1 files changed, 31 insertions, 0 deletions
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index a712b0cc3a1d..7890bd21dff6 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -3486,3 +3486,34 @@ void iommu_free_global_pasid(ioasid_t pasid)
 	ida_free(&iommu_global_pasid_ida, pasid);
 }
 EXPORT_SYMBOL_GPL(iommu_free_global_pasid);
+
+/**
+ * iommu_attach_handle_get - Return the attach handle
+ * @group: the iommu group that domain was attached to
+ * @pasid: the pasid within the group
+ * @type: matched domain type, 0 for any match
+ *
+ * Return handle or ERR_PTR(-ENOENT) on none, ERR_PTR(-EBUSY) on mismatch.
+ *
+ * Return the attach handle to the caller. The life cycle of an iommu attach
+ * handle is from the time when the domain is attached to the time when the
+ * domain is detached. Callers are required to synchronize the call of
+ * iommu_attach_handle_get() with domain attachment and detachment. The attach
+ * handle can only be used during its life cycle.
+ */
+struct iommu_attach_handle *
+iommu_attach_handle_get(struct iommu_group *group, ioasid_t pasid, unsigned int type)
+{
+	struct iommu_attach_handle *handle;
+
+	xa_lock(&group->pasid_array);
+	handle = xa_load(&group->pasid_array, pasid);
+	if (!handle)
+		handle = ERR_PTR(-ENOENT);
+	else if (type && handle->domain->type != type)
+		handle = ERR_PTR(-EBUSY);
+	xa_unlock(&group->pasid_array);
+
+	return handle;
+}
+EXPORT_SYMBOL_NS_GPL(iommu_attach_handle_get, IOMMUFD_INTERNAL);