Comment 7 for bug 1776575

@wkitty42: Since the security update was for AMD processors - are you running on Intel or AMD?

Note: I marked this regression-update and we should keep and work under that urgency unless we can prove otherwise.

I spawned a set of 64 bit guests on:
  2.0.0+dfsg-2ubuntu1.42

Then I upgraded to
  2.0.0+dfsg-2ubuntu1.43

The guests still start fine.
Then I upgraded all else which e.g. meant also a related change in libvirt.
  => Still working fine.

I only had an Intel host thou, so it might be important to learn if you run on AMD hardware and if that might be a prereq to be affected? The requested /proc/cpuinfo will have all that.

Also in addition to the Kernel Panic getting the guest log could be useful in case qemu has thrown warnigns or errors.

Summarizing, please provide:
HW Info
  - cat /proc/cpuinfo
  - sudo dmidecode
Logs:
  - journalctl -xe
  - cat /var/log/libvirt/qemu/<guestname>.log
  - dmesg

Collect the logs right after the guest crashed please.