GSOC2011 project RTEMS HyperVisor

Mon Mar 21 16:34:39 UTC 2011

I think it was established that LGPL is not sufficient for RTEMS code
base. I believe this makes an AIR-based project an unlikely candidate
for a GSOC project. Especially if the student used the AIR kernel as a
resource.  Perhaps if the AIR kernel is released under an
RTEMS-friendly license, a suitable project might be possible.

Even if a "clean room" implementation of a hypervisor is the intended
project, I'm not sure it is appropriate for a GSOC at this point in
time.  My guess is that using RTEMS as a hypervisor requires three
sub-projects that are all at or beyond the scope of a single GSOC:

1) Adding virtual memory / MMU support to RTEMS is a necessary
pre-requisite to any attempt at making a true hypervisor, and it is a
large project by itself.

2) Adding privileged/unprivileged distinction is also a pre-requisite
to implementing a hypervisor. Each candidate target will have to be
identified, and the CPU-specific context switching and interrupt
handling would need some tweaking to ensure that privilege bits are
properly managed. As far as I know, most processors just have full
privilege for the application at all times. This is a large project by
itself.

3) Implement the hypervisor itself involves primarily copying of page
tables, swapping out guests, exporting a HAL (device drivers), and
writing handlers for paravirtualized exceptions, hypercalls, and true
guest exceptions.  This is also a large project.

