/** @file | |
AsmWriteMsr64 function | |
Copyright (c) 2006 - 2021, Intel Corporation. All rights reserved.<BR> | |
SPDX-License-Identifier: BSD-2-Clause-Patent | |
**/ | |
#include <Library/RegisterFilterLib.h> | |
/** | |
Writes a 64-bit value to a Machine Specific Register(MSR), and returns the | |
value. | |
Writes the 64-bit value specified by Value to the MSR specified by Index. The | |
64-bit value written to the MSR is returned. No parameter checking is | |
performed on Index or Value, and some of these may cause CPU exceptions. The | |
caller must either guarantee that Index and Value are valid, or the caller | |
must establish proper exception handlers. This function is only available on | |
IA-32 and x64. | |
@param Index The 32-bit MSR index to write. | |
@param Value The 64-bit value to write to the MSR. | |
@return Value | |
**/ | |
UINT64 | |
EFIAPI | |
AsmWriteMsr64 ( | |
IN UINT32 Index, | |
IN UINT64 Value | |
) | |
{ | |
BOOLEAN Flag; | |
Flag = FilterBeforeMsrWrite (Index, &Value); | |
if (Flag) { | |
_asm { | |
mov edx, dword ptr [Value + 4] | |
mov eax, dword ptr [Value + 0] | |
mov ecx, Index | |
wrmsr | |
} | |
} | |
FilterAfterMsrWrite (Index, &Value); | |
return Value; | |
} |