unable to start Ubuntu guests

satimis · 05-25-2010, 10:48 AM

Hi folks,

Host - Debian 5.04
KVM

I have Debian/Windows/Ubuntu guests running on the box. For unknown reason recently all
Ubuntu guests can't start. Other guests are working. Always hanging on

Code:

kernel_thread_helper+0x7/0x10

Just tried installing a new Ubuntu 10.04 guest without success. The guest started to
boot but hanging on the screen finally.

Please help. TIA

B.R
satimis

disturbed1 · 05-25-2010, 11:32 PM

Are you using an AMD cpu by any chance, and attempting to run an x86_64 Linux distro? (I had to look at your previous posts to get this info, considering your initial post lacked some crucial information

)

If so, this is a guest kernel bug. You need to use -cpu core2duo on KVM. -cpu qemu64,phenom,host, and kvm64 all cause kernel panics when KVM is ran on an AMD host.

Quote:

KVM: allow bit 10 to be cleared in MSR_IA32_MC4_CTL

There is a quirk for AMD K8 CPUs in many Linux kernels (see
arch/x86/kernel/cpu/mcheck/mce.c:__mcheck_cpu_apply_quirks()) that
clears bit 10 in that MCE related MSR. KVM can only cope with all
zeros or all ones, so it will inject a #GP into the guest, which
will let it panic.
So lets add a quirk to the quirk and ignore this single cleared bit.
This fixes -cpu kvm64 on all machines and -cpu host on K8 machines
with some guest Linux kernels.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

If this is not the issue, you could most likely be using an ancient version of KVM. Check to make sure you are using both a recent kvm module, and qemu-kvm.

satimis · 05-26-2010, 12:15 AM

Quote:

Originally Posted by disturbed1

Are you using an AMD cpu by any chance, and attempting to run an x86_64 Linux distro? (I had to look at your previous posts to get this info, considering your initial post lacked some crucial information

)

If so, this is a guest kernel bug. You need to use -cpu core2duo on KVM. -cpu qemu64,phenom,host, and kvm64 all cause kernel panics when KVM is ran on an AMD host.

If this is not the issue, you could most likely be using an ancient version of KVM. Check to make sure you are using both a recent kvm module, and qemu-kvm.

Hi disturbed1,

Thanks for your advice.

I'm running phenom X2 cpu here.

$ sudo kvm | head -1

Code:

QEMU PC emulator version 0.9.1 (kvm-72), Copyright (c) 2003-2008 Fabrice Bellard

$ apt-cache show qemu-kvm | grep Version

Code:

Version: 0.12.4+dfsg-1~bpo50+1

Before upgrade qemu/kvm what I can't resolve is why Windows and Debian guests can start? But Ubuntu guests have problem.

B.R.
satimis

disturbed1 · 05-26-2010, 12:55 AM

Quote:

Originally Posted by satimis

Before upgrade qemu/kvm what I can't resolve is why Windows and Debian guests can start? But Ubuntu guests have problem.
B.R.
satimis

Windows does not use a Linux Kernel. Perhaps the Debian guest(s) are using kernels that don't include the quoted bug I listed above. It would help immensely if the first post included - your version of KVM, which OS works, which OS does not work.

There is a large difference between stating Ubuntu does not work, and Ubuntu 10.04 LTS x86_64 does not work. As well as Windows works, and Windows 7 64bit Home Premium works. Not to mention your commands for launching KVM. I'm still unclear if these Ubuntu VMs used to work, but no longer do. Or if, you only have issues installing an un-named version of Ubuntu.

Your KVM is OLD to put it nicely

That version was released in 2008.

satimis · 05-26-2010, 08:10 AM

Quote:

Originally Posted by disturbed1

Windows does not use a Linux Kernel. Perhaps the Debian guest(s) are using kernels that don't include the quoted bug I listed above. It would help immensely if the first post included - your version of KVM, which OS works, which OS does not work.

There is a large difference between stating Ubuntu does not work, and Ubuntu 10.04 LTS x86_64 does not work. As well as Windows works, and Windows 7 64bit Home Premium works. Not to mention your commands for launching KVM. I'm still unclear if these Ubuntu VMs used to work, but no longer do. Or if, you only have issues installing an un-named version of Ubuntu.

Your KVM is OLD to put it nicely

That version was released in 2008.

Hi disturbed1

I found my problem was caused by running the new kernel of the host (Debian 5.0 32 bit), causing all Ubuntu guests unable to boot. The kernel has been upgraded recently.

I booted the old kernal

$ uname -a

Code:

Linux vm0.debian50 2.6.26-1-686 #1 SMP Fri Mar 13 18:08:45 UTC 2009 i686 GNU/Linux

All Ubuntu guests revived (all 32 bit).

The new kernel is;

Code:

Debian GNU/Linux, kernel 2.6.26-2-686

Ubuntu 10.04 (32 bit) can be installed without problem.

Anything can I try before upgrade qemu/KVM ? Thanks

Edit:

Something I can't explain. Just rebooted to the new kernel. This time all Ubuntu guests worked including the newly installed Ubuntu 10.04 desktop. Debian and Windows guest also worked.

Funny !!!

B.R.
satimis