Re: [PATCH RFC 06/11] iommu/sva: Use attach/detach_pasid_dev in SVA interfaces

[Lu Baolu]

On 2022/3/21 16:04, Tian, Kevin wrote:
> > From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > Sent: Sunday, March 20, 2022 2:40 PM
> > +struct iommu_sva *
> > +iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void
> > *drvdata)
> > +{
> > +	int ret = -EINVAL;
> > +	struct iommu_sva *handle;
> > +	struct iommu_domain *domain;
> > +
> > +	handle = kzalloc(sizeof(*handle), GFP_KERNEL);
> > +	if (!handle)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	ret = iommu_sva_alloc_pasid(mm, 1, (1U << dev->iommu->pasid_bits)
> > - 1);
> > +	if (ret)
> > +		goto out;
> > +
> > +	domain = iommu_sva_domain_alloc(dev);
> > +	if (!domain) {
> > +		ret = -ENOMEM;
> > +		goto out;
> > +	}
> > +	domain->sva_cookie = mm;
>
> one domain can be attached by multiple devices, so this should not be
> a blind alloc.

Indeed. Perhaps we could associate the SVA domain with the mm->pasid and
add a user counter inside the domain.

Best regards,
baolu