Re: Running XEN under a Linux AMD64 DOM0

[Christoph Egger <Christoph_Egger%gmx.de@localhost>]

On Monday 31 March 2008 08:30:25 Carl Brewer wrote:
> Christoph Egger wrote:
> > Carl Brewer wrote:
> >> Christoph Egger wrote:
> >>> Luke S Crawford wrote:
> >>>> David Brownlee <abs%absd.org@localhost> writes:
> >>>>>      What is the state of play if I wanted to run a NetBSD DOMU under
> >>>>>      (someone else's) Linux AMD64 DOM0?
> >>>>>
> >>>>>      I'm assuming I'd need to run current, but can I run an i386 or
> >>>>>      only amd64 DOMU?
> >>>>
> >>>> Your provider needs to run a fairly recent version of Xen so
> >>>> 32-on-64 works,
> >>>> and then you need to run --current  (32-on-64 is acually 32-PAE on
> >>>> 64)  you can run the 32-PAE images, or 64-bit DomU images - but
> >>>> either way, you
> >>>> need to be on --current.
> >>>
> >>> That's true for PV guest. You can run NetBSD/i386 or NetBSD/amd64 as
> >>> HVM guests. These don't need to be -current, but Xen must be very
> >>> recent - 3.2.0 at minimum - or you miss necessary bugfixes, otherwise.
> >>
> >> As a general suggestion, would you advise amd64-current or
> >> i386-current for a xen dom0 server with 6GB of RAM with HVM-aware
> >> cpu's to get the best of a modern Intel C2D server?  Core2duo 8200 is
> >> hvm aware and I believe i386-cuurent is PAE capable also?  There'd be
> >> little/no performance impact from using HVM?
> >
> > I would advice amd64-current. With PAE, you don't have the full 6GB RAM
> > available due to bounce buffers.
>
> Even with trickery needed to install grub from pkgsrc?
>
> BTW, is there some sane-ish way to get i386 stuff to compile from pkgsrc
> on amd64 boxes?   It's essentially the same O/S, some mk.conf switch to
> say 'if i386, but this is amd64, cross-compile'?

No, that's not (yet) possible. This is a NetBSD limitation and not a gcc or 
pkgsrc problem. gcc -m32 works fine, but

a) #include <stdio.h>   must include the i386 version
b) The linker must find the 32bit libs

Christoph