** Description changed: ## Bug ## There are conditions where old qemu/libvirt created guests with the osxsafe or ospke cpu feature: <feature policy='require' name='osxsave'/> <feature policy='require' name='ospke'/> That feature was removed in recent qemu, this triggers issues starting some old guests definitions using it after upgrade. qemu-system-x86_64: can't apply global Broadwell-noTSX-x86_64- cpu.osxsave=on: Property '.osxsave' not found Same bug in Fedora (incomplete): => https://bugzilla.redhat.com/show_bug.cgi?id=1644848 ## What happened ## Both commandline arg drops "osxsave" / "ospke" were effective no-ops as it was - quote: "never configurable: KVM never returned OSXSAVE on GET_SUPPORTED_CPUID". See removal commits [1][2]. Discussions went on if this should be warnings instead of errors for a while (the deprecation discussion is ongoing anyway). But for now we are in the situation that calling qemu with those features makes it fail to start. I'd not want to derive from upstream qemu and the discussion on depreceation - as mentioned - is a longer one that won't resolve too soon - a.k.a we can't wait on that. The discussion at [3] reached no conclusion and was forgotten. I checked with Jiri and there was no follow on. But since specifying the features never meant anything to qemu we should at least consider libvirt to learn about that and just not specify the flags. If there is a good place for a warning we might emit one if required was set, but this is not strictly required at first. + ## when does it trigger => severity ## + + Comment 14 [4] adds more details, we checked usage through virsh, python-livbirt (uvtool, multipass, openstack) and virt-install. We only found two cases in virt-install either: + - created the guest in the past --cpu=host-model + This guest will fail to start on upgrade + - pre virt-install 2.0 (not a Ubuntu combo) it would also break with + e.g. virt-install 1.5 and qemu 3.1 with --cpu=host-copy + => Both options were not even documented anymore back n Xenial, but they are kept for compatibility. + Overall - unless we missed a more important use case - this is ugly but not show-stopping in prio. + + Obviously it also triggers if: + - libvirt XML with added <feature policy='require' name='osxsave'/> + - virt-install with --cpu ...,+osxsave / ospke + [1]: https://git.qemu.org/?p=qemu.git;a=commit;h=f1a23522b03a569f13aad49294bb4c4b1a9500c7 [2]: https://git.qemu.org/?p=qemu.git;a=commit;h=9ccb9784b57804f5c74434ad6ccb66650a015ffc [3]: https://www.mail-archive.com/[email protected]/msg561877.html + [4]: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1825195/comments/14
** Description changed: ## Bug ## There are conditions where old qemu/libvirt created guests with the osxsafe or ospke cpu feature: <feature policy='require' name='osxsave'/> <feature policy='require' name='ospke'/> That feature was removed in recent qemu, this triggers issues starting some old guests definitions using it after upgrade. qemu-system-x86_64: can't apply global Broadwell-noTSX-x86_64- cpu.osxsave=on: Property '.osxsave' not found - Same bug in Fedora (incomplete): - => https://bugzilla.redhat.com/show_bug.cgi?id=1644848 + Same bug in Fedora (incomplete) [5] for being non reproducible - + probably didn't see the new virt-install avoiding (but not fixing) it. ## What happened ## Both commandline arg drops "osxsave" / "ospke" were effective no-ops as it was - quote: "never configurable: KVM never returned OSXSAVE on GET_SUPPORTED_CPUID". See removal commits [1][2]. Discussions went on if this should be warnings instead of errors for a while (the deprecation discussion is ongoing anyway). But for now we are in the situation that calling qemu with those features makes it fail to start. I'd not want to derive from upstream qemu and the discussion on depreceation - as mentioned - is a longer one that won't resolve too soon - a.k.a we can't wait on that. The discussion at [3] reached no conclusion and was forgotten. I checked with Jiri and there was no follow on. But since specifying the features never meant anything to qemu we should at least consider libvirt to learn about that and just not specify the flags. If there is a good place for a warning we might emit one if required was set, but this is not strictly required at first. ## when does it trigger => severity ## Comment 14 [4] adds more details, we checked usage through virsh, python-livbirt (uvtool, multipass, openstack) and virt-install. We only found two cases in virt-install either: - created the guest in the past --cpu=host-model - This guest will fail to start on upgrade + This guest will fail to start on upgrade - pre virt-install 2.0 (not a Ubuntu combo) it would also break with - e.g. virt-install 1.5 and qemu 3.1 with --cpu=host-copy + e.g. virt-install 1.5 and qemu 3.1 with --cpu=host-copy => Both options were not even documented anymore back n Xenial, but they are kept for compatibility. Overall - unless we missed a more important use case - this is ugly but not show-stopping in prio. Obviously it also triggers if: - libvirt XML with added <feature policy='require' name='osxsave'/> - virt-install with --cpu ...,+osxsave / ospke [1]: https://git.qemu.org/?p=qemu.git;a=commit;h=f1a23522b03a569f13aad49294bb4c4b1a9500c7 [2]: https://git.qemu.org/?p=qemu.git;a=commit;h=9ccb9784b57804f5c74434ad6ccb66650a015ffc [3]: https://www.mail-archive.com/[email protected]/msg561877.html [4]: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1825195/comments/14 + [5]: https://bugzilla.redhat.com/show_bug.cgi?id=1644848 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1825195 Title: qemu dropped osxsave/ospke feature triggering upgrade issues To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1825195/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
