86_64 host is not supported by hypervisor - 2024

[Adam]

TWIMC:

Had an issue with VM networking that turned out to be the host. In the 
process of troubleshooting, I

    sudo apt reinstall libvirt   (and other QEMU/KVM virtualization 
dependencies)

Now I am getting this particular error when trying to use the 
host-passthrough for the CPU.

"error: unsupported configuration: CPU mode 'host-passthrough' for 
x86_64 qemu domain on x86_64 host is not supported by hypervisor"

This was working previously.  I found that two other domains are 
responding the same.

The configuration in xml file is:

    <metadata>
    <libosinfo:libosinfo 
xmlns:libosinfo="http://libosinfo.org/xmlns/libvirt/domain/1.0";>
      <libosinfo:os id="http://libosinfo.org/linux/2022"/>
    </libosinfo:libosinfo>
  </metadata>
  <memory unit='KiB'>4194304</memory>
  <currentMemory unit='KiB'>4194304</currentMemory>
  <vcpu placement='static'>2</vcpu>
  <os>
    <type arch='x86_64' machine='pc-q35-7.2'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <vmport state='off'/>
  </features>
  <cpu mode='host-passthrough' check='none' migratable='on'/>
  <clock offset='utc'>

But i now have to use this for it to work but the system is quite slow now.

 <metadata>
    <libosinfo:libosinfo 
xmlns:libosinfo="http://libosinfo.org/xmlns/libvirt/domain/1.0";>
      <libosinfo:os id="http://libosinfo.org/linux/2022"/>
    </libosinfo:libosinfo>
  </metadata>
  <memory unit='KiB'>4194304</memory>
  <currentMemory unit='KiB'>4194304</currentMemory>
  <vcpu placement='static'>2</vcpu>
  <os>
    <type arch='x86_64' machine='pc-q35-5.2'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <vmport state='off'/>
  </features>
  <cpu mode='custom' match='exact' check='none'>
    <model fallback='forbid'>qemu64</model>
  </cpu>


Any recommendations, given that this used to work.


Traceback error details are below this line:

Error starting domain: unsupported configuration: CPU mode 
'host-passthrough' for x86_64 qemu domain on x86_64 host is not 
supported by hypervisor

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/asyncjob.py", line 72, in 
cb_wrapper
    callback(asyncjob, *args, **kwargs)
  File "/usr/share/virt-manager/virtManager/asyncjob.py", line 108, in 
tmpcb
    callback(*args, **kwargs)
  File "/usr/share/virt-manager/virtManager/object/libvirtobject.py", 
line 57, in newfn
    ret = fn(self, *args, **kwargs)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/share/virt-manager/virtManager/object/domain.py", line 
1402, in startup
    self._backend.create()
  File "/usr/lib/python3/dist-packages/libvirt.py", line 1373, in create
    raise libvirtError('virDomainCreate() failed')
libvirt.libvirtError: unsupported configuration: CPU mode 
'host-passthrough' for x86_64 qemu domain on x86_64 host is not 
supported by hypervisor


Thank you,

A>AM