Kernel SRU request submitted: https://lists.ubuntu.com/archives/kernel-team/2019-March/099478.html https://lists.ubuntu.com/archives/kernel-team/2019-March/thread.html#99478
** Description changed: + SRU Justification: + + [Impact] + + * The vfio-ap driver will create a matrix device in sysfs without a + subsystem link. + + * This causes failures in libudev that might also lead to libvirt + errors. + + * A fix is upstream in master branch for kernel 5.1 + + [Fix] + + * 36360658eb5a6cf04bb9f2704d1e4ce54037ec99 3636065 "s390: vfio_ap: link + the vfio_ap devices to the vfio_ap bus subsystem" + + [Test Case] + + * An s390x machine with at least one CryptoExpress card, + where at least one AP and one 'Domain' is assigned to a particular LPAR. + + * Now running virsh nodedev-list before (and later after) construction + the matrix device should expose the issue. + + * For details about how to setup a vfio-ap matrix device see: http://kvmonz.blogspot.com/2018/12/qemu-v31-released.html + (see 2nd bullet: virtio-ap) + + [Regression Potential] + + * The regression potential can be considered as low since it only + affects the s390x platform + + * and there it only affects the usage of AP (CryptoExpress) cards and + it's driver/module + + * and again only affects the recently introduced virtual IO function of + AP (vfio-ap). + + [Other Info] + + * It was already briefly discussed here: + https://www.redhat.com/archives/libvir-list/2019-February/msg00837.html + as well as reviewed and pushed. + + * Commit 3636065 from v5.1-rc1 + + * This affects ccw cards and their vf only, NOT vf of PCI/PCIe cards! + + * For details on virtio-ap/vfio-ap see bullet #2 here: http://kvmonz.blogspot.com/2018/12/qemu-v31-released.html + _________________________ + ---Problem Description--- The vfio-ap driver will create a matrix device in sysfs without a subsystem link. This triggers failures in libudev that might also lead to libvirt errors (e.g. see https://www.redhat.com/archives/libvir-list/2019-February/msg00837.html) The proper fix is to add a subsystem link (e.g. by providing a dummy bus). - A fix for that is upstream in master branch already for kernel 5.1 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=36360658eb5a6cf04bb9f2704d1e4ce54037ec99 This need to be applied to Bionic, Cosmic and Disco -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1818854 Title: [Ubuntu] vfio-ap: add subsystem to matrix device to avoid libudev failures To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1818854/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
