1 files changed, 63 insertions, 0 deletions
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiDxeMemEncryptSevLibInternal.c b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiDxeMemEncryptSevLibInternal.c
new file mode 100644
index 0000000000..b4a9f464e2
--- /dev/null
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiDxeMemEncryptSevLibInternal.c
@@ -0,0 +1,63 @@
+/** @file
+
+  Secure Encrypted Virtualization (SEV) library helper function
+
+  Copyright (c) 2017 - 2020, AMD Incorporated. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/MemEncryptSevLib.h>
+#include <Library/PcdLib.h>
+#include <Register/QemuSmramSaveStateMap.h>
+#include <Register/SmramSaveStateMap.h>
+#include <Uefi/UefiBaseType.h>
+
+/**
+  Locate the page range that covers the initial (pre-SMBASE-relocation) SMRAM
+  Save State Map.
+
+  @param[out] BaseAddress     The base address of the lowest-address page that
+                              covers the initial SMRAM Save State Map.
+
+  @param[out] NumberOfPages   The number of pages in the page range that covers
+                              the initial SMRAM Save State Map.
+
+  @retval RETURN_SUCCESS      BaseAddress and NumberOfPages have been set on
+                              output.
+
+  @retval RETURN_UNSUPPORTED  SMM is unavailable.
+**/
+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 (QEMU_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;
+}