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Date: Wed, 11 Oct 2023 19:14:53 +0100
From: Robin Murphy <robin.murphy@....com>
To: joro@...tes.org, will@...nel.org
Cc: iommu@...ts.linux.dev, jgg@...dia.com, baolu.lu@...ux.intel.com,
linux-kernel@...r.kernel.org,
"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
Christoph Hellwig <hch@....de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH v5 6/7] iommu: Retire bus ops
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 <rafael.j.wysocki@...el.com>
Acked-by: Christoph Hellwig <hch@....de>
Acked-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Reviewed-by: Lu Baolu <baolu.lu@...ux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@...dia.com>
Signed-off-by: Robin Murphy <robin.murphy@....com>
---
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 18667dc2ff86..6962f2c99428 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -148,7 +148,7 @@ struct iommu_group_attribute iommu_group_attr_##_name = \
static LIST_HEAD(iommu_device_list);
static DEFINE_SPINLOCK(iommu_device_lock);
-static struct bus_type * const iommu_buses[] = {
+static const struct bus_type * const iommu_buses[] = {
&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 != ops)
- return -EBUSY;
iommu->ops = 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);
- for (int i = 0; i < ARRAY_SIZE(iommu_buses) && !err; i++) {
- iommu_buses[i]->iommu_ops = ops;
+ for (int i = 0; i < ARRAY_SIZE(iommu_buses) && !err; i++)
err = 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 *iommu,
list_add_tail(&iommu->list, &iommu_device_list);
spin_unlock(&iommu_device_lock);
- bus->iommu_ops = ops;
err = 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)
static int __iommu_probe_device(struct device *dev, struct list_head *group_list)
{
- const struct iommu_ops *ops = 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;
+ /*
+ * 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 = dev_iommu_fwspec_get(dev);
+ if (fwspec && fwspec->ops)
+ ops = fwspec->ops;
+ else
+ ops = iommu_ops_from_fwnode(NULL);
+
if (!ops)
return -ENODEV;
/*
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 254685085c82..13d959b3ba29 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -623,6 +623,8 @@ struct acpi_pci_root {
/* helper */
+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 56d93a1ffb7b..b78e66f3b34a 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 IOMMU
- * 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 {
const struct dev_pm_ops *pm;
- const struct iommu_ops *iommu_ops;
-
bool need_parent_lock;
};
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 <linux/slab.h>
struct cma;
+struct iommu_ops;
/*
* Values for struct dma_map_ops.flags:
--
2.39.2.101.g768bb238c484.dirty
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