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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9BD60C433EF for ; Tue, 2 Nov 2021 06:44:05 +0000 (UTC) Received: from smtp1.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 5333660F02 for ; Tue, 2 Nov 2021 06:44:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 5333660F02 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 2110480C02; Tue, 2 Nov 2021 06:44:05 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id wzF7rKFf8t0M; Tue, 2 Nov 2021 06:44:04 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp1.osuosl.org (Postfix) with ESMTPS id 0B2C080BED; Tue, 2 Nov 2021 06:44:03 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id CC8B7C0019; Tue, 2 Nov 2021 06:44:03 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id B14AAC000E for ; Tue, 2 Nov 2021 06:44:01 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 9A11E80C02 for ; Tue, 2 Nov 2021 06:44:01 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 5X-YxvbW5_sd for ; Tue, 2 Nov 2021 06:44:01 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by smtp1.osuosl.org (Postfix) with ESMTPS id DE79D80BED for ; Tue, 2 Nov 2021 06:44:00 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 85F8768AFE; Tue, 2 Nov 2021 07:43:56 +0100 (CET) Date: Tue, 2 Nov 2021 07:43:56 +0100 From: Christoph Hellwig To: Walter Wu Subject: Re: [PATCH] dma-direct: fix DMA_ATTR_NO_KERNEL_MAPPING Message-ID: <20211102064356.GB27749@lst.de> References: <20211101031558.7184-1-walter-zh.wu@mediatek.com> <76840b40fcf26a65467931a73f236982ad39989c.camel@mediatek.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Cc: wsd_upstream , Will Deacon , Linux Kernel Mailing List , Christoph Hellwig , Linux IOMMU , linux-mediatek@lists.infradead.org, Matthias Brugger , Andrew Morton , Robin Murphy , Ard Biesheuvel , Linux ARM 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, Nov 02, 2021 at 11:21:16AM +0800, Walter Wu wrote: > Our platform is arch64. We need a dynamic allocated buffer from CMA is > not to read by CPU peculative execution, so we need to remove its > kernel mapping. If your CPU speculates into unused kernel direct mappings your have a worse problem than this, because all the dma coherent allocations for non-coherent devices still have a cachable direct mapping. Will mentioned he wanted to look into getting rid of that mapping now that the core dma code has the infrastucture for that, so adding him here. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu