RE: [PATCH v1 09/16] iommufd/viommmu: Add IOMMUFD_CMD_VCMDQ_ALLOC ioctl

From: Nicolin Chen nicolinc@nvidia.com Sent: Friday, April 11, 2025 2:38 PM

+/**

• • enum iommu_vcmdq_type - Virtual Queue Type

"Virtual Command Queue Type"

• • @IOMMU_VCMDQ_TYPE_DEFAULT: Reserved for future use
• */

+enum iommu_vcmdq_data_type {

• IOMMU_VCMDQ_TYPE_DEFAULT = 0,

+};

+/**

• • struct iommu_vcmdq_alloc - ioctl(IOMMU_VCMDQ_ALLOC)
• • @size: sizeof(struct iommu_vcmdq_alloc)
• • @flags: Must be 0
• • @viommu_id: viommu ID to associate the virtual queue with
• • @type: One of enum iommu_vcmdq_type

s/ iommu_vcmdq_type/ iommu_vcmdq_data_type/

+int iommufd_vcmdq_alloc_ioctl(struct iommufd_ucmd *ucmd) +{

• struct iommu_vcmdq_alloc *cmd = ucmd->cmd;
• const struct iommu_user_data user_data = {

• .type = cmd->type,
  

• .uptr = u64_to_user_ptr(cmd->data_uptr),
  

• .len = cmd->data_len,
  

• };
• struct iommufd_vcmdq *vcmdq;
• struct iommufd_viommu *viommu;
• int rc;
• if (cmd->flags || cmd->type == IOMMU_VCMDQ_TYPE_DEFAULT)

• return -EOPNOTSUPP;
  

• if (!cmd->data_len)

• return -EINVAL;
  

• viommu = iommufd_get_viommu(ucmd, cmd->viommu_id);
• if (IS_ERR(viommu))

• return PTR_ERR(viommu);
  

• if (!viommu->ops || !viommu->ops->vcmdq_alloc) {

• rc = -EOPNOTSUPP;
  

• goto out_put_viommu;
  

• }
• vcmdq = viommu->ops->vcmdq_alloc(viommu,

• 			 user_data.len ? &user_data : NULL);
  

the length cannot be zero at this point due to earlier check.