diff --git a/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockService.c b/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockService.c
index b3f428bb42..eec8b1b1ae 100644
--- a/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockService.c
+++ b/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockService.c
@@ -829,56 +829,6 @@ ValidateFvHeader (
   return EFI_SUCCESS;
 }
 
-STATIC
-EFI_STATUS
-MarkIoMemoryRangeForRuntimeAccess (
-  EFI_PHYSICAL_ADDRESS                BaseAddress,
-  UINTN                               Length
-  )
-{
-  EFI_STATUS                          Status;
-  EFI_GCD_MEMORY_SPACE_DESCRIPTOR     GcdDescriptor;
-
-  //
-  // Mark flash region as runtime memory
-  //
-  Status = gDS->RemoveMemorySpace (
-                  BaseAddress,
-                  Length
-                  );
-
-  Status = gDS->AddMemorySpace (
-                  EfiGcdMemoryTypeMemoryMappedIo,
-                  BaseAddress,
-                  Length,
-                  EFI_MEMORY_UC | EFI_MEMORY_RUNTIME
-                  );
-  ASSERT_EFI_ERROR (Status);
-
-  Status = gDS->AllocateMemorySpace (
-                  EfiGcdAllocateAddress,
-                  EfiGcdMemoryTypeMemoryMappedIo,
-                  0,
-                  Length,
-                  &BaseAddress,
-                  gImageHandle,
-                  NULL
-                  );
-  ASSERT_EFI_ERROR (Status);
-
-  Status = gDS->GetMemorySpaceDescriptor (BaseAddress, &GcdDescriptor);
-  ASSERT_EFI_ERROR (Status);
-
-  Status = gDS->SetMemorySpaceAttributes (
-                  BaseAddress,
-                  Length,
-                  GcdDescriptor.Attributes | EFI_MEMORY_RUNTIME
-                  );
-  ASSERT_EFI_ERROR (Status);
-
-  return Status;
-}
-
 STATIC
 EFI_STATUS
 InitializeVariableFvHeader (
diff --git a/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockService.h b/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockService.h
index 1f9287b087..178f578d49 100644
--- a/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockService.h
+++ b/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockService.h
@@ -189,4 +189,11 @@ VOID
 InstallVirtualAddressChangeHandler (
   VOID
   );
+
+EFI_STATUS
+MarkIoMemoryRangeForRuntimeAccess (
+  IN EFI_PHYSICAL_ADDRESS   BaseAddress,
+  IN UINTN                  Length
+  );
+
 #endif
diff --git a/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockServiceDxe.c b/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockServiceDxe.c
index 63b308658e..37deece363 100644
--- a/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockServiceDxe.c
+++ b/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockServiceDxe.c
@@ -17,6 +17,7 @@
 #include <Guid/EventGroup.h>
 #include <Library/DebugLib.h>
 #include <Library/DevicePathLib.h>
+#include <Library/DxeServicesTableLib.h>
 #include <Library/PcdLib.h>
 #include <Library/UefiBootServicesTableLib.h>
 #include <Library/UefiRuntimeLib.h>
@@ -155,3 +156,52 @@ InstallVirtualAddressChangeHandler (
                   );
   ASSERT_EFI_ERROR (Status);
 }
+
+EFI_STATUS
+MarkIoMemoryRangeForRuntimeAccess (
+  IN EFI_PHYSICAL_ADDRESS                BaseAddress,
+  IN UINTN                               Length
+  )
+{
+  EFI_STATUS                          Status;
+  EFI_GCD_MEMORY_SPACE_DESCRIPTOR     GcdDescriptor;
+
+  //
+  // Mark flash region as runtime memory
+  //
+  Status = gDS->RemoveMemorySpace (
+                  BaseAddress,
+                  Length
+                  );
+
+  Status = gDS->AddMemorySpace (
+                  EfiGcdMemoryTypeMemoryMappedIo,
+                  BaseAddress,
+                  Length,
+                  EFI_MEMORY_UC | EFI_MEMORY_RUNTIME
+                  );
+  ASSERT_EFI_ERROR (Status);
+
+  Status = gDS->AllocateMemorySpace (
+                  EfiGcdAllocateAddress,
+                  EfiGcdMemoryTypeMemoryMappedIo,
+                  0,
+                  Length,
+                  &BaseAddress,
+                  gImageHandle,
+                  NULL
+                  );
+  ASSERT_EFI_ERROR (Status);
+
+  Status = gDS->GetMemorySpaceDescriptor (BaseAddress, &GcdDescriptor);
+  ASSERT_EFI_ERROR (Status);
+
+  Status = gDS->SetMemorySpaceAttributes (
+                  BaseAddress,
+                  Length,
+                  GcdDescriptor.Attributes | EFI_MEMORY_RUNTIME
+                  );
+  ASSERT_EFI_ERROR (Status);
+
+  return Status;
+}
diff --git a/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockServiceSmm.c b/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockServiceSmm.c
index e0617f2503..af08fa69d4 100644
--- a/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockServiceSmm.c
+++ b/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockServiceSmm.c
@@ -67,3 +67,16 @@ InstallVirtualAddressChangeHandler (
   // Nothing.
   //
 }
+
+EFI_STATUS
+MarkIoMemoryRangeForRuntimeAccess (
+  IN EFI_PHYSICAL_ADDRESS                BaseAddress,
+  IN UINTN                               Length
+  )
+{
+  //
+  // Nothing
+  //
+
+  return EFI_SUCCESS;
+}