From patchwork Mon Aug 15 16:20:02 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robin Murphy X-Patchwork-Id: 12943810 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 65548C00140 for ; Mon, 15 Aug 2022 16:21:56 +0000 (UTC) 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=c7HQHKfIM5yvl+qsrtl0rJo9BCv3bVUdE/PVXE/uLY8=; b=0afM1zTp+01Mew Mp059t/3YFBE876CicpnVkFS9Liz/iH251nrwshcZn717Ijs5/hhVozz5sKIhjzpkcTncDC3cXYYd 0oPboxpjPTSOTEMTsv7Oi1R205H5SDSDcUJxG+4NmEMvxj1tzd7zjf7X7WpkSWR6QNIcozT6ZjSUJ noDE4QOt3ZMAxPymJ+aLTF2RNkZVrIbNqFLqaVX+qXxxKZUsxLMXV9/ulrbeYIUKRgtG3aQxiEhvH M9xCNKn6Nl7oNZRjiL+fLe4rYjNXBh/sI1xGjHkzqwGGSLMzHICys2HqWw8NksZQIj1QWng+zpKRK 9F2C9LDEP3zSUCpTdVxw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oNcpp-001WaI-Dg; Mon, 15 Aug 2022 16:21:01 +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 1oNcpF-001Vnk-RE for linux-arm-kernel@lists.infradead.org; Mon, 15 Aug 2022 16:20:27 +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 71548113E; Mon, 15 Aug 2022 09:20:25 -0700 (PDT) Received: from e121345-lin.cambridge.arm.com (e121345-lin.cambridge.arm.com [10.1.196.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 385D33F70D; Mon, 15 Aug 2022 09:20:23 -0700 (PDT) From: Robin Murphy To: joro@8bytes.org Cc: will@kernel.org, iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org, baolu.lu@linux.intel.com, kevin.tian@intel.com, suravee.suthikulpanit@amd.com, vasant.hegde@amd.com, mjrosato@linux.ibm.com, schnelle@linux.ibm.com, linux-kernel@vger.kernel.org Subject: [PATCH v4 01/16] iommu/vt-d: Handle race between registration and device probe Date: Mon, 15 Aug 2022 17:20:02 +0100 Message-Id: <579f2692291bcbfc3ac64f7456fcff0d629af131.1660572783.git.robin.murphy@arm.com> X-Mailer: git-send-email 2.36.1.dirty In-Reply-To: References: MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220815_092026_014724_946BA57B X-CRM114-Status: GOOD ( 12.73 ) 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 Currently we rely on registering all our instances before initially allowing any .probe_device calls via bus_set_iommu(). In preparation for phasing out the latter, make sure we won't inadvertently return success for a device associated with a known but not yet registered instance, otherwise we'll run straight into iommu_group_get_for_dev() trying to use NULL ops. That also highlights an issue with intel_iommu_get_resv_regions() taking dmar_global_lock from within a section where intel_iommu_init() already holds it, which already exists via probe_acpi_namespace_devices() when an ANDD device is probed, but gets more obvious with the upcoming change to iommu_device_register(). Since they are both read locks it manages not to deadlock in practice, and a more in-depth rework of this locking is underway, so no attempt is made to address it here. Reviewed-by: Kevin Tian Signed-off-by: Robin Murphy --- v4: Update commit message drivers/iommu/intel/iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 7cca030a508e..65c340e2003c 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -4449,7 +4449,7 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev) u8 bus, devfn; iommu = device_to_iommu(dev, &bus, &devfn); - if (!iommu) + if (!iommu || !iommu->iommu.ops) return ERR_PTR(-ENODEV); info = kzalloc(sizeof(*info), GFP_KERNEL);