From xen-devel-bounces@lists.xen.org Tue May 20 08:27:01 2014 Received: (at maildrop) by bugs.xenproject.org; 20 May 2014 07:27:02 +0000 Received: from lists.xen.org ([50.57.142.19]) by bugs.xenproject.org with esmtp (Exim 4.80) (envelope-from ) id 1WmeRx-0007fO-Ul for xen-devel-maildrop-Eithu9ie@bugs.xenproject.org; Tue, 20 May 2014 08:27:01 +0100 Received: from localhost ([127.0.0.1] helo=lists.xen.org) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1WmeLW-0001yA-LY; Tue, 20 May 2014 07:20:22 +0000 Received: from mail6.bemta4.messagelabs.com ([85.158.143.247]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1WmeLV-0001y2-Lj for xen-devel@lists.xen.org; Tue, 20 May 2014 07:20:21 +0000 Received: from [85.158.143.35:25413] by server-1.bemta-4.messagelabs.com id C1/6C-09853-4320B735; Tue, 20 May 2014 07:20:20 +0000 X-Env-Sender: JBeulich@suse.com X-Msg-Ref: server-3.tower-21.messagelabs.com!1400570420!5631549!1 X-Originating-IP: [130.57.118.101] X-SpamReason: No, hits=0.0 required=7.0 tests= X-StarScan-Received: X-StarScan-Version: 6.11.3; banners=-,-,- X-VirusChecked: Checked Received: (qmail 24883 invoked from network); 20 May 2014 07:20:20 -0000 Received: from mail.emea.novell.com (HELO mail.emea.novell.com) (130.57.118.101) by server-3.tower-21.messagelabs.com with DHE-RSA-AES256-SHA encrypted SMTP; 20 May 2014 07:20:20 -0000 Received: from EMEA1-MTA by mail.emea.novell.com with Novell_GroupWise; Tue, 20 May 2014 08:20:20 +0100 Message-Id: <537B1E520200007800013EB7@mail.emea.novell.com> X-Mailer: Novell GroupWise Internet Agent 14.0.0 Date: Tue, 20 May 2014 08:20:18 +0100 From: "Jan Beulich" To: "Yang Z Zhang" References: <20140210080314.GA758@deinos.phlegethon.org> <20140211090202.GC92054@deinos.phlegethon.org> <20140211115553.GB97288@deinos.phlegethon.org> <52FA2C63020000780011B201@nat28.tlf.novell.com> <52FA480D.9040707@eu.citrix.com> <52FCE8BE.8050105@eu.citrix.com> <52FCF90F020000780011C29A@nat28.tlf.novell.com> <20140213162022.GE82703@deinos.phlegethon.org> In-Reply-To: Mime-Version: 1.0 Content-Disposition: inline Cc: George Dunlap , "andrew.cooper3@citrix.com" , Tim Deegan , "xen-devel@lists.xen.org" , "Keir Fraser\(keir.xen@gmail.com\)" , Jun Nakajima , Xiantao Zhang Subject: Re: [Xen-devel] [PATCH] Don't track all memory when enabling log dirty to track vram X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org >>> On 20.05.14 at 05:13, wrote: > George Dunlap wrote on 2014-05-19: >> Avoiding these by "hoping" that the guest OS doesn't DMA into a video >> buffer isn't really robust enough. I think that was Tim and Jan's > > Video buffer is only one case. How we can prevent the DMA to other reserved > region? You continue to neglect the difference: Accessing VRAM this way is legitimate (and potentially useful). And - as just said in the other reply - ideally we'd also simply ignore accesses to reserved regions (and in fact we try to, by not immediately bringing down a guest device doing such). Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel