Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757715Ab0FBJp3 (ORCPT ); Wed, 2 Jun 2010 05:45:29 -0400 Received: from 8bytes.org ([88.198.83.132]:34390 "EHLO 8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754496Ab0FBJp2 (ORCPT ); Wed, 2 Jun 2010 05:45:28 -0400 Date: Wed, 2 Jun 2010 11:45:27 +0200 From: Joerg Roedel To: Avi Kivity Cc: "Michael S. Tsirkin" , Tom Lyon , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, chrisw@sous-sol.org, hjk@linutronix.de, gregkh@suse.de, aafabbri@cisco.com, scofeldm@cisco.com Subject: Re: [PATCH] VFIO driver: Non-privileged user level PCI drivers Message-ID: <20100602094527.GD964@8bytes.org> References: <20100530130332.GM27611@redhat.com> <4C026497.8070901@redhat.com> <20100530145309.GO27611@redhat.com> <4C03A285.7060902@redhat.com> <20100531171007.GA6516@redhat.com> <4C04C085.1030107@redhat.com> <20100601095532.GA9178@redhat.com> <4C04E0E0.3070006@redhat.com> <20100601104651.GA9415@redhat.com> <4C050013.2020701@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4C050013.2020701@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 884 Lines: 23 On Tue, Jun 01, 2010 at 03:41:55PM +0300, Avi Kivity wrote: > On 06/01/2010 01:46 PM, Michael S. Tsirkin wrote: >> Main difference is that vhost works fine with unlocked >> memory, paging it in on demand. iommu needs to unmap >> memory when it is swapped out or relocated. >> > So you'd just take the memory map and not pin anything. This way you > can reuse the memory map. > > But no, it doesn't handle the dirty bitmap, so no go. IOMMU mapped memory can not be swapped out because we can't do demand paging on io-page-faults with current devices. We have to pin _all_ userspace memory that is mapped into an IOMMU domain. Joerg -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/