OvmfPkg NvVarsFileLib: Set NvVars variable after writing vars file

The volatile 'NvVars' variable indicates that the variables do
not need to be loaded from the file again. After we write the
variables out to the file, there is clearly no need to load
them back from the file.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Michael Chang <mchang@suse.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14613 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/Library/NvVarsFileLib/FsAccess.c

@@ -1,7 +1,7 @@
 /** @file
   File System Access for NvVarsFileLib
 
-  Copyright (c) 2004 - 2011, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2004 - 2013, 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
@@ -275,6 +275,39 @@ ReadNvVarsFile (
 }
 
 
+/**
+  Writes a variable to indicate that the NV variables
+  have been loaded from the file system.
+
+**/
+STATIC
+VOID
+SetNvVarsVariable (
+  VOID
+  )
+{
+  BOOLEAN                        VarData;
+  UINTN                          Size;
+
+  //
+  // Write a variable to indicate we've already loaded the
+  // variable data.  If it is found, we skip the loading on
+  // subsequent attempts.
+  //
+  Size = sizeof (VarData);
+  VarData = TRUE;
+  gRT->SetVariable (
+         L"NvVars",
+         &gEfiSimpleFileSystemProtocolGuid,
+         EFI_VARIABLE_NON_VOLATILE |
+           EFI_VARIABLE_BOOTSERVICE_ACCESS |
+           EFI_VARIABLE_RUNTIME_ACCESS,
+         Size,
+         (VOID*) &VarData
+         );
+}
+
+
 /**
   Loads the non-volatile variables from the NvVars file on the
   given file system.
@@ -332,17 +365,7 @@ LoadNvVarsFromFs (
   // variable data.  If it is found, we skip the loading on
   // subsequent attempts.
   //
-  Size = sizeof (VarData);
-  VarData = TRUE;
-  gRT->SetVariable (
-         L"NvVars",
-         &gEfiSimpleFileSystemProtocolGuid,
-         EFI_VARIABLE_NON_VOLATILE |
-           EFI_VARIABLE_BOOTSERVICE_ACCESS |
-           EFI_VARIABLE_RUNTIME_ACCESS,
-         Size,
-         (VOID*) &VarData
-         );
+  SetNvVarsVariable();
 
   DEBUG ((
     EFI_D_INFO,
@@ -475,6 +498,13 @@ SaveNvVarsToFs (
   FileHandleClose (File);
 
   if (!EFI_ERROR (Status)) {
+    //
+    // Write a variable to indicate we've already loaded the
+    // variable data.  If it is found, we skip the loading on
+    // subsequent attempts.
+    //
+    SetNvVarsVariable();
+
     DEBUG ((EFI_D_INFO, "Saved NV Variables to NvVars file\n"));
   }