Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263279AbTGAX4E (ORCPT ); Tue, 1 Jul 2003 19:56:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263428AbTGAX4E (ORCPT ); Tue, 1 Jul 2003 19:56:04 -0400 Received: from pizda.ninka.net ([216.101.162.242]:32986 "EHLO pizda.ninka.net") by vger.kernel.org with ESMTP id S263279AbTGAX4B (ORCPT ); Tue, 1 Jul 2003 19:56:01 -0400 Date: Tue, 01 Jul 2003 17:03:23 -0700 (PDT) Message-Id: <20030701.170323.59686965.davem@redhat.com> To: ak@suse.de Cc: James.Bottomley@steeleye.com, axboe@suse.de, grundler@parisc-linux.org, 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 From: "David S. Miller" In-Reply-To: <20030702015701.6007ac26.ak@suse.de> References: <1057077975.2135.54.camel@mulgrave> <20030702015701.6007ac26.ak@suse.de> X-FalunGong: Information control. X-Mailer: Mew version 2.1 on Emacs 21.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 796 Lines: 17 From: Andi Kleen Date: Wed, 2 Jul 2003 01:57:01 +0200 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 What do you mean? You map only one 4K chunk, and this is used for all the sub-1K mappings. I can only map 8K sized chunks on the sparc64 IOMMU and this works perfectly fine. - 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/