Re: [PATCH v7 12/18] x86/kexec: add support for passing kexec handover (KHO) data

Dave Hansen
2025-05-02T18:39:06Z

On 5/1/25 15:54, Changyuan Lyu wrote:
> From: Alexander Graf <graf@amazon.com>
>
> kexec handover (KHO) creates a metadata that the kernels pass between each
> other during kexec. This metadata is stored in memory and kexec image
> contains a (physical) pointer to that memory.
>
> In addition, KHO keeps "scratch regions" available for kexec: physically
> contiguous memory regions that are guaranteed to not have any memory that
> KHO would preserve. The new kernel bootstraps itself using the scratch
> regions and sets all handed over memory as in use. When subsystems that
> support KHO initialize, they introspect the KHO metadata, restore preserved
> memory regions, and retrieve their state stored in the preserved memory.
>
> Enlighten x86 kexec-file and boot path about the KHO metadata and make sure
> it gets passed along to the next kernel.

Acked-by: Dave Hansen <dave.hansen@linux.intel.com>