1 files changed, 67 insertions, 0 deletions
diff --git a/OvmfPkg/Library/AcpiPlatformLib/DxeAcpiPlatformLib.c b/OvmfPkg/Library/AcpiPlatformLib/DxeAcpiPlatformLib.c
new file mode 100644
index 0000000000..9dd9026edb
--- /dev/null
+++ b/OvmfPkg/Library/AcpiPlatformLib/DxeAcpiPlatformLib.c
@@ -0,0 +1,67 @@
+/** @file
+  OVMF ACPI support
+
+  Copyright (C) 2021, Red Hat, Inc.
+  Copyright (c) 2008 - 2012, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2012, Bei Guan <gbtju85@gmail.com>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/AcpiPlatformLib.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+
+EFI_STATUS
+EFIAPI
+GetAcpiRsdpFromMemory (
+  IN UINTN                                            StartAddress,
+  IN UINTN                                            EndAddress,
+  OUT   EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER  **RsdpPtr
+  )
+{
+  EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER  *RsdpStructurePtr;
+  UINT8                                         *AcpiPtr;
+  UINT8                                         Sum;
+
+  for (AcpiPtr = (UINT8 *)StartAddress;
+       AcpiPtr < (UINT8 *)EndAddress;
+       AcpiPtr += 0x10)
+  {
+    RsdpStructurePtr = (EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER *)
+                       (UINTN)AcpiPtr;
+
+    if (!AsciiStrnCmp ((CHAR8 *)&RsdpStructurePtr->Signature, "RSD PTR ", 8)) {
+      //
+      // RSDP ACPI 1.0 checksum for 1.0/2.0/3.0 table.
+      // This is only the first 20 bytes of the structure
+      //
+      Sum = CalculateSum8 (
+              (CONST UINT8 *)RsdpStructurePtr,
+              sizeof (EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER)
+              );
+      if (Sum != 0) {
+        return EFI_ABORTED;
+      }
+
+      if (RsdpStructurePtr->Revision >= 2) {
+        //
+        // RSDP ACPI 2.0/3.0 checksum, this is the entire table
+        //
+        Sum = CalculateSum8 (
+                (CONST UINT8 *)RsdpStructurePtr,
+                sizeof (EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER)
+                );
+        if (Sum != 0) {
+          return EFI_ABORTED;
+        }
+      }
+
+      *RsdpPtr = RsdpStructurePtr;
+      return EFI_SUCCESS;
+    }
+  }
+
+  return EFI_NOT_FOUND;
+}