[syslinux] Warm boot ISO image from Linux

[Curt Brune]

Greetings!

First big thanks to the Syslinux community.  My project, the Open
Network Install Environment (ONIE), is using isolinux to great
effect.  Works great.

I have a crazy idea I want to bounce off of you folks.

Idea: I want to "warm boot" an ISO image from Linux.

By "warm boot" I mean start executing the code (isolinux) from the
ISO without rebooting and going through the BIOS.

This is "somewhat" like kexec, but instead of jumping into a new Linux
kernel it would be jumping into whatever code the ISO image has.

Imagine a user space command "iso-kexec" existed for this purpose and
a work flow like this:

  linux:$ wget http://archive.ubuntu.com/ubuntu/dists/trusty-updates/main/installer-amd64/current/images/netboot/mini.iso
  linux:$ sudo iso-kexec mini.iso
  [ isolinux starts running from the ISO image .... ]

Part of my brain says "it is all just software, so it must be
possible".  I can see needing to make a new Linux syscall, setting up
a "boot-like" context in which the ISO can be read and executed.  Lots
of details I'm sure.

Any thoughts from folks who are familiar with the core/isolinux.asm
code?  Is this idea too crazy?

Cheers,
Curt