Re: [PATCH v3 1/9] s390: vfio_ap: link the vfio_ap devices to the vfio_ap bus subsystem

[Pierre Morel <pmorel@xxxxxxxxxxxxx>]

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@xxxxxxxxxxxxx>
>
> Didnt you want to a add a reported-by?

Yes, forgot it.

Reported-by: Marc Hartmayer <mhartmay@xxxxxxxxxxxxx>
Reported-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>



> > ---
>
>
> >   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