Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753331AbYLRUJ1 (ORCPT ); Thu, 18 Dec 2008 15:09:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752021AbYLRUJR (ORCPT ); Thu, 18 Dec 2008 15:09:17 -0500 Received: from gw.goop.org ([64.81.55.164]:46504 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751440AbYLRUJQ (ORCPT ); Thu, 18 Dec 2008 15:09:16 -0500 Message-ID: <494AADE9.8040503@goop.org> Date: Thu, 18 Dec 2008 12:09:13 -0800 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.18 (X11/20081119) MIME-Version: 1.0 To: Becky Bruce CC: FUJITA Tomonori , Ingo Molnar , 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 References: <20081216203513.GA14787@elte.hu> <20081217142637V.fujita.tomonori@lab.ntt.co.jp> <4949296F.7000701@goop.org> <20081218015705Z.fujita.tomonori@lab.ntt.co.jp> In-Reply-To: X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Becky Bruce wrote: > 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. Good, I'm glad I'm not just making things up ;) The gist of the patch is to convert all the kernel virtual addresses into struct page+offset. It's a fairly generic way to handle highmem systems, so it should work for you too. Of course, if you have a cleaner patch to achieve the same result, then we evaluate that too. J -- 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/