On 2021-03-03 17:36, Shameer Kolothum wrote:

The device iommu probe/attach might have failed leaving dev->iommu to NULL and device drivers may still invoke these functions resulting in a crash in iommu vendor driver code.

Hence make sure we check that.

Reviewed-by: Robin Murphy <robin.murphy@arm.com>

Fixes: a3a195929d40 ("iommu: Add APIs for multiple domains per device") Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> --- v2 --> v3 -Removed iommu_ops from struct dev_iommu. v1 --> v2: -Added iommu_ops to struct dev_iommu based on the discussion with Robin. -Rebased against iommu-tree core branch. --- drivers/iommu/iommu.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index d0b0a15dba84..e10cfa99057c 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -2878,10 +2878,12 @@ EXPORT_SYMBOL_GPL(iommu_fwspec_add_ids); */ int iommu_dev_enable_feature(struct device *dev, enum iommu_dev_features feat) { - const struct iommu_ops *ops = dev->bus->iommu_ops; + if (dev->iommu && dev->iommu->iommu_dev) { + const struct iommu_ops *ops = dev->iommu->iommu_dev->ops;

- if (ops && ops->dev_enable_feat) - return ops->dev_enable_feat(dev, feat); + if (ops->dev_enable_feat) + return ops->dev_enable_feat(dev, feat); + }

return -ENODEV; } @@ -2894,10 +2896,12 @@ EXPORT_SYMBOL_GPL(iommu_dev_enable_feature); */ int iommu_dev_disable_feature(struct device *dev, enum iommu_dev_features feat) { - const struct iommu_ops *ops = dev->bus->iommu_ops; + if (dev->iommu && dev->iommu->iommu_dev) { + const struct iommu_ops *ops = dev->iommu->iommu_dev->ops;

- if (ops && ops->dev_disable_feat) - return ops->dev_disable_feat(dev, feat); + if (ops->dev_disable_feat) + return ops->dev_disable_feat(dev, feat); + }

return -EBUSY; } @@ -2905,10 +2909,12 @@ EXPORT_SYMBOL_GPL(iommu_dev_disable_feature);

bool iommu_dev_feature_enabled(struct device *dev, enum iommu_dev_features feat) { - const struct iommu_ops *ops = dev->bus->iommu_ops; + if (dev->iommu && dev->iommu->iommu_dev) { + const struct iommu_ops *ops = dev->iommu->iommu_dev->ops;

- if (ops && ops->dev_feat_enabled) - return ops->dev_feat_enabled(dev, feat); + if (ops->dev_feat_enabled) + return ops->dev_feat_enabled(dev, feat); + }

return false; }