KVM running slow, old images stop working

Not sure what happened, but my old KVM images stop working and I am getting the following error.


Error starting domain: unsupported configuration: Domain requires KVM, but it is not available. Check that virtualization is enabled in the host BIOS, and host configuration is setup to load the kvm modules.


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 1407, in startup
    self._backend.create()
  File "/usr/lib64/python3.10/site-packages/libvirt.py", line 1362, in create
    raise libvirtError('virDomainCreate() failed')
libvirt.libvirtError: unsupported configuration: Domain requires KVM, but it is not available. Check that virtualization is enabled in the host BIOS, and host configuration is setup to load the kvm modules.

So I decided to create a new image, however it runs painfully slow.

$ uname -a
Linux localhost.localdomain 5.18.11-1-default #1 SMP PREEMPT_DYNAMIC Fri Jul 15 05:36:11 UTC 2022 (4fcb983) x86_64 x86_64 x86_64 GNU/Linux

SYSTEM INFO


Operating System: openSUSE Tumbleweed 20220719
KDE Plasma Version: 5.25.3
KDE Frameworks Version: 5.96.0
Qt Version: 5.15.5
Kernel Version: 5.18.11-1-default (64-bit)
Graphics Platform: X11
Processors: 24 × AMD Ryzen 9 5900X 12-Core Processor
Memory: 62.7 GiB of RAM
Graphics Processor: NVIDIA GeForce RTX 3080/PCIe/SSE2
Manufacturer: Micro-Star International Co., Ltd.
Product Name: MS-7A38
System Version: 8.0

https://forums.opensuse.org/showthread.php/572797-KVM-stops-working-when-updating-to-kernel-5-18-11-1-1

The following fixed the problem for me:


sudo systemctl restart libvirtd
systemctl enable libvirtd

As for the VM running slow, something is wrong with both the new release of kubuntu/ubuntu 22.04 LTS, created a VM using the previous LTS and everything is running buttery smooth, as well as my old existing VMs.