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] Grant Table Hyper Calls For Sharing Memory

To: Xen Developers <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] Grant Table Hyper Calls For Sharing Memory
From: Daniel Stodden <stodden@xxxxxxxxxx>
Date: Tue, 19 Aug 2008 23:37:31 -0700
Delivery-date: Tue, 19 Aug 2008 23:37:56 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <532F993CC2E6654CADFE057ADC6C2FA31BA5B9A40B@xxxxxxxxxxxxxxxxx>
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>
Organization: Fakultät für Informatik I10, Technische Universität München
References: <532F993CC2E6654CADFE057ADC6C2FA31BA5B9A40B@xxxxxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Hope I'm not mistaken, but I believe this discussion only revolves
around the fact that you don't need hypercalls to *share* pages. The
gnttab hypercall interface is only needed to *map* shared pages, not to
let other domains access a hvm's memory.

Sharing a page only requires the owner to set appropriate permissions in
her own grant table. That's just a bit of store and cmpxchg. No
hypercalling involved.

Cheers,
Daniel

On Wed, 2008-08-20 at 14:03 +0800, Kumar, Venkat wrote:
> I was following an email chain in the xen mailing list on HVM
> hypercalls on grant tables and the email chain link is below
> 
> http://lists.xensource.com/archives/html/xen-devel/2007-03/msg00688.html
> 
>  
> 
> This link says that we need not required hypercalls to share memory
> b/w HVM’s.
> 
>  
> 
> But as far as my understanding of sharing memory is concerned, I think
> the memory is shared using grant table mechanism and we would need
> Hypercall support related to grant tables to make this possible.
> 
>  
> 
> Correct me if I am wrong.
> 
>  
> 
> Or is there any other way of sharing memory or Inter domain
> communication?
> 
>  
> 
> Thx,
> 
> Venkat
> 
> ================================
> 
> Venkata Kumar Duvvuru,
> 
> LSI Engenio,
> 
> Adv. Development,
> 
> Bangalore.
> 
> Mob: +91-9880318542
> 
> Off : +91-80-41978700 ( Extn : 3544 )
> 
> ================================
> 
> 
>  
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
-- 
Daniel Stodden
LRR     -      Lehrstuhl für Rechnertechnik und Rechnerorganisation
Institut für Informatik der TU München             D-85748 Garching
http://www.lrr.in.tum.de/~stodden         mailto:stodden@xxxxxxxxxx
PGP Fingerprint: F5A4 1575 4C56 E26A 0B33  3D80 457E 82AE B0D8 735B



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

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