diff --git a/OvmfPkg/PlatformPei/ClearCache.c b/OvmfPkg/PlatformPei/ClearCache.c
new file mode 100644
index 0000000000..7d15fd925c
--- /dev/null
+++ b/OvmfPkg/PlatformPei/ClearCache.c
@@ -0,0 +1,117 @@
+/**@file
+  Install a callback to clear cache on all processors.
+  This is for conformance with the TCG "Platform Reset Attack Mitigation
+  Specification". Because clearing the CPU caches at boot doesn't impact
+  performance significantly, do it unconditionally, for simplicity's
+  sake.
+
+  Copyright (C) 2018, Red Hat, Inc.
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#include <Library/CacheMaintenanceLib.h>
+#include <Library/DebugLib.h>
+#include <Library/PeiServicesLib.h>
+#include <Ppi/MpServices.h>
+
+#include "Platform.h"
+
+/**
+  Invalidate data & instruction caches.
+  All APs execute this function in parallel. The BSP executes the function
+  separately.
+
+  @param[in,out] WorkSpace  Pointer to the input/output argument workspace
+                            shared by all processors.
+**/
+STATIC
+VOID
+EFIAPI
+ClearCache (
+  IN OUT VOID *WorkSpace
+  )
+{
+  WriteBackInvalidateDataCache ();
+  InvalidateInstructionCache ();
+}
+
+/**
+  Notification function called when EFI_PEI_MP_SERVICES_PPI becomes available.
+
+  @param[in] PeiServices      Indirect reference to the PEI Services Table.
+  @param[in] NotifyDescriptor Address of the notification descriptor data
+                              structure.
+  @param[in] Ppi              Address of the PPI that was installed.
+
+  @return  Status of the notification. The status code returned from this
+           function is ignored.
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+ClearCacheOnMpServicesAvailable (
+  IN EFI_PEI_SERVICES           **PeiServices,
+  IN EFI_PEI_NOTIFY_DESCRIPTOR  *NotifyDescriptor,
+  IN VOID                       *Ppi
+  )
+{
+  EFI_PEI_MP_SERVICES_PPI *MpServices;
+  EFI_STATUS              Status;
+
+  DEBUG ((DEBUG_INFO, "%a: %a\n", gEfiCallerBaseName, __FUNCTION__));
+
+  //
+  // Clear cache on all the APs in parallel.
+  //
+  MpServices = Ppi;
+  Status = MpServices->StartupAllAPs (
+                         (CONST EFI_PEI_SERVICES **)PeiServices,
+                         MpServices,
+                         ClearCache,          // Procedure
+                         FALSE,               // SingleThread
+                         0,                   // TimeoutInMicroSeconds: inf.
+                         NULL                 // ProcedureArgument
+                         );
+  if (EFI_ERROR (Status) && Status != EFI_NOT_STARTED) {
+    DEBUG ((DEBUG_ERROR, "%a: StartupAllAps(): %r\n", __FUNCTION__, Status));
+    return Status;
+  }
+
+  //
+  // Now clear cache on the BSP too.
+  //
+  ClearCache (NULL);
+  return EFI_SUCCESS;
+}
+
+//
+// Notification object for registering the callback, for when
+// EFI_PEI_MP_SERVICES_PPI becomes available.
+//
+STATIC CONST EFI_PEI_NOTIFY_DESCRIPTOR mMpServicesNotify = {
+  EFI_PEI_PPI_DESCRIPTOR_NOTIFY_CALLBACK | // Flags
+  EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST,
+  &gEfiPeiMpServicesPpiGuid,               // Guid
+  ClearCacheOnMpServicesAvailable          // Notify
+};
+
+VOID
+InstallClearCacheCallback (
+  VOID
+  )
+{
+  EFI_STATUS           Status;
+
+  Status = PeiServicesNotifyPpi (&mMpServicesNotify);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_ERROR, "%a: failed to set up MP Services callback: %r\n",
+      __FUNCTION__, Status));
+  }
+}
diff --git a/OvmfPkg/PlatformPei/Platform.c b/OvmfPkg/PlatformPei/Platform.c
index 5a78668126..22139a64cb 100644
--- a/OvmfPkg/PlatformPei/Platform.c
+++ b/OvmfPkg/PlatformPei/Platform.c
@@ -672,6 +672,7 @@ InitializePlatform (
     NoexecDxeInitialization ();
   }
 
+  InstallClearCacheCallback ();
   AmdSevInitialize ();
   MiscInitialization ();
   InstallFeatureControlCallback ();
diff --git a/OvmfPkg/PlatformPei/Platform.h b/OvmfPkg/PlatformPei/Platform.h
index f942e61bb4..b12a5c1f5f 100644
--- a/OvmfPkg/PlatformPei/Platform.h
+++ b/OvmfPkg/PlatformPei/Platform.h
@@ -83,6 +83,11 @@ InstallFeatureControlCallback (
   VOID
   );
 
+VOID
+InstallClearCacheCallback (
+  VOID
+  );
+
 EFI_STATUS
 InitializeXen (
   VOID
diff --git a/OvmfPkg/PlatformPei/PlatformPei.inf b/OvmfPkg/PlatformPei/PlatformPei.inf
index 9c5ad9961c..5c8dd0fe6d 100644
--- a/OvmfPkg/PlatformPei/PlatformPei.inf
+++ b/OvmfPkg/PlatformPei/PlatformPei.inf
@@ -30,6 +30,7 @@
 
 [Sources]
   AmdSev.c
+  ClearCache.c
   Cmos.c
   Cmos.h
   FeatureControl.c
@@ -54,6 +55,7 @@
 
 [LibraryClasses]
   BaseLib
+  CacheMaintenanceLib
   DebugLib
   HobLib
   IoLib