UefiCpuPkg/Include/Library/VmgExitLib.h

   1 /** @file
   2   Public header file for the VMGEXIT Support library class.
   3
   4   This library class defines some routines used when invoking the VMGEXIT
   5   instruction in support of SEV-ES and to handle #VC exceptions.
   6
   7   Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
   8   SPDX-License-Identifier: BSD-2-Clause-Patent
   9
  10 **/
  11
  12 #ifndef __VMG_EXIT_LIB_H__
  13 #define __VMG_EXIT_LIB_H__
  14
  15 #include <Protocol/DebugSupport.h>
  16 #include <Register/Amd/Ghcb.h>
  17
  18 /**
  19   Perform VMGEXIT.
  20
  21   Sets the necessary fields of the GHCB, invokes the VMGEXIT instruction and
  22   then handles the return actions.
  23
  24   @param[in, out]  Ghcb       A pointer to the GHCB
  25   @param[in]       ExitCode   VMGEXIT code to be assigned to the SwExitCode
  26                               field of the GHCB.
  27   @param[in]       ExitInfo1  VMGEXIT information to be assigned to the
  28                               SwExitInfo1 field of the GHCB.
  29   @param[in]       ExitInfo2  VMGEXIT information to be assigned to the
  30                               SwExitInfo2 field of the GHCB.
  31
  32   @retval  0                  VMGEXIT succeeded.
  33   @return                     Exception number to be propagated, VMGEXIT
  34                               processing did not succeed.
  35
  36 **/
  37 UINT64
  38 EFIAPI
  39 VmgExit (
  40   IN OUT GHCB    *Ghcb,
  41   IN     UINT64  ExitCode,
  42   IN     UINT64  ExitInfo1,
  43   IN     UINT64  ExitInfo2
  44   );
  45
  46 /**
  47   Perform pre-VMGEXIT initialization/preparation.
  48
  49   Performs the necessary steps in preparation for invoking VMGEXIT. Must be
  50   called before setting any fields within the GHCB.
  51
  52   @param[in, out]  Ghcb            A pointer to the GHCB
  53   @param[in, out]  InterruptState  A pointer to hold the current interrupt
  54                                    state, used for restoring in VmgDone ()
  55
  56 **/
  57 VOID
  58 EFIAPI
  59 VmgInit (
  60   IN OUT GHCB     *Ghcb,
  61   IN OUT BOOLEAN  *InterruptState
  62   );
  63
  64 /**
  65   Perform post-VMGEXIT cleanup.
  66
  67   Performs the necessary steps to cleanup after invoking VMGEXIT. Must be
  68   called after obtaining needed fields within the GHCB.
  69
  70   @param[in, out]  Ghcb            A pointer to the GHCB
  71   @param[in]       InterruptState  An indicator to conditionally (re)enable
  72                                    interrupts
  73
  74 **/
  75 VOID
  76 EFIAPI
  77 VmgDone (
  78   IN OUT GHCB     *Ghcb,
  79   IN     BOOLEAN  InterruptState
  80   );
  81
  82 /**
  83   Marks a specified offset as valid in the GHCB.
  84
  85   The ValidBitmap area represents the areas of the GHCB that have been marked
  86   valid. Set the bit in ValidBitmap for the input offset.
  87
  88   @param[in, out]  Ghcb       A pointer to the GHCB
  89   @param[in]       Offset     Qword offset in the GHCB to mark valid
  90
  91 **/
  92 VOID
  93 EFIAPI
  94 VmgSetOffsetValid (
  95   IN OUT GHCB           *Ghcb,
  96   IN     GHCB_REGISTER  Offset
  97   );
  98
  99 /**
 100   Checks if a specified offset is valid in the GHCB.
 101
 102   The ValidBitmap area represents the areas of the GHCB that have been marked
 103   valid. Return whether the bit in the ValidBitmap is set for the input offset.
 104
 105   @param[in]  Ghcb            A pointer to the GHCB
 106   @param[in]  Offset          Qword offset in the GHCB to mark valid
 107
 108   @retval TRUE                Offset is marked valid in the GHCB
 109   @retval FALSE               Offset is not marked valid in the GHCB
 110
 111 **/
 112 BOOLEAN
 113 EFIAPI
 114 VmgIsOffsetValid (
 115   IN GHCB           *Ghcb,
 116   IN GHCB_REGISTER  Offset
 117   );
 118
 119 /**
 120   Handle a #VC exception.
 121
 122   Performs the necessary processing to handle a #VC exception.
 123
 124   The base library function returns an error equal to VC_EXCEPTION,
 125   to be propagated to the standard exception handling stack.
 126
 127   @param[in, out]  ExceptionType  Pointer to an EFI_EXCEPTION_TYPE to be set
 128                                   as value to use on error.
 129   @param[in, out]  SystemContext  Pointer to EFI_SYSTEM_CONTEXT
 130
 131   @retval  EFI_SUCCESS            Exception handled
 132   @retval  EFI_UNSUPPORTED        #VC not supported, (new) exception value to
 133                                   propagate provided
 134   @retval  EFI_PROTOCOL_ERROR     #VC handling failed, (new) exception value to
 135                                   propagate provided
 136
 137 **/
 138 EFI_STATUS
 139 EFIAPI
 140 VmgExitHandleVc (
 141   IN OUT EFI_EXCEPTION_TYPE  *ExceptionType,
 142   IN OUT EFI_SYSTEM_CONTEXT  SystemContext
 143   );
 144
 145 #endif