RE: [PATCH 12/14] iommufd: Add IOMMU_HWPT_ALLOC

From: Jason Gunthorpe jgg@nvidia.com Sent: Saturday, February 25, 2023 8:28 AM

+int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd) +{

• struct iommu_hwpt_alloc *cmd = ucmd->cmd;
• struct iommufd_hw_pagetable *hwpt;
• struct iommufd_device *idev;
• struct iommufd_ioas *ioas;
• int rc;
• if (cmd->flags)

• return -EOPNOTSUPP;
  

miss a check on the __reserved field.

+/**

• • struct iommu_hwpt_alloc - ioctl(IOMMU_HWPT_ALLOC)
• • @size: sizeof(struct iommu_hwpt_alloc)
• • @flags: Must be 0
• • @dev_id: The device to allocate this HWPT for
• • @pt_id: The IOAS to connect this HWPT to
• • @out_hwpt_id: The ID of the new HWPT
• • @__reserved: Must be 0
• • Explicitly allocate a hardware page table object. This is the same object
• • type that is returned by iommufd_device_attach() and represents the
• • underlying iommu driver's iommu_domain kernel object.
• • A normal HWPT will be created with the mappings from the given IOAS.
• */

'normal' is a confusing word in this context.