[RFC PATCH 01/11] iommupt: Add RISC-V Second-stage (iohgatp) page table support

[Jason Gunthorpe]

On Tue, Apr 28, 2026 at 09:13:49PM +0800, fangyu.yu at linux.alibaba.com wrote:
> @@ -263,6 +281,22 @@ riscvpt_iommu_fmt_init(struct pt_iommu_riscv_64 *iommu_table,
>  	case 57:
>  		pt_top_set_level(&table->common, 4);
>  		break;
> +	/*
> +	 * Second-stage (iohgatp): Sv39x4 / Sv48x4 / Sv57x4.
> +	 * The top level is the same as for the first-stage counterpart.
> +	 */
> +	case 41:
> +		pt_top_set_level(&table->common, 2);
> +		table->second_stage = true;
> +		break;

Second stage needs to be an explicit PT_FEAT not implicitly deduced
based on the vasz.

Jason