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] [RFC Patch] Support for making an E820 PCI hole in tools

To: Keir Fraser <keir@xxxxxxx>
Subject: Re: [Xen-devel] [RFC Patch] Support for making an E820 PCI hole in toolstack (xl + xm)
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Date: Mon, 15 Nov 2010 11:32:38 -0800
Cc: stefano.stabellini@xxxxxxxxxxxxx, xen-devel@xxxxxxxxxxxxxxxxxxx, bruce.edge@xxxxxxxxx, gianni.tedesco@xxxxxxxxxx, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Delivery-date: Mon, 15 Nov 2010 11:33:26 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <C9072F4C.A08F%keir@xxxxxxx>
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: <C9072F4C.A08F%keir@xxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.12) Gecko/20101027 Fedora/3.1.6-1.fc13 Lightning/1.0b3pre Thunderbird/3.1.6
On 11/15/2010 10:41 AM, Keir Fraser wrote:
>> Oh, there was another reason that I so obvious that I completly forgot. DomU
>> has no idea where the host PCI hole starts. In most cases it is at 3GB (or
>> even
>> further up - 3.5GB), but a quick look for 'Allocating PCI resources starting
>> at' 
>> at Google shows that there are some that start at 1.2G.
> Hm, true. We could give you access to XENMEM_machine_memory_map? It's not
> really got any big secrets or privileged things in it. :-)
>
> Or, is there much disadvantage, to having a static really big PCI hole? Say
> starting at 1GB? The advantage of this would be the ability to hotplug PCI
> devices to a domU even across save/restore/migrate -- this may not work so
> well if you commit yourself to the hole size of the original host, and the
> restore/migrate target host has a bigger hole!

Well, the other question is whether the devices have to have the same
pfn as mfn within the hole.  We're emulating the PCI config space anyway
- couldn't we stick the passthrough PCI space at 3G regardless of where
it is on the real hardware?

    J

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

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