OvmfPkg: Reserve and init EmuVariableNvStore in Pei-less Startup

EmuVariableNvStore is reserved and init with below 2 functions defined in
PlatformInitLib:
 - PlatformReserveEmuVariableNvStore
 - PlatformInitEmuVariableNvStore

PlatformInitEmuVariableNvStore works when secure boot feature is enabled.
This is because secure boot needs the EFI variables (PK/KEK/DB/DBX, etc)
and EmuVariableNvStore is cleared when OVMF is launched with -bios
parameter.

Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>

Author: mxu9

OvmfPkg/Library/PeilessStartupLib/PeilessStartup.c

@@ -42,6 +42,7 @@ InitializePlatform (
   )
 {
   UINT32  LowerMemorySize;
+  VOID    *VariableStore;
 
   DEBUG ((DEBUG_INFO, "InitializePlatform in Pei-less boot\n"));
   PlatformDebugDumpCmos ();
@@ -79,6 +80,12 @@ InitializePlatform (
     LowerMemorySize
     ));
 
+  VariableStore                                  = PlatformReserveEmuVariableNvStore ();
+  PlatformInfoHob->PcdEmuVariableNvStoreReserved = (UINT64)(UINTN)VariableStore;
+ #ifdef SECURE_BOOT_FEATURE_ENABLED
+  PlatformInitEmuVariableNvStore (VariableStore);
+ #endif
+
   if (TdIsEnabled ()) {
     PlatformTdxPublishRamRegions ();
   } else {