MdePkg/Library/BaseLib/X64/ReadMsr64.c

   1 /** @file
   2   CpuBreakpoint function.
   3
   4   Copyright (c) 2006 - 2021, Intel Corporation. All rights reserved.<BR>
   5   SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 /**
  10   Microsoft Visual Studio 7.1 Function Prototypes for I/O Intrinsics.
  11 **/
  12
  13 #include <Library/RegisterFilterLib.h>
  14
  15 unsigned __int64 __readmsr (int register);
  16
  17 #pragma intrinsic(__readmsr)
  18
  19 /**
  20   Read data to MSR.
  21
  22   @param  Index                Register index of MSR.
  23
  24   @return Value read from MSR.
  25
  26 **/
  27 UINT64
  28 EFIAPI
  29 AsmReadMsr64 (
  30   IN UINT32  Index
  31   )
  32 {
  33   UINT64                            Value;
  34   BOOLEAN                           Flag;
  35
  36   Flag = FilterBeforeMsrRead (Index, &Value);
  37   if (Flag) {
  38     Value = __readmsr (Index);
  39   }
  40   FilterAfterMsrRead (Index, &Value);
  41
  42   return Value;
  43 }
  44