MdePkg/Library/BaseLib/X64/WriteMsr64.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 void
  16 __writemsr (
  17   unsigned long     Register,
  18   unsigned __int64  Value
  19   );
  20
  21 #pragma intrinsic(__writemsr)
  22
  23 /**
  24   Write data to MSR.
  25
  26   @param  Index                The register index of MSR.
  27   @param  Value                Data wants to be written.
  28
  29   @return Value written to MSR.
  30
  31 **/
  32 UINT64
  33 EFIAPI
  34 AsmWriteMsr64 (
  35   IN UINT32  Index,
  36   IN UINT64  Value
  37   )
  38 {
  39   BOOLEAN  Flag;
  40
  41   Flag = FilterBeforeMsrWrite (Index, &Value);
  42   if (Flag) {
  43     __writemsr (Index, Value);
  44   }
  45
  46   FilterAfterMsrWrite (Index, &Value);
  47
  48   return Value;
  49 }