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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 78C77C43214 for ; Wed, 28 Jul 2021 15:59:49 +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 4A05B60F93 for ; Wed, 28 Jul 2021 15:59:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4A05B60F93 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com 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 29B9283AAA; Wed, 28 Jul 2021 15:59:49 +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 1HFtU-oIfPll; Wed, 28 Jul 2021 15:59:48 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp1.osuosl.org (Postfix) with ESMTPS id 1409C83AA2; Wed, 28 Jul 2021 15:59:48 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id E57DAC001A; Wed, 28 Jul 2021 15:59:47 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 896E9C0024 for ; Wed, 28 Jul 2021 15:59:46 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 6A832608A1 for ; Wed, 28 Jul 2021 15:59:46 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id t7RaZ9pslNuQ for ; Wed, 28 Jul 2021 15:59:45 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp3.osuosl.org (Postfix) with ESMTP id B491A6089C for ; Wed, 28 Jul 2021 15:59:45 +0000 (UTC) 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 330F613D5; Wed, 28 Jul 2021 08:59:45 -0700 (PDT) Received: from 010265703453.arm.com (unknown [10.57.36.146]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id AD6AC3F70D; Wed, 28 Jul 2021 08:59:43 -0700 (PDT) From: Robin Murphy To: joro@8bytes.org, will@kernel.org Subject: [PATCH v2 22/24] iommu: Allow enabling non-strict mode dynamically Date: Wed, 28 Jul 2021 16:58:43 +0100 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Cc: linux-kernel@vger.kernel.org, dianders@chromium.org, iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org 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" Allocating and enabling a flush queue is in fact something we can reasonably do while a DMA domain is active, without having to rebuild it from scratch. Thus we can allow a strict -> non-strict transition from sysfs without requiring to unbind the device's driver, which is of particular interest to users who want to make selective relaxations to critical devices like the one serving their root filesystem. Disabling and draining a queue also seems technically possible to achieve without rebuilding the whole domain, but would certainly be more involved. Furthermore there's not such a clear use-case for tightening up security *after* the device may already have done whatever it is that you don't trust it not to do, so we only consider the relaxation case. Signed-off-by: Robin Murphy --- drivers/iommu/iommu.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 25c1adc1ec67..be399d630953 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -3200,6 +3200,13 @@ static int iommu_change_dev_def_domain(struct iommu_group *group, goto out; } + /* We can bring up a flush queue without tearing down the domain */ + if (type == IOMMU_DOMAIN_DMA_FQ && prev_dom->type == IOMMU_DOMAIN_DMA) { + prev_dom->type = IOMMU_DOMAIN_DMA_FQ; + ret = iommu_dma_init_fq(prev_dom); + goto out; + } + /* Sets group->default_domain to the newly allocated domain */ ret = iommu_group_alloc_default_domain(dev->bus, group, type); if (ret) @@ -3240,9 +3247,9 @@ static int iommu_change_dev_def_domain(struct iommu_group *group, } /* - * Changing the default domain through sysfs requires the users to ubind the - * drivers from the devices in the iommu group. Return failure if this doesn't - * meet. + * Changing the default domain through sysfs requires the users to unbind the + * drivers from the devices in the iommu group, except for a DMA -> DMA-FQ + * transition. Return failure if this isn't met. * * We need to consider the race between this and the device release path. * device_lock(dev) is used here to guarantee that the device release path @@ -3318,7 +3325,8 @@ static ssize_t iommu_group_store_type(struct iommu_group *group, /* Check if the device in the group still has a driver bound to it */ device_lock(dev); - if (device_is_bound(dev)) { + if (device_is_bound(dev) && !(req_type == IOMMU_DOMAIN_DMA_FQ && + group->default_domain->type == IOMMU_DOMAIN_DMA)) { pr_err_ratelimited("Device is still bound to driver\n"); ret = -EBUSY; goto out; -- 2.25.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu