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] early_cpu_init() and identify_cpu()

To: Jan Beulich <jbeulich@xxxxxxxxxx>, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] early_cpu_init() and identify_cpu()
From: Keir Fraser <keir@xxxxxxxxxxxxx>
Date: Tue, 17 Jul 2007 11:23:27 +0100
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Tue, 17 Jul 2007 03:21:21 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <C2C25554.128FF%keir@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/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcfIW2hAppVaXzROEdy/GAAX8io7RQAARsdX
Thread-topic: [Xen-devel] early_cpu_init() and identify_cpu()
User-agent: Microsoft-Entourage/11.3.3.061214
On 17/7/07 11:15, "Keir Fraser" <keir@xxxxxxxxxxxxx> wrote:

> If we just mapped the 4kB-rounded region specified by lfb_base to
> lfb_base+lfb_size (as determined via the VBE Get Mode Info call) as WC,
> would that be safe?

Actually this is probably okay because any software that does want to access
command queues (e.g., X server) will have its own mapping that will not
specify PAT.WC. In contrast MTRR type specification is used by all mappings
of that physical address range. So long as aliasing of WC and UC was not a
problem, this would work fine. But I think it's WC aliasing with WB/WT that
is a problem.

 -- Keir


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