OvmfPkg/PlatformPei: rewrite MemTypeInfo HOB production logic

[mirror_edk2.git] / OvmfPkg / PlatformPei / MemTypeInfo.c

/** @file\r
  Produce the memory type information HOB.\r
\r
  Copyright (C) 2017-2020, Red Hat, Inc.\r
\r
  SPDX-License-Identifier: BSD-2-Clause-Patent\r
**/\r
\r
#include <Guid/MemoryTypeInformation.h>\r
#include <Library/BaseLib.h>\r
#include <Library/DebugLib.h>\r
#include <Library/HobLib.h>\r
#include <Library/PcdLib.h>\r
#include <Library/PeiServicesLib.h>\r
#include <Ppi/ReadOnlyVariable2.h>\r
#include <Uefi/UefiMultiPhase.h>\r
\r
#include "Platform.h"\r
\r
//\r
// The NumberOfPages values below are ad-hoc. They are updated sporadically at\r
// best (please refer to git-blame for past updates). The values capture a set\r
// of BIN hints that made sense at a particular time, for some (now likely\r
// unknown) workloads / boot paths.\r
//\r
STATIC EFI_MEMORY_TYPE_INFORMATION mMemoryTypeInformation[] = {\r
  { EfiACPIMemoryNVS,       0x004 },\r
  { EfiACPIReclaimMemory,   0x008 },\r
  { EfiReservedMemoryType,  0x004 },\r
  { EfiRuntimeServicesData, 0x024 },\r
  { EfiRuntimeServicesCode, 0x030 },\r
  { EfiMaxMemoryType,       0x000 }\r
};\r
\r
STATIC\r
VOID\r
BuildMemTypeInfoHob (\r
  VOID\r
  )\r
{\r
  BuildGuidDataHob (\r
    &gEfiMemoryTypeInformationGuid,\r
    mMemoryTypeInformation,\r
    sizeof mMemoryTypeInformation\r
    );\r
}\r
\r
/**\r
  Refresh the mMemoryTypeInformation array (which we'll turn into the\r
  MemoryTypeInformation HOB) from the MemoryTypeInformation UEFI variable.\r
\r
  Normally, the DXE IPL PEIM builds the HOB from the UEFI variable. But it does\r
  so *transparently*. Instead, we consider the UEFI variable as a list of\r
  hints, for updating our HOB defaults:\r
\r
  - Record types not covered in mMemoryTypeInformation are ignored. In\r
    particular, this hides record types from the UEFI variable that may lead to\r
    reboots without benefiting SMM security, such as EfiBootServicesData.\r
\r
  - Records that would lower the defaults in mMemoryTypeInformation are also\r
    ignored.\r
\r
  @param[in] ReadOnlyVariable2  The EFI_PEI_READ_ONLY_VARIABLE2_PPI used for\r
                                retrieving the MemoryTypeInformation UEFI\r
                                variable.\r
**/\r
STATIC\r
VOID\r
RefreshMemTypeInfo (\r
  IN EFI_PEI_READ_ONLY_VARIABLE2_PPI *ReadOnlyVariable2\r
  )\r
{\r
  UINTN                       DataSize;\r
  EFI_MEMORY_TYPE_INFORMATION Entries[EfiMaxMemoryType + 1];\r
  EFI_STATUS                  Status;\r
  UINTN                       NumEntries;\r
  UINTN                       HobRecordIdx;\r
\r
  //\r
  // Read the MemoryTypeInformation UEFI variable from the\r
  // gEfiMemoryTypeInformationGuid namespace.\r
  //\r
  DataSize = sizeof Entries;\r
  Status = ReadOnlyVariable2->GetVariable (\r
                                ReadOnlyVariable2,\r
                                EFI_MEMORY_TYPE_INFORMATION_VARIABLE_NAME,\r
                                &gEfiMemoryTypeInformationGuid,\r
                                NULL,\r
                                &DataSize,\r
                                Entries\r
                                );\r
  if (EFI_ERROR (Status)) {\r
    //\r
    // If the UEFI variable does not exist (EFI_NOT_FOUND), we can't use it for\r
    // udpating mMemoryTypeInformation.\r
    //\r
    // If the UEFI variable exists but Entries is too small to hold it\r
    // (EFI_BUFFER_TOO_SMALL), then the variable contents are arguably invalid.\r
    // That's because Entries has room for every distinct EFI_MEMORY_TYPE,\r
    // including the terminator record with EfiMaxMemoryType. Thus, we can't\r
