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I'm trying to create an x86 64 bit guest machine on an old Debian Lenny x86 64 bit hypervisor using HVM. The physical CPU is a first generation Intel i7 with VT-x support. Xen recognizes the VT-x support with the line (XEN) HVM: VMX enabled when running xm dmesg.

The Xen version according to xm info is 3.2.

I tried with newest installer ISO images of Debian Squeeze (6.0) and Ubuntu Oneiric Ocelot (11.10). The x86 64 bit version freezes the guest system shortly after starting, if I mount the x86 32 bit installer image, everything runs fine.

How can I fix this?

IRC user krt in ##xen on recommended setting acpi = 0 in the guest configuration file. This did not solve this problem.

Here is the guest configuration file I'm currently using:

arch = 'amd64'

device_model = '/usr/lib/xen-default/bin/qemu-dm'

#  Kernel + memory size
kernel      = '/usr/lib/xen-default/boot/hvmloader'

builder = 'hvm'
acpi = 0
#xen_platform_pci = 0

memory      = 1024
shadow_memory = 8

#  Disk device(s).
#root        = '/dev/sda2 ro'
disk        = [

# boot on floppy (a), hard disk (c) or CD-ROM (d)
# default: hard disk, cd-rom, floppy
boot = 'dc'

#  Hostname
name        = 'fraumann'

#  Networking
vif         = [ 'ip=,mac=00:16:3E:9F:3C:31' ] # IP changed for the public

sdl = 0
vnc = 1
vnclisten = 'localhost'
vncconsole = 1
stdvga = 0
serial = 'pty'
usbdevice = 'tablet'

#  Behaviour
on_poweroff = 'destroy'
on_reboot   = 'restart'
on_crash    = 'restart'

vcpus = 4
extra = 'xencons=tty1'
share|improve this question
check the /var/log/xen/qemu/*log for the working and non-working one – Todd Deshane Nov 17 '11 at 14:18
@ToddDeshane I only have /var/log/xen/qemu-dm-NN.log files where NN is the domain id. The log for the 32 bit working machine and the 64 bit malfunctioning one are completely identical apart of the ids being different. No luck there, I guess. – aef Nov 17 '11 at 22:55
OK. So the next place to look would be the xend logs (/var/log/xend). If those are no good we can turn up the verbosity of errors in the xend config file. – Todd Deshane Nov 19 '11 at 3:38
Also, I think this question and discussion might be better on the xen users mailing list: – Todd Deshane Nov 19 '11 at 3:40
I just replaced the server where this problem was happening, so I don't care anymore about this. – aef Nov 29 '12 at 0:18

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