From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F0157C3A59B for ; Sat, 17 Aug 2019 06:50:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CFD5D2077C for ; Sat, 17 Aug 2019 06:50:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726033AbfHQGuR (ORCPT ); Sat, 17 Aug 2019 02:50:17 -0400 Received: from verein.lst.de ([213.95.11.211]:60648 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725832AbfHQGuQ (ORCPT ); Sat, 17 Aug 2019 02:50:16 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 70BE768B05; Sat, 17 Aug 2019 08:50:12 +0200 (CEST) Date: Sat, 17 Aug 2019 08:50:11 +0200 From: Christoph Hellwig To: Julien Grall Cc: Christoph Hellwig , Stefano Stabellini , Konrad Rzeszutek Wilk , xen-devel@lists.xenproject.org, iommu@lists.linux-foundation.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [Xen-devel] [PATCH 07/11] swiotlb-xen: provide a single page-coherent.h header Message-ID: <20190817065011.GA18599@lst.de> References: <20190816130013.31154-1-hch@lst.de> <20190816130013.31154-8-hch@lst.de> <9a3261c6-5d92-cf6b-1ae8-3a8e8b5ef0d4@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9a3261c6-5d92-cf6b-1ae8-3a8e8b5ef0d4@arm.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 16, 2019 at 11:40:43PM +0100, Julien Grall wrote: > I am not sure I agree with this rename. The implementation of the helpers > are very Arm specific as this is assuming Dom0 is 1:1 mapped. > > This was necessary due to the lack of IOMMU on Arm platforms back then. > But this is now a pain to get rid of it on newer platform... So if you look at the final version of the header after the whole series, what assumes a 1:1 mapping? It all just is if (pfn_valid()) local cache sync; else call into the arch code; are you concerned that the local cache sync might have to be split up more for a non-1:1 map in that case? We could just move the xen_dma_* routines into the arch instead of __xen_dma, but it really helps to have a common interface header.