“fancy isolinux screen on install isos hang xen/kvm HVM guests”
https://bugs.launchpad.net/ubuntu/+bug/83642
Bug is in state “confirmed” and while the
concensus on the bug thread is “we probably shouldn’t be doing
fancy things in protected mode”, this seems like a fairly important
distro to be borked for 3.2 (or 3.1.1 whatever).
I’ve verified this using the i386 Ubuntu tip: http://cdimage.ubuntu.com/releases/gutsy/tribe-5/gutsy-desktop-i386.iso
FYI
John Zulauf
Quoting the Ubuntu bug:
I'm working
with ubuntu on Xen right now, and this is a very bad problem. Both the server
and desktop install CD's, for both dapper and edgy, use fancy full screen (vbe
based?) isolinux install screens. Could we please do away with these screens on
the server or alternate install CD? These fancy screens are causing fully
virtualized guests that try to boot from these CD's to crash before the boot
screen is even drawn. This is true for both Xen and KVM.
To clarify,
this does not cause the -host- to crash, just the guest, but you get a blank
screen and wonder what happened.
Background
(mostly speculation, but I think it's right):
Intel designed VT in a strange way, such that only protected mode instructions
are allowed o be virtualized. Anything done in real mode must be
emulated...every instruction. The Xen and KVM folks have emulated enough to get
things working, but have not handled every instruction, including apparently
some of the fancy (VBE?) graphics isolinux on the ubuntu boot cd's is using.
(FreeBSD's btx loader also has problems)
For reference,
AMD's SVM analogue does, in fact, virtualize real mode instructions on the
processor, and I'm able to boot all install CD's just fine on an AMD machine.
This is an Intel VT .... 'quirk'.
The mini.iso
network install CD loads just fine and works, and I can install over an
emulated network. And that CD includes a splash screen w/ isolinux, so it's not
all VBE operations that cause problems. You should still be able to have a
splash screen, but more then that might cause the problems.
I've filed a
bug against Xen about this, and I just tried KVM and ran into the same issue,
so I'm assuming it's th same problem. But until the Xen folks figure out what
instructions need to be emulated, and take enough time to care, or Intel comes
out with an updated VT implementation that does what AMD's does, we can't just
boot up a ubuntu install CD on virtual machines and have it work.
My requested
solution is that isolinux use just the standard (preferably text) menu and
options on the server and/or alternate install CD. Having one full, officially
supported install CD that doesn't crash Xen/KVM when trying to install a ubuntu
would go a long way towards helping those of us trying to use ubuntu in a
virtual environment out. Besides, while I really appreciate all the fancy boot
options for a desktop machine, but I would prefer a plain text option for
servers anyway. I do, however, see why some would like the opposite.
Would it be
possible to get the feisty 'server' install CD to forgo the fancy bootup
options?
NOTE: I think
I understand what's going on, but if I'm missing something obvious, please tell
me.
