Re: [RFC v1 0/4] Make KHO Stateless

[Jason Gunthorpe <jgg@nvidia.com>]

On Tue, Sep 16, 2025 at 07:50:15PM -0700, Jason Miu wrote:
> This series transitions KHO from an xarray-based metadata tracking
> system with serialization to using page table like data structures
> that can be passed directly to the next kernel.
> 
> The key motivations for this change are to:
> - Eliminate the need for data serialization before kexec.
> - Remove the former KHO state machine by deprecating the finalize
>   and abort states.
> - Pass preservation metadata more directly to the next kernel via the FDT.
> 
> The new approach uses a per-order page table structure (kho_order_table,
> kho_page_table, kho_bitmap_table) to mark preserved pages. The physical
> address of the root `kho_order_table` is passed in the FDT, allowing the
> next kernel to reconstruct the preserved memory map.

It is not a "page table" structure, it is just a radix tree with bits
as the leaf.

Jason