Subject: [PATCH v3] 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.

Fixes: a3a195929d40 ("iommu: Add APIs for multiple domains per device")
Signed-off-by: Shameer Kolothum <[email protected]>
---
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;
}
--
2.17.1


2021-03-09 12:54:46

by Robin Murphy

[permalink] [raw]
Subject: Re: [PATCH v3] iommu: Check dev->iommu in iommu_dev_xxx functions

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 <[email protected]>

> Fixes: a3a195929d40 ("iommu: Add APIs for multiple domains per device")
> Signed-off-by: Shameer Kolothum <[email protected]>
> ---
> 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;
> }
>

2021-03-18 09:50:25

by Joerg Roedel

[permalink] [raw]
Subject: Re: [PATCH v3] iommu: Check dev->iommu in iommu_dev_xxx functions

On Wed, Mar 03, 2021 at 05:36:11PM +0000, 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.
>
> Fixes:?a3a195929d40 ("iommu: Add APIs for multiple domains per device")
> Signed-off-by: Shameer Kolothum <[email protected]>
> ---
> 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(-)

Applied, thanks.