WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

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

To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] Fwd: [PATCH 0/18] Nested Virtualization: Overview
From: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Date: Thu, 15 Apr 2010 16:25:42 +0100
Cc: Christoph Egger <Christoph.Egger@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Thu, 15 Apr 2010 08:26:51 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <C7ECE7F4.1165A%keir.fraser@xxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <201004151520.31527.Christoph.Egger@xxxxxxx> <C7ECE7F4.1165A%keir.fraser@xxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.18 (2008-05-17)
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.

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.

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

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

-- 
Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, XenServer Engineering
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel