On 2021-02-12 14:54, Shameerali Kolothum Thodi wrote:
Hi Robin/Joerg,
-----Original Message-----
From: Shameer Kolothum [mailto:shameerali.kolothum.th...@huawei.com]
Sent: 01 February 2021 12:41
To: linux-kernel@vger.kernel.org; io...@lists.linux-foundation.org
Cc: j...@8bytes.org; robin.mur...@arm.com; jean-phili...@linaro.org;
w...@kernel.org; Zengtao (B) <prime.z...@hisilicon.com>;
linux...@openeuler.org
Subject: [Linuxarm] [PATCH v2] iommu: Check dev->iommu in iommu_dev_xxx
functions
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.
Also added iommu_ops to the "struct dev_iommu" and set it if the dev
is successfully associated with an iommu.
Fixes: a3a195929d40 ("iommu: Add APIs for multiple domains per device")
Signed-off-by: Shameer Kolothum <shameerali.kolothum.th...@huawei.com>
---
v1 --> v2:
-Added iommu_ops to struct dev_iommu based on the discussion with Robin.
-Rebased against iommu-tree core branch.
A gentle ping on this...
Is there a convincing justification for maintaining yet another copy of
the ops pointer rather than simply dereferencing iommu_dev->ops at point
of use?
Robin.
Thanks,
Shameer
---
drivers/iommu/iommu.c | 19 +++++++------------
include/linux/iommu.h | 2 ++
2 files changed, 9 insertions(+), 12 deletions(-)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index fd76e2f579fe..6023d0b7c542 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -217,6 +217,7 @@ static int __iommu_probe_device(struct device *dev,
struct list_head *group_list
}
dev->iommu->iommu_dev = iommu_dev;
+ dev->iommu->ops = iommu_dev->ops;
group = iommu_group_get_for_dev(dev);
if (IS_ERR(group)) {
@@ -2865,10 +2866,8 @@ 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 (ops && ops->dev_enable_feat)
- return ops->dev_enable_feat(dev, feat);
+ if (dev->iommu && dev->iommu->ops->dev_enable_feat)
+ return dev->iommu->ops->dev_enable_feat(dev, feat);
return -ENODEV;
}
@@ -2881,10 +2880,8 @@
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 (ops && ops->dev_disable_feat)
- return ops->dev_disable_feat(dev, feat);
+ if (dev->iommu && dev->iommu->ops->dev_disable_feat)
+ return dev->iommu->ops->dev_disable_feat(dev, feat);
return -EBUSY;
}
@@ -2892,10 +2889,8 @@
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 (ops && ops->dev_feat_enabled)
- return ops->dev_feat_enabled(dev, feat);
+ if (dev->iommu && dev->iommu->ops->dev_feat_enabled)
+ return dev->iommu->ops->dev_feat_enabled(dev, feat);
return false;
}
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 524ffc2ff64f..ff0c76bdfb67 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -354,6 +354,7 @@ struct iommu_fault_param {
* @fault_param: IOMMU detected device fault reporting data
* @fwspec: IOMMU fwspec data
* @iommu_dev: IOMMU device this device is linked to
+ * @ops: iommu-ops for talking to the iommu_dev
* @priv: IOMMU Driver private data
*
* TODO: migrate other per device data pointers under iommu_dev_data,
e.g.
@@ -364,6 +365,7 @@ struct dev_iommu {
struct iommu_fault_param *fault_param;
struct iommu_fwspec *fwspec;
struct iommu_device *iommu_dev;
+ const struct iommu_ops *ops;
void *priv;
};
--
2.17.1
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