Commit 2a918911 authored by Guixin Liu's avatar Guixin Liu Committed by Jason Gunthorpe
Browse files

iommufd: Register iommufd mock devices with fwspec 

Since the bus ops were retired the iommu subsystem changed to using fwspec
to match the iommu driver to the iommu device. If a device has a NULL
fwspec then it is matched to the first iommu driver with a NULL fwspec,
effectively disabling support for systems with more than one non-fwspec
iommu driver.

Thus, if the iommufd selfest are run in an x86 system that registers a
non-fwspec iommu driver they fail to bind their mock devices to the mock
iommu driver.

Fix this by allocating a software fwnode for mock iommu driver's
iommu_device, and set it to the device which mock iommu driver created.

This is done by adding a new helper iommu_mock_device_add() which abuses
the internals of the fwspec system to establish a fwspec before the device
is added and is careful not to leak it. A matching dummy fwspec is
automatically added to the mock iommu driver.

Test by "make -C toosl/testing/selftests TARGETS=iommu run_tests":
PASSED: 229 / 229 tests passed.

In addition, this issue is also can be found on amd platform, and
also tested on a amd machine.

Link: https://patch.msgid.link/r/20250925054730.3877-1-kanie@linux.alibaba.com


Fixes: 17de3f5f ("iommu: Retire bus ops")
Signed-off-by: default avatarGuixin Liu <kanie@linux.alibaba.com>
Reviewed-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Tested-by: default avatarQinyun Tan <qinyuntan@linux.alibaba.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 1d235d84

drivers/iommu/iommu-priv.h

+2 −0
Original line number Diff line number Diff line
@@ -37,6 +37,8 @@ void iommu_device_unregister_bus(struct iommu_device *iommu, 
				 const struct bus_type *bus,

				 struct notifier_block *nb);



int iommu_mock_device_add(struct device *dev, struct iommu_device *iommu);



struct iommu_attach_handle *iommu_attach_handle_get(struct iommu_group *group,

						    ioasid_t pasid,

						    unsigned int type);

drivers/iommu/iommu.c

+26 −0
Original line number Diff line number Diff line
@@ -304,6 +304,7 @@ void iommu_device_unregister_bus(struct iommu_device *iommu, 
				 struct notifier_block *nb)

{

	bus_unregister_notifier(bus, nb);

	fwnode_remove_software_node(iommu->fwnode);

	iommu_device_unregister(iommu);

}

EXPORT_SYMBOL_GPL(iommu_device_unregister_bus);
@@ -326,6 +327,12 @@ int iommu_device_register_bus(struct iommu_device *iommu, 
	if (err)

		return err;



	iommu->fwnode = fwnode_create_software_node(NULL, NULL);

	if (IS_ERR(iommu->fwnode)) {

		bus_unregister_notifier(bus, nb);

		return PTR_ERR(iommu->fwnode);

	}



	spin_lock(&iommu_device_lock);

	list_add_tail(&iommu->list, &iommu_device_list);

	spin_unlock(&iommu_device_lock);
@@ -335,9 +342,28 @@ int iommu_device_register_bus(struct iommu_device *iommu, 
		iommu_device_unregister_bus(iommu, bus, nb);

		return err;

	}

	WRITE_ONCE(iommu->ready, true);

	return 0;

}

EXPORT_SYMBOL_GPL(iommu_device_register_bus);



int iommu_mock_device_add(struct device *dev, struct iommu_device *iommu)

{

	int rc;



	mutex_lock(&iommu_probe_device_lock);

	rc = iommu_fwspec_init(dev, iommu->fwnode);

	mutex_unlock(&iommu_probe_device_lock);



	if (rc)

		return rc;



	rc = device_add(dev);

	if (rc)

		iommu_fwspec_free(dev);

	return rc;

}

EXPORT_SYMBOL_GPL(iommu_mock_device_add);

#endif



static struct dev_iommu *dev_iommu_get(struct device *dev)

drivers/iommu/iommufd/selftest.c

+1 −1
Original line number Diff line number Diff line
@@ -1126,7 +1126,7 @@ static struct mock_dev *mock_dev_create(unsigned long dev_flags) 
		goto err_put;

	}



	rc = device_add(&mdev->dev);

	rc = iommu_mock_device_add(&mdev->dev, &mock_iommu.iommu_dev);

	if (rc)

		goto err_put;

	return mdev;