[fedora-virt] kvm, xen and what requires H/W virt support?

[Robert P. J. Day]

On Tue, 2 Feb 2010, Justin M. Forbes wrote:

> On Mon, Feb 01, 2010 at 05:23:48PM -0500, Robert P. J. Day wrote:
> >
> >   i might have asked this once and forgotten the answer but here:
> >
> > http://fedoraproject.org/wiki/Docs/Beats/Virtualization
> >
> > the caution near the bottom:
> >
> > "KVM requires hardware virtualization features in the host system.
> > Systems lacking hardware virtualization do not support Xen guests
> > at this time."
> >
> >   i'm confused since this seems to be mixing two issues -- what
> > basic KVM requires, as opposed to which systems support Xen
> > guests.  would there be a clearer way to word that?
>
> Well, I am not sure where this is coming from at all.  Technically
> speaking F-12 doesn't support any xen guests, as we have no dom0,
> though it will happily run *as* a xen guest in either paravirt or
> fullvirt. Perhaps the intention was to point out that systems
> without hardare virt capabilities cannot run xen either, since we
> don't ship a dom0?

  not sure where *what* is coming from?  the note in question, or my
apparent confusion? :-)

  maybe i phrased it badly.  if i were to read just the first sentence
of that note:

"KVM requires hardware virtualization features in the host system."

then, IMHO, the obvious logical consequence of that (redundantly)
would be to say,

"Therefore, if your system does not have H/W virt support, you simply
cannot run KVM."

  but after i read that first sentence (which made perfect sense), i
have no idea how that logically leads into that subsequent sentence:

"Systems lacking hardware virtualization do not support Xen guests
at this time."

  regardless of the truth of that claim, it just doesn't seem to
follow from the first sentence.  in short, what's it doing there?  how
are those two points related?  what does that have to do with KVM?  or
am i just being dense?

rday
--



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Robert P. J. Day                               Waterloo, Ontario, CANADA

            Linux Consulting, Training and Kernel Pedantry.

Web page:                                          http://crashcourse.ca
Twitter:                                       http://twitter.com/rpjday
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