OvmfPkg/CpuHotplugSmm/FirstSmiHandlerContext.h

   1 /** @file
   2   Define the FIRST_SMI_HANDLER_CONTEXT structure, which is an exchange area
   3   between the SMM Monarch and the hot-added CPU, for relocating the SMBASE of
   4   the hot-added CPU.
   5
   6   Copyright (c) 2020, Red Hat, Inc.
   7
   8   SPDX-License-Identifier: BSD-2-Clause-Patent
   9 **/
  10
  11 #ifndef FIRST_SMI_HANDLER_CONTEXT_H_
  12 #define FIRST_SMI_HANDLER_CONTEXT_H_
  13
  14 //
  15 // The following structure is used to communicate between the SMM Monarch
  16 // (running the root MMI handler) and the hot-added CPU (handling its first
  17 // SMI). It is placed at SMM_DEFAULT_SMBASE, which is in SMRAM under QEMU's
  18 // "SMRAM at default SMBASE" feature.
  19 //
  20 #pragma pack (1)
  21 typedef struct {
  22   //
  23   // When ApicIdGate is MAX_UINT64, then no hot-added CPU may proceed with
  24   // SMBASE relocation.
  25   //
  26   // Otherwise, the hot-added CPU whose APIC ID equals ApicIdGate may proceed
  27   // with SMBASE relocation.
  28   //
  29   // This field is intentionally wider than APIC_ID (UINT32) because we need a
  30   // "gate locked" value that is different from all possible APIC_IDs.
  31   //
  32   UINT64 ApicIdGate;
  33   //
  34   // The new SMBASE value for the hot-added CPU to set in the SMRAM Save State
  35   // Map, before leaving SMM with the RSM instruction.
  36   //
  37   UINT32 NewSmbase;
  38   //
  39   // The hot-added CPU sets this field to 1 right before executing the RSM
  40   // instruction. This tells the SMM Monarch to proceed to polling the last
  41   // byte of the normal RAM reserved page (Post-SMM Pen).
  42   //
  43   UINT8 AboutToLeaveSmm;
  44 } FIRST_SMI_HANDLER_CONTEXT;
  45 #pragma pack ()
  46
  47 #endif // FIRST_SMI_HANDLER_CONTEXT_H_