Re: [Xen-devel] Fwd: [PATCH 0/18] Nested Virtualization: Overview

[Christoph Egger <Christoph.Egger@xxxxxxx>]

On Thursday 15 April 2010 17:25:42 Tim Deegan wrote:
> At 15:57 +0100 on 15 Apr (1271347060), Keir Fraser wrote:
> > > patch 04: obsolete gfn_to_mfn_current and remove it.
> > >                   gfn_to_mfn_current is redundant to
> > > gfn_to_mfn(current->domain, ...)
> > >                   This patch reduces the size of patch 17.
> >
> > This one (at least -- there may be others) needs an ack from Tim.
>
> I've already asked for some measurement to show the effect of removing
> gfn_to_mfn_current() on shadow pagetable performance.

Yes, I couldn't do since tools were broken and couldn't even start a guest.
This is fixed since c/s 21187.

> The other patches that I was CC'd on look mostly OK, except for
> introducing some clunky (and wide) y_to_z(x_to_y(foo_to_x(foo)))
> patterns that I'm sure could be done a bit more neatly.

Yes, you see that pattern in patch 06/18. In patch 17/18 you see
that pattern changed again in a better shape.

BTW: I think, I forgot to CC you in patch 18/18.

> I'll read the PDFs tomorrow and have a proper look at the patches then.

Thanks.

Christoph


> Cheers,
>
> Tim.
>
> > > patch 05: hvm_set_cr0: Allow guest to switch into paged real mode.
> > >                   This makes hvmloader boot when we use xen in xen.
> >
> > What if we are not running a nestedhvm guest, or otherwise on a system
> > not supporting paged real mode? Is it wise to remove the check in that
> > case? Even where we *do* support nestedhvm, should all guest writes to
> > CR0 be allowed to bypass that check (Isn't paged real mode
> > architecturally only allowed to be entered via VMRUN)?
> >
> > More generally, I will allow these patches to sit for a week or two to
> > give time for potential reviewers to digest them.
> >
> >  Thanks,
> >  Keir
> >
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-devel



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