This is the second version of this patch. The first version was part of a patch series on VFIO AP IRQ. The goal of this patch is to standardize the device-driver interface for the VFIO_AP ap_matrix_device to satisfy user-land tools working on hot-plug (UDEV/LIBVIRT). Christian Borntraeger reported libvirt looping when a matrix device was available before the libvirt start. Marc Hartmayer debugged this and circumvented this in libvirt: https://www.redhat.com/archives/libvir-list/2019-February/msg00837.html Pierre Morel (1): s390: vfio_ap: link the vfio_ap devices to the vfio_ap bus subsystem drivers/s390/crypto/vfio_ap_drv.c | 48 +++++++++++++++++++++++++++++------ drivers/s390/crypto/vfio_ap_ops.c | 4 +-- drivers/s390/crypto/vfio_ap_private.h | 1 + 3 files changed, 43 insertions(+), 10 deletions(-) -- 2.7.4