OvmfPkg/PlatformPei/MemTypeInfo.c

   1 /** @file
   2   Produce the memory type information HOB.
   3
   4   Copyright (C) 2017-2020, Red Hat, Inc.
   5
   6   SPDX-License-Identifier: BSD-2-Clause-Patent
   7 **/
   8
   9 #include <Guid/MemoryTypeInformation.h>
  10 #include <Library/BaseLib.h>
  11 #include <Library/DebugLib.h>
  12 #include <Library/HobLib.h>
  13 #include <Library/PcdLib.h>
  14 #include <Library/PeiServicesLib.h>
  15 #include <Ppi/ReadOnlyVariable2.h>
  16 #include <Uefi/UefiMultiPhase.h>
  17
  18 #include "Platform.h"
  19
  20 #define MEMORY_TYPE_INFO_DEFAULT(Type) \
  21   { Type, FixedPcdGet32 (PcdMemoryType ## Type) }
  22
  23 STATIC EFI_MEMORY_TYPE_INFORMATION  mMemoryTypeInformation[] = {
  24   MEMORY_TYPE_INFO_DEFAULT (EfiACPIMemoryNVS),
  25   MEMORY_TYPE_INFO_DEFAULT (EfiACPIReclaimMemory),
  26   MEMORY_TYPE_INFO_DEFAULT (EfiReservedMemoryType),
  27   MEMORY_TYPE_INFO_DEFAULT (EfiRuntimeServicesCode),
  28   MEMORY_TYPE_INFO_DEFAULT (EfiRuntimeServicesData),
  29   { EfiMaxMemoryType,                               0}
  30 };
  31
  32 STATIC
  33 VOID
  34 BuildMemTypeInfoHob (
  35   VOID
  36   )
  37 {
  38   BuildGuidDataHob (
  39     &gEfiMemoryTypeInformationGuid,
  40     mMemoryTypeInformation,
  41     sizeof mMemoryTypeInformation
  42     );
  43 }
  44
  45 /**
  46   Refresh the mMemoryTypeInformation array (which we'll turn into the
  47   MemoryTypeInformation HOB) from the MemoryTypeInformation UEFI variable.
  48
  49   Normally, the DXE IPL PEIM builds the HOB from the UEFI variable. But it does
  50   so *transparently*. Instead, we consider the UEFI variable as a list of
  51   hints, for updating our HOB defaults:
  52
  53   - Record types not covered in mMemoryTypeInformation are ignored. In
  54     particular, this hides record types from the UEFI variable that may lead to
  55     reboots without benefiting SMM security, such as EfiBootServicesData.
  56
  57   - Records that would lower the defaults in mMemoryTypeInformation are also
  58     ignored.
  59
  60   @param[in] ReadOnlyVariable2  The EFI_PEI_READ_ONLY_VARIABLE2_PPI used for
  61                                 retrieving the MemoryTypeInformation UEFI
  62                                 variable.
  63 **/
  64 STATIC
  65 VOID
  66 RefreshMemTypeInfo (
  67   IN EFI_PEI_READ_ONLY_VARIABLE2_PPI  *ReadOnlyVariable2
  68   )
  69 {
  70   UINTN                        DataSize;
  71   EFI_MEMORY_TYPE_INFORMATION  Entries[EfiMaxMemoryType + 1];
  72   EFI_STATUS                   Status;
  73   UINTN                        NumEntries;
  74   UINTN                        HobRecordIdx;
  75
  76   //
  77   // Read the MemoryTypeInformation UEFI variable from the
  78   // gEfiMemoryTypeInformationGuid namespace.
  79   //
  80   DataSize = sizeof Entries;
  81   Status   = ReadOnlyVariable2->GetVariable (
  82                                   ReadOnlyVariable2,
  83                                   EFI_MEMORY_TYPE_INFORMATION_VARIABLE_NAME,
  84                                   &gEfiMemoryTypeInformationGuid,
  85                                   NULL,
  86                                   &DataSize,
  87                                   Entries
  88                                   );
  89   if (EFI_ERROR (Status)) {
  90     //
  91     // If the UEFI variable does not exist (EFI_NOT_FOUND), we can't use it for
  92     // udpating mMemoryTypeInformation.
  93     //
  94     // If the UEFI variable exists but Entries is too small to hold it
  95     // (EFI_BUFFER_TOO_SMALL), then the variable contents are arguably invalid.
  96     // That's because Entries has room for every distinct EFI_MEMORY_TYPE,
  97     // including the terminator record with EfiMaxMemoryType. Thus, we can't
  98     // use the UEFI variable for updating mMemoryTypeInformation.
  99     //
 100     // If the UEFI variable couldn't be read for some other reason, we
 101     // similarly can't use it for udpating mMemoryTypeInformation.
