Smm.c File Reference

Routines for operations related to System Management Mode (SMM). More...

#include "pch.h"

Functions
UINT64	SmmReadSmiCount ()
BOOLEAN	SmmTriggerPowerSmi ()
BOOLEAN	SmmPerformSmiOperation (SMI_OPERATION_PACKETS *SmiOperationRequest, BOOLEAN ApplyFromVmxRootMode)
	Perform actions related to System Management Interrupts (SMIs).

Detailed Description

Routines for operations related to System Management Mode (SMM).

Author

Sina Karvandi (sina@.nosp@m.hype.nosp@m.rdbg..nosp@m.org)

Version

0.15

Date

2025-08-02

Copyright

This project is released under the GNU Public License v3.

Function Documentation

SmmPerformSmiOperation()

BOOLEAN SmmPerformSmiOperation	(	SMI_OPERATION_PACKETS *	SmiOperationRequest,
		BOOLEAN	ApplyFromVmxRootMode )

Perform actions related to System Management Interrupts (SMIs).

Parameters

SmiOperationRequest
ApplyFromVmxRootMode

Returns

BOOLEAN

{
    BOOLEAN Status = FALSE;
 
    UNREFERENCED_PARAMETER(ApplyFromVmxRootMode);
 
    //
    // Check the SMI operation type and perform the corresponding action
    //
    switch (SmiOperationRequest->SmiOperationType)
    {
    case SMI_OPERATION_REQUEST_TYPE_READ_COUNT:
 
        //
        // Read the SMI count from the MSR
        //
        SmiOperationRequest->SmiCount = SmmReadSmiCount();
 
        Status = TRUE;
        break;
 
    case SMI_OPERATION_REQUEST_TYPE_TRIGGER_POWER_SMI:
 
        if (SmmTriggerPowerSmi())
        {
            //
            // If the SMI was triggered successfully
            //
            Status = TRUE;
        }
        else
        {
            //
            // If the SMI was not triggered successfully, set error status
            //
            SmiOperationRequest->KernelStatus = DEBUGGER_ERROR_UNABLE_TO_TRIGGER_SMI;
        }
 
        break;
 
    default:
 
        Status                            = FALSE;
        SmiOperationRequest->KernelStatus = DEBUGGER_ERROR_INVALID_SMI_OPERATION_PARAMETERS;
 
        break;
    }
 
    //
    // Set the status of the SMI operation request
    //
    if (Status)
    {
        SmiOperationRequest->KernelStatus = DEBUGGER_OPERATION_WAS_SUCCESSFUL;
    }
 
    return Status;
}

SmmReadSmiCount()

UINT64 SmmReadSmiCount

(

)

{
    UINT64 SmiCount = 0;
 
    //
    // Read the SMI count from MSR
    //
    SmiCount = (UINT64)CpuReadMsr(MSR_SMI_COUNT);
 
    return SmiCount;
}

SmmTriggerPowerSmi()

BOOLEAN SmmTriggerPowerSmi

(

)

{
    UINT8 SmmResponse = 0;
 
    //
    // check the initial value received from 0xB3 port
    //
    SmmResponse = CpuIoInByte(0xb2);
 
    //
    // write to 0xB2 port to cause SMI
    //
    CpuIoOutByte(0xb2, SMI_TRIGGER_POWER_VALUE);
 
    //
    // Check the response in port 0xB3
    //
    SmmResponse = CpuIoInByte(0xb2);
 
    if (SmmResponse == SMI_TRIGGER_POWER_VALUE)
    {
        //
        // If the response is SMI_TRIGGER_POWER_VALUE, it means the SMI was triggered successfully
        //
        return TRUE;
    }
    else
    {
        //
        // If the response is not SMI_TRIGGER_POWER_VALUE, it means the SMI was not triggered successfully
        //
        return FALSE;
    }
}