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=unavailable 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 284A4C432C3 for ; Sat, 16 Nov 2019 06:24:52 +0000 (UTC) Received: from lists.ozlabs.org (unknown [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 989972073B for ; Sat, 16 Nov 2019 06:24:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 989972073B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 47FQDc5zX5zF53G for ; Sat, 16 Nov 2019 17:24:48 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lst.de (client-ip=213.95.11.211; helo=verein.lst.de; envelope-from=hch@lst.de; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=lst.de Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 47FQBk1mkqzF46j for ; Sat, 16 Nov 2019 17:23:07 +1100 (AEDT) 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 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) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Alexey Kardashevskiy , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, linuxppc-dev@lists.ozlabs.org, Christoph Hellwig Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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