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-ia64-devel

Re: [Xen-ia64-devel] Question: Special linux dom0 handling in vcpu_trans

To: tgingold@xxxxxxx
Subject: Re: [Xen-ia64-devel] Question: Special linux dom0 handling in vcpu_translate()
From: Dietmar Hahn <dietmar.hahn@xxxxxxxxxxxxxxxxxxx>
Date: Mon, 25 Jun 2007 10:29:06 +0200
Cc: Xen-ia64-devel <xen-ia64-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Mon, 25 Jun 2007 01:26:49 -0700
Domainkey-signature: s=s768; d=fujitsu-siemens.com; c=nofws; q=dns; b=pqKKHTAWZkI1GJG+xpM6DlqTVM25SkXxP0mGWwNGdc77P3HZ+YxBntjZsC/NbSkEQc59gd5zP1Ndc2OgM1AKMrWiv4mS4J3E0KHmX55l+0Tlo9E6unQE8W5LXFsinD+E;
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <1182412190.467a2d9e6969c@xxxxxxxxxxx>
List-help: <mailto:xen-ia64-devel-request@lists.xensource.com?subject=help>
List-id: Discussion of the ia64 port of Xen <xen-ia64-devel.lists.xensource.com>
List-post: <mailto:xen-ia64-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-ia64-devel>, <mailto:xen-ia64-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-ia64-devel>, <mailto:xen-ia64-devel-request@lists.xensource.com?subject=unsubscribe>
References: <200706210909.12575.dietmar.hahn@xxxxxxxxxxxxxxxxxxx> <1182412190.467a2d9e6969c@xxxxxxxxxxx>
Sender: xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: KMail/1.9.6
Am Donnerstag, 21. Juni 2007 schrieb tgingold@xxxxxxx:
> Quoting Dietmar Hahn <dietmar.hahn@xxxxxxxxxxxxxxxxxxx>:
> > Hi,
> >
> > in vcpu_translate I found some lines of code which seems to be an
> > optimization
> > for the linux dom0:
>
> ...
>
> > I found this, because mini-os uses the same scheme. Now the hypervisor
> > does the itc for mini-os with a linux kernel identity mapped pte!
> > In general this may leads to problems if other systems with similar
> > region scheme are running on xen.
> > In particular I have here the problem that using protection keys for such
> > addresses is impossible!
> > Is it possible to do this optimization for the linux kernel another way?
>
> I think this special linux optimization should be enabled by the OS. We
> should add an hypercall (or a SAL call) for this.
>
> Tristan.

The question  is, should I add an optimization call specific to linux or 
specific to single optimization features.
Are there any other implicit optimisations for linux in the hypervisor?

I would add an hypercall. This can be called in setup_arch() after 
setup_xen_features().
 The struct arch_domain has to be extended with an optimisation flag.
What is your opinion?

Dietmar.

_______________________________________________
Xen-ia64-devel mailing list
Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-ia64-devel