[PATCH RFCv2 05/13] iommu: Turn fault_data to iommufd private pointer

[Tian, Kevin]

> From: Nicolin Chen <nicolinc at nvidia.com>
> Sent: Saturday, January 11, 2025 11:32 AM
> 
> @@ -224,8 +224,10 @@ struct iommu_domain {
>  		      phys_addr_t msi_addr);
>  #endif
> 
> -	void *fault_data;
> -	union {
> +	union { /* Pointer usable by owner of the domain */
> +		struct iommufd_hw_pagetable *iommufd_hwpt; /* iommufd
> */
> +	};
> +	union { /* Fault handler */

hmm is it better to rename it as "void *private;" and let the caller
do type conversion?