one possible issue with ovmf fvb

[maobibo@loongson.cn]

Hi Gerd,

  I am porting Loongarch Qemu uefi bios, and I want to use reuse ovmf code. And I encounter one problem
when using OvmfPkg/EmuVariableFvbRuntimeDxe/Fvb.c

  here is piece of code:
-----------------------------------------------------------
  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, (UINT32)(UINTN) Ptr);
  ASSERT_RETURN_ERROR (PcdStatus);

On my tcg vm, Ptr will be 64-bit physical address if memory exceeds 4G, I do not know whether there is similar issue on x64 ovmf.
ditto for the following PcdFlashNvStorageFtwSpareBase/PcdFlashNvStorageFtwWorkingBase

Can uefi bios manage memory beyond 4G?


regards
bibo, mao