fvb.c - edk2 - Git at Google

 /** @file
   Firmware Block Services to support emulating non-volatile variables
   by pretending that a memory buffer is storage for the NV variables.

   Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
   SPDX-License-Identifier: BSD-2-Clause-Patent

 **/

 #include "PiDxe.h"
 #include <Guid/EventGroup.h>
 #include <Guid/SystemNvDataGuid.h>
 #include <Guid/VariableFormat.h>

 #include <Protocol/FirmwareVolumeBlock.h>
 #include <Protocol/DevicePath.h>

 #include <Library/UefiLib.h>
 #include <Library/UefiDriverEntryPoint.h>
 #include <Library/BaseLib.h>
 #include <Library/UefiRuntimeLib.h>
 #include <Library/DebugLib.h>
 #include <Library/BaseMemoryLib.h>
 #include <Library/MemoryAllocationLib.h>
 #include <Library/UefiBootServicesTableLib.h>
 #include <Library/DevicePathLib.h>
 #include <Library/PcdLib.h>
 #include <Library/PlatformFvbLib.h>
 #include "Fvb.h"

 #define EFI_AUTHENTICATED_VARIABLE_GUID \
 { 0xaaf32c78, 0x947b, 0x439a, { 0xa1, 0x80, 0x2e, 0x14, 0x4e, 0xc3, 0x77, 0x92 } }

 //
 // Virtual Address Change Event
 //
 // This is needed for runtime variable access.
 //
 EFI_EVENT  mEmuVarsFvbAddrChangeEvent = NULL;

 //
 // This is the single instance supported by this driver.  It
 // supports the FVB and Device Path protocols.
 //
 EFI_FW_VOL_BLOCK_DEVICE  mEmuVarsFvb = {
   FVB_DEVICE_SIGNATURE,
   {     // DevicePath
     {
       {
         HARDWARE_DEVICE_PATH,
         HW_MEMMAP_DP,
         {
           sizeof (MEMMAP_DEVICE_PATH),
           0
         }
       },
       EfiMemoryMappedIO,
       0,
       0,
     },
     {
       END_DEVICE_PATH_TYPE,
       END_ENTIRE_DEVICE_PATH_SUBTYPE,
       {
         sizeof (EFI_DEVICE_PATH_PROTOCOL),
         0
       }
     }
   },
   NULL,               // BufferPtr
   EMU_FVB_BLOCK_SIZE, // BlockSize
   EMU_FVB_SIZE,       // Size
   {     // FwVolBlockInstance
     FvbProtocolGetAttributes,
     FvbProtocolSetAttributes,
     FvbProtocolGetPhysicalAddress,
     FvbProtocolGetBlockSize,
     FvbProtocolRead,
     FvbProtocolWrite,
     FvbProtocolEraseBlocks,
     NULL
   },
 };

 /**
   Notification function of EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE.

   This is a notification function registered on EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE event.
   It converts pointer to new virtual address.

   @param  Event        Event whose notification function is being invoked.
   @param  Context      Pointer to the notification function's context.

 **/
 VOID
 EFIAPI
 FvbVirtualAddressChangeEvent (
   IN EFI_EVENT  Event,
   IN VOID       *Context
   )
 {
   EfiConvertPointer (0x0, &mEmuVarsFvb.BufferPtr);
 }

 //
 // FVB protocol APIs
 //

 /**
   The GetPhysicalAddress() function retrieves the base address of
   a memory-mapped firmware volume. This function should be called
   only for memory-mapped firmware volumes.

   @param This     Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.

   @param Address  Pointer to a caller-allocated
                   EFI_PHYSICAL_ADDRESS that, on successful
                   return from GetPhysicalAddress(), contains the
                   base address of the firmware volume.

   @retval EFI_SUCCESS       The firmware volume base address is returned.

   @retval EFI_NOT_SUPPORTED The firmware volume is not memory mapped.

 **/
 EFI_STATUS
 EFIAPI
 FvbProtocolGetPhysicalAddress (
   IN CONST  EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL  *This,
   OUT       EFI_PHYSICAL_ADDRESS                 *Address
   )
 {
   EFI_FW_VOL_BLOCK_DEVICE  *FvbDevice;

   FvbDevice = FVB_DEVICE_FROM_THIS (This);

   *Address = (EFI_PHYSICAL_ADDRESS)(UINTN)FvbDevice->BufferPtr;

   return EFI_SUCCESS;
 }

 /**
   The GetBlockSize() function retrieves the size of the requested
   block. It also returns the number of additional blocks with
   the identical size. The GetBlockSize() function is used to
   retrieve the block map (see EFI_FIRMWARE_VOLUME_HEADER).


   @param This           Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.

   @param Lba            Indicates the block for which to return the size.

   @param BlockSize      Pointer to a caller-allocated UINTN in which
                         the size of the block is returned.

   @param NumberOfBlocks Pointer to a caller-allocated UINTN in
                         which the number of consecutive blocks,
                         starting with Lba, is returned. All
                         blocks in this range have a size of
                         BlockSize.


   @retval EFI_SUCCESS             The firmware volume base address is returned.

   @retval EFI_INVALID_PARAMETER   The requested LBA is out of range.

 **/
 EFI_STATUS
 EFIAPI
 FvbProtocolGetBlockSize (
   IN CONST  EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL  *This,
   IN        EFI_LBA                              Lba,
   OUT       UINTN                                *BlockSize,
   OUT       UINTN                                *NumberOfBlocks
   )
 {
   EFI_FW_VOL_BLOCK_DEVICE  *FvbDevice;

   if (Lba >= EMU_FVB_NUM_TOTAL_BLOCKS) {
     return EFI_INVALID_PARAMETER;
   }

   FvbDevice = FVB_DEVICE_FROM_THIS (This);

   *BlockSize      = FvbDevice->BlockSize;
   *NumberOfBlocks = (UINTN)(EMU_FVB_NUM_TOTAL_BLOCKS - Lba);

   return EFI_SUCCESS;
 }

 /**
   The GetAttributes() function retrieves the attributes and
   current settings of the block. Status Codes Returned

   @param This       Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.

   @param Attributes Pointer to EFI_FVB_ATTRIBUTES_2 in which the
                     attributes and current settings are
                     returned. Type EFI_FVB_ATTRIBUTES_2 is defined
                     in EFI_FIRMWARE_VOLUME_HEADER.

   @retval EFI_SUCCESS The firmware volume attributes were
                       returned.

 **/
 EFI_STATUS
 EFIAPI
 FvbProtocolGetAttributes (
   IN CONST  EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL  *This,
   OUT       EFI_FVB_ATTRIBUTES_2                 *Attributes
   )
 {
   *Attributes =
     (EFI_FVB_ATTRIBUTES_2)(
                            EFI_FVB2_READ_ENABLED_CAP |
                            EFI_FVB2_READ_STATUS |
                            EFI_FVB2_WRITE_ENABLED_CAP |
                            EFI_FVB2_WRITE_STATUS |
                            EFI_FVB2_ERASE_POLARITY
                            );

   return EFI_SUCCESS;
 }

 /**
   The SetAttributes() function sets configurable firmware volume
   attributes and returns the new settings of the firmware volume.

