Re: [PATCH v7 3/4] iommufd: Add IOMMU_GET_HW_INFO

[Jason Gunthorpe]

On Fri, Aug 11, 2023 at 12:15:00AM -0700, Yi Liu wrote:

> +static int iommufd_get_hw_info(struct iommufd_ucmd *ucmd)
> +{
> +	struct iommu_hw_info *cmd = ucmd->cmd;
> +	unsigned int length = cmd->data_len;
> +	struct iommufd_device *idev;
> +	void __user *user_ptr;
> +	u32 hw_info_type;
> +	int rc = 0;
> +
> +	if (cmd->flags || cmd->__reserved || !cmd->data_len)
> +		return -EOPNOTSUPP;

Is there a reason to block 0 data_len? I think this should work. The
code looks OK?

Jason