Messages in this thread | | | Subject | Re: [PATCH v5 05/13] s390: vfio-ap: register matrix device with VFIO mdev framework | From | Halil Pasic <> | Date | Fri, 11 May 2018 19:18:38 +0200 |
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On 05/07/2018 05:11 PM, Tony Krowiak wrote: > Registers the matrix device created by the VFIO AP device > driver with the VFIO mediated device framework. > Registering the matrix device will create the sysfs > structures needed to create mediated matrix devices > each of which will be used to configure the AP matrix > for a guest and connect it to the VFIO AP device driver. > [..] > diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c > new file mode 100644 > index 0000000..d7d36fb > --- /dev/null > +++ b/drivers/s390/crypto/vfio_ap_ops.c > @@ -0,0 +1,106 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Adjunct processor matrix VFIO device driver callbacks. > + * > + * Copyright IBM Corp. 2017 > + * Author(s): Tony Krowiak <akrowiak@linux.vnet.ibm.com> > + * > + */ > +#include <linux/string.h> > +#include <linux/vfio.h> > +#include <linux/device.h> > +#include <linux/list.h> > +#include <linux/ctype.h> > + > +#include "vfio_ap_private.h" > + > +#define VFOP_AP_MDEV_TYPE_HWVIRT "passthrough" > +#define VFIO_AP_MDEV_NAME_HWVIRT "VFIO AP Passthrough Device" > + > +static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev) > +{ > + struct ap_matrix *ap_matrix = to_ap_matrix(mdev_parent_dev(mdev)); > + > + ap_matrix->available_instances--; > + > + return 0; > +} > + > +static int vfio_ap_mdev_remove(struct mdev_device *mdev) > +{ > + struct ap_matrix *ap_matrix = to_ap_matrix(mdev_parent_dev(mdev)); > + > + ap_matrix->available_instances++; > + > + return 0; > +} > +
The above functions seem to be called with the lock of this auto-generated mdev parent device held. That's why we don't have to care about synchronization ourselves, right?
A small comment in the code could be helpful for mdev non-experts. Hell, I would even consider documenting it for all mdev -- took me some time to figure out.
[..]
> +int vfio_ap_mdev_register(struct ap_matrix *ap_matrix) > +{ > + int ret; > + > + ret = mdev_register_device(&ap_matrix->device, &vfio_ap_matrix_ops); > + if (ret) > + return ret; > + > + ap_matrix->available_instances = AP_MATRIX_MAX_AVAILABLE_INSTANCES; > + > + return 0; > +} > + > +void vfio_ap_mdev_unregister(struct ap_matrix *ap_matrix) > +{ > + ap_matrix->available_instances--;
What is this for? I don't understand.
Regards, Halil
> + mdev_unregister_device(&ap_matrix->device); > +}
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