   @param This         Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.

   @param Attributes   On input, Attributes is a pointer to
                       EFI_FVB_ATTRIBUTES_2 that contains the
                       desired firmware volume settings. On
                       successful return, it contains the new
                       settings of the firmware volume. Type
                       EFI_FVB_ATTRIBUTES_2 is defined in
                       EFI_FIRMWARE_VOLUME_HEADER.

   @retval EFI_SUCCESS           The firmware volume attributes were returned.

   @retval EFI_INVALID_PARAMETER The attributes requested are in
                                 conflict with the capabilities
                                 as declared in the firmware
                                 volume header.

 **/
 EFI_STATUS
 EFIAPI
 FvbProtocolSetAttributes (
   IN CONST  EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL  *This,
   IN OUT    EFI_FVB_ATTRIBUTES_2                 *Attributes
   )
 {
   return EFI_ACCESS_DENIED;
 }

 /**
   Erases and initializes a firmware volume block.

   The EraseBlocks() function erases one or more blocks as denoted
   by the variable argument list. The entire parameter list of
   blocks must be verified before erasing any blocks. If a block is
   requested that does not exist within the associated firmware
   volume (it has a larger index than the last block of the
   firmware volume), the EraseBlocks() function must return the
   status code EFI_INVALID_PARAMETER without modifying the contents
   of the firmware volume. Implementations should be mindful that
   the firmware volume might be in the WriteDisabled state. If it
   is in this state, the EraseBlocks() function must return the
   status code EFI_ACCESS_DENIED without modifying the contents of
   the firmware volume. All calls to EraseBlocks() must be fully
   flushed to the hardware before the EraseBlocks() service
   returns.

   @param This   Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL
                 instance.

   @param ...    The variable argument list is a list of tuples.
                 Each tuple describes a range of LBAs to erase
                 and consists of the following:
                 - An EFI_LBA that indicates the starting LBA
                 - A UINTN that indicates the number of blocks to
                   erase

                 The list is terminated with an
                 EFI_LBA_LIST_TERMINATOR. For example, the
                 following indicates that two ranges of blocks
                 (5-7 and 10-11) are to be erased: EraseBlocks
                 (This, 5, 3, 10, 2, EFI_LBA_LIST_TERMINATOR);

   @retval EFI_SUCCESS The erase request was successfully
                       completed.

   @retval EFI_ACCESS_DENIED   The firmware volume is in the
                               WriteDisabled state.
   @retval EFI_DEVICE_ERROR  The block device is not functioning
                             correctly and could not be written.
                             The firmware device may have been
                             partially erased.
   @retval EFI_INVALID_PARAMETER One or more of the LBAs listed
                                 in the variable argument list do
                                 not exist in the firmware volume.

 **/
 EFI_STATUS
 EFIAPI
 FvbProtocolEraseBlocks (
   IN CONST  EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL  *This,
   ...
   )
 {
   EFI_FW_VOL_BLOCK_DEVICE  *FvbDevice;
   VA_LIST                  Args;
   EFI_LBA                  StartingLba;
   UINTN                    NumOfLba;
   UINT8                    *ErasePtr;
   UINTN                    EraseSize;

   FvbDevice = FVB_DEVICE_FROM_THIS (This);

   //
   // Check input parameters
   //
   VA_START (Args, This);
   do {
     StartingLba = VA_ARG (Args, EFI_LBA);
     if (StartingLba == EFI_LBA_LIST_TERMINATOR) {
       break;
     }

     NumOfLba = VA_ARG (Args, UINTN);

     if ((StartingLba > EMU_FVB_NUM_TOTAL_BLOCKS) ||
         (NumOfLba > EMU_FVB_NUM_TOTAL_BLOCKS - StartingLba))
     {
       VA_END (Args);
       return EFI_INVALID_PARAMETER;
     }
   } while (1);

   VA_END (Args);

   //
   // Erase blocks
   //
   VA_START (Args, This);
   do {
     StartingLba = VA_ARG (Args, EFI_LBA);
     if (StartingLba == EFI_LBA_LIST_TERMINATOR) {
       break;
     }

     NumOfLba = VA_ARG (Args, UINTN);

     ErasePtr  = FvbDevice->BufferPtr;
     ErasePtr += (UINTN)StartingLba * FvbDevice->BlockSize;
     EraseSize = NumOfLba * FvbDevice->BlockSize;

     SetMem (ErasePtr, EraseSize, ERASED_UINT8);
   } while (1);

   VA_END (Args);

   //
   // Call platform hook
   //
   VA_START (Args, This);
   PlatformFvbBlocksErased (This, Args);
   VA_END (Args);

   return EFI_SUCCESS;
 }

 /**
   Writes the specified number of bytes from the input buffer to the block.

   The Write() function writes the specified number of bytes from
   the provided buffer to the specified block and offset. If the
   firmware volume is sticky write, the caller must ensure that
   all the bits of the specified range to write are in the
   EFI_FVB_ERASE_POLARITY state before calling the Write()
   function, or else the result will be unpredictable. This
   unpredictability arises because, for a sticky-write firmware
   volume, a write may negate a bit in the EFI_FVB_ERASE_POLARITY
   state but cannot flip it back again. In general, before
   calling the Write() function, the caller should call the
   EraseBlocks() function first to erase the specified block to
   write. A block erase cycle will transition bits from the
   (NOT)EFI_FVB_ERASE_POLARITY state back to the
   EFI_FVB_ERASE_POLARITY state. Implementations should be
   mindful that the firmware volume might be in the WriteDisabled
   state. If it is in this state, the Write() function must
   return the status code EFI_ACCESS_DENIED without modifying the
   contents of the firmware volume. The Write() function must
   also prevent spanning block boundaries. If a write is
   requested that spans a block boundary, the write must store up
   to the boundary but not beyond. The output parameter NumBytes
   must be set to correctly indicate the number of bytes actually
   written. The caller must be aware that a write may be
   partially completed. All writes, partial or otherwise, must be
   fully flushed to the hardware before the Write() service
   returns.

   @param This     Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.

   @param Lba      The starting logical block index to write to.

   @param Offset   Offset into the block at which to begin writing.

   @param NumBytes Pointer to a UINTN. At entry, *NumBytes
                   contains the total size of the buffer. At
                   exit, *NumBytes contains the total number of
                   bytes actually written.

   @param Buffer   Pointer to a caller-allocated buffer that
                   contains the source for the write.

   @retval EFI_SUCCESS         The firmware volume was written successfully.

   @retval EFI_BAD_BUFFER_SIZE The write was attempted across an
                               LBA boundary. On output, NumBytes
                               contains the total number of bytes
                               actually written.

   @retval EFI_ACCESS_DENIED   The firmware volume is in the
                               WriteDisabled state.

