From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <Ian.Campbell@citrix.com>
Subject: Re: [PATCH v2 3/4] xen/arm: introduce
 GNTTABOP_cache_flush
Date: Wed, 8 Oct 2014 13:17:30 +0100
Message-ID: <1412770650.9247.27.camel@citrix.com>
References: <alpine.DEB.2.02.1410031543550.17038@kaball.uk.xensource.com>
	<1412347845-27755-3-git-send-email-stefano.stabellini@eu.citrix.com>
	<5432B382.3040000@citrix.com>
	<alpine.DEB.2.02.1410081248250.17038@kaball.uk.xensource.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
In-Reply-To: <alpine.DEB.2.02.1410081248250.17038@kaball.uk.xensource.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: julien.grall@citrix.com, xen-devel@lists.xensource.com, David Vrabel <david.vrabel@citrix.com>
List-Id: xen-devel@lists.xenproject.org

On Wed, 2014-10-08 at 12:54 +0100, Stefano Stabellini wrote:
> > Instead of this hypercall, could the guest clean/invalidate by set/way?
> >  I guess this would need a suitable IPA which could be obtained by some
> > (offset) 1:1 mapping in the stage 2 tables?
> 
> I wish I could: as the clean/invalidate by set/way is implementation
> specific, there is now way to use it to clean a specific range of
> addresses.

Clean by set/way is basically unusable except in very specific
circumstances (e.g. tearing down prior to a suspend). It's certainly not
usable on an active SMP system.

http://lists.xen.org/archives/html/xen-devel/2014-10/msg00709.html

Ian.