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=-8.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 5A595C433E0 for ; Wed, 8 Jul 2020 15:29:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 34036206DF for ; Wed, 8 Jul 2020 15:29:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="viyDx+ee" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730108AbgGHP32 (ORCPT ); Wed, 8 Jul 2020 11:29:28 -0400 Received: from casper.infradead.org ([90.155.50.34]:37122 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729022AbgGHP32 (ORCPT ); Wed, 8 Jul 2020 11:29:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:In-Reply-To:References; bh=N8lHywqGbtnmlIc888+bV79uuU+fuqr8NT0KCg3mTcg=; b=viyDx+ee5J2iBJ3SHuhkTe64ex nPggVaOCNbVbq3gLYgaZn/l9njs3icaTSUoD2+VtbEHFctvNdK67a4IcxTeamhz9ucJm5ski4dEO9 SUMBENSbNZVJ61wfmqFFiqHdlbUGQXpCZc+u/1FF1jRy62DxPVVzMdSRobfQ4xjGEZu/cciBdvZXu wacHtK8QaMqFAMl3xVXcdP9QTzFIy/Dvafd40JRsN0fjgpoYKuFaDepQybQwX13pVKyXQcnZISmPZ Q5q3+RdAwhwGOaH14t0dGyNhFA6pQpsNfGKTwS7qChg1UbMSaJtGEKdacdn7hZ4CLrnGSFSNGb8EU FA572Rtg==; Received: from 213-225-32-40.nat.highway.a1.net ([213.225.32.40] helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jtByQ-0002A2-VT; Wed, 08 Jul 2020 15:27:13 +0000 From: Christoph Hellwig To: iommu@lists.linux-foundation.org, Alexey Kardashevskiy Cc: linuxppc-dev@lists.ozlabs.org, Lu Baolu , Greg Kroah-Hartman , Joerg Roedel , Robin Murphy , Jesper Dangaard Brouer , =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , Daniel Borkmann , linux-kernel@vger.kernel.org Subject: generic DMA bypass flag v4 Date: Wed, 8 Jul 2020 17:24:44 +0200 Message-Id: <20200708152449.316476-1-hch@lst.de> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi all, I've recently beeing chatting with Lu about using dma-iommu and per-device DMA ops in the intel IOMMU driver, and one missing feature in dma-iommu is a bypass mode where the direct mapping is used even when an iommu is attached to improve performance. The powerpc code already has a similar mode, so I'd like to move it to the core DMA mapping code. As part of that I noticed that the current powerpc code has a little bug in that it used the wrong check in the dma_sync_* routines to see if the direct mapping code is used. These two patches just add the generic code and move powerpc over, the intel IOMMU bits will require a separate discussion. The x86 AMD Gart code also has a bypass mode, but it is a lot strange, so I'm not going to touch it for now. Note that as-is this breaks the XSK buffer pool, which unfortunately poked directly into DMA internals. A fix for that is already queued up in the netdev tree. Jesper and XDP gang: this should not regress any performance as the dma-direct calls are now inlined into the out of line DMA mapping calls. But if you can verify the performance numbers that would be greatly appreciated. A git tree is available here: git://git.infradead.org/users/hch/misc.git dma-bypass.4 Gitweb: git.infradead.org/users/hch/misc.git/shortlog/refs/heads/dma-bypass.4 Changes since v3: - add config options for the dma ops bypass and dma ops themselves to not increase the size of tinyconfig builds Changes since v2: - move the dma mapping helpers out of line - check for possible direct mappings using the dma mask Changes since v1: - rebased to the current dma-mapping-for-next tree Diffstat: arch/alpha/Kconfig | 1 arch/arm/Kconfig | 1 arch/ia64/Kconfig | 1 arch/mips/Kconfig | 1 arch/parisc/Kconfig | 1 arch/powerpc/Kconfig | 2 arch/powerpc/include/asm/device.h | 5 arch/powerpc/kernel/dma-iommu.c | 90 +------------ arch/s390/Kconfig | 1 arch/sparc/Kconfig | 1 arch/x86/Kconfig | 1 drivers/iommu/Kconfig | 2 drivers/misc/mic/Kconfig | 1 drivers/vdpa/Kconfig | 1 drivers/xen/Kconfig | 1 include/linux/device.h | 11 + include/linux/dma-direct.h | 104 +++++++++++++++ include/linux/dma-mapping.h | 251 ++++---------------------------------- kernel/dma/Kconfig | 12 + kernel/dma/Makefile | 3 kernel/dma/direct.c | 74 ----------- kernel/dma/mapping.c | 214 ++++++++++++++++++++++++++++++-- 22 files changed, 385 insertions(+), 394 deletions(-)