[coreboot] kexec of Xen hypervisor from a Linux payload

[Trammell Hudson]

I've successfully built a 4.6.4 Linux kernel payload for CoreBoot and
flashed it onto the top 4 MB of the boot ROM on my Thinkpad x230.
The runtime is a dynamic linked busybox with glibc, as well as a copy
of the kexec binary from my Ubuntu laptop.

kexec of a xen kernel (multiboot-x86) results in an immediate reboot
into the coreboot payload:

https://www.flickr.com/photos/osr/27913702804/lightbox

kexec of a Linux kernel produces the expected result (panic in this
case since I didn't pass any additional parameters to find a root fs):

https://www.flickr.com/photos/osr/27914585663/lightbox

This might be a xen problem (triple fault leading to reset vector?)
rather than a coreboot issue, however the same Xen hypervisor config
works with grub2 on the drive loaded by seabios payload.

There is this old document that describes a "--vmm" option to kexec,
but that doesn't seem to exist in the current kexec tree:

https://xenbits.xen.org/docs/4.3-testing/misc/kexec_and_kdump.txt

-- 
Trammell