From patchwork Mon Aug 15 16:20:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robin Murphy X-Patchwork-Id: 12943822 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 E32F1C25B0D for ; Mon, 15 Aug 2022 16:23:58 +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=ALIxvBTu9LqLPgT1ljzWM3dXX6fF3Gugnw0zCmd6yRg=; b=PxU/+XVkps0rP4 Z6bV4lzhiOHyj+/xeEy6dR12bqY/AkJpgN+H8o2S3Kq6qylrDNPMDhzGBo1pY+TaQYV+ezvE7gqv+ cMDKHZzITF6y1kDKOfq5Y3HEgjsHfaY0e+jGOhm+6cCigbgm2mEeC265EsF7PF8hSw7PTeq4E1SOM 93I5ykboX3UlzzH78K8QVhmae4B9Qp8kmJ4LNzSFE8MlujHqmhNNK4W6KuV/xJw0cacFEgVjuFWA7 PPG/aTP8SUX+3ynDXP8qufuqIo/KgFB0h1SrZQnNOsJwCSgnsCCayADX/nRVsz+7bf1NSmQZquwwt MF2K5IMpM8G+g38r3B6A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oNcrK-001YBg-CE; Mon, 15 Aug 2022 16:22:34 +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 1oNcpM-001VxE-UD for linux-arm-kernel@lists.infradead.org; Mon, 15 Aug 2022 16:20:34 +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 15E54113E; Mon, 15 Aug 2022 09:20:32 -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 D13C83F70D; Mon, 15 Aug 2022 09:20:29 -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 05/16] iommu: Move bus setup to IOMMU device registration Date: Mon, 15 Aug 2022 17:20:06 +0100 Message-Id: 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_092033_125283_D42E648A X-CRM114-Status: GOOD ( 17.88 ) 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 Move the bus setup to iommu_device_register(). This should allow bus_iommu_probe() to be correctly replayed for multiple IOMMU instances, and leaves bus_set_iommu() as a glorified no-op to be cleaned up next. At this point we can also handle cleanup better than just rolling back the most-recently-touched bus upon failure - which may release devices owned by other already-registered instances, and still leave devices on other buses with dangling pointers to the failed instance. Now it's easy to clean up the exact footprint of a given instance, no more, no less. Tested-by: Marek Szyprowski Reviewed-By: Krishna Reddy Reviewed-by: Kevin Tian Tested-by: Matthew Rosato # s390 Tested-by: Niklas Schnelle # s390 Signed-off-by: Robin Murphy --- v4: Factor out the ops check in iommu_device_register() to keep the loop even simpler, and comment the nominal change in behaviour drivers/iommu/iommu.c | 55 +++++++++++++++++++++++-------------------- 1 file changed, 30 insertions(+), 25 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index a8d14f2a1035..4db0874a5ed6 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -188,6 +188,14 @@ static int __init iommu_subsys_init(void) } subsys_initcall(iommu_subsys_init); +static int remove_iommu_group(struct device *dev, void *data) +{ + if (dev->iommu && dev->iommu->iommu_dev == data) + iommu_release_device(dev); + + return 0; +} + /** * iommu_device_register() - Register an IOMMU hardware instance * @iommu: IOMMU handle for the instance @@ -199,9 +207,18 @@ subsys_initcall(iommu_subsys_init); int iommu_device_register(struct iommu_device *iommu, const struct iommu_ops *ops, struct device *hwdev) { + int err = 0; + /* We need to be able to take module references appropriately */ if (WARN_ON(is_module_address((unsigned long)ops) && !ops->owner)) return -EINVAL; + /* + * Temporarily enforce global restriction to a single driver. This was + * already the de-facto behaviour, since any possible combination of + * existing drivers would compete for at least the PCI or platform bus. + */ + if (iommu_buses[0]->iommu_ops && iommu_buses[0]->iommu_ops != ops) + return -EBUSY; iommu->ops = ops; if (hwdev) @@ -210,12 +227,22 @@ int iommu_device_register(struct iommu_device *iommu, spin_lock(&iommu_device_lock); list_add_tail(&iommu->list, &iommu_device_list); spin_unlock(&iommu_device_lock); - return 0; + + for (int i = 0; i < ARRAY_SIZE(iommu_buses) && !err; i++) { + iommu_buses[i]->iommu_ops = ops; + err = bus_iommu_probe(iommu_buses[i]); + } + if (err) + iommu_device_unregister(iommu); + return err; } EXPORT_SYMBOL_GPL(iommu_device_register); void iommu_device_unregister(struct iommu_device *iommu) { + for (int i = 0; i < ARRAY_SIZE(iommu_buses); i++) + bus_for_each_dev(iommu_buses[i], NULL, iommu, remove_iommu_group); + spin_lock(&iommu_device_lock); list_del(&iommu->list); spin_unlock(&iommu_device_lock); @@ -1644,13 +1671,6 @@ static int probe_iommu_group(struct device *dev, void *data) return ret; } -static int remove_iommu_group(struct device *dev, void *data) -{ - iommu_release_device(dev); - - return 0; -} - static int iommu_bus_notifier(struct notifier_block *nb, unsigned long action, void *data) { @@ -1822,27 +1842,12 @@ int bus_iommu_probe(struct bus_type *bus) */ int bus_set_iommu(struct bus_type *bus, const struct iommu_ops *ops) { - int err; - - if (ops == NULL) { - bus->iommu_ops = NULL; - return 0; - } - - if (bus->iommu_ops != NULL) + if (bus->iommu_ops && ops && bus->iommu_ops != ops) return -EBUSY; bus->iommu_ops = ops; - /* Do IOMMU specific setup for this bus-type */ - err = bus_iommu_probe(bus); - if (err) { - /* Clean up */ - bus_for_each_dev(bus, NULL, NULL, remove_iommu_group); - bus->iommu_ops = NULL; - } - - return err; + return 0; } EXPORT_SYMBOL_GPL(bus_set_iommu);