 102     //
 103     DEBUG ((DEBUG_ERROR, "%a: GetVariable(): %r\n", __FUNCTION__, Status));
 104     return;
 105   }
 106
 107   //
 108   // Sanity-check the UEFI variable size against the record size.
 109   //
 110   if (DataSize % sizeof Entries[0] != 0) {
 111     DEBUG ((
 112       DEBUG_ERROR,
 113       "%a: invalid UEFI variable size %Lu\n",
 114       __FUNCTION__,
 115       (UINT64)DataSize
 116       ));
 117     return;
 118   }
 119
 120   NumEntries = DataSize / sizeof Entries[0];
 121
 122   //
 123   // For each record in mMemoryTypeInformation, except the terminator record,
 124   // look up the first match (if any) in the UEFI variable, based on the memory
 125   // type.
 126   //
 127   for (HobRecordIdx = 0;
 128        HobRecordIdx < ARRAY_SIZE (mMemoryTypeInformation) - 1;
 129        HobRecordIdx++)
 130   {
 131     EFI_MEMORY_TYPE_INFORMATION  *HobRecord;
 132     UINTN                        Idx;
 133     EFI_MEMORY_TYPE_INFORMATION  *VariableRecord;
 134
 135     HobRecord = &mMemoryTypeInformation[HobRecordIdx];
 136
 137     for (Idx = 0; Idx < NumEntries; Idx++) {
 138       VariableRecord = &Entries[Idx];
 139
 140       if (VariableRecord->Type == HobRecord->Type) {
 141         break;
 142       }
 143     }
 144
 145     //
 146     // If there is a match, allow the UEFI variable to increase NumberOfPages.
 147     //
 148     if ((Idx < NumEntries) &&
 149         (HobRecord->NumberOfPages < VariableRecord->NumberOfPages))
 150     {
 151       DEBUG ((
 152         DEBUG_VERBOSE,
 153         "%a: Type 0x%x: NumberOfPages 0x%x -> 0x%x\n",
 154         __FUNCTION__,
 155         HobRecord->Type,
 156         HobRecord->NumberOfPages,
 157         VariableRecord->NumberOfPages
 158         ));
 159
 160       HobRecord->NumberOfPages = VariableRecord->NumberOfPages;
 161     }
 162   }
 163 }
 164
 165 /**
 166   Notification function called when EFI_PEI_READ_ONLY_VARIABLE2_PPI becomes
 167   available.
 168
 169   @param[in] PeiServices      Indirect reference to the PEI Services Table.
 170   @param[in] NotifyDescriptor Address of the notification descriptor data
 171                               structure.
 172   @param[in] Ppi              Address of the PPI that was installed.
 173
 174   @return  Status of the notification. The status code returned from this
 175            function is ignored.
 176 **/
 177 STATIC
 178 EFI_STATUS
 179 EFIAPI
 180 OnReadOnlyVariable2Available (
 181   IN EFI_PEI_SERVICES           **PeiServices,
 182   IN EFI_PEI_NOTIFY_DESCRIPTOR  *NotifyDescriptor,
 183   IN VOID                       *Ppi
 184   )
 185 {
 186   DEBUG ((DEBUG_VERBOSE, "%a\n", __FUNCTION__));
 187
 188   RefreshMemTypeInfo (Ppi);
 189   BuildMemTypeInfoHob ();
 190   return EFI_SUCCESS;
 191 }
 192
 193 //
 194 // Notification object for registering the callback, for when
 195 // EFI_PEI_READ_ONLY_VARIABLE2_PPI becomes available.
 196 //
 197 STATIC CONST EFI_PEI_NOTIFY_DESCRIPTOR  mReadOnlyVariable2Notify = {
 198   (EFI_PEI_PPI_DESCRIPTOR_NOTIFY_DISPATCH |
 199    EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST),  // Flags
 200   &gEfiPeiReadOnlyVariable2PpiGuid,         // Guid
 201   OnReadOnlyVariable2Available              // Notify
 202 };
 203
 204 VOID
 205 MemTypeInfoInitialization (
 206   VOID
 207   )
 208 {
 209   EFI_STATUS  Status;
 210
 211   if (!FeaturePcdGet (PcdSmmSmramRequire)) {
 212     //
 213     // EFI_PEI_READ_ONLY_VARIABLE2_PPI will never be available; install
 214     // the default memory type information HOB right away.
 215     //
 216     BuildMemTypeInfoHob ();
 217     return;
 218   }
 219
 220   Status = PeiServicesNotifyPpi (&mReadOnlyVariable2Notify);
 221   if (EFI_ERROR (Status)) {
 222     DEBUG ((
 223       DEBUG_ERROR,
 224       "%a: failed to set up R/O Variable 2 callback: %r\n",
 225       __FUNCTION__,
 226       Status
 227       ));
 228     ASSERT (FALSE);
 229     CpuDeadLoop ();
 230   }
 231 }