PeiDxeMemEncryptSevLibInternal.c

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#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/MemEncryptSevLib.h>
#include <Library/PcdLib.h>
#include <Register/Amd/SmramSaveStateMap.h>
#include <Register/SmramSaveStateMap.h>
#include <Uefi/UefiBaseType.h>
 
RETURN_STATUS
EFIAPI
MemEncryptSevLocateInitialSmramSaveStateMapPages (
  OUT UINTN  *BaseAddress,
  OUT UINTN  *NumberOfPages
  )
{
  UINTN  MapStart;
  UINTN  MapEnd;
  UINTN  MapPagesStart; // MapStart rounded down to page boundary
  UINTN  MapPagesEnd;   // MapEnd rounded up to page boundary
  UINTN  MapPagesSize;  // difference between MapPagesStart and MapPagesEnd
 
  if (!FeaturePcdGet (PcdSmmSmramRequire)) {
    return RETURN_UNSUPPORTED;
  }
 
  MapStart      = SMM_DEFAULT_SMBASE + SMRAM_SAVE_STATE_MAP_OFFSET;
  MapEnd        = MapStart + sizeof (AMD_SMRAM_SAVE_STATE_MAP);
  MapPagesStart = MapStart & ~(UINTN)EFI_PAGE_MASK;
  MapPagesEnd   = ALIGN_VALUE (MapEnd, EFI_PAGE_SIZE);
  MapPagesSize  = MapPagesEnd - MapPagesStart;
 
  ASSERT ((MapPagesSize & EFI_PAGE_MASK) == 0);
 
  *BaseAddress   = MapPagesStart;
  *NumberOfPages = MapPagesSize >> EFI_PAGE_SHIFT;
 
  return RETURN_SUCCESS;
}