   @retval EFI_DEVICE_ERROR    The block device is malfunctioning
                               and could not be written.


 **/
 EFI_STATUS
 EFIAPI
 FvbProtocolWrite (
   IN CONST  EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL  *This,
   IN        EFI_LBA                              Lba,
   IN        UINTN                                Offset,
   IN OUT    UINTN                                *NumBytes,
   IN        UINT8                                *Buffer
   )
 {
   EFI_FW_VOL_BLOCK_DEVICE  *FvbDevice;
   UINT8                    *FvbDataPtr;
   EFI_STATUS               Status;

   FvbDevice = FVB_DEVICE_FROM_THIS (This);

   if ((Lba >= EMU_FVB_NUM_TOTAL_BLOCKS) ||
       (Offset > FvbDevice->BlockSize))
   {
     return EFI_INVALID_PARAMETER;
   }

   Status = EFI_SUCCESS;
   if (*NumBytes > FvbDevice->BlockSize - Offset) {
     *NumBytes = FvbDevice->BlockSize - Offset;
     Status    = EFI_BAD_BUFFER_SIZE;
   }

   FvbDataPtr  = FvbDevice->BufferPtr;
   FvbDataPtr += (UINTN)Lba * FvbDevice->BlockSize;
   FvbDataPtr += Offset;

   CopyMem (FvbDataPtr, Buffer, *NumBytes);
   PlatformFvbDataWritten (This, Lba, Offset, *NumBytes, Buffer);
   return Status;
 }

 /**
   Reads the specified number of bytes into a buffer from the specified block.

   The Read() function reads the requested number of bytes from the
   requested block and stores them in the provided buffer.
   Implementations should be mindful that the firmware volume
   might be in the ReadDisabled state. If it is in this state,
   the Read() function must return the status code
   EFI_ACCESS_DENIED without modifying the contents of the
   buffer. The Read() function must also prevent spanning block
   boundaries. If a read is requested that would span a block
   boundary, the read must read up to the boundary but not
   beyond. The output parameter NumBytes must be set to correctly
   indicate the number of bytes actually read. The caller must be
   aware that a read may be partially completed.

   @param This     Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.

   @param Lba      The starting logical block index
                   from which to read.

   @param Offset   Offset into the block at which to begin reading.

   @param NumBytes Pointer to a UINTN. At entry, *NumBytes
                   contains the total size of the buffer. At
                   exit, *NumBytes contains the total number of
                   bytes read.

   @param Buffer   Pointer to a caller-allocated buffer that will
                   be used to hold the data that is read.

   @retval EFI_SUCCESS         The firmware volume was read successfully
                               and contents are in Buffer.

   @retval EFI_BAD_BUFFER_SIZE Read attempted across an LBA
                               boundary. On output, NumBytes
                               contains the total number of bytes
                               returned in Buffer.

   @retval EFI_ACCESS_DENIED   The firmware volume is in the
                               ReadDisabled state.

   @retval EFI_DEVICE_ERROR    The block device is not
                               functioning correctly and could
                               not be read.

 **/
 EFI_STATUS
 EFIAPI
 FvbProtocolRead (
   IN CONST  EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL  *This,
   IN        EFI_LBA                              Lba,
   IN        UINTN                                Offset,
   IN OUT    UINTN                                *NumBytes,
   IN OUT    UINT8                                *Buffer
   )
 {
   EFI_FW_VOL_BLOCK_DEVICE  *FvbDevice;
   UINT8                    *FvbDataPtr;
   EFI_STATUS               Status;

   FvbDevice = FVB_DEVICE_FROM_THIS (This);

   if ((Lba >= EMU_FVB_NUM_TOTAL_BLOCKS) ||
       (Offset > FvbDevice->BlockSize))
   {
     return EFI_INVALID_PARAMETER;
   }

   Status = EFI_SUCCESS;
   if (*NumBytes > FvbDevice->BlockSize - Offset) {
     *NumBytes = FvbDevice->BlockSize - Offset;
     Status    = EFI_BAD_BUFFER_SIZE;
   }

   FvbDataPtr  = FvbDevice->BufferPtr;
   FvbDataPtr += (UINTN)Lba * FvbDevice->BlockSize;
   FvbDataPtr += Offset;

   CopyMem (Buffer, FvbDataPtr, *NumBytes);
   PlatformFvbDataRead (This, Lba, Offset, *NumBytes, Buffer);
   return Status;
 }

 /**
   Check the integrity of firmware volume header.

   @param[in] FwVolHeader - A pointer to a firmware volume header

   @retval  EFI_SUCCESS   - The firmware volume is consistent
   @retval  EFI_NOT_FOUND - The firmware volume has been corrupted.

 **/
 EFI_STATUS
 ValidateFvHeader (
   IN EFI_FIRMWARE_VOLUME_HEADER  *FwVolHeader
   )
 {
   UINT16  Checksum;

   //
   // Verify the header revision, header signature, length
   // Length of FvBlock cannot be 2**64-1
   // HeaderLength cannot be an odd number
   //
   if ((FwVolHeader->Revision != EFI_FVH_REVISION) ||
       (FwVolHeader->Signature != EFI_FVH_SIGNATURE) ||
       (FwVolHeader->FvLength != EMU_FVB_SIZE) ||
       (FwVolHeader->HeaderLength != EMU_FV_HEADER_LENGTH)
       )
   {
     DEBUG ((DEBUG_INFO, "EMU Variable FVB: Basic FV headers were invalid\n"));
     return EFI_NOT_FOUND;
   }

   //
   // Verify the header checksum
   //
   Checksum = CalculateSum16 ((VOID *)FwVolHeader, FwVolHeader->HeaderLength);

   if (Checksum != 0) {
     DEBUG ((DEBUG_INFO, "EMU Variable FVB: FV checksum was invalid\n"));
     return EFI_NOT_FOUND;
   }

   return EFI_SUCCESS;
 }

 /**
   Initializes the FV Header and Variable Store Header
   to support variable operations.

