Univention Bugzilla – Bug 39827
UVMM: Windows 10 (64bit) doesn't boot on Intel CPU
Last modified: 2020-02-07 15:36:50 CET
Windows 10 final iso doesn't boot, error message is SYSTEM_THREAD_EXCEPTION_NOT_HANDLED. I used the Windows 8 template, maybe the new Windows 10 template (Bug 39335) would fix this, but I doubt it.
I testet with Win10_English_x64.iso, symlinked on smarta.
(In reply to Arvid Requate from comment #1)
> I testet with Win10_English_x64.iso, symlinked on smarta.
Try it on kiwik.
*** Bug 39875 has been marked as a duplicate of this bug. ***
From Bug #39875:
Workaround: Report CPU as core2duo. Edit the libvirt xml file and add a core2duo cpu entry as described at 
See also updates on 
We should recheck this with updated virtualization components in UCS 4.2, or we could expand uvmm to support cpu models which would be defined in uvmm OS templates
Happened at a customer.
Maybe this solves it (as core2duo is very old):
1. Use `virsh capabilities | 'grep <model>'` to get Host-CPU-Model
2. Check `virsh cpu-models --arch x86_64` if it is included
3. Use `virsh edit $VM` and add
<cpu mode="custom" match="exact"><model fallback="allow">Nehalem</model></cpu>
May have negative effects when migration such a domain between hosts with different CPUs.
I migrated UCS 4.1 to UCS 4.2-2.
In UCS 4.1 I used a similar workaround as described in #4 for a Win10 machine.
For UCS 4.2 I needed to remove entire <cpu> tag from configuration. Otherwise Win10 stalled while showing boot logo with 100% CPU load.
(In reply to Philipp Hahn from comment #6)
> Maybe this solves it (as core2duo is very old):
> 3. Use `virsh edit $VM` and add
Use <cpu mode="host-model"/> instead. This will insert a description of the host CPU.
Windows Server 2k12R2 crashes with the default "kvm64" CPU as soon as the Hyper-V Enlightments are added; Changing the CPU model to the host model fixed the issue and Windows booted again.
We should default to that mode, but make it configurable through UVMM (and the profiles).
Still a problem.
Just encountered this with Windows 2012 R2 DE. Manually editing the XML as Philipp described solved the problem.
Would be great if UVMM did this itself.
Probably another case: 2020020621000588
We really need to change the default in UVMM from "kvm" to something more sensible like "host-model".
UVMM at least should allow selecting "host-model" easily in addition to UCRV "uvmm/vm/cpu/host-model".
Also note that all models in UVMM after "SandyBridge" may not work because the livirt CPU definition is based on the original feature list; some of them are buggy and were later disabled by Intel through a µCode update. The unusable modules should be filtered out:
print(c.getDomainCapabilities('/usr/bin/qemu-system-x86_64', 'x86_64', 'pc', 'kvm'))