Hello Daniel, thanks for providing the results on your testing. This looks like a kernel issue, I think what we need is testing with different kernels to check when the regression happened.
The kernel team maintains kernel builds of the mainline kernel (i.e. without Ubuntu changes). Instructions on how to test those kernels are here: https://wiki.ubuntu.com/Kernel/MainlineBuilds Would you be able to verify that (1) the issue also happens with the mainline kernels (2) which kernel version regressed (bisecting between versions)? Given that this issue is difficult to reproduce (requires specific hardware) we need to rely in your testing to make progress. I added a kernel task to the bug. ** Also affects: linux (Ubuntu) Importance: Undecided Status: New ** Changed in: libvirt (Ubuntu) Status: New => Incomplete -- 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/2003226 Title: libvirt live migrate to a lower generation processor freeze the migrated vm Status in libvirt package in Ubuntu: Incomplete Status in linux package in Ubuntu: New Bug description: Hi, i have several libvirt hosts servers with differents CPU generation, in particular : - older generation : Intel Xeon E5-2640 v4 2.40GHz - newer generation : Intel Xeon Gold 5215 2.50GHz i recently re-install all this servers into ubuntu server 22.04.1 and since, when i live migrate a VM from a new generation processor to older generation processor the migrated guest freeze without generating any error logs. if i migrate the opposite way ( older cpu to newer cpu ) it works perfectly. previous version of hosts ( same hardware on ubuntu 16.04 ) did not present the problem the live migration is done with the following command ( issued from a third server playing the role of 'virtual-center' ) : virsh -c qemu+ssh://root@new_server/system migrate --verbose --live --undefinesource --persistent --unsafe guest_name qemu+ssh://root@old_server/system this one freeze the guest while the opposite migration : virsh -c qemu+ssh://root@old_server/system migrate --verbose --live --undefinesource --persistent --unsafe guest_name qemu+ssh://root@new_server/system works without problem migrate between 2 servers with same generation CPU also works perfectly the cpu configuration of guest is generic : <cpu mode='custom' match='exact' check='full'> <model fallback='forbid'>qemu64</model> <feature policy='require' name='x2apic'/> <feature policy='require' name='hypervisor'/> <feature policy='require' name='lahf_lm'/> <feature policy='disable' name='svm'/> </cpu> i have tried several ( almost all ) other virtual cpu configuration , always with the same problem. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/2003226/+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
