Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264192AbTGBQkq (ORCPT ); Wed, 2 Jul 2003 12:40:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264202AbTGBQkq (ORCPT ); Wed, 2 Jul 2003 12:40:46 -0400 Received: from dsl2.external.hp.com ([192.25.206.7]:39173 "EHLO dsl2.external.hp.com") by vger.kernel.org with ESMTP id S264192AbTGBQkp (ORCPT ); Wed, 2 Jul 2003 12:40:45 -0400 Date: Wed, 2 Jul 2003 10:55:10 -0600 From: Grant Grundler To: Andi Kleen Cc: James Bottomley , axboe@suse.de, grundler@parisc-linux.org, davem@redhat.com, suparna@in.ibm.com, linux-kernel@vger.kernel.org, alex_williamson@hp.com, bjorn_helgaas@hp.com Subject: Re: [RFC] block layer support for DMA IOMMU bypass mode II Message-ID: <20030702165510.GC11739@dsl2.external.hp.com> References: <1057077975.2135.54.camel@mulgrave> <20030702015701.6007ac26.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030702015701.6007ac26.ak@suse.de> User-Agent: Mutt/1.3.28i X-Home-Page: http://www.parisc-linux.org/ Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 824 Lines: 17 On Wed, Jul 02, 2003 at 01:57:01AM +0200, Andi Kleen wrote: > The K8 IOMMU cannot support this virtually contiguous thing. The reason > is that there is no guarantee that an entry in a sglist is a multiple > of page size. And the aperture can only map 4K sized chunks, like > a CPU MMU. So e.g. when you have an sglist with multiple 1K entries there is > no way to get them continuous in IOMMU space (short of copying) Can two adjacent IOMMU entries be used to map two 1K buffers? Assume the 1st buffer ends on a 4k alignment and the next one starts on a 4k alignment. grant - 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/