RE: [PATCH v2 04/11] iommufd: Pass parent hwpt and user_data to iommufd_hw_pagetable_alloc()

Tian, Kevin
2023-05-19T09:06:31Z

> From: Liu, Yi L <yi.l.liu@intel.com>
> Sent: Thursday, May 11, 2023 10:39 PM
> @@ -61,6 +63,8 @@ int iommufd_hw_pagetable_enforce_cc(struct
> iommufd_hw_pagetable *hwpt)
> * @ictx: iommufd context
> * @ioas: IOAS to associate the domain with
> * @idev: Device to get an iommu_domain for
> + * @parent: Optional parent HWPT to associate with the domain with

remove the trailing "the domain with"

> @@ -73,14 +77,22 @@ int iommufd_hw_pagetable_enforce_cc(struct
> iommufd_hw_pagetable *hwpt)
> */
> struct iommufd_hw_pagetable *
> iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct
> iommufd_ioas *ioas,
> - struct iommufd_device *idev, bool
> immediate_attach)
> + struct iommufd_device *idev,
> + struct iommufd_hw_pagetable *parent,
> + union iommu_domain_user_data *user_data,
> + bool immediate_attach)
> {
> const struct iommu_ops *ops = dev_iommu_ops(idev->dev);
> + struct iommu_domain *parent_domain = NULL;
> struct iommufd_hw_pagetable *hwpt;
> + bool type_unmanaged, type_nested;
> int rc;
>
> lockdep_assert_held(&ioas->mutex);
>
> + if ((user_data || parent) && !ops->domain_alloc_user)
> + return ERR_PTR(-EOPNOTSUPP);

Do we allow specifying parent w/o user_data?

> @@ -99,6 +117,15 @@ iommufd_hw_pagetable_alloc(struct iommufd_ctx
> *ictx, struct iommufd_ioas *ioas,
> goto out_abort;
> }
>
> + /* It must be either NESTED or UNMANAGED, depending on
> parent_domain */
> + type_nested = hwpt->domain->type == IOMMU_DOMAIN_NESTED;
> + type_unmanaged = hwpt->domain->type ==
> IOMMU_DOMAIN_UNMANAGED;

no need of one-time used variables. Just put the conditions directly
in WARN_ON.

> + if (WARN_ON((parent_domain && !type_nested) ||
> + (!parent_domain && !type_unmanaged))) {
> + rc = -EINVAL;
> + goto out_abort;
> + }
> +

probably just WARN_ON_ONCE() to mark that driver has problem?