It looks like this bug is related to leaking of the PKRU bit. Applying the patch from Proxmox mentioned in https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2036675 resolves the issue
** Summary changed: - 5.15.0-76: Qemu live migration causes VMs to crash but works with HWE kernel + 5.15.0-76: Qemu live migration regression due to PKRU leakage -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2025987 Title: 5.15.0-76: Qemu live migration regression due to PKRU leakage Status in linux package in Ubuntu: Incomplete Status in qemu package in Ubuntu: Incomplete Bug description: I am trying to live migrate Qemu VMs between Amd Zen3 to Zen2 servers. What we expect: VMs continue to run after live-migrate What happened: VMs instantly get stuck after migration with 100% CPU usage. All Nodes are running Ubuntu 22.04. We have tested Kernel releases back to 5.15.0-70. Nodes running Ubuntu 5.19.0-43.44~22.04.1-generic 5.19.17 : Zen2 -> Zen3 migration: OK Zen3 -> Zen2 migration: OK Nodes running Ubuntu 5.15.0-76.83-generic 5.15.99 : Zen2 -> Zen3 migration: OK Zen3 -> Zen2 migration: NOT OK Mixed Kernel versions: Zen2 5.15.0-76.83-generic -> Zen3 5.19.0-43.44~22.04.1-generic -> OK Zen3 5.19.0-43.44~22.04.1-generic -> Zen2 5.15.0-76.83-generic -> OK Zen2 5.19.0-43.44~22.04.1-generic -> Zen3 5.15.0-76.83-generic -> OK Zen3 5.15.0-76.83-generic -> Zen2 5.19.0-43.44~22.04.1-generic -> NOT OK We've tested it with fresh started and with live-migrated VMs, getting same results. Its probably related to KVM: SVM: fix tsc scaling cache logic https://linux.googlesource.com/linux/kernel/git/torvalds/linux/+/11d39e8cc43e1c6737af19ca9372e590061b5ad2 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2025987/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
