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 ((DEBUG_ERROR, "%a: invalid UEFI variable size %Lu\n", __FUNCTION__,
 112       (UINT64)DataSize));
 113     return;
 114   }
 115   NumEntries = DataSize / sizeof Entries[0];
 116
 117   //
 118   // For each record in mMemoryTypeInformation, except the terminator record,
 119   // look up the first match (if any) in the UEFI variable, based on the memory
 120   // type.
 121   //
 122   for (HobRecordIdx = 0;
 123        HobRecordIdx < ARRAY_SIZE (mMemoryTypeInformation) - 1;
 124        HobRecordIdx++) {
 125     EFI_MEMORY_TYPE_INFORMATION *HobRecord;
 126     UINTN                       Idx;
 127     EFI_MEMORY_TYPE_INFORMATION *VariableRecord;
 128
 129     HobRecord = &mMemoryTypeInformation[HobRecordIdx];
 130
 131     for (Idx = 0; Idx < NumEntries; Idx++) {
 132       VariableRecord = &Entries[Idx];
 133
 134       if (VariableRecord->Type == HobRecord->Type) {
 135         break;
 136       }
 137     }
 138
 139     //
 140     // If there is a match, allow the UEFI variable to increase NumberOfPages.
 141     //
 142     if (Idx < NumEntries &&
 143         HobRecord->NumberOfPages < VariableRecord->NumberOfPages) {
 144       DEBUG ((DEBUG_VERBOSE, "%a: Type 0x%x: NumberOfPages 0x%x -> 0x%x\n",
 145         __FUNCTION__, HobRecord->Type, HobRecord->NumberOfPages,
 146         VariableRecord->NumberOfPages));
 147
 148       HobRecord->NumberOfPages = VariableRecord->NumberOfPages;
 149     }
 150   }
 151 }
 152
 153 /**
 154   Notification function called when EFI_PEI_READ_ONLY_VARIABLE2_PPI becomes
 155   available.
 156
 157   @param[in] PeiServices      Indirect reference to the PEI Services Table.
 158   @param[in] NotifyDescriptor Address of the notification descriptor data
 159                               structure.
 160   @param[in] Ppi              Address of the PPI that was installed.
 161
 162   @return  Status of the notification. The status code returned from this
 163            function is ignored.
 164 **/
 165 STATIC
 166 EFI_STATUS
 167 EFIAPI
 168 OnReadOnlyVariable2Available (
 169   IN EFI_PEI_SERVICES           **PeiServices,
 170   IN EFI_PEI_NOTIFY_DESCRIPTOR  *NotifyDescriptor,
 171   IN VOID                       *Ppi
 172   )
 173 {
 174   DEBUG ((DEBUG_VERBOSE, "%a\n", __FUNCTION__));
 175
 176   RefreshMemTypeInfo (Ppi);
 177   BuildMemTypeInfoHob ();
 178   return EFI_SUCCESS;
 179 }
 180
 181 //
 182 // Notification object for registering the callback, for when
 183 // EFI_PEI_READ_ONLY_VARIABLE2_PPI becomes available.
 184 //
 185 STATIC CONST EFI_PEI_NOTIFY_DESCRIPTOR mReadOnlyVariable2Notify = {
 186   (EFI_PEI_PPI_DESCRIPTOR_NOTIFY_DISPATCH |
 187    EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST),  // Flags
 188   &gEfiPeiReadOnlyVariable2PpiGuid,         // Guid
 189   OnReadOnlyVariable2Available              // Notify
 190 };
 191
 192 VOID
 193 MemTypeInfoInitialization (
 194   VOID
 195   )
 196 {
 197   EFI_STATUS Status;
 198
 199   if (!FeaturePcdGet (PcdSmmSmramRequire)) {
 200     //
 201     // EFI_PEI_READ_ONLY_VARIABLE2_PPI will never be available; install
 202     // the default memory type information HOB right away.
 203     //
 204     BuildMemTypeInfoHob ();
 205     return;
 206   }
 207
 208   Status = PeiServicesNotifyPpi (&mReadOnlyVariable2Notify);
 209   if (EFI_ERROR (Status)) {
 210     DEBUG ((DEBUG_ERROR, "%a: failed to set up R/O Variable 2 callback: %r\n",
 211       __FUNCTION__, Status));
 212     ASSERT (FALSE);
 213     CpuDeadLoop ();
 214   }
 215 }