Found it. This happens as soon as you install tuned, which auto-starts tuned.service. After "systemctl stop tuned", QEMU works again. Retitled accordingly, so this is not a regression.
** Summary changed: - Regression: Fails to boot cirros image + Fails to boot cirros QEMU image with tuned running ** Package changed: qemu (Ubuntu) => tuned (Ubuntu) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1774000 Title: Fails to boot cirros QEMU image with tuned running To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/tuned/+bug/1774000/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs