[coreboot] kexec of Xen hypervisor from a Linux payload

[Trammell Hudson]

On Mon, Jul 25, 2016 at 02:42:11PM +0200, Zoran Stojsavljevic wrote:
> [...]
> *Probably some module required for your baremetal fedora is missing
> in initramfs. First of all, remove "quiet" option to receive more
> details. If that's about missing module, you can regenerate initramfs:

The system boots fine under coreboot+seabios, so I'm fairly
certain it isn't an initrd problem.  There are no modules at
all in the kernel that I've embedded as the coreboot payload.
Even without quiet there is no output after the "kexec_core:
Starting new kernel" message.

I did find this note from 2008 that mentioned a similar
issue regarding xen, kexec and coreboot:

http://ward.vandewege.net/blog/2008/08/kexecing-into-a-xen-kernel/

# The no-real-mode option stops Xen from doing some bios
# calls, and it also tells it to ignore the e820 bios table.
# Note that you need to pass no-real-mode as the first xen
# command line argument, otherwise it won’t work.
# 
# And somehow that solves the problem for Xen 3.1.3 and 3.1.4,
# both under qemu + coreboot and qemu + bochs. Kexec’ing into
# Xen 3.1.2 triple-faults qemu under qemu + coreboot, but
# works fine under qemu + bochs. That smells like a coreboot
# bug. I’ll try on real hardware tomorrow to see if this bug
# is specific to our qemu port, or a more general coreboot
# problem. To be continued..

"no-real-mode" does not affect my results on real hardware.
I'm still seeing what looks like a triple fault, leading to
coreboot being restarted.  At least it gets back to the
prompt in less than a second...

-- 
Trammell