.text:00017279 MSR_RecordLastBranchInfo proc near      ; CODE XREF: .text:0001340Bp

.text:00017279                 cmp     cs:MSR_LBR_BitEnabled, 0

.text:00017281                 jnz     short @RecordLastBranchInfo

.text:00017283                 retn

.text:00017284 ; ---------------------------------------------------------------------------

.text:00017284

.text:00017284 @RecordLastBranchInfo:          ; CODE XREF: MSR_RecordLastBranchInfo+8j

.text:00017284                 pusha

.text:00017285                 mov     ebp, esp

.text:00017287                 push    ds

.text:00017288                 db      66h

.text:00017288                 mov     ds, cs:wNTICE_SS

.text:00017290                 mov     ecx, 1DBh       ; LastBranchFromIP

.text:00017290                                         ; "Last Branch From EIP"

.text:00017295                 call    c_RDMSR

.text:0001729A                 mov     dMSR_LAST_BRANCH_0, eax

.text:0001729F                 mov     ecx, 1DCh       ; LastBranchToIP

.text:0001729F                                         ; "Last Branch To EIP"

.text:000172A4                 call    c_RDMSR

.text:000172A9                 mov     dMSR_LAST_BRANCH_1, eax

.text:000172AE                 mov     ecx, 1D9h       ; DebugCtlMSR

.text:000172AE                                         ; "Debug Control"

.text:000172B3                 call    c_RDMSR

.text:000172B8                 or      eax, 1          ; Set LBR bit of IA32_DEBUGCTL MSR

.text:000172BB                 call    c_WRMSR

.text:000172C0                 pop     ds

.text:000172C1                 popa

.text:000172C2                 retn

.text:000172C2 MSR_RecordLastBranchInfo endp

////////////////////////////////////////////////////////////////////////

//  GetMSRDevice::GETMSR_READMSR_Handler

//

//	Routine Description:

//		Handler for IO Control Code GETMSR_READMSR

//

//	Parameters:

//		I - IRP containing IOCTL request

//

//	Return Value:

//		NTSTATUS - Status code indicating success or failure

//

//	Comments:

//		This routine implements the GETMSR_READMSR function.

//		This routine runs at passive level.

//



NTSTATUS GetMSRDevice::GETMSR_READMSR_Handler(KIrp I)

{

	NTSTATUS status = STATUS_SUCCESS;



	t << "Entering GetMSRDevice::GETMSR_READMSR_Handler, " << I << EOL;

// TODO:	Verify that the input parameters are correct

//			If not, return STATUS_INVALID_PARAMETER



// TODO:	Handle the the GETMSR_READMSR request, or 

//			defer the processing of the IRP (i.e. by queuing) and set

//			status to STATUS_PENDING.



// TODO:	Assuming that the request was handled here. Set I.Information

//			to indicate how much data to copy back to the user.

	unsigned long Buffer_Data = 0;



	// Get the buffer data sent in (if any)

	memcpy(&Buffer_Data,I.IoctlBuffer(),sizeof(Buffer_Data));

	

	//t << "Buffer_Data is " << Buffer_Data << EOL;



	//t << "Output buffer size is " << I.IoctlOutputBufferSize() << EOL;



	// Read the MSR

	

	// DEBUGCTLMSR is      0x1D9

	// LASTBRANCHFROMIP is 0x1DB

	// LASTBRANCHTOIP is   0x1DC

	// LASTINTFROMIP is    0x1DD

	// LASTINTTOIP   is    0x1DE

	

	// How to read an MSR register: 

	// Load ECX with the register's address (above)

	// execute the rdmsr command

	// Values returned in EDX : EAX  - EDX is high dword, EAX is low dword.

	

	_asm 

	{

		int 3

		push eax

		push ecx

		mov ecx, 0x1DB

		rdmsr

		mov Buffer_Data,eax

		pop ecx

		pop eax

	}



	// Copy the value of the MSR back out to caller

	memcpy(I.IoctlBuffer(),&Buffer_Data,sizeof(Buffer_Data));

	

	I.Information() = sizeof(Buffer_Data);



	return status;

}