Re: [Xen-users] FreeBSD + Xen 3.2.1 + HVM assorted problems

[Joe Auty <joe@xxxxxxxxxxxxxxx>]

Freddie Cash wrote:
> On Tue, Jul 1, 2008 at 11:31 PM, Joe Auty <joe@xxxxxxxxxxxxxxx> wrote:
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > Well, I solved one of my problems (problem #2) - The 64 bit version of
> > FreeBSD does not work as a guest OS :)
> Yes it does.  64-bit 6.3 and 7.0 both run in Xen 3.2 HVMs -- if you
> use AMD CPUs.  There's a bunch of niggles in the Intel CPU
> virtualisation implementation that cause FreeBSD guests to crash/not
> work.  Supposedly, these are fixed in Xen 3.2.1.  However, we don't
> use Intel CPUs, so we've never been bitten by these issues.
>
> If you search the -stable and -current mailing lists, I posted the
> config files I used to get FreeBSD 6.3 and 7.0 running in Xen 3.2 HVMs
> on Debian (using the kernel from Ubuntu).
>
> However, if you want things to be simple, stop using Xen and stick to
> KVM, especially with KVM-70 and Linux Kernel 2.6.24.

I beg to differ, as I've been wrestling with this non-stop over the last 
several days.
You're absolutely right that Intel is a sticking point, and I'm on Intel 
hardware which has compounded the problem. You're right that this is 
fixed in 3.2.1 with Xen custom built with the "vmxassist=n" option. My 
install was derived myself from an RPM I modified to add this option, I 
have yet to try compiling this by hand since I've been getting compile 
errors... So, you might end up being right here, but so far this has not 
been the case for me.
With my custom Xen install, I can get past the BTX halted errors that 
occurred before I recompiled Xen via my source RPM, but the FBSD kernel 
doesn't want to properly recognize disks that have been presented to the 
domain.
I can take my domain config and point it at the 7.0 disk one 386 CD and 
have it boot just beautifully, and then point the exact same config at 
the amd64 disk one CD and have it stuck at "unable to mount root". This 
is all under CentOS 5.2.
You're right that KVM might ultimately be a better option for me... I've 
gotten FreeBSD to work in KVM weeks ago - it was a piece of cake. What 
I'd like to do is benchmark i386 FreeBSD in Xen vs. amd64 FreeBSD in KVM 
to see which is faster. If you'd like I can share my results.
I'd also be happy to inform you guys of when/if I get FreeBSD amd64 7 
working, as well as provide instructions...


--
Joe Auty
NetMusician: web publishing software for musicians
http://www.netmusician.org
joe@xxxxxxxxxxxxxxx

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