diff --git a/OvmfPkg/Include/Pcd/CpuHotEjectData.h b/OvmfPkg/Include/Pcd/CpuHotEjectData.h
new file mode 100644
index 0000000000..0671437552
--- /dev/null
+++ b/OvmfPkg/Include/Pcd/CpuHotEjectData.h
@@ -0,0 +1,60 @@
+/** @file
+  Definition for the CPU_HOT_EJECT_DATA structure, which shares
+  CPU hot-eject state between OVMF's SmmCpuFeaturesLib instance in
+  PiSmmCpuDxeSmm, and CpuHotplugSmm.
+
+  CPU_HOT_EJECT_DATA is allocated in SMRAM, and pointed-to by
+  PcdCpuHotEjectDataAddress.
+
+  PcdCpuHotEjectDataAddress is valid when SMM_REQUIRE is TRUE
+  and PcdCpuMaxLogicalProcessorNumber > 1.
+
+  Copyright (C) 2021, Oracle Corporation.
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#ifndef CPU_HOT_EJECT_DATA_H_
+#define CPU_HOT_EJECT_DATA_H_
+
+/**
+  CPU Hot-eject handler, called from SmmCpuFeaturesRendezvousExit()
+  on each CPU at exit from SMM.
+
+  @param[in] ProcessorNum      ProcessorNum denotes the CPU exiting SMM,
+                               and will be used as an index into
+                               CPU_HOT_EJECT_DATA->QemuSelectorMap. It is
+                               identical to the processor handle in
+                               EFI_SMM_CPU_SERVICE_PROTOCOL.
+**/
+typedef
+VOID
+(EFIAPI *CPU_HOT_EJECT_HANDLER) (
+  IN UINTN  ProcessorNum
+  );
+
+//
+// CPU_EJECT_QEMU_SELECTOR_INVALID marks CPUs not being ejected in
+// CPU_HOT_EJECT_DATA->QemuSelectorMap.
+//
+// QEMU CPU Selector is UINT32, so we choose an invalid value larger
+// than that type.
+//
+#define CPU_EJECT_QEMU_SELECTOR_INVALID       (MAX_UINT64)
+
+typedef struct {
+  //
+  // Maps ProcessorNum -> QemuSelector for pending hot-ejects
+  //
+  volatile UINT64 *QemuSelectorMap;
+  //
+  // Handler to do the CPU ejection
+  //
+  volatile CPU_HOT_EJECT_HANDLER Handler;
+  //
+  // Entries in the QemuSelectorMap
+  //
+  UINT32 ArrayLength;
+} CPU_HOT_EJECT_DATA;
+
+#endif // CPU_HOT_EJECT_DATA_H_
diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index 4348bb45c6..9629707020 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -352,6 +352,10 @@
   #  This PCD is only accessed if PcdSmmSmramRequire is TRUE (see below).
   gUefiOvmfPkgTokenSpaceGuid.PcdQ35SmramAtDefaultSmbase|FALSE|BOOLEAN|0x34
 
+  ## This PCD adds a communication channel between OVMF's SmmCpuFeaturesLib
+  #  instance in PiSmmCpuDxeSmm, and CpuHotplugSmm.
+  gUefiOvmfPkgTokenSpaceGuid.PcdCpuHotEjectDataAddress|0|UINT64|0x46
+
 [PcdsFeatureFlag]
   gUefiOvmfPkgTokenSpaceGuid.PcdQemuBootOrderPciTranslation|TRUE|BOOLEAN|0x1c
   gUefiOvmfPkgTokenSpaceGuid.PcdQemuBootOrderMmioTranslation|FALSE|BOOLEAN|0x1d