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

[Baolu Lu]

On 2023/7/13 15:49, Tian, Kevin wrote:
> > From: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> > 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