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
  16 __readmsr (
  17   int register
  18   );
  19
  20 #pragma intrinsic(__readmsr)
  21
  22 /**
  23   Read data to MSR.
  24
  25   @param  Index                Register index of MSR.
  26
  27   @return Value read from MSR.
  28
  29 **/
  30 UINT64
  31 EFIAPI
  32 AsmReadMsr64 (
  33   IN UINT32  Index
  34   )
  35 {
  36   UINT64   Value;
  37   BOOLEAN  Flag;
  38
  39   Flag = FilterBeforeMsrRead (Index, &Value);
  40   if (Flag) {
  41     Value = __readmsr (Index);
  42   }
  43
  44   FilterAfterMsrRead (Index, &Value);
  45
  46   return Value;
  47 }