RE: Zen and Pacifica

RE: Zen and Pacifica

[Petersson, Mats]

> -----Original Message-----
> From: xen-devel-bounces@lists.xensource.com 
> [mailto:xen-devel-bounces@lists.xensource.com] On Behalf Of 
> Dave Feustel
> Sent: 31 March 2006 17:52
> To: xen-devel@lists.xensource.com
> Cc: Mark Williamson
> Subject: Re: [Xen-devel] Zen and Pacifica
> 
> On Friday 31 March 2006 10:41, Mark Williamson wrote:
> > > I expect to buy an AMD64 Pacifica-enabled computer in the 
> 2nd half 
> > > of this year to use with OpenBSD in 64-bit mode. I would 
> like to use 
> > > Xen, but as far as I have been able  to determine, Xen 
> 3.0 does not 
> > > support AMD Pacifica.
> > > Am I wrong about that?
> > 
> > It'll be supported in the 3.0.2 release - it's in the 
> -unstable tree 
> > right now.
> 
> Will 3.0.2 support running unmodified operating systems?
> That's the feature I need to run OpenBSD under Xen.

Yes, absolutely. However, I must "warn" you that OpenBSD is not on our
"target-list", so it's possible (although somewhat unlikely) that it
will not work right - every OS has it's own quirks during specific small
sections of code (switch from real to protected mode [particularly code
that "abuses" this switch, like "Big Real-Mode" can cause problems, as
the internal state of the processor and the "apparent state" aren't the
same[1]], page table updates, special IO operations, etc) that may need
some special attention in the hypervisor. 

I'm not at all saying "Don't do this", but rather setting your
expectations that it's a small possibility that something is broken.
It's probably not very hard to fix if it is, it just takes someones time
to figure out why it's broken, and how to fix it - usually, it's just a
simple case of another "if (x) do_something_special();" in some
function. And I'd say there's 98% chance that it works just fine as is.
2% risk that there's a problem... 

Also, there's a few months yet until the second half of this year, so we
may well have fixed all the remaining bugs 'til then... ;-)

[1] If anyone wants more details on how this works, please fire me a
personal mail... ;-)

--
Mats
> 
> When is 3.0.2 likely to be released?
> 
> Thanks,
> Dave 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
> 
> 

Re: Zen and Pacifica

[Dave Feustel]

On Monday 03 April 2006 09:33, Petersson, Mats wrote:

> > Will 3.0.2 support running unmodified operating systems?
> > That's the feature I need to run OpenBSD under Xen.
> 
> Yes, absolutely. However, I must "warn" you that OpenBSD is not on our
> "target-list", so it's possible (although somewhat unlikely) that it
> will not work right - every OS has it's own quirks during specific small
> sections of code (switch from real to protected mode [particularly code
> that "abuses" this switch, like "Big Real-Mode" can cause problems, as
> the internal state of the processor and the "apparent state" aren't the
> same[1]], page table updates, special IO operations, etc) that may need
> some special attention in the hypervisor. 

Well, I'm not buying a new system until I can get one with the AMD SVR 
(formerly known as Pacifica) revision F chip version, so there are still a
few months to go. Once I have the system, I will get busy trying to run
OpenBSD on Xen. I am prepared for xen startup issues with openbsd.

> I'm not at all saying "Don't do this", but rather setting your
> expectations that it's a small possibility that something is broken.
> It's probably not very hard to fix if it is, it just takes someones time
> to figure out why it's broken, and how to fix it - usually, it's just a
> simple case of another "if (x) do_something_special();" in some
> function. And I'd say there's 98% chance that it works just fine as is.
> 2% risk that there's a problem... 
> 
> Also, there's a few months yet until the second half of this year, so we
> may well have fixed all the remaining bugs 'til then... ;-)

Patience is a virtue, particularly where AMD is concerned :-). 
All good things come to those who wait.
Good Things Take Time.

