Re: [Qemu-devel] SMP for PReP architecture

Re: [Qemu-devel] SMP for PReP architecture

[Alexander Graf]

On 29.06.2012, at 15:55, Eli Lewis wrote:

> 
> 
> Hi all,
> 
> 
> I would like to use qemu to emulate a muliticore PowerPC  PReP machine but it see that the SMP is not
> supported for the PReP architecture. In fact, running:
> 
> 
> qemu-system-ppc -M prep -smp 2
> 
> It returns this message:
> 
> 
> Number of SMP cpus requested (2), exceeds max cpus supported by machine `prep' (1)
> 
> 
> Does anyone know if this functionality is under development or if there is a patch that
> solves this problem? 

CC'ing Andreas, the PREP maintainer.

My rough estimate would be a simple "no, unless you do it" though :). Why would you need emulated SMP on PReP?


Alex

Re: [Qemu-devel] SMP for PReP architecture

[Eli Lewis]

Thank you
for your replay.
I need to modify
and test a very simple kernel (actually running on a single-core only) on
a multi-core PReP platform; I currently have no real multi-core HW so I am looking
for a multi-core PReP emulator. 

Eli



----- Original Message -----
From: Alexander Graf <agraf@suse.de>
To: Eli Lewis <elielieli300@yahoo.com>
Cc: qemu-devel qemu-devel <qemu-devel@nongnu.org>; Andreas Färber <afaerber@suse.de>
Sent: Sunday, July 1, 2012 10:36 PM
Subject: Re: [Qemu-devel] SMP for PReP architecture


On 29.06.2012, at 15:55, Eli Lewis wrote:

> 
> 
> Hi all,
> 
> 
> I would like to use qemu to emulate a muliticore PowerPC  PReP machine but it see that the SMP is not
> supported for the PReP architecture. In fact, running:
> 
> 
> qemu-system-ppc -M prep -smp 2
> 
> It returns this message:
> 
> 
> Number of SMP cpus requested (2), exceeds max cpus supported by machine `prep' (1)
> 
> 
> Does anyone know if this functionality is under development or if there is a patch that
> solves this problem? 

CC'ing Andreas, the PREP maintainer.

My rough estimate would be a simple "no, unless you do it" though :). Why would you need emulated SMP on PReP?


Alex

Re: [Qemu-devel] SMP for PReP architecture

[Alexander Graf]

On 02.07.2012, at 11:05, Eli Lewis wrote:

> Thank you
> for your replay.

Please don't top-post :).

> I need to modify
> and test a very simple kernel (actually running on a single-core only) on
> a multi-core PReP platform; I currently have no real multi-core HW so I am looking
> for a multi-core PReP emulator. 

Why would anyone do PReP today still?


Alex

Re: [Qemu-devel] SMP for PReP architecture

[Eli Lewis]

>>  I need to modify

>>  and test a very simple kernel (actually running on a single-core only) on
>>  a multi-core PReP platform; I currently have no real multi-core HW so I am 
> looking
>>  for a multi-core PReP emulator. 
> 
> Why would anyone do PReP today still?


Good
question :-) 

I
am working on an European project about real-time embedded systems and we are
interested in modifying a real-time kernel for PowerPC. The most simplest RTOS
we found was POK, a kernel that supports PReP BSP
only (actually it runs also on x86 and Leon3 but we were interested in PowerPc). So we modified POK and performed some experiment on single core, now we would
like to modifyand run it on a
multicore.
Eli

Re: [Qemu-devel] SMP for PReP architecture

[Alexander Graf]

On 02.07.2012, at 12:10, Eli Lewis wrote:

>>> I need to modify
> 
>>> and test a very simple kernel (actually running on a single-core only) on
>>> a multi-core PReP platform; I currently have no real multi-core HW so I am 
>> looking
>>> for a multi-core PReP emulator. 
>> 
>> Why would anyone do PReP today still?
> 
> 
> Good
> question :-) 
> 
> I
> am working on an European project about real-time embedded systems and we are
> interested in modifying a real-time kernel for PowerPC. The most simplest RTOS
> we found was POK, a kernel that supports PReP BSP
> only (actually it runs also on x86 and Leon3 but we were interested in PowerPc). So we modified POK and performed some experiment on single core, now we would
> like to modifyand run it on a
> multicore.

