diff --git a/OvmfPkg/Include/OvmfPlatforms.h b/OvmfPkg/Include/OvmfPlatforms.h
new file mode 100644
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+++ b/OvmfPkg/Include/OvmfPlatforms.h
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+/** @file
+  OVMF Platform definitions
+
+  Copyright (c) 2014, Gabriel L. Somlo <somlo@cmu.edu>
+
+  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 __OVMF_PLATFORMS_H__
+#define __OVMF_PLATFORMS_H__
+
+#include <Library/PciLib.h>
+#include <IndustryStandard/Pci22.h>
+
+//
+// Host Bridge Device ID (DID) values for PIIX4 and Q35/MCH
+//
+#define INTEL_82441_DEVICE_ID     0x1237  // PIIX4
+#define INTEL_Q35_MCH_DEVICE_ID   0x29C0  // Q35
+
+//
+// OVMF Host Bridge DID Address
+//
+#define OVMF_HOSTBRIDGE_DID \
+  PCI_LIB_ADDRESS (0, 0, 0, PCI_DEVICE_ID_OFFSET)
+
+//
+// Power Management Device and Function numbers for PIIX4 and Q35/MCH
+//
+#define OVMF_PM_DEVICE_PIIX4  0x01
+#define OVMF_PM_FUNC_PIIX4    0x03
+#define OVMF_PM_DEVICE_Q35    0x1f
+#define OVMF_PM_FUNC_Q35      0x00
+
+//
+// Power Management Register access for PIIX4 and Q35/MCH
+//
+#define POWER_MGMT_REGISTER_PIIX4(Offset) \
+  PCI_LIB_ADDRESS (0, OVMF_PM_DEVICE_PIIX4, OVMF_PM_FUNC_PIIX4, (Offset))
+#define POWER_MGMT_REGISTER_Q35(Offset) \
+  PCI_LIB_ADDRESS (0, OVMF_PM_DEVICE_Q35, OVMF_PM_FUNC_Q35, (Offset))
+
+#endif