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    SubjectRe: [PATCH v3 1/9] s390: vfio_ap: link the vfio_ap devices to the vfio_ap bus subsystem
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    On 14/02/2019 16:01, Christian Borntraeger wrote:
    >
    >
    > On 14.02.2019 14:51, Pierre Morel 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.
    >>
    >> We restrict the number of allowed devices to a single one.
    >>
    >> 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
    >> 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.
    >>
    >> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
    >
    > Didnt you want to a add a reported-by?

    Yes, forgot it.

    Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
    Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>



    >> ---
    >
    >
    >> drivers/s390/crypto/vfio_ap_drv.c | 63 +++++++++++++++++++++++++++++++----
    >> drivers/s390/crypto/vfio_ap_ops.c | 4 +--
    >> drivers/s390/crypto/vfio_ap_private.h | 1 +
    >> 3 files changed, 60 insertions(+), 8 deletions(-)
    >>
    >> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
    >> index 31c6c84..1fd5fe6 100644
    >> --- a/drivers/s390/crypto/vfio_ap_drv.c
    >> +++ b/drivers/s390/crypto/vfio_ap_drv.c
    >> @@ -24,8 +24,9 @@ MODULE_LICENSE("GPL v2");
    >>
    >> static struct ap_driver vfio_ap_drv;
    >>
    >> -static struct device_type vfio_ap_dev_type = {
    >> - .name = VFIO_AP_DEV_TYPE_NAME,
    >> +struct matrix_driver {
    >> + struct device_driver drv;
    >> + int device_count;
    >> };
    >>
    >> struct ap_matrix_dev *matrix_dev;
    >> @@ -62,6 +63,41 @@ 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);
    >> +static int matrix_remove(struct device *dev);
    >> +static struct matrix_driver matrix_driver = {
    >> + .drv = {
    >> + .name = "vfio_ap",
    >> + .bus = &matrix_bus,
    >> + .probe = matrix_probe,
    >> + .remove = matrix_remove,
    >> + },
    >> +};
    >> +
    >> +static int matrix_probe(struct device *dev)
    >> +{
    >> + if (matrix_driver.device_count)
    >> + return -EEXIST;
    >> + matrix_driver.device_count++;
    >> + return 0;
    >> +}
    >> +
    >> +static int matrix_remove(struct device *dev)
    >> +{
    >> + matrix_driver.device_count--;
    >> + return 0;
    >> +}
    >> +
    >> static int vfio_ap_matrix_dev_create(void)
    >> {
    >> int ret;
    >> @@ -71,6 +107,10 @@ static int vfio_ap_matrix_dev_create(void)
    >> if (IS_ERR(root_device))
    >> return PTR_ERR(root_device);
    >>
    >> + ret = bus_register(&matrix_bus);
    >> + if (ret)
    >> + goto bus_register_err;
    >> +
    >> matrix_dev = kzalloc(sizeof(*matrix_dev), GFP_KERNEL);
    >> if (!matrix_dev) {
    >> ret = -ENOMEM;
    >> @@ -87,30 +127,41 @@ static int vfio_ap_matrix_dev_create(void)
    >> mutex_init(&matrix_dev->lock);
    >> INIT_LIST_HEAD(&matrix_dev->mdev_list);
    >>
    >> - matrix_dev->device.type = &vfio_ap_dev_type;
    >> dev_set_name(&matrix_dev->device, "%s", VFIO_AP_DEV_NAME);
    >> matrix_dev->device.parent = root_device;
    >> + matrix_dev->device.bus = &matrix_bus;
    >> matrix_dev->device.release = vfio_ap_matrix_dev_release;
    >> - matrix_dev->device.driver = &vfio_ap_drv.driver;
    >> + matrix_dev->vfio_ap_drv = &vfio_ap_drv;
    >>
    >> ret = device_register(&matrix_dev->device);
    >> if (ret)
    >> goto matrix_reg_err;
    >>
    >> + ret = driver_register(&matrix_driver.drv);
    >> + if (ret)
    >> + goto matrix_drv_err;
    >> +
    >> return 0;
    >>
    >> +matrix_drv_err:
    >> + device_unregister(&matrix_dev->device);
    >> matrix_reg_err:
    >> put_device(&matrix_dev->device);
    >> matrix_alloc_err:
    >> + bus_unregister(&matrix_bus);
    >> +bus_register_err:
    >> root_device_unregister(root_device);
    >> -
    >> return ret;
    >> }
    >>
    >> static void vfio_ap_matrix_dev_destroy(void)
    >> {
    >> + struct device *root_device = matrix_dev->device.parent;
    >> +
    >> + driver_unregister(&matrix_driver.drv);
    >> device_unregister(&matrix_dev->device);
    >> - root_device_unregister(matrix_dev->device.parent);
    >> + bus_unregister(&matrix_bus);
    >> + root_device_unregister(root_device);
    >> }
    >>
    >> static int __init vfio_ap_init(void)
    >> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
    >> index 272ef42..900b9cf 100644
    >> --- a/drivers/s390/crypto/vfio_ap_ops.c
    >> +++ b/drivers/s390/crypto/vfio_ap_ops.c
    >> @@ -198,8 +198,8 @@ static int vfio_ap_verify_queue_reserved(unsigned long *apid,
    >> qres.apqi = apqi;
    >> qres.reserved = false;
    >>
    >> - ret = driver_for_each_device(matrix_dev->device.driver, NULL, &qres,
    >> - vfio_ap_has_queue);
    >> + ret = driver_for_each_device(&matrix_dev->vfio_ap_drv->driver, NULL,
    >> + &qres, vfio_ap_has_queue);
    >> if (ret)
    >> return ret;
    >>
    >> diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
    >> index 5675492..76b7f98 100644
    >> --- a/drivers/s390/crypto/vfio_ap_private.h
    >> +++ b/drivers/s390/crypto/vfio_ap_private.h
    >> @@ -40,6 +40,7 @@ struct ap_matrix_dev {
    >> struct ap_config_info info;
    >> struct list_head mdev_list;
    >> struct mutex lock;
    >> + struct ap_driver *vfio_ap_drv;
    >> };
    >>
    >> extern struct ap_matrix_dev *matrix_dev;
    >>


    --
    Pierre Morel
    Linux/KVM/QEMU in Böblingen - Germany

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