6.17-stable review patch. If anyone has any objections, please let me know.
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From: Guixin Liu kanie@linux.alibaba.com
[ Upstream commit 2a918911ed3d0841923525ed0fe707762ee78844 ]
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: 17de3f5fdd35 ("iommu: Retire bus ops") Signed-off-by: Guixin Liu kanie@linux.alibaba.com Reviewed-by: Lu Baolu baolu.lu@linux.intel.com Tested-by: Qinyun Tan qinyuntan@linux.alibaba.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/iommu-priv.h | 2 ++ drivers/iommu/iommu.c | 26 ++++++++++++++++++++++++++ drivers/iommu/iommufd/selftest.c | 2 +- 3 files changed, 29 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/iommu-priv.h b/drivers/iommu/iommu-priv.h index e236b932e7668..c95394cd03a77 100644 --- a/drivers/iommu/iommu-priv.h +++ b/drivers/iommu/iommu-priv.h @@ -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); diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 060ebe330ee16..59244c744eabd 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -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) diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c index 61686603c7693..de178827a078a 100644 --- a/drivers/iommu/iommufd/selftest.c +++ b/drivers/iommu/iommufd/selftest.c @@ -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;