RE: [PATCH v10 04/12] iommu: Add attach/detach_dev_pasid iommu interface

[Tian, Kevin]

> From: Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>
> Sent: Sunday, July 24, 2022 5:14 PM
> 
> On 2022/7/23 22:11, Jason Gunthorpe wrote:
> >> +void iommu_detach_device_pasid(struct iommu_domain *domain,
> struct device *dev,
> >> +			       ioasid_t pasid)
> >> +{
> >> +	struct iommu_group *group = iommu_group_get(dev);
> >> +
> >> +	mutex_lock(&group->mutex);
> >> +	domain->ops->block_dev_pasid(domain, dev, pasid);
> > I still really this OP, it is nonsense to invoke 'block_dev_pasid' on
> > a domain, it should be on the iommu ops and it should not take in a
> > domain parameter. This is why I prefer we write it as
> >
> > domain->ops->set_dev_pasid(group->blocking_domain, dev, pasid);
> >
> 
> I originally plan to refactor this after both Intel and ARM SMMUv3
> drivers have real blocking domain supports. After revisiting this, it
> seems that the only difficulty is how to check whether a domain is a
> blocking domain. I am going to use below checking code:
> 
> +	/*
> +	 * Detach the domain if a blocking domain is set. Check the
> +	 * right domain type once the IOMMU driver supports a real
> +	 * blocking domain.
> +	 */
> +	if (!domain || domain->type == IOMMU_DOMAIN_UNMANAGED) {
> 
> Does this work for you?
> 

Or you can call __iommu_group_alloc_blocking_domain() in the sva
path and then just check whether the domain is equal to
group->blocking_domain here.