   @param[in]  Ptr - Location to initialize the headers

 **/
 VOID
 InitializeFvAndVariableStoreHeaders (
   IN  VOID  *Ptr
   )
 {
   //
   // Templates for authenticated variable FV header
   //
   STATIC FVB_FV_HDR_AND_VARS_TEMPLATE  FvAndAuthenticatedVarTemplate = {
     { // EFI_FIRMWARE_VOLUME_HEADER FvHdr;
       // UINT8                     ZeroVector[16];
       { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },

       // EFI_GUID                  FileSystemGuid;
       EFI_SYSTEM_NV_DATA_FV_GUID,

       // UINT64                    FvLength;
       EMU_FVB_SIZE,

       // UINT32                    Signature;
       EFI_FVH_SIGNATURE,

       // EFI_FVB_ATTRIBUTES_2      Attributes;
       0x4feff,

       // UINT16                    HeaderLength;
       EMU_FV_HEADER_LENGTH,

       // UINT16                    Checksum;
       0,

       // UINT16                    ExtHeaderOffset;
       0,

       // UINT8                     Reserved[1];
       { 0 },

       // UINT8                     Revision;
       EFI_FVH_REVISION,

       // EFI_FV_BLOCK_MAP_ENTRY    BlockMap[1];
       {
         {
           EMU_FVB_NUM_TOTAL_BLOCKS, // UINT32 NumBlocks;
           EMU_FVB_BLOCK_SIZE        // UINT32 Length;
         }
       }
     },
     // EFI_FV_BLOCK_MAP_ENTRY     EndBlockMap;
     { 0, 0 }, // End of block map
     { // VARIABLE_STORE_HEADER      VarHdr;
       // EFI_GUID  Signature;     // need authenticated variables for secure boot
       EFI_AUTHENTICATED_VARIABLE_GUID,

       // UINT32  Size;
       (
         FixedPcdGet32 (PcdFlashNvStorageVariableSize) -
         OFFSET_OF (FVB_FV_HDR_AND_VARS_TEMPLATE, VarHdr)
       ),

       // UINT8   Format;
       VARIABLE_STORE_FORMATTED,

       // UINT8   State;
       VARIABLE_STORE_HEALTHY,

       // UINT16  Reserved;
       0,

       // UINT32  Reserved1;
       0
     }
   };

   EFI_FIRMWARE_VOLUME_HEADER  *Fv;

   //
   // Copy the template structure into the location
   //
   CopyMem (
     Ptr,
     &FvAndAuthenticatedVarTemplate,
     sizeof FvAndAuthenticatedVarTemplate
     );

   //
   // Update the checksum for the FV header
   //
   Fv           = (EFI_FIRMWARE_VOLUME_HEADER *)Ptr;
   Fv->Checksum = CalculateCheckSum16 (Ptr, Fv->HeaderLength);
 }

 /**
   Main entry point.

   @param[in] ImageHandle    The firmware allocated handle for the EFI image.
   @param[in] SystemTable    A pointer to the EFI System Table.

   @retval EFI_SUCCESS       Successfully initialized.

 **/
 EFI_STATUS
 EFIAPI
 FvbInitialize (
   IN EFI_HANDLE        ImageHandle,
   IN EFI_SYSTEM_TABLE  *SystemTable
   )
 {
   EFI_STATUS            Status;
   VOID                  *Ptr;
   VOID                  *SubPtr;
   BOOLEAN               Initialize;
   EFI_HANDLE            Handle;
   EFI_PHYSICAL_ADDRESS  Address;
   RETURN_STATUS         PcdStatus;

   DEBUG ((DEBUG_INFO, "EMU Variable FVB Started\n"));

   //
   // Verify that the PCD's are set correctly.
   //
   ASSERT (
     FixedPcdGet32 (PcdFlashNvStorageFtwSpareSize) %
     EMU_FVB_BLOCK_SIZE == 0
     );
   if (
       (PcdGet32 (PcdFlashNvStorageVariableSize) +
        PcdGet32 (PcdFlashNvStorageFtwWorkingSize)
       ) >
       EMU_FVB_NUM_SPARE_BLOCKS * EMU_FVB_BLOCK_SIZE
       )
   {
     DEBUG ((DEBUG_ERROR, "EMU Variable invalid PCD sizes\n"));
     return EFI_INVALID_PARAMETER;
   }

   if (PcdGet64 (PcdFlashNvStorageVariableBase64) != 0) {
     DEBUG ((
       DEBUG_INFO,
       "Disabling EMU Variable FVB since "
       "flash variables appear to be supported.\n"
       ));
     return EFI_ABORTED;
   }

   //
   // By default we will initialize the FV contents.  But, if
   // PcdEmuVariableNvStoreReserved is non-zero, then we will
   // use this location for our buffer.
   //
   // If this location does not have a proper FV header, then
   // we will initialize it.
   //
   Initialize = TRUE;
   if (PcdGet64 (PcdEmuVariableNvStoreReserved) != 0) {
     Ptr = (VOID *)(UINTN)PcdGet64 (PcdEmuVariableNvStoreReserved);
     DEBUG ((
       DEBUG_INFO,
       "EMU Variable FVB: Using pre-reserved block at %p\n",
       Ptr
       ));
     Status = ValidateFvHeader (Ptr);
     if (!EFI_ERROR (Status)) {
       DEBUG ((DEBUG_INFO, "EMU Variable FVB: Found valid pre-existing FV\n"));
       Initialize = FALSE;
     }
   } else {
     Ptr = AllocateRuntimePages (EFI_SIZE_TO_PAGES (EMU_FVB_SIZE));
   }

   mEmuVarsFvb.BufferPtr = Ptr;

   //
   // Initialize the main FV header and variable store header
   //
   if (Initialize) {
     SetMem (Ptr, EMU_FVB_SIZE, ERASED_UINT8);
     InitializeFvAndVariableStoreHeaders (Ptr);
   }

   PcdStatus = PcdSet64S (PcdFlashNvStorageVariableBase64, (UINTN)Ptr);
   ASSERT_RETURN_ERROR (PcdStatus);

   //
   // Initialize the Fault Tolerant Write data area
   //
   SubPtr    = (VOID *)((UINT8 *)Ptr + PcdGet32 (PcdFlashNvStorageVariableSize));
   PcdStatus = PcdSet64S (
                 PcdFlashNvStorageFtwWorkingBase64,
                 (UINTN)SubPtr
                 );
   ASSERT_RETURN_ERROR (PcdStatus);

   //
   // Initialize the Fault Tolerant Write spare block
   //
   SubPtr = (VOID *)((UINT8 *)Ptr +
                     EMU_FVB_NUM_SPARE_BLOCKS * EMU_FVB_BLOCK_SIZE);
   PcdStatus = PcdSet64S (
                 PcdFlashNvStorageFtwSpareBase64,
                 (UINTN)SubPtr
                 );
   ASSERT_RETURN_ERROR (PcdStatus);

   //
   // Setup FVB device path
   //
   Address                                              = (EFI_PHYSICAL_ADDRESS)(UINTN)Ptr;
   mEmuVarsFvb.DevicePath.MemMapDevPath.StartingAddress = Address;
   mEmuVarsFvb.DevicePath.MemMapDevPath.EndingAddress   = Address + EMU_FVB_SIZE - 1;

   //
   // Install the protocols
   //
   DEBUG ((DEBUG_INFO, "Installing FVB for EMU Variable support\n"));
   Handle = 0;
   Status = gBS->InstallMultipleProtocolInterfaces (
                   &Handle,
                   &gEfiFirmwareVolumeBlock2ProtocolGuid,
                   &mEmuVarsFvb.FwVolBlockInstance,
                   &gEfiDevicePathProtocolGuid,
                   &mEmuVarsFvb.DevicePath,
                   NULL
                   );
   ASSERT_EFI_ERROR (Status);

   //
   // Register for the virtual address change event
   //
   Status = gBS->CreateEventEx (
                   EVT_NOTIFY_SIGNAL,
                   TPL_NOTIFY,
                   FvbVirtualAddressChangeEvent,
                   NULL,
                   &gEfiEventVirtualAddressChangeGuid,
                   &mEmuVarsFvbAddrChangeEvent
                   );
   ASSERT_EFI_ERROR (Status);

   return EFI_SUCCESS;
 }
	/** @file
	Firmware Block Services to support emulating non-volatile variables
	by pretending that a memory buffer is storage for the NV variables.

	Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
	SPDX-License-Identifier: BSD-2-Clause-Patent

	**/

	#include "PiDxe.h"
	#include <Guid/EventGroup.h>
	#include <Guid/SystemNvDataGuid.h>
	#include <Guid/VariableFormat.h>

	#include <Protocol/FirmwareVolumeBlock.h>
	#include <Protocol/DevicePath.h>

	#include <Library/UefiLib.h>
	#include <Library/UefiDriverEntryPoint.h>
	#include <Library/BaseLib.h>
	#include <Library/UefiRuntimeLib.h>
	#include <Library/DebugLib.h>
	#include <Library/BaseMemoryLib.h>
	#include <Library/MemoryAllocationLib.h>
	#include <Library/UefiBootServicesTableLib.h>
	#include <Library/DevicePathLib.h>
	#include <Library/PcdLib.h>
	#include <Library/PlatformFvbLib.h>
	#include "Fvb.h"

	#define EFI_AUTHENTICATED_VARIABLE_GUID \
	{ 0xaaf32c78, 0x947b, 0x439a, { 0xa1, 0x80, 0x2e, 0x14, 0x4e, 0xc3, 0x77, 0x92 } }

	//
	// Virtual Address Change Event
	//
	// This is needed for runtime variable access.
	//
	EFI_EVENT mEmuVarsFvbAddrChangeEvent = NULL;

	//
	// This is the single instance supported by this driver. It
	// supports the FVB and Device Path protocols.
	//
	EFI_FW_VOL_BLOCK_DEVICE mEmuVarsFvb = {
	FVB_DEVICE_SIGNATURE,
	{ // DevicePath
	{
	{
	HARDWARE_DEVICE_PATH,
	HW_MEMMAP_DP,
	{
	sizeof (MEMMAP_DEVICE_PATH),
	0
	}
	},
	EfiMemoryMappedIO,
	0,
	0,
	},
	{
	END_DEVICE_PATH_TYPE,
	END_ENTIRE_DEVICE_PATH_SUBTYPE,
	{
	sizeof (EFI_DEVICE_PATH_PROTOCOL),
	0
	}
	}
	},
	NULL, // BufferPtr
	EMU_FVB_BLOCK_SIZE, // BlockSize
	EMU_FVB_SIZE, // Size
	{ // FwVolBlockInstance
	FvbProtocolGetAttributes,
	FvbProtocolSetAttributes,
	FvbProtocolGetPhysicalAddress,
	FvbProtocolGetBlockSize,
	FvbProtocolRead,
	FvbProtocolWrite,
	FvbProtocolEraseBlocks,
	NULL
	},
	};

	/**
	Notification function of EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE.

	This is a notification function registered on EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE event.
	It converts pointer to new virtual address.

	@param Event Event whose notification function is being invoked.
	@param Context Pointer to the notification function's context.

	**/
	VOID
	EFIAPI
	FvbVirtualAddressChangeEvent (
	IN EFI_EVENT Event,
	IN VOID *Context
	)
	{
	EfiConvertPointer (0x0, &mEmuVarsFvb.BufferPtr);
	}

	//
	// FVB protocol APIs
	//

	/**
	The GetPhysicalAddress() function retrieves the base address of
	a memory-mapped firmware volume. This function should be called
	only for memory-mapped firmware volumes.

	@param This Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.

	@param Address Pointer to a caller-allocated
	EFI_PHYSICAL_ADDRESS that, on successful
	return from GetPhysicalAddress(), contains the
	base address of the firmware volume.

	@retval EFI_SUCCESS The firmware volume base address is returned.

	@retval EFI_NOT_SUPPORTED The firmware volume is not memory mapped.

	**/
	EFI_STATUS
	EFIAPI
	FvbProtocolGetPhysicalAddress (
	IN CONST EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL *This,
	OUT EFI_PHYSICAL_ADDRESS *Address
	)
	{
	EFI_FW_VOL_BLOCK_DEVICE *FvbDevice;

	FvbDevice = FVB_DEVICE_FROM_THIS (This);

	*Address = (EFI_PHYSICAL_ADDRESS)(UINTN)FvbDevice->BufferPtr;

	return EFI_SUCCESS;
	}

	/**
	The GetBlockSize() function retrieves the size of the requested
	block. It also returns the number of additional blocks with
	the identical size. The GetBlockSize() function is used to
	retrieve the block map (see EFI_FIRMWARE_VOLUME_HEADER).


	@param This Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.

	@param Lba Indicates the block for which to return the size.

	@param BlockSize Pointer to a caller-allocated UINTN in which
	the size of the block is returned.

	@param NumberOfBlocks Pointer to a caller-allocated UINTN in
	which the number of consecutive blocks,
	starting with Lba, is returned. All
	blocks in this range have a size of
	BlockSize.


	@retval EFI_SUCCESS The firmware volume base address is returned.

	@retval EFI_INVALID_PARAMETER The requested LBA is out of range.

	**/
	EFI_STATUS
	EFIAPI
	FvbProtocolGetBlockSize (
	IN CONST EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL *This,
	IN EFI_LBA Lba,
	OUT UINTN *BlockSize,
	OUT UINTN *NumberOfBlocks
	)
	{
	EFI_FW_VOL_BLOCK_DEVICE *FvbDevice;

	if (Lba >= EMU_FVB_NUM_TOTAL_BLOCKS) {
	return EFI_INVALID_PARAMETER;
	}

	FvbDevice = FVB_DEVICE_FROM_THIS (This);

	*BlockSize = FvbDevice->BlockSize;
	*NumberOfBlocks = (UINTN)(EMU_FVB_NUM_TOTAL_BLOCKS - Lba);

	return EFI_SUCCESS;
	}

	/**
	The GetAttributes() function retrieves the attributes and
	current settings of the block. Status Codes Returned

	@param This Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.

	@param Attributes Pointer to EFI_FVB_ATTRIBUTES_2 in which the
	attributes and current settings are
	returned. Type EFI_FVB_ATTRIBUTES_2 is defined
	in EFI_FIRMWARE_VOLUME_HEADER.

	@retval EFI_SUCCESS The firmware volume attributes were
	returned.

	**/
	EFI_STATUS
	EFIAPI
	FvbProtocolGetAttributes (
	IN CONST EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL *This,
	OUT EFI_FVB_ATTRIBUTES_2 *Attributes
	)
	{
	*Attributes =
	(EFI_FVB_ATTRIBUTES_2)(
	EFI_FVB2_READ_ENABLED_CAP \|
	EFI_FVB2_READ_STATUS \|
	EFI_FVB2_WRITE_ENABLED_CAP \|
	EFI_FVB2_WRITE_STATUS \|
	EFI_FVB2_ERASE_POLARITY
	);

	return EFI_SUCCESS;
	}

	/**
	The SetAttributes() function sets configurable firmware volume
	attributes and returns the new settings of the firmware volume.

	@param This Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.

	@param Attributes On input, Attributes is a pointer to
	EFI_FVB_ATTRIBUTES_2 that contains the
	desired firmware volume settings. On
	successful return, it contains the new
	settings of the firmware volume. Type
	EFI_FVB_ATTRIBUTES_2 is defined in
	EFI_FIRMWARE_VOLUME_HEADER.

	@retval EFI_SUCCESS The firmware volume attributes were returned.

	@retval EFI_INVALID_PARAMETER The attributes requested are in
	conflict with the capabilities
	as declared in the firmware
	volume header.

	**/
	EFI_STATUS
	EFIAPI
	FvbProtocolSetAttributes (
	IN CONST EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL *This,
	IN OUT EFI_FVB_ATTRIBUTES_2 *Attributes
	)
	{
	return EFI_ACCESS_DENIED;
	}

	/**
	Erases and initializes a firmware volume block.

	The EraseBlocks() function erases one or more blocks as denoted
	by the variable argument list. The entire parameter list of
	blocks must be verified before erasing any blocks. If a block is
	requested that does not exist within the associated firmware
	volume (it has a larger index than the last block of the
	firmware volume), the EraseBlocks() function must return the
	status code EFI_INVALID_PARAMETER without modifying the contents
	of the firmware volume. Implementations should be mindful that
	the firmware volume might be in the WriteDisabled state. If it
	is in this state, the EraseBlocks() function must return the
	status code EFI_ACCESS_DENIED without modifying the contents of
	the firmware volume. All calls to EraseBlocks() must be fully
	flushed to the hardware before the EraseBlocks() service
	returns.

	@param This Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL
	instance.

	@param ... The variable argument list is a list of tuples.
	Each tuple describes a range of LBAs to erase
	and consists of the following:
	- An EFI_LBA that indicates the starting LBA
	- A UINTN that indicates the number of blocks to
	erase

	The list is terminated with an
	EFI_LBA_LIST_TERMINATOR. For example, the
	following indicates that two ranges of blocks
	(5-7 and 10-11) are to be erased: EraseBlocks
	(This, 5, 3, 10, 2, EFI_LBA_LIST_TERMINATOR);

	@retval EFI_SUCCESS The erase request was successfully
	completed.

	@retval EFI_ACCESS_DENIED The firmware volume is in the
	WriteDisabled state.
	@retval EFI_DEVICE_ERROR The block device is not functioning
	correctly and could not be written.
	The firmware device may have been
	partially erased.
	@retval EFI_INVALID_PARAMETER One or more of the LBAs listed
	in the variable argument list do
	not exist in the firmware volume.

	**/
	EFI_STATUS
	EFIAPI
	FvbProtocolEraseBlocks (
	IN CONST EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL *This,
	...
	)
	{
	EFI_FW_VOL_BLOCK_DEVICE *FvbDevice;
	VA_LIST Args;
	EFI_LBA StartingLba;
	UINTN NumOfLba;
	UINT8 *ErasePtr;
	UINTN EraseSize;

	FvbDevice = FVB_DEVICE_FROM_THIS (This);

	//
	// Check input parameters
	//
	VA_START (Args, This);
	do {
	StartingLba = VA_ARG (Args, EFI_LBA);
	if (StartingLba == EFI_LBA_LIST_TERMINATOR) {
	break;
	}

	NumOfLba = VA_ARG (Args, UINTN);

	if ((StartingLba > EMU_FVB_NUM_TOTAL_BLOCKS) \|\|
	(NumOfLba > EMU_FVB_NUM_TOTAL_BLOCKS - StartingLba))
	{
	VA_END (Args);
	return EFI_INVALID_PARAMETER;
	}
	} while (1);

	VA_END (Args);

	//
	// Erase blocks
	//
	VA_START (Args, This);
	do {
	StartingLba = VA_ARG (Args, EFI_LBA);
	if (StartingLba == EFI_LBA_LIST_TERMINATOR) {
	break;
	}

	NumOfLba = VA_ARG (Args, UINTN);

	ErasePtr = FvbDevice->BufferPtr;
	ErasePtr += (UINTN)StartingLba * FvbDevice->BlockSize;
	EraseSize = NumOfLba * FvbDevice->BlockSize;

	SetMem (ErasePtr, EraseSize, ERASED_UINT8);
	} while (1);

	VA_END (Args);

	//
	// Call platform hook
	//
	VA_START (Args, This);
	PlatformFvbBlocksErased (This, Args);
	VA_END (Args);

	return EFI_SUCCESS;
	}

	/**
	Writes the specified number of bytes from the input buffer to the block.

	The Write() function writes the specified number of bytes from
	the provided buffer to the specified block and offset. If the
	firmware volume is sticky write, the caller must ensure that
	all the bits of the specified range to write are in the
	EFI_FVB_ERASE_POLARITY state before calling the Write()
	function, or else the result will be unpredictable. This
	unpredictability arises because, for a sticky-write firmware
	volume, a write may negate a bit in the EFI_FVB_ERASE_POLARITY
	state but cannot flip it back again. In general, before
	calling the Write() function, the caller should call the
	EraseBlocks() function first to erase the specified block to
	write. A block erase cycle will transition bits from the
	(NOT)EFI_FVB_ERASE_POLARITY state back to the
	EFI_FVB_ERASE_POLARITY state. Implementations should be
	mindful that the firmware volume might be in the WriteDisabled
	state. If it is in this state, the Write() function must
	return the status code EFI_ACCESS_DENIED without modifying the
	contents of the firmware volume. The Write() function must
	also prevent spanning block boundaries. If a write is
	requested that spans a block boundary, the write must store up
	to the boundary but not beyond. The output parameter NumBytes
	must be set to correctly indicate the number of bytes actually
	written. The caller must be aware that a write may be
	partially completed. All writes, partial or otherwise, must be
	fully flushed to the hardware before the Write() service
	returns.

	@param This Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.

	@param Lba The starting logical block index to write to.

	@param Offset Offset into the block at which to begin writing.

	@param NumBytes Pointer to a UINTN. At entry, *NumBytes
	contains the total size of the buffer. At
	exit, *NumBytes contains the total number of
	bytes actually written.

	@param Buffer Pointer to a caller-allocated buffer that
	contains the source for the write.

	@retval EFI_SUCCESS The firmware volume was written successfully.

	@retval EFI_BAD_BUFFER_SIZE The write was attempted across an
	LBA boundary. On output, NumBytes
	contains the total number of bytes
	actually written.

	@retval EFI_ACCESS_DENIED The firmware volume is in the
	WriteDisabled state.

	@retval EFI_DEVICE_ERROR The block device is malfunctioning
	and could not be written.


