UefiCpuPkg/Library/CpuCommonFeaturesLib/LimitCpuIdMaxval.c

   1 /** @file
   2   LimitCpuidMaxval Feature.
   3
   4   Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include "CpuCommonFeatures.h"
  16
  17 /**
  18   Detects if LimitCpuidMaxval feature supported on current processor.
  19
  20   @param[in]  ProcessorNumber  The index of the CPU executing this function.
  21   @param[in]  CpuInfo          A pointer to the REGISTER_CPU_FEATURE_INFORMATION
  22                                structure for the CPU executing this function.
  23   @param[in]  ConfigData       A pointer to the configuration buffer returned
  24                                by CPU_FEATURE_GET_CONFIG_DATA.  NULL if
  25                                CPU_FEATURE_GET_CONFIG_DATA was not provided in
  26                                RegisterCpuFeature().
  27
  28   @retval TRUE     LimitCpuidMaxval feature is supported.
  29   @retval FALSE    LimitCpuidMaxval feature is not supported.
  30
  31   @note This service could be called by BSP/APs.
  32 **/
  33 BOOLEAN
  34 EFIAPI
  35 LimitCpuidMaxvalSupport (
  36   IN UINTN                             ProcessorNumber,
  37   IN REGISTER_CPU_FEATURE_INFORMATION  *CpuInfo,
  38   IN VOID                              *ConfigData  OPTIONAL
  39   )
  40 {
  41   UINT32  Eax;
  42
  43   AsmCpuid (CPUID_SIGNATURE, &Eax, NULL, NULL, NULL);
  44   return (Eax > 3);
  45 }
  46
  47 /**
  48   Initializes LimitCpuidMaxval feature to specific state.
  49
  50   @param[in]  ProcessorNumber  The index of the CPU executing this function.
  51   @param[in]  CpuInfo          A pointer to the REGISTER_CPU_FEATURE_INFORMATION
  52                                structure for the CPU executing this function.
  53   @param[in]  ConfigData       A pointer to the configuration buffer returned
  54                                by CPU_FEATURE_GET_CONFIG_DATA.  NULL if
  55                                CPU_FEATURE_GET_CONFIG_DATA was not provided in
  56                                RegisterCpuFeature().
  57   @param[in]  State            If TRUE, then the LimitCpuidMaxval feature must be enabled.
  58                                If FALSE, then the LimitCpuidMaxval feature must be disabled.
  59
  60   @retval RETURN_SUCCESS       LimitCpuidMaxval feature is initialized.
  61
  62   @note This service could be called by BSP only.
  63 **/
  64 RETURN_STATUS
  65 EFIAPI
  66 LimitCpuidMaxvalInitialize (
  67   IN UINTN                             ProcessorNumber,
  68   IN REGISTER_CPU_FEATURE_INFORMATION  *CpuInfo,
  69   IN VOID                              *ConfigData,  OPTIONAL
  70   IN BOOLEAN                           State
  71   )
  72 {
  73   CPU_REGISTER_TABLE_WRITE_FIELD (
  74     ProcessorNumber,
  75     Msr,
  76     MSR_IA32_MISC_ENABLE,
  77     MSR_IA32_MISC_ENABLE_REGISTER,
  78     Bits.LimitCpuidMaxval,
  79     (State) ? 1 : 0
  80     );
  81   return RETURN_SUCCESS;
  82 }