    // use the UEFI variable for updating mMemoryTypeInformation.\r
    //\r
    // If the UEFI variable couldn't be read for some other reason, we\r
    // similarly can't use it for udpating mMemoryTypeInformation.\r
    //\r
    DEBUG ((DEBUG_ERROR, "%a: GetVariable(): %r\n", __FUNCTION__, Status));\r
    return;\r
  }\r
\r
  //\r
  // Sanity-check the UEFI variable size against the record size.\r
  //\r
  if (DataSize % sizeof Entries[0] != 0) {\r
    DEBUG ((DEBUG_ERROR, "%a: invalid UEFI variable size %Lu\n", __FUNCTION__,\r
      (UINT64)DataSize));\r
    return;\r
  }\r
  NumEntries = DataSize / sizeof Entries[0];\r
\r
  //\r
  // For each record in mMemoryTypeInformation, except the terminator record,\r
  // look up the first match (if any) in the UEFI variable, based on the memory\r
  // type.\r
  //\r
  for (HobRecordIdx = 0;\r
       HobRecordIdx < ARRAY_SIZE (mMemoryTypeInformation) - 1;\r
       HobRecordIdx++) {\r
    EFI_MEMORY_TYPE_INFORMATION *HobRecord;\r
    UINTN                       Idx;\r
    EFI_MEMORY_TYPE_INFORMATION *VariableRecord;\r
\r
    HobRecord = &mMemoryTypeInformation[HobRecordIdx];\r
\r
    for (Idx = 0; Idx < NumEntries; Idx++) {\r
      VariableRecord = &Entries[Idx];\r
\r
      if (VariableRecord->Type == HobRecord->Type) {\r
        break;\r
      }\r
    }\r
\r
    //\r
    // If there is a match, allow the UEFI variable to increase NumberOfPages.\r
    //\r
    if (Idx < NumEntries &&\r
        HobRecord->NumberOfPages < VariableRecord->NumberOfPages) {\r
      DEBUG ((DEBUG_VERBOSE, "%a: Type 0x%x: NumberOfPages 0x%x -> 0x%x\n",\r
        __FUNCTION__, HobRecord->Type, HobRecord->NumberOfPages,\r
        VariableRecord->NumberOfPages));\r
\r
      HobRecord->NumberOfPages = VariableRecord->NumberOfPages;\r
    }\r
  }\r
}\r
\r
/**\r
  Notification function called when EFI_PEI_READ_ONLY_VARIABLE2_PPI becomes\r
  available.\r
\r
  @param[in] PeiServices      Indirect reference to the PEI Services Table.\r
  @param[in] NotifyDescriptor Address of the notification descriptor data\r
                              structure.\r
  @param[in] Ppi              Address of the PPI that was installed.\r
\r
  @return  Status of the notification. The status code returned from this\r
           function is ignored.\r
**/\r
STATIC\r
EFI_STATUS\r
EFIAPI\r
OnReadOnlyVariable2Available (\r
  IN EFI_PEI_SERVICES           **PeiServices,\r
  IN EFI_PEI_NOTIFY_DESCRIPTOR  *NotifyDescriptor,\r
  IN VOID                       *Ppi\r
  )\r
{\r
  DEBUG ((DEBUG_VERBOSE, "%a\n", __FUNCTION__));\r
\r
  RefreshMemTypeInfo (Ppi);\r
  BuildMemTypeInfoHob ();\r
  return EFI_SUCCESS;\r
}\r
\r
//\r
// Notification object for registering the callback, for when\r
// EFI_PEI_READ_ONLY_VARIABLE2_PPI becomes available.\r
//\r
STATIC CONST EFI_PEI_NOTIFY_DESCRIPTOR mReadOnlyVariable2Notify = {\r
  (EFI_PEI_PPI_DESCRIPTOR_NOTIFY_DISPATCH |\r
   EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST),  // Flags\r
  &gEfiPeiReadOnlyVariable2PpiGuid,         // Guid\r
  OnReadOnlyVariable2Available              // Notify\r
};\r
\r
VOID\r
MemTypeInfoInitialization (\r
  VOID\r
  )\r
{\r
  EFI_STATUS Status;\r
\r
  if (!FeaturePcdGet (PcdSmmSmramRequire)) {\r
    //\r
    // EFI_PEI_READ_ONLY_VARIABLE2_PPI will never be available; install\r
    // the default memory type information HOB right away.\r
    //\r
    BuildMemTypeInfoHob ();\r
    return;\r
  }\r
\r
  Status = PeiServicesNotifyPpi (&mReadOnlyVariable2Notify);\r
  if (EFI_ERROR (Status)) {\r
    DEBUG ((DEBUG_ERROR, "%a: failed to set up R/O Variable 2 callback: %r\n",\r
      __FUNCTION__, Status));\r
    ASSERT (FALSE);\r
    CpuDeadLoop ();\r
  }\r
}\r