On Thu, Oct 17, 2024 at 02:15:00PM -0300, Jason Gunthorpe wrote:
> On Wed, Oct 09, 2024 at 09:38:08AM -0700, Nicolin Chen wrote:
>
> > +static struct iommufd_viommu *
> > +mock_viommu_alloc(struct iommu_device *iommu_dev, struct iommu_domain *domain,
> > + struct iommufd_ctx *ictx, unsigned int viommu_type)
> > +{
> > + struct mock_iommu_device *mock_iommu =
> > + container_of(iommu_dev, struct mock_iommu_device, iommu_dev);
> > + struct mock_viommu *mock_viommu;
> > +
> > + if (viommu_type != IOMMU_VIOMMU_TYPE_SELFTEST)
> > + return ERR_PTR(-EOPNOTSUPP);
>
> What about the default viommu? What happens then?
IOMMU_VIOMMU_TYPE_DEFAULT is allocated by the core, it won't go
down to iommu_ops->viommu_alloc (this function).
> > + mock_viommu = iommufd_viommu_alloc(ictx, mock_viommu, core,
> > + &mock_viommu_ops);
> > + if (IS_ERR(mock_viommu))
> > + return ERR_CAST(mock_viommu);
> > +
> > + if (!refcount_inc_not_zero(&mock_iommu->users)) {
>
> It would be a bug if the iommu_dev being passed in was somehow
> released while iommufd had hold of it through vfio. So just use
> refcount_inc()
OK.
Thanks
Nicolin
