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-ppc-devel

[Xen-ia64-devel] RE: PG_arch_1 conflict

To: "Hollis Blanchard" <hollisb@xxxxxxxxxx>
Subject: [Xen-ia64-devel] RE: PG_arch_1 conflict
From: "Magenheimer, Dan (HP Labs Fort Collins)" <dan.magenheimer@xxxxxx>
Date: Fri, 10 Mar 2006 12:54:06 -0800
Cc: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>, xen-ppc-devel@xxxxxxxxxxxxxxxxxxx, xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Fri, 10 Mar 2006 20:54:50 +0000
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
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>
Sender: xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcZEgq0h1VH8Y/clRam0XjXlc6AxcgAANATA
Thread-topic: PG_arch_1 conflict
See previous discussion at:

http://lists.xensource.com/archives/html/xen-devel/2005-12/msg00238.html


The issue is that PG_arch_1 is reserved for arch-specific
usage, the paravirtualization changes for Xenlinux utilize
it (to mark foreign pages) because it was otherwise unused
in Linux/x86.  But Xen is no longer an arch.

Grep'ing for "PageForeign" in -sparse will show most (all?)
of the actual uses of it.  Nearly all are in x86-specific
code.  But one is in netback_init().

Dan

> -----Original Message-----
> From: Hollis Blanchard [mailto:hollisb@xxxxxxxxxx] 
> Sent: Friday, March 10, 2006 1:38 PM
> To: Magenheimer, Dan (HP Labs Fort Collins)
> Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx; Keir Fraser; 
> xen-ppc-devel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: PG_arch_1 conflict
> 
> Magenheimer, Dan (HP Labs Fort Collins) wrote:
> > We're not quite to the point of bringing up networking
> > yet but in digging through the mailing list archive,
> > I was reminded of a problem that we will soon run into:
> > Xenlinux/x86 utilizes the PG_arch_1 bit to represent
> > a "foreign" page.  Linux/ia64 (and I think Linux/ppc)
> > use the PG_arch_1 bit for arch-dep purposes.
> > 
> > It this conflict is not resolved before Xenlinux/ia64
> > supports networking, there will likely be some very
> > interesting bugs...
> 
> What is the actual issue here? Where is the code dealing with 
> PG_arch_1?
> 
> -- 
> Hollis Blanchard
> IBM Linux Technology Center
> 

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

<Prev in Thread] Current Thread [Next in Thread>