From patchwork Wed Aug 11 12:21:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robin Murphy X-Patchwork-Id: 12431163 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=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 5D3FCC43214 for ; Wed, 11 Aug 2021 12:37:16 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 28C5E610A2 for ; Wed, 11 Aug 2021 12:37:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 28C5E610A2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=A2fkt3+66It0SsIZ7ECJ8q3M3HmTykQbwxVrNfC6RcA=; b=f3ooqwnIcLHe41 24AfhziRqDUXX6zYa6Zse/eVNKjTDH7+LLWDPkdqz0feQV0RpAuDuZE199Xn4yVKkXXuDLwUyLsOh itqJpDOGvrFwUpbL9ul041UPVWmVv3tVZfK9xuARJaBVEqF6Lngke+UTcSAgXpaxqvDF9aslPGeAy flMT9svD2MyYH3+/qNT5S2jIUoSQVs3nWWaeYQHOf4IUlM5mzH3+5x+ENlH1GeLBCkVxP7HawH9ey nEejIRpgdwB0/ZTBU3KGImfpE26qKPz+hYtXhmbCAA9hWF+OjXKFKqdHq1/VaMcnWdUsqGhXOgATm tgvhCnm6Xct3V79p62TA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mDnSP-0075cT-1M; Wed, 11 Aug 2021 12:35:41 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mDnFh-006ygw-QJ for linux-arm-kernel@lists.infradead.org; Wed, 11 Aug 2021 12:22:35 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 675761396; Wed, 11 Aug 2021 05:22:33 -0700 (PDT) Received: from 010265703453.arm.com (unknown [10.57.36.146]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 9FE9B3F718; Wed, 11 Aug 2021 05:22:31 -0700 (PDT) From: Robin Murphy To: joro@8bytes.org, will@kernel.org Cc: iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, suravee.suthikulpanit@amd.com, baolu.lu@linux.intel.com, john.garry@huawei.com, dianders@chromium.org, rajatja@google.com, chenxiang66@hisilicon.com Subject: [PATCH v4 21/24] iommu: Expose DMA domain strictness via sysfs Date: Wed, 11 Aug 2021 13:21:35 +0100 Message-Id: <0e08da5ed4069fd3473cfbadda758ca983becdbf.1628682049.git.robin.murphy@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210811_052233_984162_16D9425A X-CRM114-Status: GOOD ( 14.49 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The sysfs interface for default domain types exists primarily so users can choose the performance/security tradeoff relevant to their own workload. As such, the choice between the policies for DMA domains fits perfectly as an additional point on that scale - downgrading a particular device from a strict default to non-strict may be enough to let it reach the desired level of performance, while still retaining more peace of mind than with a wide-open identity domain. Now that we've abstracted non-strict mode as a distinct type of DMA domain, allow it to be chosen through the user interface as well. Reviewed-by: Lu Baolu Reviewed-by: John Garry Signed-off-by: Robin Murphy --- v3: Summarise the implications in the documentation for completeness --- Documentation/ABI/testing/sysfs-kernel-iommu_groups | 6 +++++- drivers/iommu/iommu.c | 2 ++ 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/Documentation/ABI/testing/sysfs-kernel-iommu_groups b/Documentation/ABI/testing/sysfs-kernel-iommu_groups index eae2f1c1e11e..b15af6a5bc08 100644 --- a/Documentation/ABI/testing/sysfs-kernel-iommu_groups +++ b/Documentation/ABI/testing/sysfs-kernel-iommu_groups @@ -42,8 +42,12 @@ Description: /sys/kernel/iommu_groups//type shows the type of default ======== ====================================================== DMA All the DMA transactions from the device in this group are translated by the iommu. + DMA-FQ As above, but using batched invalidation to lazily + remove translations after use. This may offer reduced + overhead at the cost of reduced memory protection. identity All the DMA transactions from the device in this group - are not translated by the iommu. + are not translated by the iommu. Maximum performance + but zero protection. auto Change to the type the device was booted with. ======== ====================================================== diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 55ca5bf3cafc..b141161d5bbc 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -3267,6 +3267,8 @@ static ssize_t iommu_group_store_type(struct iommu_group *group, req_type = IOMMU_DOMAIN_IDENTITY; else if (sysfs_streq(buf, "DMA")) req_type = IOMMU_DOMAIN_DMA; + else if (sysfs_streq(buf, "DMA-FQ")) + req_type = IOMMU_DOMAIN_DMA_FQ; else if (sysfs_streq(buf, "auto")) req_type = 0; else