	**/
	EFI_STATUS
	EFIAPI
	FvbProtocolWrite (
	IN CONST EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL *This,
	IN EFI_LBA Lba,
	IN UINTN Offset,
	IN OUT UINTN *NumBytes,
	IN UINT8 *Buffer
	)
	{
	EFI_FW_VOL_BLOCK_DEVICE *FvbDevice;
	UINT8 *FvbDataPtr;
	EFI_STATUS Status;

	FvbDevice = FVB_DEVICE_FROM_THIS (This);

	if ((Lba >= EMU_FVB_NUM_TOTAL_BLOCKS) \|\|
	(Offset > FvbDevice->BlockSize))
	{
	return EFI_INVALID_PARAMETER;
	}

	Status = EFI_SUCCESS;
	if (*NumBytes > FvbDevice->BlockSize - Offset) {
	*NumBytes = FvbDevice->BlockSize - Offset;
	Status = EFI_BAD_BUFFER_SIZE;
	}

	FvbDataPtr = FvbDevice->BufferPtr;
	FvbDataPtr += (UINTN)Lba * FvbDevice->BlockSize;
	FvbDataPtr += Offset;

	CopyMem (FvbDataPtr, Buffer, *NumBytes);
	PlatformFvbDataWritten (This, Lba, Offset, *NumBytes, Buffer);
	return Status;
	}

	/**
	Reads the specified number of bytes into a buffer from the specified block.

	The Read() function reads the requested number of bytes from the
	requested block and stores them in the provided buffer.
	Implementations should be mindful that the firmware volume
	might be in the ReadDisabled state. If it is in this state,
	the Read() function must return the status code
	EFI_ACCESS_DENIED without modifying the contents of the
	buffer. The Read() function must also prevent spanning block
	boundaries. If a read is requested that would span a block
	boundary, the read must read up to the boundary but not
	beyond. The output parameter NumBytes must be set to correctly
	indicate the number of bytes actually read. The caller must be
	aware that a read may be partially completed.

	@param This Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.

	@param Lba The starting logical block index
	from which to read.

	@param Offset Offset into the block at which to begin reading.

	@param NumBytes Pointer to a UINTN. At entry, *NumBytes
	contains the total size of the buffer. At
	exit, *NumBytes contains the total number of
	bytes read.

	@param Buffer Pointer to a caller-allocated buffer that will
	be used to hold the data that is read.

	@retval EFI_SUCCESS The firmware volume was read successfully
	and contents are in Buffer.

	@retval EFI_BAD_BUFFER_SIZE Read attempted across an LBA
	boundary. On output, NumBytes
	contains the total number of bytes
	returned in Buffer.

	@retval EFI_ACCESS_DENIED The firmware volume is in the
	ReadDisabled state.

	@retval EFI_DEVICE_ERROR The block device is not
	functioning correctly and could
	not be read.

	**/
	EFI_STATUS
	EFIAPI
	FvbProtocolRead (
	IN CONST EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL *This,
	IN EFI_LBA Lba,
	IN UINTN Offset,
	IN OUT UINTN *NumBytes,
	IN OUT UINT8 *Buffer
	)
	{
	EFI_FW_VOL_BLOCK_DEVICE *FvbDevice;
	UINT8 *FvbDataPtr;
	EFI_STATUS Status;

	FvbDevice = FVB_DEVICE_FROM_THIS (This);

	if ((Lba >= EMU_FVB_NUM_TOTAL_BLOCKS) \|\|
	(Offset > FvbDevice->BlockSize))
	{
	return EFI_INVALID_PARAMETER;
	}

	Status = EFI_SUCCESS;
	if (*NumBytes > FvbDevice->BlockSize - Offset) {
	*NumBytes = FvbDevice->BlockSize - Offset;
	Status = EFI_BAD_BUFFER_SIZE;
	}

	FvbDataPtr = FvbDevice->BufferPtr;
	FvbDataPtr += (UINTN)Lba * FvbDevice->BlockSize;
	FvbDataPtr += Offset;

	CopyMem (Buffer, FvbDataPtr, *NumBytes);
	PlatformFvbDataRead (This, Lba, Offset, *NumBytes, Buffer);
	return Status;
	}

	/**
	Check the integrity of firmware volume header.

	@param[in] FwVolHeader - A pointer to a firmware volume header

	@retval EFI_SUCCESS - The firmware volume is consistent
	@retval EFI_NOT_FOUND - The firmware volume has been corrupted.

	**/
	EFI_STATUS
	ValidateFvHeader (
	IN EFI_FIRMWARE_VOLUME_HEADER *FwVolHeader
	)
	{
	UINT16 Checksum;

	//
	// Verify the header revision, header signature, length
	// Length of FvBlock cannot be 2**64-1
	// HeaderLength cannot be an odd number
	//
	if ((FwVolHeader->Revision != EFI_FVH_REVISION) \|\|
	(FwVolHeader->Signature != EFI_FVH_SIGNATURE) \|\|
	(FwVolHeader->FvLength != EMU_FVB_SIZE) \|\|
	(FwVolHeader->HeaderLength != EMU_FV_HEADER_LENGTH)
	)
	{
	DEBUG ((DEBUG_INFO, "EMU Variable FVB: Basic FV headers were invalid\n"));
	return EFI_NOT_FOUND;
	}

	//
	// Verify the header checksum
	//
	Checksum = CalculateSum16 ((VOID *)FwVolHeader, FwVolHeader->HeaderLength);

	if (Checksum != 0) {
	DEBUG ((DEBUG_INFO, "EMU Variable FVB: FV checksum was invalid\n"));
	return EFI_NOT_FOUND;
	}

	return EFI_SUCCESS;
	}

	/**
	Initializes the FV Header and Variable Store Header
	to support variable operations.

	@param[in] Ptr - Location to initialize the headers

	**/
	VOID
	InitializeFvAndVariableStoreHeaders (
	IN VOID *Ptr
	)
	{
	//
	// Templates for authenticated variable FV header
	//
	STATIC FVB_FV_HDR_AND_VARS_TEMPLATE FvAndAuthenticatedVarTemplate = {
	{ // EFI_FIRMWARE_VOLUME_HEADER FvHdr;
	// UINT8 ZeroVector[16];
	{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },

	// EFI_GUID FileSystemGuid;
	EFI_SYSTEM_NV_DATA_FV_GUID,

	// UINT64 FvLength;
	EMU_FVB_SIZE,

	// UINT32 Signature;
	EFI_FVH_SIGNATURE,

	// EFI_FVB_ATTRIBUTES_2 Attributes;
	0x4feff,

	// UINT16 HeaderLength;
	EMU_FV_HEADER_LENGTH,

	// UINT16 Checksum;
	0,

	// UINT16 ExtHeaderOffset;
	0,

	// UINT8 Reserved[1];
	{ 0 },

	// UINT8 Revision;
	EFI_FVH_REVISION,

	// EFI_FV_BLOCK_MAP_ENTRY BlockMap[1];
	{
	{
	EMU_FVB_NUM_TOTAL_BLOCKS, // UINT32 NumBlocks;
	EMU_FVB_BLOCK_SIZE // UINT32 Length;
	}
	}
	},
	// EFI_FV_BLOCK_MAP_ENTRY EndBlockMap;
	{ 0, 0 }, // End of block map
	{ // VARIABLE_STORE_HEADER VarHdr;
	// EFI_GUID Signature; // need authenticated variables for secure boot
	EFI_AUTHENTICATED_VARIABLE_GUID,

