Comment 16 for bug 1866870

I tried with a guest XML matching yours (other than disk setup).
I didn't get those errors you reported even when using your config.

Notable differences to my default - your guest has:
- a rather old chip type (Penryn is a 2007 chip)
- a rather old machine type (uses xenial which matches ~pc-i440fx-2.5)
This probably based on when the system was created.
But since you also have the same issues on the windows guest which has the modern:
  <type arch='x86_64' machine='pc-q35-4.2'>hvm</type>
  <cpu mode='host-model' check='partial'/>
So this isn't a route we need to go down...

Note: I tried this on kernel 5.4.0-14-generic with some common not too old & not too new chips
- Intel(R) Xeon(R) CPU E5-2620
- AMD Opteron(tm) Processor 4226

Then I remembered that you followed to disable nesting and after all vmx-* you see in the warnings could be related.

I ran this and restarted my guests:
# sudo rmmod kvm_intel
# sudo modprobe kvm_intel nested=0
or
# sudo rmmod kvm_amd
# sudo modprobe kvm_amd nested=0

Even then I didn't get the same warnings or crashes you got.

FYI: maybe related (similar symptom - which could be anything as we know, but still worth a link): https://bugzilla.redhat.com/show_bug.cgi?id=1718584