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A bunch of questions about getting a working NetBSD/xen system


I've been struggling for a month or two now with a xen install and have a few general questions that I'm hoping will clear up my foggy understanding of how things are supposed to work:

0. The goal: To have a NetBSD/xen dom0 machine on which to host guest
   machines. Ideally this should:

     o run on netbsd-x-stable whatever that is at the time.
     o run unmodified oses; i.e. HVM support.

1. What I have:

     o Dual 3Ghz 64-bit Xeons.
     o 4G Ram.
     o Tyan S5360 Mb.

   From looking at the CPU specs it would appear that they have the
   Intel VT technology needed for HVM support.

   It does not appear that my BIOS supports this though. If I use
   "cpuctl identify" I do not see the "VT" instruction listed, and
   nowhere in my dmesg output do I have an indication that it's
   turned off in the Bios as some sources (NetBSD wiki's xen page)

   So - first question: Will it work? Or am I stuck with non-HVM and
   only modified kernels?

   Is there a way to make the system HVM-aware when the BIOS
   apparently isn't?

2. I've been running a -current kernel as it's been suggested that
   only -current kernels will work. But then I've seen somewhere
   that netbsd-5 should work fine.

   Can I use netbsd-5 instead of -current for DOM0/PAE yet?

3. I have DOM0 working with -current. But it seems awfully slow! Disk
   I/O and also net I/O seem to be much slower than normal. Is there
   anything that needs to be done to have reasonable performance in
   DOM0. Will the DOMU's be able to perform well despite the slowness
   in DOM0?

4. Is it "bad" practice to use the DOM0 for anything other than
   serving the guest oses? For example - bad idea to build.sh the
   system in DOM0 or compile pkgsrc packages?

5. If I'm able to get an HVM setup going, will NetBSD run unmodified
   as a guest?

6. What's the deal with SMP on xen? I see the following in dmesg:

     cpu0 at mainbus0 apid 0: (boot processor)
     cpu1 at mainbus0 apid 6: (application processor)
     cpu2 at mainbus0 apid 1: (application processor)
     cpu3 at mainbus0 apid 7: (application processor)

   and things like "top" only show one processor active. Last time I
   think I saw this separation of "boot" vs. "application" processor
   was in netbsd-2 or -3, I think.

   What should I expect to see here in DOM0?

   Can I run SMP guests?

Any help would be great. I've tried to search and test for answers to these and could not find anything clear online.

Thanks very much,


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