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