From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757548AbXIEUUU (ORCPT ); Wed, 5 Sep 2007 16:20:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754377AbXIEUUG (ORCPT ); Wed, 5 Sep 2007 16:20:06 -0400 Received: from il.qumranet.com ([82.166.9.18]:42048 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756672AbXIEUUD (ORCPT ); Wed, 5 Sep 2007 16:20:03 -0400 Message-ID: <46DF0EC2.7090408@qumranet.com> Date: Wed, 05 Sep 2007 23:17:06 +0300 From: Avi Kivity User-Agent: Thunderbird 2.0.0.5 (X11/20070719) MIME-Version: 1.0 To: Rusty Russell CC: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kvm-devel@lists.sourceforge.net, general@lists.openfabrics.org Subject: Re: [kvm-devel] [PATCH][RFC] pte notifiers -- support for external page tables References: <11890207643068-git-send-email-avi@qumranet.com> <1189022183.10802.184.camel@localhost.localdomain> In-Reply-To: <1189022183.10802.184.camel@localhost.localdomain> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Rusty Russell wrote: > On Wed, 2007-09-05 at 22:32 +0300, Avi Kivity wrote: > >> [resend due to bad alias expansion resulting in some recipients >> being bogus] >> >> Some hardware and software systems maintain page tables outside the normal >> Linux page tables, which reference userspace memory. This includes >> Infiniband, other RDMA-capable devices, and kvm (with a pending patch). >> > > And lguest. I can't tell until I've actually implemented it, but I > think it will seriously reduce the need for page pinning which is why > only root can currently launch guests. > > Ah yes, lguest. > My concern is locking: this is called with the page lock held, and I > guess we have to bump the guest out if it's currently running. > This will complicate kvm's locking too. We usually take kvm->lock to do mmu ops, but that is now a mutex. -- Any sufficiently difficult bug is indistinguishable from a feature. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH][RFC] pte notifiers -- support for external page tables Date: Wed, 05 Sep 2007 23:17:06 +0300 Message-ID: <46DF0EC2.7090408@qumranet.com> References: <11890207643068-git-send-email-avi@qumranet.com> <1189022183.10802.184.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, general-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org To: Rusty Russell Return-path: In-Reply-To: <1189022183.10802.184.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Rusty Russell wrote: > On Wed, 2007-09-05 at 22:32 +0300, Avi Kivity wrote: > >> [resend due to bad alias expansion resulting in some recipients >> being bogus] >> >> Some hardware and software systems maintain page tables outside the normal >> Linux page tables, which reference userspace memory. This includes >> Infiniband, other RDMA-capable devices, and kvm (with a pending patch). >> > > And lguest. I can't tell until I've actually implemented it, but I > think it will seriously reduce the need for page pinning which is why > only root can currently launch guests. > > Ah yes, lguest. > My concern is locking: this is called with the page lock held, and I > guess we have to bump the guest out if it's currently running. > This will complicate kvm's locking too. We usually take kvm->lock to do mmu ops, but that is now a mutex. -- Any sufficiently difficult bug is indistinguishable from a feature. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <46DF0EC2.7090408@qumranet.com> Date: Wed, 05 Sep 2007 23:17:06 +0300 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [kvm-devel] [PATCH][RFC] pte notifiers -- support for external page tables References: <11890207643068-git-send-email-avi@qumranet.com> <1189022183.10802.184.camel@localhost.localdomain> In-Reply-To: <1189022183.10802.184.camel@localhost.localdomain> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rusty Russell Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kvm-devel@lists.sourceforge.net, general@lists.openfabrics.org List-ID: Rusty Russell wrote: > On Wed, 2007-09-05 at 22:32 +0300, Avi Kivity wrote: > >> [resend due to bad alias expansion resulting in some recipients >> being bogus] >> >> Some hardware and software systems maintain page tables outside the normal >> Linux page tables, which reference userspace memory. This includes >> Infiniband, other RDMA-capable devices, and kvm (with a pending patch). >> > > And lguest. I can't tell until I've actually implemented it, but I > think it will seriously reduce the need for page pinning which is why > only root can currently launch guests. > > Ah yes, lguest. > My concern is locking: this is called with the page lock held, and I > guess we have to bump the guest out if it's currently running. > This will complicate kvm's locking too. We usually take kvm->lock to do mmu ops, but that is now a mutex. -- Any sufficiently difficult bug is indistinguishable from a feature. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org