diff --git a/OvmfPkg/Include/Library/QemuFwCfgS3Lib.h b/OvmfPkg/Include/Library/QemuFwCfgS3Lib.h
new file mode 100644
index 0000000000..1c473610d1
--- /dev/null
+++ b/OvmfPkg/Include/Library/QemuFwCfgS3Lib.h
@@ -0,0 +1,39 @@
+/** @file
+  S3 support for QEMU fw_cfg
+
+  This library class enables driver modules (a) to query whether S3 support was
+  enabled on the QEMU command line, (b) to produce fw_cfg DMA operations that
+  are to be replayed at S3 resume time.
+
+  Copyright (C) 2017, 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.
+**/
+
+#ifndef __FW_CFG_S3_LIB__
+#define __FW_CFG_S3_LIB__
+
+/**
+  Determine if S3 support is explicitly enabled.
+
+  @retval  TRUE   If S3 support is explicitly enabled. Other functions in this
+                  library may be called (subject to their individual
+                  restrictions).
+
+           FALSE  Otherwise. This includes unavailability of the firmware
+                  configuration interface. No other function in this library
+                  must be called.
+**/
+BOOLEAN
+EFIAPI
+QemuFwCfgS3Enabled (
+  VOID
+  );
+
+#endif
diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index a0c76a5bb4..3490f7ca7c 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -35,6 +35,10 @@
   #
   QemuFwCfgLib|Include/Library/QemuFwCfgLib.h
 
+  ##  @libraryclass  S3 support for QEMU fw_cfg
+  #
+  QemuFwCfgS3Lib|Include/Library/QemuFwCfgS3Lib.h
+
   ##  @libraryclass  Rewrite the BootOrder NvVar based on QEMU's "bootorder"
   #                  fw_cfg file.
   #