From nobody Thu Dec 18 07:20:56 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5EEDFC61D85 for ; Tue, 21 Nov 2023 18:05:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234531AbjKUSFn (ORCPT ); Tue, 21 Nov 2023 13:05:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234432AbjKUSFH (ORCPT ); Tue, 21 Nov 2023 13:05:07 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B9C161990 for ; Tue, 21 Nov 2023 10:04:39 -0800 (PST) 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 0C8361BB0; Tue, 21 Nov 2023 10:05:09 -0800 (PST) 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 E6CE33F6C4; Tue, 21 Nov 2023 10:04:20 -0800 (PST) From: Robin Murphy To: joro@8bytes.org, will@kernel.org Cc: iommu@lists.linux.dev, jgg@nvidia.com, baolu.lu@linux.intel.com, linux-kernel@vger.kernel.org, jsnitsel@redhat.com, "Rafael J . Wysocki" , Christoph Hellwig , Greg Kroah-Hartman Subject: [PATCH v6 6/7] iommu: Retire bus ops Date: Tue, 21 Nov 2023 18:04:02 +0000 Message-Id: X-Mailer: git-send-email 2.39.2.101.g768bb238c484.dirty In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" With the rest of the API internals converted, it's time to finally tackle probe_device and how we bootstrap the per-device ops association to begin with. This ends up being disappointingly straightforward, since fwspec users are already doing it in order to find their of_xlate callback, and it works out that we can easily do the equivalent for other drivers too. Then shuffle the remaining awareness of iommu_ops into the couple of core headers that still need it, and breathe a sigh of relief. Ding dong the bus ops are gone! CC: Rafael J. Wysocki Acked-by: Christoph Hellwig Acked-by: Greg Kroah-Hartman Reviewed-by: Lu Baolu Reviewed-by: Jason Gunthorpe Reviewed-by: Jerry Snitselaar Signed-off-by: Robin Murphy --- v4: Don't forget new reference in iommu_device_register_bus() --- drivers/iommu/iommu.c | 31 ++++++++++++++++++------------- include/acpi/acpi_bus.h | 2 ++ include/linux/device.h | 1 - include/linux/device/bus.h | 5 ----- include/linux/dma-map-ops.h | 1 + 5 files changed, 21 insertions(+), 19 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 88aeae0acd9b..254f42b4220b 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -148,7 +148,7 @@ struct iommu_group_attribute iommu_group_attr_##_name = =3D \ static LIST_HEAD(iommu_device_list); static DEFINE_SPINLOCK(iommu_device_lock); =20 -static struct bus_type * const iommu_buses[] =3D { +static const struct bus_type * const iommu_buses[] =3D { &platform_bus_type, #ifdef CONFIG_PCI &pci_bus_type, @@ -257,13 +257,6 @@ int iommu_device_register(struct iommu_device *iommu, /* 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 !=3D ops) - return -EBUSY; =20 iommu->ops =3D ops; if (hwdev) @@ -273,10 +266,8 @@ int iommu_device_register(struct iommu_device *iommu, list_add_tail(&iommu->list, &iommu_device_list); spin_unlock(&iommu_device_lock); =20 - for (int i =3D 0; i < ARRAY_SIZE(iommu_buses) && !err; i++) { - iommu_buses[i]->iommu_ops =3D ops; + for (int i =3D 0; i < ARRAY_SIZE(iommu_buses) && !err; i++) err =3D bus_iommu_probe(iommu_buses[i]); - } if (err) iommu_device_unregister(iommu); return err; @@ -329,7 +320,6 @@ int iommu_device_register_bus(struct iommu_device *iomm= u, list_add_tail(&iommu->list, &iommu_device_list); spin_unlock(&iommu_device_lock); =20 - bus->iommu_ops =3D ops; err =3D bus_iommu_probe(bus); if (err) { iommu_device_unregister_bus(iommu, bus, nb); @@ -496,12 +486,27 @@ static void iommu_deinit_device(struct device *dev) =20 static int __iommu_probe_device(struct device *dev, struct list_head *grou= p_list) { - const struct iommu_ops *ops =3D dev->bus->iommu_ops; + const struct iommu_ops *ops; + struct iommu_fwspec *fwspec; struct iommu_group *group; static DEFINE_MUTEX(iommu_probe_device_lock); struct group_device *gdev; int ret; =20 + /* + * For FDT-based systems and ACPI IORT/VIOT, drivers register IOMMU + * instances with non-NULL fwnodes, and client devices should have been + * identified with a fwspec by this point. Otherwise, we can currently + * assume that only one of Intel, AMD, s390, PAMU or legacy SMMUv2 can + * be present, and that any of their registered instances has suitable + * ops for probing, and thus cheekily co-opt the same mechanism. + */ + fwspec =3D dev_iommu_fwspec_get(dev); + if (fwspec && fwspec->ops) + ops =3D fwspec->ops; + else + ops =3D iommu_ops_from_fwnode(NULL); + if (!ops) return -ENODEV; /* diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h index afeed6e72049..383efddb4a67 100644 --- a/include/acpi/acpi_bus.h +++ b/include/acpi/acpi_bus.h @@ -626,6 +626,8 @@ struct acpi_pci_root { =20 /* helper */ =20 +struct iommu_ops; + bool acpi_dma_supported(const struct acpi_device *adev); enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev); int acpi_iommu_fwspec_init(struct device *dev, u32 id, diff --git a/include/linux/device.h b/include/linux/device.h index d7a72a8749ea..0314dbbdb534 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -42,7 +42,6 @@ struct class; struct subsys_private; struct device_node; struct fwnode_handle; -struct iommu_ops; struct iommu_group; struct dev_pin_info; struct dev_iommu; diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h index ae10c4322754..e25aab08f873 100644 --- a/include/linux/device/bus.h +++ b/include/linux/device/bus.h @@ -62,9 +62,6 @@ struct fwnode_handle; * this bus. * @pm: Power management operations of this bus, callback the specific * device driver's pm-ops. - * @iommu_ops: IOMMU specific operations for this bus, used to attach IOM= MU - * driver implementations to a bus and allow the driver to do - * bus-specific setup * @need_parent_lock: When probing or removing a device on this bus, the * device core should lock the device's parent. * @@ -104,8 +101,6 @@ struct bus_type { =20 const struct dev_pm_ops *pm; =20 - const struct iommu_ops *iommu_ops; - bool need_parent_lock; }; =20 diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h index f2fc203fb8a1..a52e508d1869 100644 --- a/include/linux/dma-map-ops.h +++ b/include/linux/dma-map-ops.h @@ -11,6 +11,7 @@ #include =20 struct cma; +struct iommu_ops; =20 /* * Values for struct dma_map_ops.flags: --=20 2.39.2.101.g768bb238c484.dirty