-Gedare

On Mon, Mar 21, 2011 at 10:57 AM, Tobias Schoofs <Tobias.Schoofs at gmx.net> wrote:
> 1) Yes, it does. There is a library that implements all services from ARINC 653 Part 1 and a subset of Part2. This library, however, is closed software.
>
> 2) The AIR kernel is Lesser GPL and, as such, open source.
>
> 3) The code will be release very soon, i.e. in the course of the next months.
>
> I will provide more information in an e-mail directly to you, since this is not of general interest to the mailing list.
>
> Regards,
>
> Tobias
>
> -------- Original-Nachricht --------
>> Datum: Mon, 21 Mar 2011 22:07:39 +0800 (CST)
>> Von: "张文杰" <157724595 at 163.com>
>> An: "Tobias Schoofs" <Tobias.Schoofs at gmx.net>
>> CC: Jean-Jacques.Metge at cnes.fr, rtems-users at rtems.org
>> Betreff: RE: GSOC2011 project RTEMS HyperVisor
>
>> Dear Tobias:
>> Thanks for your replay, actually i misunderstand the AIR system. And the
>> work AIR system has done is what i want to implement. My thought is also
>> to implement a para-virtualisation hypervisor that can run RTEMS and other
>> OS.(RTEMS as a guest OS). I do not plan to implement a full-virtualisation
>> hypervisor.
>> I has some question about AIR:
>> 1). AIR has also implement the ARINC 653 APEX on RTEMS?
>> 2). All the AIR source code is released  under GPL?
>> 3). When does AIR source code released? could you send me a copy of source
>> code foracademic research now?
>>
>> Wenjie
>> Best Regards
>>
>>
>>
>>
>> At 2011-03-21 21:43:52，"Tobias Schoofs" <Tobias.Schoofs at gmx.net> wrote:
>>
>> >Dear Wenjie,
>> >
>> >your understanding of the AIR system is not 100% correct.
>> >
>> >AIR is a hypervisor that uses para-virtualisation.
>> >
>> >RTEMS is a guest OS for this hypervisor. The guest has to be prepared
>> (para-virtualised) to run on top of the hypervisor. RTEMS is currently our
>> main target, but there may be other OSes as well (e.g. Linux).
>> >
>> >Finally, the AIR hypervisor uses RTEMS *additionally* as hardware
>> abstraction layer (HAL), i.e. the hypervisor itself is based on RTEMS. For this
>> purpose, we have implemented MMU support as well as superuser/user level
>> support in RTEMS.
>> >
>> >The code is under Lesser GPL and will be made available to the RTEMS
>> community.
>> >
>> >From one of your previous e-mails, I got the impression that you plan a
>> hypervisor that does run-time virtualisation. (You mentioned that you do not
>> want to change the guest OS.) I am not sure that you will be able to
>> provide sufficient certification/qualification evidence for such a complex
>> software. At least in areas where ARINC 653 is applied,
>> certification/qualification processes are very demanding. For this reason, available, commercial
>> hypervirsors (VxWorks 653, PikeOS) use para-virtualisation, not full run-time
>> virtualisation.
>> >
>> >Regards,
>> >
>> >Tobias
>> >
>> >
>> >-------- Original-Nachricht --------
>> >> Datum: Mon, 21 Mar 2011 20:31:31 +0800 (CST)
>> >> Von: "张文杰" <157724595 at 163.com>
>> >> An: "Metge Jean-Jacques" <Jean-Jacques.Metge at cnes.fr>
>> >> CC: RTEMS Users <rtems-users at rtems.org>
>> >> Betreff: RE: GSOC2011 project RTEMS HyperVisor
>> >
>> >> AIR/AIR IIseems that it hasimplemented ARINC 653 interface in RTEMS,
>> but i
>> >> do
>> >> not know if these implements is opened. If it is opened we also modify
>> >> their work,
>> >> Because ARINC 653 interface should be based on Hypervisor architecture
>> >> whereas
>> >> AIR implement is based on native RTEMS. XtratuM is a independent
>> >> Hypervisor which
>> >> has nothing to do with other OS, but my thought is to add a Hypervisor
>> to
>> >> RTEMS. Just
>> >> reference the implement of XtratuM
>> >>
>> >>
>> >> At 2011-03-21 16:21:12，"Metge Jean-Jacques"
>> <Jean-Jacques.Metge at cnes.fr>
>> >> wrote:
>> >> 
>> >> Hi,
>> >>
>> >> For my information, what do you exactly intend to do in the frame of
>> this
>> >> GSOC, that would not have been already done, either in the frame of
>> AIR/AIR
>> >> II or in the frame of XtratuM ?
>> >>
>> >> Best regards
>> >>
>> >> Jean-Jacques METGE
>> >> French Space Agency
>> >>
>> >>
>> >> De :rtems-users-bounces at rtems.org
>> [mailto:rtems-users-bounces at rtems.org]De
>> >> la part de ???
>> >> Envoyé : dimanche 20 mars 2011 14:57
>> >> À : 张文杰
>> >> Cc : RTEMS Users
>> >> Objet : Re:GSOC2011 project RTEMS HyperVisor
>> >>
>> >>
>> >> Sorry for forgetting add the reference link.
>> >> [1]. http://www.rtems.com/wiki/index.php/RTEMSHyperVisor
>> >> [2]. http://air.di.fc.ul.pt/air/?Home
>> >> [3].http://www.xtratum.org/
>> >> [4]. http://www.helenos.org/
>> >>
>> >>
>> >> At 2011-03-20 21:50:39，"张文杰" <157724595 at 163.com> wrote:
>> >> Hi, all:
>> >> I am a student who is preparing for participating the GSOC2011 RTEMS.
>> My
>> >> interested project isRTEMS HyperVisor [1]. This
>> >> project ‘s ultimate goal is to make RTEMS support to run multiple
>> >> operating systems（like Linux or uclinux) and meantime RTEMS can be
>> >> adapted to fullfill the requirements defined in the ARINC 653 standard.
>> So
>> >> the project is divided into two milestone tasks: 1) add a HyperVisor to
>> >> RTEMS. the design of HyperVisor is compatible with ARINC 653 standard.
>> 2).
>> >> implement ARINC 653 interface in
>> >> RTEMS which can reference the a ESA project named AIR[2].
>> >> Hypervisor, also called virtual machine monitor (VMM), is one of
>> >> virtualization techniqueswhich allow multiple operating systems.
>> >> For embedded systems it must have real-time capability. And there is
>> also
>> >> a challenge to the resource-constrained embedded
>> >> systems, becausesupport for virtualization requiresmemory protection
>> (in
>> >> the form of a memory management unit or at least a
>> >> memory protection unit) and a distinction between user mode and
>> privileged
>> >> mode, which rules out many microcontrollers. About the implement of
>> >> HyperVisor for RTEMS there are two projects we can reference. First is
>> project
>> >> XtratuM [3] which is a small
>> >> native (bare-metal) hypervisor, now the RTEMS has been ported to
>> XtratuM
>> >> run as a guest OS and its design use ARINC 653 as
>> >> a reference although ARINC-653 is not directly applicable to the
>> >> hypervisor systems. Another project is HelenOS operating
>> >> system [4] which is designed as a relatively small microkernel assisted
>> >> with a set of userspace drivers and server tasks, Its kernel
>> >> is a good reference candidate for the design of Hypervisor.
>> >> This is just my initial thoughts, if there is any inappropriate please
>> >> point out.Do not hesitate to add your comments.
>> >>
>> >> Wenjie Zhang
>> >> Best Regards
>> >>
>> >>
>> >>
>> >>
>> >
>> >--
>> >GMX DSL Doppel-Flat ab 19,99 Euro/mtl.! Jetzt mit
>> >gratis Handy-Flat! http://portal.gmx.net/de/go/dsl
>
> --
> Empfehlen Sie GMX DSL Ihren Freunden und Bekannten und wir
> belohnen Sie mit bis zu 50,- Euro! https://freundschaftswerbung.gmx.de
> _______________________________________________
> rtems-users mailing list
> rtems-users at rtems.org
> http://www.rtems.org/mailman/listinfo/rtems-users
>