1 files changed, 47 insertions, 0 deletions
diff --git a/roms/edk2/OvmfPkg/CpuHotplugSmm/FirstSmiHandlerContext.h b/roms/edk2/OvmfPkg/CpuHotplugSmm/FirstSmiHandlerContext.h
new file mode 100644
index 000000000..029de4cde
--- /dev/null
+++ b/roms/edk2/OvmfPkg/CpuHotplugSmm/FirstSmiHandlerContext.h
@@ -0,0 +1,47 @@
+/** @file
+  Define the FIRST_SMI_HANDLER_CONTEXT structure, which is an exchange area
+  between the SMM Monarch and the hot-added CPU, for relocating the SMBASE of
+  the hot-added CPU.
+
+  Copyright (c) 2020, Red Hat, Inc.
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#ifndef FIRST_SMI_HANDLER_CONTEXT_H_
+#define FIRST_SMI_HANDLER_CONTEXT_H_
+
+//
+// The following structure is used to communicate between the SMM Monarch
+// (running the root MMI handler) and the hot-added CPU (handling its first
+// SMI). It is placed at SMM_DEFAULT_SMBASE, which is in SMRAM under QEMU's
+// "SMRAM at default SMBASE" feature.
+//
+#pragma pack (1)
+typedef struct {
+  //
+  // When ApicIdGate is MAX_UINT64, then no hot-added CPU may proceed with
+  // SMBASE relocation.
+  //
+  // Otherwise, the hot-added CPU whose APIC ID equals ApicIdGate may proceed
+  // with SMBASE relocation.
+  //
+  // This field is intentionally wider than APIC_ID (UINT32) because we need a
+  // "gate locked" value that is different from all possible APIC_IDs.
+  //
+  UINT64 ApicIdGate;
+  //
+  // The new SMBASE value for the hot-added CPU to set in the SMRAM Save State
+  // Map, before leaving SMM with the RSM instruction.
+  //
+  UINT32 NewSmbase;
+  //
+  // The hot-added CPU sets this field to 1 right before executing the RSM
+  // instruction. This tells the SMM Monarch to proceed to polling the last
+  // byte of the normal RAM reserved page (Post-SMM Pen).
+  //
+  UINT8 AboutToLeaveSmm;
+} FIRST_SMI_HANDLER_CONTEXT;
+#pragma pack ()
+
+#endif // FIRST_SMI_HANDLER_CONTEXT_H_