OvmfPkg/EmuVariableFvbRuntimeDxe: stop using PcdVariableStoreSize

In commit 62f43f7c19, we set PcdVariableStoreSize to the same value as
PcdFlashNvStorageVariableSize (which in turn comes from VARS_LIVE_SIZE in
"OvmfPkg.fdf.inc").

This equality between both PCDs is a false requirement from
EmuVariableFvbRuntimeDxe. FVB drivers should use
PcdFlashNvStorageVariableSize for supporting non-volatile variables (even
if they happen to be kept in RAM only), along the other PcdFlashNvStorage*
PCDs. Whereas PcdVariableStoreSize is for variables that are volatile at
the gRT->SetVariable() / gRT->GetVariable() API level.

(PlatformPei too bases the preallocation for EmuVariableFvbRuntimeDxe on
PcdFlashNvStorageFtwSpareSize.)

Replace PcdVariableStoreSize in EmuVariableFvbRuntimeDxe with the
same-value PcdFlashNvStorageVariableSize. This means no change in
behavior, and it allows us to increase PcdVariableStoreSize in a later
patch without disturbing EmuVariableFvbRuntimeDxe (or PlatformPei).

Cc: Anthony Perard <anthony.perard@citrix.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Gary Ching-Pang Lin <glin@suse.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Julien Grall <julien.grall@linaro.org>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Gary Lin <glin@suse.com>
Tested-by: Gary Lin <glin@suse.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

OvmfPkg/EmuVariableFvbRuntimeDxe/Fvb.c

@@ -665,7 +665,7 @@ InitializeFvAndVariableStoreHeaders (
 
       // UINT32  Size;
       (
-        FixedPcdGet32 (PcdVariableStoreSize) -
+        FixedPcdGet32 (PcdFlashNvStorageVariableSize) -
         OFFSET_OF (FVB_FV_HDR_AND_VARS_TEMPLATE, VarHdr)
       ),
 
@@ -733,7 +733,7 @@ FvbInitialize (
   ASSERT (FixedPcdGet32 (PcdFlashNvStorageFtwSpareSize) %
           EMU_FVB_BLOCK_SIZE == 0);
   if (
-       (PcdGet32 (PcdVariableStoreSize) +
+       (PcdGet32 (PcdFlashNvStorageVariableSize) +
         PcdGet32 (PcdFlashNvStorageFtwWorkingSize)
        ) >
        EMU_FVB_NUM_SPARE_BLOCKS * EMU_FVB_BLOCK_SIZE
@@ -788,7 +788,7 @@ FvbInitialize (
   //
   // Initialize the Fault Tolerant Write data area
   //
-  SubPtr = (VOID*) ((UINT8*) Ptr + PcdGet32 (PcdVariableStoreSize));
+  SubPtr = (VOID*) ((UINT8*) Ptr + PcdGet32 (PcdFlashNvStorageVariableSize));
   PcdStatus = PcdSet32S (PcdFlashNvStorageFtwWorkingBase,
                 (UINT32)(UINTN) SubPtr);
   ASSERT_RETURN_ERROR (PcdStatus);

OvmfPkg/EmuVariableFvbRuntimeDxe/Fvb.inf

@@ -58,12 +58,11 @@
   gEfiDevicePathProtocolGuid                    # PROTOCOL ALWAYS_PRODUCED
 
 [FixedPcd]
-  gEfiMdeModulePkgTokenSpaceGuid.PcdVariableStoreSize
+  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableSize
   gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwWorkingSize
   gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwSpareSize
 
 [Pcd]
-  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableSize
   gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase64
   gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwWorkingBase
   gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwSpareBase