On Wed, Feb 26, 2020 at 11:39:59AM -0800, Jacob Pan wrote:

quoted

@@ -442,11 +444,20 @@ static void iommu_sva_unbind_locked(struct

iommu_bond *bond) 
 void iommu_sva_unbind_generic(struct iommu_sva *handle)
 {
+	int pasid;
 	struct iommu_param *param = handle->dev->iommu_param;
 
 	if (WARN_ON(!param))
 		return;
 
+	/*
+	 * Caller stopped the device from issuing PASIDs, now make
sure they are
+	 * out of the fault queue.
+	 */
+	pasid = iommu_sva_get_pasid_generic(handle);
+	if (pasid != IOMMU_PASID_INVALID)
+		iopf_queue_flush_dev(handle->dev, pasid);
+

I have an ordering concern.
The caller can only stop the device issuing page request but there will
be in-flight request inside the IOMMU. If we flush here before clearing
the PASID context, there might be new request coming in before the
detach.

The goal of this flush is also to clear the IOMMU PRI queue. It calls the
IOMMU's flush() callback before flushing the workqueue. So when this
returns, there shouldn't be any more pending fault.

Thanks,
Jean

How about detach first then flush? Then anything come after the detach
would be faults. Flush will be clean.

quoted

 	mutex_lock(&param->sva_lock);
 	mutex_lock(&iommu_sva_lock);
 	iommu_sva_unbind_locked(to_iommu_bond(handle));

@@ -484,6 +495,10 @@ int iommu_sva_enable(struct device *dev, struct

iommu_sva_param *sva_param) goto err_unlock;
 	}
 
+	ret = iommu_register_device_fault_handler(dev,
iommu_queue_iopf, dev);
+	if (ret)
+		goto err_unlock;
+
 	dev->iommu_param->sva_param = new_param;
 	mutex_unlock(&param->sva_lock);
 	return 0;

@@ -521,6 +536,7 @@ int iommu_sva_disable(struct device *dev)
 		goto out_unlock;
 	}
 
+	iommu_unregister_device_fault_handler(dev);
 	kfree(param->sva_param);
 	param->sva_param = NULL;
 out_unlock:

[Jacob Pan]

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