iommu: Allow the thread binding device

hulk inclusion
category: feature
bugzilla: 14369
CVE: NA
-------------------

iommu pasid bond to device
Signed-off-by: NJiankang Chen <chenjiankang1@huawei.com>
Signed-off-by: NFang Lijun <fanglijun3@huawei.com>
Reviewed-by: NHanjun Guo <guohanjun@huawei.com>
Reviewed-by: NZhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/iommu/iommu-sva.c

@@ -679,9 +679,10 @@ int __iommu_sva_bind_device(struct device *dev, struct mm_struct *mm,
 	}
 	spin_unlock(&iommu_sva_lock);
 
-	if (bond)
-		return -EEXIST;
-
+	if (bond) {
+		*pasid = bond->io_mm->pasid;
+		return ret;
+	}
 	/* Require identical features within an io_mm for now */
 	if (io_mm && (flags != io_mm->flags)) {
 		io_mm_put(io_mm);