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

[Tian, Kevin]

> From: Nicolin Chen <nicolinc at 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.