Re: Re: Vertualization of Unmodified Operating Systems

[Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>]

Dave Feustel wrote:
> On Saturday 15 April 2006 17:53, Anthony Liguori wrote:
> 
>>On Sat, 15 Apr 2006 17:39:10 -0500, Dave Feustel wrote:
>>
>>
>>>AMD Pacifica and Intel's VT make possible the virtualization of unmodified
>>>operating systems. Is it still necessary to add code to the hypervisor to
>>>support specific operating systems, or can Xen, as written, support any
>>>arbitrary OS that successfully boots on a PC? (I'm thinking of the BSDs
>>>here).
>>
>>This sort of thing has been addressed here before. 
> 
> 
> I know this and I appreciate your patience. I definitely don't
> pick things up or figure things out as quickly now as I did 
> when I was younger.
> 
> 
>>While theoritically, 
>>VT and SVM ought to allow any OS to run under Xen, in practice, if an OS
>>hasn't been tested as a guest under Xen, it is likely to turn up some bugs
>>or incompleteness.  Over time, this will certainly be a less of an issue.
>>
>>The problem has to do with the fact that different OS's will use different
>>instructions when accessing things like page tables.  Right now, Xen only
>>emulates the instructions that we know are used by the systems we test
>>with (things like Linux and certain versions of Windows).
> 
> 
> Xen and OpenBSD running under Xen are rapidly rising to the top of my list
> of things to work with as general availability of AM2-socket motherboards and 
> revision F AMD64 chips approaches. Xen and hardware virtualization have been
> for a while now at the very top of the list of topics I follow in the news.

OpenBSD 3.9 works quite fine (installed using the native installer in
the virtualized environment!) as an unmodified guest on my Intel VT box,
with following caveats:

*) pcn(4) - aka AMD Pcnet does not seem to work well with the emulated
one (send works - receive does not)

*) ne(4) does work but is complaining about corrupted nic memory under
heavy traffic (does not seem to affect it much other than logging th errors)


Stefan