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 <pmo...@linux.ibm.com>
Didnt you want to a add a reported-by?
> ---
> 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;
>