Well, PReP is dead since the mid-90's, no [1]? :) I'd be surprised if you could get recent hardware still supporting it. Plus, I don't think it really makes all that much sense. PReP is basically a 90's x86 machine with PPC CPU. Not exactly what you'd consider elegant design.

Why not go for something that has a bit wider architecture support and multi-core support built in, like rtems?

  http://wiki.rtems.org/wiki/index.php/BoardSupportPackageInformation

That would allow you to go with actual available hardware, like something based on FSL e500 or AMCC 44x cores. For e500, we even have SMP emulation support in QEMU.


Alex

[1] http://en.wikipedia.org/wiki/PReP

Re: [Qemu-devel] SMP for PReP architecture

[Eli Lewis]

> 

> Well, PReP is dead since the mid-90's, no [1]? :) I'd be surprised if 
> you could get recent hardware still supporting it. Plus, I don't think it 
> really makes all that much sense. PReP is basically a 90's x86 machine with 
> PPC CPU. Not exactly what you'd consider elegant design.
> 
> Why not go for something that has a bit wider architecture support and 
> multi-core support built in, like rtems?
> 
>   http://wiki.rtems.org/wiki/index.php/BoardSupportPackageInformation
> 
> That would allow you to go with actual available hardware, like something based 
> on FSL e500 or AMCC 44x cores. For e500, we even have SMP emulation support in 
> QEMU.


Thank you
for your suggestion, but we need to use our modified version of POK.
Maybe
we can change the BSP of POK in order to support the MPC8544DS board. In QEmu, is the SMP emulation supported for all e500  or for the e500v2 only?
Eli

Re: [Qemu-devel] SMP for PReP architecture

[Alexander Graf]

On 02.07.2012, at 19:44, Eli Lewis wrote:

>> 
> 
>> Well, PReP is dead since the mid-90's, no [1]? :) I'd be surprised if 
>> you could get recent hardware still supporting it. Plus, I don't think it 
>> really makes all that much sense. PReP is basically a 90's x86 machine with 
>> PPC CPU. Not exactly what you'd consider elegant design.
>> 
>> Why not go for something that has a bit wider architecture support and 
>> multi-core support built in, like rtems?
>> 
>>   http://wiki.rtems.org/wiki/index.php/BoardSupportPackageInformation
>> 
>> That would allow you to go with actual available hardware, like something based 
>> on FSL e500 or AMCC 44x cores. For e500, we even have SMP emulation support in 
>> QEMU.
> 
> 
> Thank you
> for your suggestion, but we need to use our modified version of POK.

Ah, too bad :).

> Maybe
> we can change the BSP of POK in order to support the MPC8544DS board.

It's not only the board. Kernel mode is vastly different from the 601 you're probably targeting today.

> In QEmu, is the SMP emulation supported for all e500  or for the e500v2 only?

It should work with all e500 cores. Keep in mind that QEMU doesn't implement 100% of the spec yet though, so if you encounter issues, let me know.


Alex

Re: [Qemu-devel] SMP for PReP architecture

[Eli Lewis]

> 

>>  Maybe
>>  we can change the BSP of POK in order to support the MPC8544DS board.
> 
> It's not only the board. Kernel mode is vastly different from the 601 
> you're probably targeting today.
> 


Currently POK
supposes to run on a sort of ppc750 processor (I am invoking Qemu with -cpu
ppc32) . Could you please suggest me some useful documentation that could help me
perform the POK porting? 
>>  In QEmu, is the SMP emulation supported for all e500  or for the e500v2 
> only?
> 
> It should work with all e500 cores. Keep in mind that QEMU doesn't implement 
> 100% of the spec yet though, so if you encounter issues, let me know.
 
Where I can
find (if any) a list of the functionalities implemented/not implemented? 

Thank you again for your patient.

Eli

Re: [Qemu-devel] SMP for PReP architecture

[Alexander Graf]

On 03.07.2012, at 07:07, Eli Lewis wrote:

>> 
> 
>>> Maybe
>>> we can change the BSP of POK in order to support the MPC8544DS board.
>> 
>> It's not only the board. Kernel mode is vastly different from the 601 
>> you're probably targeting today.
>> 
> 
> 
> Currently POK
> supposes to run on a sort of ppc750 processor (I am invoking Qemu with -cpu
> ppc32) . Could you please suggest me some useful documentation that could help me
> perform the POK porting? 

Stuart, Scott, is there any helpful documentation available for 750 -> e500 conversion?

>>> In QEmu, is the SMP emulation supported for all e500  or for the e500v2 
>> only?
>> 
>> It should work with all e500 cores. Keep in mind that QEMU doesn't implement 
>> 100% of the spec yet though, so if you encounter issues, let me know.
>  
> Where I can
> find (if any) a list of the functionalities implemented/not implemented? 

There is no list :). Most of the bits not implemented are SPRs, so you will quickly find out. They will throw an error at you.


Alex

Re: [Qemu-devel] SMP for PReP architecture

[Scott Wood]

On 07/03/2012 02:45 PM, Alexander Graf wrote:
> 
> On 03.07.2012, at 07:07, Eli Lewis wrote:
> 
>>>
>>
>>>> Maybe
>>>> we can change the BSP of POK in order to support the MPC8544DS board.
>>>
>>> It's not only the board. Kernel mode is vastly different from the 601 
>>> you're probably targeting today.
>>>
>>
>>
>> Currently POK
>> supposes to run on a sort of ppc750 processor (I am invoking Qemu with -cpu
>> ppc32) . Could you please suggest me some useful documentation that could help me
>> perform the POK porting? 
> 
> Stuart, Scott, is there any helpful documentation available for 750 -> e500 conversion?

Read the chip manuals, the ISA and/or EREF, and look at what Linux does
differently for each.

What is POK?

>>>> In QEmu, is the SMP emulation supported for all e500  or for the e500v2 
>>> only?
>>>
>>> It should work with all e500 cores. Keep in mind that QEMU doesn't implement 
>>> 100% of the spec yet though, so if you encounter issues, let me know.
>>  
>> Where I can
>> find (if any) a list of the functionalities implemented/not implemented? 
> 
> There is no list :). Most of the bits not implemented are SPRs, so you will quickly find out. They will throw an error at you.

Only if the SPR is entirely unimplemented, not if a certain bit or
semantic isn't implemented.

-Scott

Re: [Qemu-devel] SMP for PReP architecture

[Eli Lewis]

>> 

>>  Stuart, Scott, is there any helpful documentation available for 750 -> 
> e500 conversion?
> 
> Read the chip manuals, the ISA and/or EREF, and look at what Linux does
> differently for each.

Thank you!
 
> What is POK?

A simple real time embedded OS.
http://pok.safety-critical.net/

Eli

Re: [Qemu-devel] SMP for PReP architecture

[Andreas Färber]

Hi,

Am 29.06.2012 15:55, schrieb Eli Lewis:
> 
> I would like to use qemu to emulate a muliticore PowerPC  PReP machine but it see that the SMP is not
> supported for the PReP architecture. In fact, running:
> 
> 
> qemu-system-ppc -M prep -smp 2
> 
> It returns this message:
> 
> 
> Number of SMP cpus requested (2), exceeds max cpus supported by machine `prep' (1)
> 
> 
> Does anyone know if this functionality is under development or if there is a patch that
> solves this problem?

No, I don't think that is currently under development. Recent PReP
development has focusses on properly modelling the needed devices (e.g.,
pc87312).

There are patches around to add a new 40P PReP machine [1] but I don't
remember whether that was SMP-capable. The BeBox [2] has two processors
but our emulation attempts didn't get very far yet.

Regards,
Andreas

[1] http://wiki.qemu.org/Features/40p
[2] http://wiki.qemu.org/Features/BeBox

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