1 files changed, 27 insertions, 0 deletions
diff --git a/roms/edk2/OvmfPkg/Library/PlatformHasIoMmuLib/PlatformHasIoMmuLib.c b/roms/edk2/OvmfPkg/Library/PlatformHasIoMmuLib/PlatformHasIoMmuLib.c
new file mode 100644
index 000000000..7c4ef769d
--- /dev/null
+++ b/roms/edk2/OvmfPkg/Library/PlatformHasIoMmuLib/PlatformHasIoMmuLib.c
@@ -0,0 +1,27 @@
+/** @file
+  A hook-in library for MdeModulePkg/Bus/Pci/PciHostBridgeDxe.
+
+  Plugging this library instance into PciHostBridgeDxe makes
+  PciHostBridgeDxe depend on the platform's dynamic decision whether
+  to provide IOMMU implementation (usually through IoMmuDxe driver).
+
+  Copyright (C) 2017, Red Hat, Inc.
+  Copyright (C) 2017, AMD, Inc.
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Base.h>
+
+RETURN_STATUS
+EFIAPI
+PlatformHasIoMmuInitialize (
+  VOID
+  )
+{
+  //
+  // Do nothing, just imbue PciHostBridgeDxe with a protocol dependency on
+  // gIoMmuAbsentProtocolGuid OR gEdkiiIoMmuProtocolGuid.
+  //
+  return RETURN_SUCCESS;
+}