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/
Home Products Support Community News


[Xen-devel] RE: [PATCH] calling zap_low_mappings breaks xen boot on the

To: "Keir Fraser" <keir@xxxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] RE: [PATCH] calling zap_low_mappings breaks xen boot on the es7000
From: "Subrahmanian, Raj" <raj.subrahmanian@xxxxxxxxxx>
Date: Fri, 25 May 2007 08:24:24 -0400
Delivery-date: Fri, 25 May 2007 05:22:44 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <C27B13C5.F6DB%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: AceWvpt92gNeWwKxEdy09AAWy6hiGQCvyjGgABwt3PsA5BuyYAAY6zVDADksAjA=
Thread-topic: [PATCH] calling zap_low_mappings breaks xen boot on the es7000
>>> Either we should just delay the zap_low_mappings() call, or 
>fix your 
>>> code to map_domain_page()/unmap_domain_page(). How late in boot do 
>>> you need the low mappings?
>> This patch delays the zap_low_mappings() call until after the 
>> smp_prepare_cpus call. With this patch, I am able to run Xen on the 
>> ES7000 and a Dell SC 1430.
>So where is the late low-memory access happening? There's not 
>that much es7000-specific code. It can't be hard to fix 
>properly. If the physical pointer is known to be below 1MB you 
>can just __va() it. If not you may need to use a fixmap, or 
>acpi_map_table, or just __va() only on x86_64. I'd like to 
>keep the zap as early as possible to catch truly erroneous low 
I will look into that code and fix it.
If you don't mind me asking, what exactly does zap_low_mappings do? I am
not able to figure it out looking at the code.

Xen-devel mailing list