[PATCH v8 03/10] iommu: Add iommu_copy_struct_from_user_array helper

Yi Liu
2023-12-27T16:14:03Z

From: Nicolin Chen <nicolinc@nvidia.com>

Wrap up the data pointer/num sanity and __iommu_copy_struct_from_user
call for iommu drivers to copy driver specific data at a specific location
in the struct iommu_user_data_array, and iommu_respond_struct_to_user_array()
to copy response to a specific location in the struct iommu_user_data_array.

And expect it to be used in cache_invalidate_user ops for example.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Co-developed-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
include/linux/iommu.h | 74 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 74 insertions(+)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 93c0d12dd047..c3434c9eaa6d 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -341,6 +341,80 @@ static inline int __iommu_copy_struct_from_user(
sizeof(*kdst), \
offsetofend(typeof(*kdst), min_last))

+/**
+ * __iommu_copy_struct_from_user_array - Copy iommu driver specific user space
+ * data from an iommu_user_data_array
+ * @dst_data: Pointer to an iommu driver specific user data that is defined in
+ * include/uapi/linux/iommufd.h
+ * @src_array: Pointer to a struct iommu_user_data_array for a user space array
+ * @data_type: The data type of the @dst_data. Must match with @src_array.type
+ * @index: Index to the location in the array to copy user data from
+ * @data_len: Length of current user data structure, i.e. sizeof(struct _dst)
+ * @min_len: Initial length of user data structure for backward compatibility.
+ * This should be offsetofend using the last member in the user data
+ * struct that was initially added to include/uapi/linux/iommufd.h
+ */
+static inline int
+__iommu_copy_struct_from_user_array(void *dst_data,
+ const struct iommu_user_data_array *src_array,
+ unsigned int data_type, unsigned int index,
+ size_t data_len, size_t min_len)
+{
+ struct iommu_user_data src_data;
+
+ if (WARN_ON(!src_array || index >= src_array->entry_num))
+ return -EINVAL;
+ if (!src_array->entry_num)
+ return -EINVAL;
+ src_data.uptr = src_array->uptr + src_array->entry_len * index;
+ src_data.len = src_array->entry_len;
+ src_data.type = src_array->type;
+
+ return __iommu_copy_struct_from_user(dst_data, &src_data, data_type,
+ data_len, min_len);
+}
+
+/**
+ * iommu_copy_struct_from_user_array - Copy iommu driver specific user space
+ * data from an iommu_user_data_array
+ * @kdst: Pointer to an iommu driver specific user data that is defined in
+ * include/uapi/linux/iommufd.h
+ * @user_array: Pointer to a struct iommu_user_data_array for a user space
+ * array
+ * @data_type: The data type of the @kdst. Must match with @user_array->type
+ * @index: Index to the location in the array to copy user data from
+ * @min_last: The last memember of the data structure @kdst points in the
+ * initial version.
+ * Return 0 for success, otherwise -error.
+ */
+#define iommu_copy_struct_from_user_array(kdst, user_array, data_type, \
+ index, min_last) \
+ __iommu_copy_struct_from_user_array(kdst, user_array, data_type, \
+ index, sizeof(*kdst), \
+ offsetofend(typeof(*kdst), \
+ min_last))
+
+/**
+ * iommu_respond_struct_to_user_array - Copy the response in @ksrc back to
+ * a specific entry of user array
+ * @user_array: Pointer to a struct iommu_user_data_array for a user space
+ * array
+ * @index: Index to the location in the array to copy response
+ * @ksrc: Pointer to kernel structure
+ * @klen: Length of @ksrc struct
+ *
+ * This only copies response of one entry (@index) in @user_array.
+ */
+static inline int
+iommu_respond_struct_to_user_array(const struct iommu_user_data_array *array,
+ unsigned int index, void *ksrc, size_t klen)
+{
+ if (copy_to_user(array->uptr + array->entry_len * index,
+ ksrc, min_t(size_t, array->entry_len, klen)))
+ return -EFAULT;
+ return 0;
+}
+
/**
* struct iommu_ops - iommu ops and capabilities
* @capable: check capability
--
2.34.1