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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 73E07C43467 for ; Thu, 8 Oct 2020 08:28:05 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (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 04A1C21531 for ; Thu, 8 Oct 2020 08:28:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 04A1C21531 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=8bytes.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id 88E7086E50; Thu, 8 Oct 2020 08:28:04 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id YUgtBYIWTcRT; Thu, 8 Oct 2020 08:28:03 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by whitealder.osuosl.org (Postfix) with ESMTP id D04F186E3A; Thu, 8 Oct 2020 08:28:03 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id B7F2DC016F; Thu, 8 Oct 2020 08:28:03 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 78E1AC0051 for ; Thu, 8 Oct 2020 08:28:02 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 5FED986BA7 for ; Thu, 8 Oct 2020 08:28:02 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id WFQtifAhleIV for ; Thu, 8 Oct 2020 08:28:02 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from theia.8bytes.org (8bytes.org [81.169.241.247]) by fraxinus.osuosl.org (Postfix) with ESMTPS id CE69F86BA5 for ; Thu, 8 Oct 2020 08:28:01 +0000 (UTC) Received: by theia.8bytes.org (Postfix, from userid 1000) id 5FA562FB; Thu, 8 Oct 2020 10:27:59 +0200 (CEST) Date: Thu, 8 Oct 2020 10:27:57 +0200 From: Joerg Roedel To: Christoph Hellwig Subject: Re: [PATCH 2/3] drm/msm: add DRM_MSM_GEM_SYNC_CACHE for non-coherent cache maintenance Message-ID: <20201008082757.GB3107@8bytes.org> References: <20201001002709.21361-1-jonathan@marek.ca> <20201001002709.21361-3-jonathan@marek.ca> <20201002075321.GA7547@infradead.org> <20201005082914.GA31702@infradead.org> <3e0b91be-e4a4-4ea5-7d58-6e71b8d51932@marek.ca> <20201006072306.GA12834@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201006072306.GA12834@infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) Cc: Jonathan Marek , David Airlie , freedreno@lists.freedesktop.org, open list , "open list:DRM DRIVER FOR MSM ADRENO GPU" , iommu@lists.linux-foundation.org, Daniel Vetter , "open list:DRM DRIVER FOR MSM ADRENO GPU" , Sean Paul , Robin Murphy X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Tue, Oct 06, 2020 at 08:23:06AM +0100, Christoph Hellwig wrote: > If people want to use the "raw" IOMMU API with not cache coherent > devices we'll need a cache maintainance API that goes along with it. > It could either be formally part of the IOMMU API or be separate. The IOMMU-API does not care about the caching effects of DMA, is manages IO address spaces for devices. I also don't know how this would be going to be implemented, the IOMMU-API does not have the concept of handles for mapped ranges and does not care about CPU virtual addresses (which are needed for cache flushes) of the memory it maps into IO page-tables. So I think a cache management API should be separate from the IOMMU-API. Regards, Joerg _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu