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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 86217C433DB for ; Tue, 30 Mar 2021 13:12:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 54217619BB for ; Tue, 30 Mar 2021 13:12:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232096AbhC3NMN (ORCPT ); Tue, 30 Mar 2021 09:12:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:52402 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232289AbhC3NL4 (ORCPT ); Tue, 30 Mar 2021 09:11:56 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3807E6190A; Tue, 30 Mar 2021 13:11:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1617109915; bh=E7y/dbAAWo9buKdnhgJzSLhrZuvZjF7e5JPqlaZDmKA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nAM/OfXEJ+5P0AOFZGxwgS6k50PSZ6ZL+0SdM34bRXqilkdD1BMlp5kMlv2jKqeXJ RFq44I5uncbXNQhliA7OD3QPB8lN5hZkxWoXcop6y/Y1IBJ/rcfxLyHIo2tS0SpYkp OrUIMp3MFAVbY8783Qbhv1kqq1hoEVaLylEPRKuYQXQBu5/MlghjYIEFwHWboYdrOO pByYsjfgLgrsFLdpXDlg/y+xqfu7E4iOvnHrOCmu5gaK38t1EdeblYuZ40EdwPrZjo qX1I0Z4jkjNv3rxdihUqdwy79Vet1JWSllchMLwPrvfbEnP8SACK28FDZ/JTY6Eypo iicajwfBXpXWA== Date: Tue, 30 Mar 2021 14:11:49 +0100 From: Will Deacon To: Christoph Hellwig Cc: Joerg Roedel , Li Yang , Michael Ellerman , David Woodhouse , Lu Baolu , linuxppc-dev@lists.ozlabs.org, linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, Robin Murphy Subject: Re: [PATCH 16/18] iommu: remove DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE Message-ID: <20210330131149.GP5908@willie-the-truck> References: <20210316153825.135976-1-hch@lst.de> <20210316153825.135976-17-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210316153825.135976-17-hch@lst.de> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Tue, Mar 16, 2021 at 04:38:22PM +0100, Christoph Hellwig wrote: > From: Robin Murphy > > Instead make the global iommu_dma_strict paramete in iommu.c canonical by > exporting helpers to get and set it and use those directly in the drivers. > > This make sure that the iommu.strict parameter also works for the AMD and > Intel IOMMU drivers on x86. As those default to lazy flushing a new > IOMMU_CMD_LINE_STRICT is used to turn the value into a tristate to > represent the default if not overriden by an explicit parameter. > > Signed-off-by: Robin Murphy . > [ported on top of the other iommu_attr changes and added a few small > missing bits] > Signed-off-by: Christoph Hellwig > --- > drivers/iommu/amd/iommu.c | 23 +------- > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 50 +--------------- > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 1 - > drivers/iommu/arm/arm-smmu/arm-smmu.c | 27 +-------- > drivers/iommu/dma-iommu.c | 9 +-- > drivers/iommu/intel/iommu.c | 64 ++++----------------- > drivers/iommu/iommu.c | 27 ++++++--- > include/linux/iommu.h | 4 +- > 8 files changed, 40 insertions(+), 165 deletions(-) I really like this cleanup, but I can't help wonder if it's going in the wrong direction. With SoCs often having multiple IOMMU instances and a distinction between "trusted" and "untrusted" devices, then having the flush-queue enabled on a per-IOMMU or per-domain basis doesn't sound unreasonable to me, but this change makes it a global property. For example, see the recent patch from Lu Baolu: https://lore.kernel.org/r/20210225061454.2864009-1-baolu.lu@linux.intel.com Will