Dave Feustel

> [1] If anyone wants more details on how this works, please fire me a
> personal mail... ;-)
> 
> --
> Mats
> > 
> > When is 3.0.2 likely to be released?
> > 
> > Thanks,
> > Dave 
> > 
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xensource.com
> > http://lists.xensource.com/xen-devel
> > 
> > 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
> 

-- 
Lose, v., experience a loss, get rid of, "lose the weight"
Loose, adj., not tight, let go, free, "loose clothing"

Zen and Pacifica

[Dave Feustel]

All,

I expect to buy an AMD64 Pacifica-enabled computer
in the 2nd half of this year to use with OpenBSD in 64-bit 
mode. I would like to use Xen, but as far as I have been 
able  to determine, Xen 3.0 does not support AMD Pacifica. 
Am I wrong about that?

Thanks,
Dave Feustel
-- 
Lose, v., experience a loss, get rid of, "lose the weight"
Loose, adj., not tight, let go, free, "loose clothing"

Re: Zen and Pacifica

[Mark Williamson]

> I expect to buy an AMD64 Pacifica-enabled computer
> in the 2nd half of this year to use with OpenBSD in 64-bit
> mode. I would like to use Xen, but as far as I have been
> able  to determine, Xen 3.0 does not support AMD Pacifica.
> Am I wrong about that?

It'll be supported in the 3.0.2 release - it's in the -unstable tree right 
now.

Cheers,
Mark

Re: Zen and Pacifica

[Dave Feustel]

On Friday 31 March 2006 10:41, Mark Williamson wrote:
> > I expect to buy an AMD64 Pacifica-enabled computer
> > in the 2nd half of this year to use with OpenBSD in 64-bit
> > mode. I would like to use Xen, but as far as I have been
> > able  to determine, Xen 3.0 does not support AMD Pacifica.
> > Am I wrong about that?
> 
> It'll be supported in the 3.0.2 release - it's in the -unstable tree right 
> now.

Will 3.0.2 support running unmodified operating systems?
That's the feature I need to run OpenBSD under Xen.

When is 3.0.2 likely to be released?

Thanks,
Dave 

Re: Zen and Pacifica

[Mark Williamson]

> > It'll be supported in the 3.0.2 release - it's in the -unstable tree
> > right now.
>
> Will 3.0.2 support running unmodified operating systems?
> That's the feature I need to run OpenBSD under Xen.

Yes, but the support is quite new and is limited in some ways (IO performance, 
no suspend/resume, no migration yet) but it can run unmodified OSes on both 
VT and Pacifica hardware.

> When is 3.0.2 likely to be released?

Within a week or two, maybe...  It's in -rc at the moment.  Previous released 
of 3.x also had unmodified OS support, but only on VT (and there have been 
fixes and optimisations since then)

Cheers,
Mark

Re: Zen and Pacifica

[M.A. Williamson]

>I'm somewhat curious about your mercurial setup - could you briefly
>outline which trees I need to check out in order to maintain "testing"
>but fairly stable code?

In general, -testing contains the stable release plus some bugfixes. When 
new releases happen, the development tree (-unstable) gets swept into 
-testing and new disruptive development resumes in -unstable. Bugfixes 
generally get applied to -unstable but will also make it into testing if a) 
users have complained about those bugs and b) they are more likely to get 
there if users help backport and test those fixes from -unstable to 
-testing.

You may find you want to at least monitor the -testing tree and see what 
fixes have occurred. Of course the most effortless way to get updates is 
probably to get a distro from SuSE / RedHat / someone else that includes 
Xen and then get updates as RPMs along with everything else. You could also 
use the yum repository on the XenSource site, that also contains updates if 
you have a supported distro. I'm not sure how often they update, because I 
don't use them.

Keir posted a more detailed description within the past week or two - it 
should be in the archives so you may be able to find it on 
lists.xensource.com

Cheeres,
Mark