Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753296AbYLRVDV (ORCPT ); Thu, 18 Dec 2008 16:03:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752169AbYLRVDK (ORCPT ); Thu, 18 Dec 2008 16:03:10 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:48328 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751568AbYLRVDJ (ORCPT ); Thu, 18 Dec 2008 16:03:09 -0500 Date: Thu, 18 Dec 2008 22:02:31 +0100 From: Ingo Molnar To: Becky Bruce Cc: FUJITA Tomonori , Jeremy Fitzhardinge , Linux Kernel Mailing List , xen-devel@lists.xensource.com, x86@kernel.org, ian.campbell@citrix.com, jbeulich@novell.com, joerg.roedel@amd.com, Benjamin Herrenschmidt Subject: Re: [PATCH 00 of 14] swiotlb/x86: lay groundwork for xen dom0 use of swiotlb Message-ID: <20081218210231.GB24271@elte.hu> References: <20081216203513.GA14787@elte.hu> <20081217142637V.fujita.tomonori@lab.ntt.co.jp> <4949296F.7000701@goop.org> <20081218015705Z.fujita.tomonori@lab.ntt.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Becky Bruce wrote: >> Can you be more specific? What architecture is plan to use highmem >> support in swiotlb? > > 32-bit powerpc needs this support - I was actually about to push a > similar set of patches. We have several processors that support 36 bits > of physical address space and do not have any iommu capability. The > rest of the kernel support for those processors is now in place, so > swiotlb is the last piece of the puzzle for that to be fully functional. > I need to take a closer look at this series to see exactly what it's > doing and how it differs from what I've been testing. > > So there is another immediate use case, and I'd really hate to see this > code duplicated. It should be entirely possible to remove the > assumption that we can save off the VA of the original buffer, which is > the thing that precludes HIGHMEM support, and still have nice readable, > maintainable code. you can have a look at Jeremy's current lineup of patches in tip/core/iotlb: http://people.redhat.com/mingo/tip.git/README (also integrated into tip/master) What would be needed to make it suit your usecase too? Ingo -- 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/