- 1 year ago
IA32_MISC_ENABLE Register in C#. How to access
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The IA32_MISC_ENABLE
MSR (Model-Specific Register) is an x86 processor register that allows configuration of a variety of processor features. To access this register from C# code, you will need to use P/Invoke to call the native rdmsr
and wrmsr
functions.
Here is some example C# code to read the IA32_MISC_ENABLE
MSR:
csharpusing System;
using System.Runtime.InteropServices;
class Program
{
[DllImport("kernel32.dll")]
static extern uint GetLastError();
[DllImport("kernel32.dll", SetLastError = true)]
static extern IntPtr CreateFile(
string lpFileName,
uint dwDesiredAccess,
uint dwShareMode,
IntPtr lpSecurityAttributes,
uint dwCreationDisposition,
uint dwFlagsAndAttributes,
IntPtr hTemplateFile
);
[DllImport("kernel32.dll", SetLastError = true)]
static extern bool DeviceIoControl(
IntPtr hDevice,
uint dwIoControlCode,
IntPtr lpInBuffer,
uint nInBufferSize,
out ulong lpOutBuffer,
uint nOutBufferSize,
out uint lpBytesReturned,
IntPtr lpOverlapped
);
[DllImport("kernel32.dll", SetLastError = true)]
static extern bool CloseHandle(IntPtr hObject);
static uint CTL_CODE(uint DeviceType, uint Function, uint Method, uint Access)
{
return (DeviceType << 16) | (Access << 14) | (Function << 2) | Method;
}
static void Main(string[] args)
{
// Open a handle to the physical memory device
var handle = CreateFile(@"\\.\\PHYSICALMEMORY", 0, 0, IntPtr.Zero, 0, 0, IntPtr.Zero);
if (handle == IntPtr.Zero)
{
Console.WriteLine("Error: " + GetLastError());
return;
}
// Calculate the MSR number
const uint IA32_MISC_ENABLE_MSR = 0x1a0;
uint msr = IA32_MISC_ENABLE_MSR & 0xffffffff;
// Build the IOCTL code
uint code = CTL_CODE(0x9c4e0e21, 0x7f92, 0x4471, 0xb3e8);
ulong inBuf = msr;
ulong outBuf;
uint bytesReturned;
// Call DeviceIoControl to read the MSR
if (!DeviceIoControl(handle, code, ref inBuf, sizeof(ulong), out outBuf, sizeof(ulong), out bytesReturned, IntPtr.Zero))
{
Console.WriteLine("Error: " + GetLastError());
CloseHandle(handle);
return;
}
Console.WriteLine("IA32_MISC_ENABLE = 0x{0:x16}", outBuf);
// Close the handle
CloseHandle(handle);
}
}
This code uses the CreateFile
and DeviceIoControl
functions to read the IA32_MISC_ENABLE
MSR from physical memory. The MSR number is specified as 0x1a0
, and the function CTL_CODE
is used to build the appropriate IOCTL code to pass to DeviceIoControl
. The outBuf
variable is used to hold the result of the read operation, and is printed to the console.