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] Xen hypervisor hangs on booting against c/s 16925

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] Xen hypervisor hangs on booting against c/s 16925
From: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Date: Tue, 29 Jan 2008 11:58:20 +0000
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Jan Beulich <jbeulich@xxxxxxxxxx>
Delivery-date: Tue, 29 Jan 2008 04:03:20 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <C3C4AE68.1B8DE%Keir.Fraser@xxxxxxxxxxxx>
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>
Organization: Red Hat UK Cyf., Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, Y Deyrnas Gyfunol. Cofrestrwyd yng Nghymru a Lloegr o'r rhif cofrestru 3798903
References: <479F086B.76E4.0078.0@xxxxxxxxxx> <C3C4AE68.1B8DE%Keir.Fraser@xxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
On Tue, 29 Jan 2008 10:20:24 +0000
Keir Fraser <Keir.Fraser@xxxxxxxxxxxx> wrote:

> Isn't the memory map below 1MB well known, and no I/O exists down there
> except for VGA? Below that is conventional RAM; above that is ROM space.

Low 640K RAM
Above that ISA hole
Above that ROM (often shadowed into RAM)

Of the 640K RAM the low page is owned by the BIOS as are pages above the
EBDA. Some systems also use a 1 page EBDA to hide hardware bugs with
DMA prefetches running off the end of the 640K of RAM into I/O space.

The E820 map then tells you which bits of the 640K are owned by the BIOS
ACPI layer.

The ISA window is all non-cachable device mmio but rarely used for
anything but the PCI routed legacy VGA and MDA.

Alan

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