On Mon, Nov 01, 2021 at 04:11:42PM -0500, Eric W. Biederman wrote:

I seem to remember the consensus when this was reviewed that it was
unnecessary and there is already support for doing something like
this at a more fine grained level so we don't need a new kexec hook.

Well, the executive summary is that you have a guest whose memory *and*
registers are encrypted so the hypervisor cannot have a poke inside and
reset the vCPU like it would normally do. So you need to do that dance
differently, i.e, the patchset.

If you try to kexec such a guest now, it'll init only the BSP, as Joerg
said. So I guess a single-threaded kdump.

And yes, one of the prominent use cases is kdumping from such a guest,
as distros love doing kdump for debugging.

I hope that explains it better.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette