> Only Ubuntu 20 OS is failing to work on Ubuntu 18 host. We've had cases where only certain guest versions would use e.g. some instructions and something like might be broken in this case as well.
So could you confirm that: - an Ubuntu 18.04 guest in an otherwise same setup works fine? - an Ubuntu 21.04 guest in an otherwise same setup works fine as well? > Tried with different CPU modes like pass-through/host-model but did not helped. Those are both rather powerful (many features) have you tried a weak one with only basic features? <cpu mode='custom'> <model fallback='forbid'>qemu64</model> </cpu> > xml : https://pastebin.com/1cxUybqt Host-passthrough is definitely the most powerful, but also the least safe/compatible one. As I said above try with qemu64 and if working enable features one by one until we found the one that breaks you. > Those those the only messages appearing in vnc + > log : https://pastebin.com/0kh8EuWK Well, they need to come from somewhere. If it would be qemu that crashed your VNC connection would have terminated. Also the log does not report qemu crashes (they'd be there). So we can assume - to some extent - that it is guest processes that fail. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1941844 Title: KVM ubuntu 20 VPS on Ryzen 9 5950X with Ubuntu 18.04 on Host is failing to boot To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1941844/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs