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Re: efi Grub2 of Ubuntu 10.10 x64 fails to execute on qemu with -enable-

From: Adhyas Avasthi
Subject: Re: efi Grub2 of Ubuntu 10.10 x64 fails to execute on qemu with -enable-kvm
Date: Thu, 11 Nov 2010 10:54:28 -0800

I get your point, but that just stops "some" people from using Grub2
for EFI Development work and to look for other options. Unfortunately,
people who also want to boot regular OSes on their EFI BIOSes (besides
their own OSes which they want to convert to pure EFI) suffer because
regular OSes (at least Ubuntu) have chosen Grub 2 as their platform,
and a lot of companies out their do wish to run Ubuntu in a VM. Some
of my clients wish to develop certain EFI applications or run time OS
applications using EFI, for which they have chosen Virtual Machines as
their development platforms and wish to boot to Ubuntu on EFI on qemu.
Without KVM, the guest is really not usable as it is very very slow.
They do have their own BIOS ports and expose certain vendor specific
Run Time services to use and expose to the users through the custom

Let me see if I can root cause the bug (err, workaround/issue) myself.
I do need to make it work for the client as it is their requirement to
boot a Linux OS in a VM on pure EFI world, so practically it is an
issue whether we as a community choose to acknowledge it or not. As of
now, KVM does execute all other x64 bit code successfully (including
the entire 64-bit kernel), so I would put a little bit more faith on
KVM. Let me see why I crash using kvm on qemu-kvm-0.13.0. My host
kernel is 2.6.32 but that should not matter because I have updated my
kvm-kmod for that kernel anyway. Am compiling a new kernel to see if
the issue still exists for 2.6.36 kernel.

BTW, when you say you loaded Grub2, what does that mean? Does it mean
you were able to boot to the OS as well? Or just see the Grub menu
screen or command prompt? I am just curious what works with 0.12.5 and
I can try to put my Ubuntu DVD image as well to see if I can match
what you have. Are there any command line parameters I can pass to the
EFI Grub2 boot loader when I invoke it manually from the EFI Shell, to
see any more information about the crash? Also, I haven't yet fully
understood how to enable more debug (EFI BIOS dumps all debug I want
on the serial port) from within the boot loader if I build it myself,
any pointers on that will be useful.

PS: I would still appreciate if I can ask questions on this mailing
list while I debug this issue, and I can get some help where I am


> KVM like any kind of acceleration is imprecise. Because of it results of
> testing under kvm not always reflect the real state of things. For
> testing bootloader capabilities speed doesn't matter. When testing
> userspace firmware shouldn't matter and if you boot using
> coreboot-on-qemu+grub or grub-as-qemu-firmware you can check for
> firmware independance (you need to boot in graphics mode).
> EFI is only a pain. While it's important to check that GRUB works with
> it on real machines and faithful emulators, there is really no point in
> using it when you don't need to.
> It's better to just use SeaBIOS with qemu if you need to use Ubuntu in VM.
> This being said I was able to load Linux amd64 on kvm 0.12.5 using
> 64-bit tianocore and 1.99~beta0 GRUB on Intel(R) Core(TM) i5 CPU       M
> 540  @ 2.53GHz.
> While if someone figures it out and offers a sane workaround (not a
> "fix", it's not our bug, but inherent disadvantage of kvm) it can be
> accepted, there is no point in spending time on it

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