Re: [PATCH 1/1] iommu/vt-d: Fix RID2PASID setup failure

[Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>]

On 2022/6/21 10:54, Tian, Kevin wrote:
> > From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > Sent: Monday, June 20, 2022 4:17 PM
> > @@ -2564,7 +2564,7 @@ static int domain_add_dev_info(struct
> > dmar_domain *domain, struct device *dev)
> >   			ret = intel_pasid_setup_second_level(iommu,
> > domain,
> >   					dev, PASID_RID2PASID);
> >   		spin_unlock_irqrestore(&iommu->lock, flags);
> > -		if (ret) {
> > +		if (ret && ret != -EBUSY) {
> >   			dev_err(dev, "Setup RID2PASID failed\n");
> >   			dmar_remove_one_dev_info(dev);
> >   			return ret;
> > --
> > 2.25.1
>
> It's cleaner to avoid this error at the first place, i.e. only do the
> setup when the first device is attached to the pasid table.

The logic that identifies the first device might introduce additional
unnecessary complexity. Devices that share a pasid table are rare. I
even prefer to give up sharing tables so that the code can be
simpler.:-)

--
Best regards,
baolu