On 19.02.2019 10:22, Cornelia Huck wrote: > On Mon, 18 Feb 2019 19:08:48 +0100 > Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote: > >> Libudev relies on having a subsystem link for non-root devices. To >> avoid libudev (and potentially other userspace tools) choking on the >> matrix device let us introduce a vfio_ap bus and with that the vfio_ap >> bus subsytem, and make the matrix device reside within it. >> >> Doing this we need to suppress the forced link from the matrix device to >> the vfio_ap driver and we suppress the device_type we do not need > > s/suppress/remove/ ? > >> anymore. >> >> Since the associated matrix driver is not the vfio_ap driver any more, >> we have to change the search for the devices on the vfio_ap driver in >> the function vfio_ap_verify_queue_reserved. >> >> Reported-by: Marc Hartmayer <mhartmay@xxxxxxxxxxxxx> >> Reported-by: Christian Borntraeger <borntraeger@xxxxxxxxxx> >> Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx> >> --- >> 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(-) > > (...) > >> @@ -62,6 +58,27 @@ static void vfio_ap_matrix_dev_release(struct device *dev) >> kfree(matrix_dev); >> } >> >> +static int matrix_bus_match(struct device *dev, struct device_driver *drv) >> +{ >> + return 1; >> +} >> + >> +static struct bus_type matrix_bus = { >> + .name = "vfio_ap", >> + .match = &matrix_bus_match, >> +}; >> + >> +static int matrix_probe(struct device *dev) >> +{ >> + return 0; >> +} > > I don't think you need this (the important function is the match > function of the bus). Yes, with diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c index 8e45559795429..8ceec41afe322 100644 --- a/drivers/s390/crypto/vfio_ap_drv.c +++ b/drivers/s390/crypto/vfio_ap_drv.c @@ -68,15 +68,9 @@ static struct bus_type matrix_bus = { .match = &matrix_bus_match, }; -static int matrix_probe(struct device *dev) -{ - return 0; -} - static struct device_driver matrix_driver = { .name = "vfio_ap", .bus = &matrix_bus, - .probe = matrix_probe, }; static int vfio_ap_matrix_dev_create(void) on top things still look fine. > >> + >> +static struct device_driver matrix_driver = { >> + .name = "vfio_ap", >> + .bus = &matrix_bus, >> + .probe = matrix_probe, >> +}; >> + >> static int vfio_ap_matrix_dev_create(void) >> { >> int ret; > > It's a bit annoying that we need to introduce a bus that basically does > nothing, but I think this looks sane. > > Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx> >