[PATCH v2 06/40] iommu/sva: Search mm by PASID

Jean-Philippe Brucker
2018-05-11T19:06:07Z

The fault handler will need to find an mm given its PASID. This is the
reason we have an IDR for storing address spaces, so hook it up.

Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker-5wv7dgnIgG8@public.gmane.org>
---
drivers/iommu/iommu-sva.c | 26 ++++++++++++++++++++++++++
include/linux/iommu.h | 6 ++++++
2 files changed, 32 insertions(+)

diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
index e9afae2537a2..5abe0f0b445c 100644
--- a/drivers/iommu/iommu-sva.c
+++ b/drivers/iommu/iommu-sva.c
@@ -736,3 +736,29 @@ void __iommu_sva_unbind_dev_all(struct device *dev)
}
}
EXPORT_SYMBOL_GPL(__iommu_sva_unbind_dev_all);
+
+/**
+ * iommu_sva_find() - Find mm associated to the given PASID
+ * @pasid: Process Address Space ID assigned to the mm
+ *
+ * Returns the mm corresponding to this PASID, or NULL if not found. A reference
+ * to the mm is taken, and must be released with mmput().
+ */
+struct mm_struct *iommu_sva_find(int pasid)
+{
+ struct io_mm *io_mm;
+ struct mm_struct *mm = NULL;
+
+ spin_lock(&iommu_sva_lock);
+ io_mm = idr_find(&iommu_pasid_idr, pasid);
+ if (io_mm && io_mm_get_locked(io_mm)) {
+ if (mmget_not_zero(io_mm->mm))
+ mm = io_mm->mm;
+
+ io_mm_put_locked(io_mm);
+ }
+ spin_unlock(&iommu_sva_lock);
+
+ return mm;
+}
+EXPORT_SYMBOL_GPL(iommu_sva_find);
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index caa6f79785b9..faf3390ce89d 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -1001,6 +1001,7 @@ extern int __iommu_sva_bind_device(struct device *dev, struct mm_struct *mm,
extern int __iommu_sva_unbind_device(struct device *dev, int pasid);
extern void __iommu_sva_unbind_dev_all(struct device *dev);

+extern struct mm_struct *iommu_sva_find(int pasid);
#else /* CONFIG_IOMMU_SVA */
static inline int iommu_sva_device_init(struct device *dev,
unsigned long features,
@@ -1030,6 +1031,11 @@ static inline int __iommu_sva_unbind_device(struct device *dev, int pasid)
static inline void __iommu_sva_unbind_dev_all(struct device *dev)
{
}
+
+static inline struct mm_struct *iommu_sva_find(int pasid)
+{
+ return NULL;
+}
#endif /* CONFIG_IOMMU_SVA */

#endif /* __LINUX_IOMMU_H */
--
2.17.0