Re: [PATCH v3 08/11] iommufd/selftest: Add IOMMU_VIOMMU_TYPE_SELFTEST

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?

• 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()

Jason