Re: Port DragonFly to Xen platform

[Sylvestre Gallon <ccna.syl@xxxxxxxxx>]

On Wed, Mar 24, 2010 at 1:23 PM, Chris Turner
<c.turner@199technologies.org> wrote:
> Sylvestre Gallon wrote:
>> It's not that I am not up to it or that I think that I am not able to
>> do it, but I will probably need more help and more mentoring to
>> implement a kvm-like subsystem than to port dragonflybsd to xen.
>
> Aggelos Economopoulos wrote:
>>
>> What kind of changes would you have to make to our core kernel code for
>> Xen support?
>
> Was thinking about this again myself - as someone who has mucked around with
> merging various things into vkernel / from other os's -
>
> (assuming you are new to developing on any of the BSD-like systems or
> similar)
>
> you might simply take a look at what it would take to make either possible
> before you commit to one approach or the other -
>
> I'd suggest first investigating how the dragonfly VKERNEL works (as you'll
> need to be adding a new 'architecture' anyhow - and VKERNEL is a good
> example of a quasi-architecture that is part 'real' (e.g. i386), and
> partially 'virtual' (e.g. vkernel's supporting vmspace) - so it would be
> useful to know for either approach.
>
> After you get some kind of understanding of this, perhaps adding some silly
> little change to get a hang of the build process, etc,
>
> perhaps take a look at the NetBSD Xen implementation (as I'd suspect it is
> the best place to start for a port), to see if this approach still makes
> sense..
>
> In the process you'll be able to see how things might work and decide on the
> best approach / pluses and minuses - one thing I can think of offhand is
> that Xen might need more driver work, whereas something native might be able
> to be 'kludged' around .. with xen, you'll need a host platform and also a
> dragonfly dev system (so two build systems / source trees to deal
> with/learn), whereas dragonfly would be one, etc.
>
> of course there are things in the other direction as well but as noted
> before I am biased :)
>
> other side effect of this is at the end of this, you'll know what you're
> getting into - and also have a dev system in place!
>
> anyhow, good luck with your investigation and look forward to hearing about
> your progress in either case..
>
> - Chris
>

OK,

I will have fun this week with vkernel and Xen, and afterwards I will try
to do some research, write a report and submit it on the mailling list.

The report will deal with :

- what I need to upgrade into DragonFlyBSD tree to
 support Xen, what has been done in netbsd, which driver
 are modified, etc...
- the way the vkernel can be upgraded to work on pc64.
- What can be done to add a KVM-like implementation
 in a vkernel-like fashion.

Thanks for your time and your help.

Cheers,
-- 
Sylvestre Gallon