How I can use IPIs to schedule a work on other CPUs?

NTDEV
1

Does anybody know how to schedule some function execution on different CPU via
IPIs?
By now I do the same via DPCs. But I want to do it as fast as it is possible.

Dmitry

2

Microsoft uses the IPI for their actions, and provides no way of supporting
a user defined capability. Hacking around there is a great way to corrupt
the system.

–
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting
Remove StopSpam from the email to reply

“Dmitry Bazhenov” wrote in message
news:xxxxx@ntdev…
> Does anybody know how to schedule some function execution on different CPU
> via
> IPIs?
> By now I do the same via DPCs. But I want to do it as fast as it is
> possible.
> –
> Dmitry
>
>

3

First you must chose a vector for IPI commands, one that is usually available is for example 0xFF.
The IPI commands are calls over an INT vector and are called as an INT operation.

So, you must prepare an area for serving your chosen INT vector, with some code. For example:

My_INT_FF:

_asm Push eax

Do something.....

_asm Pop eax

_asm IRET

To prepare for the IPI call...
You must get the address of the APIC area.
The APIC physical address is obtained using MSR register #0x1B.
For example some code as the following would do the work:

_asm mov ecx,0x1b
_asm rdmsr //the value is returned in eax:edx, bits 12 to 35
_asm and eax,0xFFFFF000
_asm mov[apic],eax

Then map the obtained address using MmMapIoSpace.

pa.LowPart = apic;
pa.HighPart = -1;
APIC_Address = MmMapIoSpace(pa, 4096, MmNonCached);

Now you can send an IPI command with the following code, for example for sending an IPI command to vector 0xFF:

_asm Mov eax, APIC_Address
_asm Add eax,0x300

Wait1://Wait until ready
_asm Test dword ptr[eax],0x1000 //Status (bit 12 of Second dword)
_asm Jnz Wait1

_asm Mov eax, APIC_Address
_asm Add eax,0x310 //;offset of high dword in icr
_asm Mov [eax],0 //;high dword
_asm sub eax,0x10 //;low dword, 16 bytes lower
_asm mov ebx, 0x000c40ff //;= 000000000000,11,0,0,0,1,0,0,0,000,11111111
_asm Mov[eax], ebx

//Now an INT is produced on the requested CPU ...

Wait2: //wait until operation is complete; that is to say, until interrupt is called
_asm Test dword ptr[eax],0x1000 //Status (bit 12 of second dword)
_asm Jnz Wait2

-----Mensaje original-----
De: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com]En nombre de Dmitry Bazhenov
Enviado el: mi?rcoles, 23 de noviembre de 2005 16:00
Para: Windows System Software Devs Interest List
Asunto: [ntdev] How I can use IPIs to schedule a work on other CPUs?

Does anybody know how to schedule some function execution on different CPU via
IPIs?
By now I do the same via DPCs. But I want to do it as fast as it is possible.

Dmitry

Questions? First check the Kernel Driver FAQ at http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@pandasoftware.es
To unsubscribe send a blank email to xxxxx@lists.osr.com

4

KeSetTargetProcessorDpc

Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com

----- Original Message -----
From: “Dmitry Bazhenov”
To: “Windows System Software Devs Interest List”
Sent: Wednesday, November 23, 2005 6:00 PM
Subject: [ntdev] How I can use IPIs to schedule a work on other CPUs?

> Does anybody know how to schedule some function execution on different CPU
via
> IPIs?
> By now I do the same via DPCs. But I want to do it as fast as it is possible.
> –
> Dmitry
>
>
> —
> Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256
>
> You are currently subscribed to ntdev as: xxxxx@storagecraft.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com

5

Yes, IPI is only used as underlying mechanism for a) cache invalidations b)
targeted DPCs c) some dispatcher stuff.

Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com

----- Original Message -----
From: “Don Burn”
Newsgroups: ntdev
To: “Windows System Software Devs Interest List”
Sent: Wednesday, November 23, 2005 6:02 PM
Subject: Re:[ntdev] How I can use IPIs to schedule a work on other CPUs?

> Microsoft uses the IPI for their actions, and provides no way of supporting
> a user defined capability. Hacking around there is a great way to corrupt
> the system.
>
>
> –
> Don Burn (MVP, Windows DDK)
> Windows 2k/XP/2k3 Filesystem and Driver Consulting
> Remove StopSpam from the email to reply
>
>
>
>
> “Dmitry Bazhenov” wrote in message
> news:xxxxx@ntdev…
> > Does anybody know how to schedule some function execution on different CPU
> > via
> > IPIs?
> > By now I do the same via DPCs. But I want to do it as fast as it is
> > possible.
> > –
> > Dmitry
> >
> >
>
>
>
> —
> Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256
>
> You are currently subscribed to ntdev as: xxxxx@storagecraft.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com