Re: [PATCH v10 5/7] iommu/vt-d: Make prq draining code generic

[Baolu Lu <baolu.lu@linux.intel.com>]

On 2023/7/13 15:49, Tian, Kevin wrote:
>> From: Jacob Pan <jacob.jun.pan@linux.intel.com>
>> Sent: Thursday, July 13, 2023 12:34 AM
>>
>> -	/* Domain type specific cleanup: */
>>   	domain = iommu_get_domain_for_dev_pasid(dev, pasid, 0);
>> -	if (domain) {
>> -		switch (domain->type) {
>> -		case IOMMU_DOMAIN_SVA:
>> -			intel_svm_remove_dev_pasid(dev, pasid);
>> -			break;
>> -		default:
>> -			/* should never reach here */
>> -			WARN_ON(1);
>> -			break;
>> -		}
>> +	if (!domain)
>> +		goto out_tear_down;
> 
> WARN_ON()

Why?

My understanding is that remve_device_pasid could be call in any context
including no domain attached.

> 
>>   		 * large and has to be physically contiguous. So it's
>>   		 * hard to be as defensive as we might like.
>>   		 */
>> -		intel_pasid_tear_down_entry(iommu, dev, svm->pasid,
>> false);
>> -		intel_svm_drain_prq(dev, svm->pasid);
> 
> after removing the 2 lines the comment above becomes stale.

Yes.

> 
>> -static void intel_svm_drain_prq(struct device *dev, u32 pasid)
>> +void intel_drain_pasid_prq(struct device *dev, u32 pasid)
>>   {
>>   	struct device_domain_info *info;
>>   	struct dmar_domain *domain;
> 
> later we should move generic prq handling logic out of svm.c into
> a new prq.c

Yes.

Best regards,
baolu