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] Re: Next steps with pv_ops for Xen

To: Derek Murray <Derek.Murray@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] Re: Next steps with pv_ops for Xen
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Date: Wed, 05 Dec 2007 10:12:02 -0800
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Eduardo Habkost <ehabkost@xxxxxxxxxx>, Juan Quintela <quintela@xxxxxxxxxx>, Jan Beulich <jbeulich@xxxxxxxxxx>, Glauber de Oliveira Costa <gcosta@xxxxxxxxxx>, Chris Wright <chrisw@xxxxxxxxxxxx>, "virtualization@xxxxxxxxxxxxxx" <virtualization@xxxxxxxxxxxxxx>, Gerd Hoffmann <kraxel@xxxxxxxxxx>
Delivery-date: Wed, 05 Dec 2007 10:12:34 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <47569014.8080008@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>
References: <1195682725.6726.48.camel@xxxxxxxxxxxxxxxxxxxxx> <4753FC6A.4020601@xxxxxxxxxx> <4754024C.7020905@xxxxxxxxxxxx> <47540FB8.8000106@xxxxxxxxxx> <475417E7.9070006@xxxxxxxxxxxx> <47546931.2090602@xxxxxxxxxx> <475520A1.6080909@xxxxxxxxxxxx> <475541A8.7030100@xxxxxxxxxx> <1196771999.10809.18.camel@xxxxxxxxxxxxxxxxxxxxx> <4755B158.3030008@xxxxxxxxxx> <47569014.8080008@xxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird 2.0.0.9 (X11/20071115)
Derek Murray wrote:
> Ultimately, fork calls dup_mm, which calls, dup_mmap, which calls
> copy_{page,pud,pmd,pte}_range, which calls copy_one_pte, which calls
> set_pte_at, which hypercalls HYPERVISOR_update_va_mapping.
>
> The hypercall will not succeed and will return an error code
> indicating the reason for this. Therefore the PTE will not be set.
> There appears to be no way to propagate this error through the Linux
> VM code, because there is no concept of a PTE update failing. I could
> add return codes to all those functions, but I don't fancy their
> chances upstream....

Could we use one of the software-defined bits in the PTE to indicate
that this is a foreign/granted PTE, and have set_pte_at behave
differently if you pass it a pte with this bit set?

    J

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

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