OvmfPkg/SmmAccess/SmmAccess2Dxe.c

   1 /** @file
   2
   3   A DXE_DRIVER providing SMRAM access by producing EFI_SMM_ACCESS2_PROTOCOL.
   4
   5   Q35 TSEG is expected to have been verified and set up by the SmmAccessPei
   6   driver.
   7
   8   Copyright (C) 2013, 2015, Red Hat, Inc.<BR>
   9   Copyright (c) 2009 - 2010, Intel Corporation. All rights reserved.<BR>
  10
  11   SPDX-License-Identifier: BSD-2-Clause-Patent
  12
  13 **/
  14
  15 #include <Library/DebugLib.h>
  16 #include <Library/PcdLib.h>
  17 #include <Library/UefiBootServicesTableLib.h>
  18 #include <Protocol/SmmAccess2.h>
  19
  20 #include "SmramInternal.h"
  21
  22 /**
  23   Opens the SMRAM area to be accessible by a boot-service driver.
  24
  25   This function "opens" SMRAM so that it is visible while not inside of SMM.
  26   The function should return EFI_UNSUPPORTED if the hardware does not support
  27   hiding of SMRAM. The function should return EFI_DEVICE_ERROR if the SMRAM
  28   configuration is locked.
  29
  30   @param[in] This           The EFI_SMM_ACCESS2_PROTOCOL instance.
  31
  32   @retval EFI_SUCCESS       The operation was successful.
  33   @retval EFI_UNSUPPORTED   The system does not support opening and closing of
  34                             SMRAM.
  35   @retval EFI_DEVICE_ERROR  SMRAM cannot be opened, perhaps because it is
  36                             locked.
  37 **/
  38 STATIC
  39 EFI_STATUS
  40 EFIAPI
  41 SmmAccess2DxeOpen (
  42   IN EFI_SMM_ACCESS2_PROTOCOL  *This
  43   )
  44 {
  45   return SmramAccessOpen (&This->LockState, &This->OpenState);
  46 }
  47
  48 /**
  49   Inhibits access to the SMRAM.
  50
  51   This function "closes" SMRAM so that it is not visible while outside of SMM.
  52   The function should return EFI_UNSUPPORTED if the hardware does not support
  53   hiding of SMRAM.
  54
  55   @param[in] This           The EFI_SMM_ACCESS2_PROTOCOL instance.
  56
  57   @retval EFI_SUCCESS       The operation was successful.
  58   @retval EFI_UNSUPPORTED   The system does not support opening and closing of
  59                             SMRAM.
  60   @retval EFI_DEVICE_ERROR  SMRAM cannot be closed.
  61 **/
  62 STATIC
  63 EFI_STATUS
  64 EFIAPI
  65 SmmAccess2DxeClose (
  66   IN EFI_SMM_ACCESS2_PROTOCOL  *This
  67   )
  68 {
  69   return SmramAccessClose (&This->LockState, &This->OpenState);
  70 }
  71
  72 /**
  73   Inhibits access to the SMRAM.
  74
  75   This function prohibits access to the SMRAM region.  This function is usually
  76   implemented such that it is a write-once operation.
  77
  78   @param[in] This          The EFI_SMM_ACCESS2_PROTOCOL instance.
  79
  80   @retval EFI_SUCCESS      The device was successfully locked.
  81   @retval EFI_UNSUPPORTED  The system does not support locking of SMRAM.
  82 **/
  83 STATIC
  84 EFI_STATUS
  85 EFIAPI
  86 SmmAccess2DxeLock (
  87   IN EFI_SMM_ACCESS2_PROTOCOL  *This
  88   )
  89 {
  90   return SmramAccessLock (&This->LockState, &This->OpenState);
  91 }
  92
  93 /**
  94   Queries the memory controller for the possible regions that will support
  95   SMRAM.
  96
  97   @param[in]     This           The EFI_SMM_ACCESS2_PROTOCOL instance.
  98   @param[in,out] SmramMapSize   A pointer to the size, in bytes, of the
  99                                 SmramMemoryMap buffer.
 100   @param[in,out] SmramMap       A pointer to the buffer in which firmware
 101                                 places the current memory map.
 102
 103   @retval EFI_SUCCESS           The chipset supported the given resource.
 104   @retval EFI_BUFFER_TOO_SMALL  The SmramMap parameter was too small.  The
 105                                 current buffer size needed to hold the memory
 106                                 map is returned in SmramMapSize.
 107 **/
 108 STATIC
 109 EFI_STATUS
 110 EFIAPI
 111 SmmAccess2DxeGetCapabilities (
 112   IN CONST EFI_SMM_ACCESS2_PROTOCOL  *This,
 113   IN OUT UINTN                       *SmramMapSize,
 114   IN OUT EFI_SMRAM_DESCRIPTOR        *SmramMap
 115   )
 116 {
 117   return SmramAccessGetCapabilities (This->LockState, This->OpenState,
 118            SmramMapSize, SmramMap);
 119 }
 120
 121 //
 122 // LockState and OpenState will be filled in by the entry point.
 123 //
 124 STATIC EFI_SMM_ACCESS2_PROTOCOL mAccess2 = {
 125   &SmmAccess2DxeOpen,
 126   &SmmAccess2DxeClose,
 127   &SmmAccess2DxeLock,
 128   &SmmAccess2DxeGetCapabilities
 129 };
 130
 131 //
 132 // Entry point of this driver.
 133 //
 134 EFI_STATUS
 135 EFIAPI
 136 SmmAccess2DxeEntryPoint (
 137   IN EFI_HANDLE       ImageHandle,
 138   IN EFI_SYSTEM_TABLE *SystemTable
 139   )
 140 {
 141   //
 142   // This module should only be included if SMRAM support is required.
 143   //
 144   ASSERT (FeaturePcdGet (PcdSmmSmramRequire));
 145
 146   InitQ35TsegMbytes ();
 147   GetStates (&mAccess2.LockState, &mAccess2.OpenState);
 148   return gBS->InstallMultipleProtocolInterfaces (&ImageHandle,
 149                 &gEfiSmmAccess2ProtocolGuid, &mAccess2,
 150                 NULL);
 151 }