[SeaBIOS] about [SeaBIOS PATCH] Try to hard-reboot on rerun of post even on emulators.

[Amos Kong]

Hi Kevin,

When I use old seabios in some stable linux release, some bootable
devices (2 ide disks) would be lost when I try to restart guest by
Ctrl+Alt+Delete during boot stage.

Releated Red Hat BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1129549

I found an upstream commit [1] fixed this bug, but when I backport
this patch to old seabios, guest will shutdown when I try to restart
by Ctrl+Alt+Delete during boot stage.

Kevin, can you help to describe that:
"Unfortunately, kvm does not keep a  pristine copy of the BIOS at 0xffff0000"
It's a kvm (userspace, QEMU) bug?

If it's a qemu-kvm bug, I should also fix this bz in old stable release.

[1] ===========================================
commit 244caf86f11f5f65d166d91704f64cb673167abc
Author: Kevin O'Connor 
Date:   Wed Sep 15 21:48:16 2010 -0400

Try to hard-reboot on rerun of post even on emulators.

Extend the hard-reboot logic to qemu and kvm.  On qemu, a reboot will
    not reset the memory settings for 0xc0000-0xfffff, so copy that memory
    area manually before rebooting.  Unfortunately, kvm does not keep a
    pristine copy of the BIOS at 0xffff0000, so detect that case and
    shutdown the machine.

Two backport dependences:
  [PATCH] Try to hard-reboot processor on rerun of post under coreboot.
  [PATCH] Don't do shadow copying of optionroms when CONFIG_OPTIONROMS_DEPLOYED.