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/** @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;
}
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