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] Sharing grant_table pages between 2 miniOS

To: "Lamia M. Youseff" <lyouseff@xxxxxxxxxxx>
Subject: Re: [Xen-devel] Sharing grant_table pages between 2 miniOS
From: Kieran Mansley <kmansley@xxxxxxxxxxxxxx>
Date: Tue, 15 May 2007 09:44:32 +0100
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Tue, 15 May 2007 01:42:58 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <46492A62.4020705@xxxxxxxxxxx>
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: <46492A62.4020705@xxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
On Mon, 2007-05-14 at 20:34 -0700, Lamia M. Youseff wrote:
> Dear All,
> I am doing a small experiment with grant table to share 4 pages of 
> memory between 2 miniOS, but have not been successful. For some reason, 
> my GNTTABOP_map_grant_ref returns -1

Is it possible that the grant_operation_permitted() call during the
map_grant_ref operation is failing?  The code in question is this (from
include/xen/iocap.h):

/*
 * Until TLB flushing issues are sorted out we consider it unsafe for
 * domains with no hardware-access privileges to perform grant
map/transfer
 * operations.
 */
#define grant_operation_permitted(d)                    \
    (!rangeset_is_empty((d)->iomem_caps))

If this is the case, giving the granting domain some iomem capability
should allow you to do what you want.  I'm not sure what the TLB
flushing issues are, or what the plan is to get a proper solution to
this.

Kieran



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

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