	// UINT32 Size;
	(
	FixedPcdGet32 (PcdFlashNvStorageVariableSize) -
	OFFSET_OF (FVB_FV_HDR_AND_VARS_TEMPLATE, VarHdr)
	),

	// UINT8 Format;
	VARIABLE_STORE_FORMATTED,

	// UINT8 State;
	VARIABLE_STORE_HEALTHY,

	// UINT16 Reserved;
	0,

	// UINT32 Reserved1;
	0
	}
	};

	EFI_FIRMWARE_VOLUME_HEADER *Fv;

	//
	// Copy the template structure into the location
	//
	CopyMem (
	Ptr,
	&FvAndAuthenticatedVarTemplate,
	sizeof FvAndAuthenticatedVarTemplate
	);

	//
	// Update the checksum for the FV header
	//
	Fv = (EFI_FIRMWARE_VOLUME_HEADER *)Ptr;
	Fv->Checksum = CalculateCheckSum16 (Ptr, Fv->HeaderLength);
	}

	/**
	Main entry point.

	@param[in] ImageHandle The firmware allocated handle for the EFI image.
	@param[in] SystemTable A pointer to the EFI System Table.

	@retval EFI_SUCCESS Successfully initialized.

	**/
	EFI_STATUS
	EFIAPI
	FvbInitialize (
	IN EFI_HANDLE ImageHandle,
	IN EFI_SYSTEM_TABLE *SystemTable
	)
	{
	EFI_STATUS Status;
	VOID *Ptr;
	VOID *SubPtr;
	BOOLEAN Initialize;
	EFI_HANDLE Handle;
	EFI_PHYSICAL_ADDRESS Address;
	RETURN_STATUS PcdStatus;

	DEBUG ((DEBUG_INFO, "EMU Variable FVB Started\n"));

	//
	// Verify that the PCD's are set correctly.
	//
	ASSERT (
	FixedPcdGet32 (PcdFlashNvStorageFtwSpareSize) %
	EMU_FVB_BLOCK_SIZE == 0
	);
	if (
	(PcdGet32 (PcdFlashNvStorageVariableSize) +
	PcdGet32 (PcdFlashNvStorageFtwWorkingSize)
	) >
	EMU_FVB_NUM_SPARE_BLOCKS * EMU_FVB_BLOCK_SIZE
	)
	{
	DEBUG ((DEBUG_ERROR, "EMU Variable invalid PCD sizes\n"));
	return EFI_INVALID_PARAMETER;
	}

	if (PcdGet64 (PcdFlashNvStorageVariableBase64) != 0) {
	DEBUG ((
	DEBUG_INFO,
	"Disabling EMU Variable FVB since "
	"flash variables appear to be supported.\n"
	));
	return EFI_ABORTED;
	}

	//
	// By default we will initialize the FV contents. But, if
	// PcdEmuVariableNvStoreReserved is non-zero, then we will
	// use this location for our buffer.
	//
	// If this location does not have a proper FV header, then
	// we will initialize it.
	//
	Initialize = TRUE;
	if (PcdGet64 (PcdEmuVariableNvStoreReserved) != 0) {
	Ptr = (VOID *)(UINTN)PcdGet64 (PcdEmuVariableNvStoreReserved);
	DEBUG ((
	DEBUG_INFO,
	"EMU Variable FVB: Using pre-reserved block at %p\n",
	Ptr
	));
	Status = ValidateFvHeader (Ptr);
	if (!EFI_ERROR (Status)) {
	DEBUG ((DEBUG_INFO, "EMU Variable FVB: Found valid pre-existing FV\n"));
	Initialize = FALSE;
	}
	} else {
	Ptr = AllocateRuntimePages (EFI_SIZE_TO_PAGES (EMU_FVB_SIZE));
	}

	mEmuVarsFvb.BufferPtr = Ptr;

	//
	// Initialize the main FV header and variable store header
	//
	if (Initialize) {
	SetMem (Ptr, EMU_FVB_SIZE, ERASED_UINT8);
	InitializeFvAndVariableStoreHeaders (Ptr);
	}

	PcdStatus = PcdSet64S (PcdFlashNvStorageVariableBase64, (UINTN)Ptr);
	ASSERT_RETURN_ERROR (PcdStatus);

	//
	// Initialize the Fault Tolerant Write data area
	//
	SubPtr = (VOID )((UINT8 )Ptr + PcdGet32 (PcdFlashNvStorageVariableSize));
	PcdStatus = PcdSet64S (
	PcdFlashNvStorageFtwWorkingBase64,
	(UINTN)SubPtr
	);
	ASSERT_RETURN_ERROR (PcdStatus);

	//
	// Initialize the Fault Tolerant Write spare block
	//
	SubPtr = (VOID )((UINT8 )Ptr +
	EMU_FVB_NUM_SPARE_BLOCKS * EMU_FVB_BLOCK_SIZE);
	PcdStatus = PcdSet64S (
	PcdFlashNvStorageFtwSpareBase64,
	(UINTN)SubPtr
	);
	ASSERT_RETURN_ERROR (PcdStatus);

	//
	// Setup FVB device path
	//
	Address = (EFI_PHYSICAL_ADDRESS)(UINTN)Ptr;
	mEmuVarsFvb.DevicePath.MemMapDevPath.StartingAddress = Address;
	mEmuVarsFvb.DevicePath.MemMapDevPath.EndingAddress = Address + EMU_FVB_SIZE - 1;

	//
	// Install the protocols
	//
	DEBUG ((DEBUG_INFO, "Installing FVB for EMU Variable support\n"));
	Handle = 0;
	Status = gBS->InstallMultipleProtocolInterfaces (
	&Handle,
	&gEfiFirmwareVolumeBlock2ProtocolGuid,
	&mEmuVarsFvb.FwVolBlockInstance,
	&gEfiDevicePathProtocolGuid,
	&mEmuVarsFvb.DevicePath,
	NULL
	);
	ASSERT_EFI_ERROR (Status);

	//
	// Register for the virtual address change event
	//
	Status = gBS->CreateEventEx (
	EVT_NOTIFY_SIGNAL,
	TPL_NOTIFY,
	FvbVirtualAddressChangeEvent,
	NULL,
	&gEfiEventVirtualAddressChangeGuid,
	&mEmuVarsFvbAddrChangeEvent
	);
	ASSERT_EFI_ERROR (Status);

	return EFI_SUCCESS;
	}