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=-7.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 1A814C432C3 for ; Sat, 16 Nov 2019 06:23:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D1C922073B for ; Sat, 16 Nov 2019 06:23:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726174AbfKPGXB (ORCPT ); Sat, 16 Nov 2019 01:23:01 -0500 Received: from verein.lst.de ([213.95.11.211]:47899 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725978AbfKPGXB (ORCPT ); Sat, 16 Nov 2019 01:23:01 -0500 Received: by verein.lst.de (Postfix, from userid 2407) id 0EC8968BE1; Sat, 16 Nov 2019 07:22:58 +0100 (CET) Date: Sat, 16 Nov 2019 07:22:58 +0100 From: Christoph Hellwig To: Robin Murphy Cc: Christoph Hellwig , iommu@lists.linux-foundation.org, Alexey Kardashevskiy , Greg Kroah-Hartman , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: generic DMA bypass flag Message-ID: <20191116062258.GA8913@lst.de> References: <20191113133731.20870-1-hch@lst.de> <20191114074105.GC26546@lst.de> <9c8f4d7b-43e0-a336-5d93-88aef8aae716@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9c8f4d7b-43e0-a336-5d93-88aef8aae716@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, Nov 15, 2019 at 06:12:48PM +0000, Robin Murphy wrote: > And is that any different from where you would choose to "just" set a > generic bypass flag? Same spots, as intel-iommu moves from the identify to a dma domain when setting a 32-bit mask. But that means once a 32-bit mask is set we can't ever go back to the 64-bit one. And we had a couple drivers playing interesting games there. FYI, this is the current intel-iommu WIP conversion to the dma bypass flag: http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/dma-bypass