Re: [PATCH v7 02/15] s390/vfio-ap: manage link between queue struct and matrix mdev

[Tony Krowiak]

On 4/9/20 11:06 AM, Cornelia Huck wrote:
> On Tue,  7 Apr 2020 15:20:02 -0400
> Tony Krowiak <akrowiak@xxxxxxxxxxxxx> wrote:
>
> > A vfio_ap_queue structure is created for each queue device probed. To
> > ensure that the matrix mdev to which a queue's APQN is assigned is linked
> > to the queue structure as long as the queue device is bound to the vfio_ap
> > device driver, let's go ahead and manage these links when the queue device
> > is probed and removed as well as whenever an adapter or domain is assigned
> > to or unassigned from the matrix mdev.
> >
> > Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
> > ---
> >   drivers/s390/crypto/vfio_ap_ops.c | 75 ++++++++++++++++++++++++++++---
> >   1 file changed, 70 insertions(+), 5 deletions(-)
> (...)
>
> > @@ -536,6 +531,31 @@ static int vfio_ap_mdev_verify_no_sharing(struct ap_matrix_mdev *matrix_mdev)
> >   	return 0;
> >   }
> >   
> > +/**
> > + * vfio_ap_mdev_qlinks_for_apid
> Hm... maybe the function name should express that there's some actual
> (un)linking going on?
>
> vfio_ap_mdev_link_by_apid?
>
> Or make this vfio_ap_mdev_link_queues() and pass in an indicator whether
> the passed value is an apid or an aqid? Both function names look so
> very similar to be easily confused (at least to me).

Forget my last response, I like your function names better.

> > + *
> > + * @matrix_mdev: a matrix mediated device
> > + * @apqi:	 the APID of one or more APQNs assigned to @matrix_mdev
> > + *
> > + * Set the link to @matrix_mdev for each queue device bound to the vfio_ap
> > + * device driver with an APQN assigned to @matrix_mdev with the specified @apid.
> > + *
> > + * Note: If @matrix_mdev is NULL, the link to @matrix_mdev will be severed.
> > + */
> > +static void vfio_ap_mdev_qlinks_for_apid(struct ap_matrix_mdev *matrix_mdev,
> > +					 unsigned long apid)
> > +{
> > +	unsigned long apqi;
> > +	struct vfio_ap_queue *q;
> > +
> > +	for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm,
> > +			     matrix_mdev->matrix.aqm_max + 1) {
> > +		q = vfio_ap_get_queue(AP_MKQID(apid, apqi));
> > +		if (q)
> > +			q->matrix_mdev = matrix_mdev;
> > +	}
> > +}
> > +
> >   /**
> >    * assign_adapter_store
> >    *
> (...)
>
> > @@ -682,6 +704,31 @@ vfio_ap_mdev_verify_queues_reserved_for_apqi(struct ap_matrix_mdev *matrix_mdev,
> >   	return 0;
> >   }
> >   
> > +/**
> > + * vfio_ap_mdev_qlinks_for_apqi
> See my comment above.
>
> > + *
> > + * @matrix_mdev: a matrix mediated device
> > + * @apqi:	 the APQI of one or more APQNs assigned to @matrix_mdev
> > + *
> > + * Set the link to @matrix_mdev for each queue device bound to the vfio_ap
> > + * device driver with an APQN assigned to @matrix_mdev with the specified @apqi.
> > + *
> > + * Note: If @matrix_mdev is NULL, the link to @matrix_mdev will be severed.
> > + */
> > +static void vfio_ap_mdev_qlinks_for_apqi(struct ap_matrix_mdev *matrix_mdev,
> > +					 unsigned long apqi)
> > +{
> > +	unsigned long apid;
> > +	struct vfio_ap_queue *q;
> > +
> > +	for_each_set_bit_inv(apid, matrix_mdev->matrix.apm,
> > +			     matrix_mdev->matrix.apm_max + 1) {
> > +		q = vfio_ap_get_queue(AP_MKQID(apid, apqi));
> > +		if (q)
> > +			q->matrix_mdev = matrix_mdev;
> > +	}
> > +}
> > +
> >   /**
> >    * assign_domain_store
> >    *
> (...)
>
> > @@ -1270,6 +1319,21 @@ void vfio_ap_mdev_unregister(void)
> >   	mdev_unregister_device(&matrix_dev->device);
> >   }
> >   
> > +static void vfio_ap_mdev_for_queue(struct vfio_ap_queue *q)
> vfio_ap_queue_link_mdev()? It is the other direction from the linking
> above.

See my comment above.

> > +{
> > +	unsigned long apid = AP_QID_CARD(q->apqn);
> > +	unsigned long apqi = AP_QID_QUEUE(q->apqn);
> > +	struct ap_matrix_mdev *matrix_mdev;
> > +
> > +	list_for_each_entry(matrix_mdev, &matrix_dev->mdev_list, node) {
> > +		if (test_bit_inv(apid, matrix_mdev->matrix.apm) &&
> > +		    test_bit_inv(apqi, matrix_mdev->matrix.aqm)) {
> > +			q->matrix_mdev = matrix_mdev;
> > +			break;
> > +		}
> > +	}
> > +}
> > +
> >   int vfio_ap_mdev_probe_queue(struct ap_queue *queue)
> >   {
> >   	struct vfio_ap_queue *q;
> > @@ -1282,6 +1346,7 @@ int vfio_ap_mdev_probe_queue(struct ap_queue *queue)
> >   	dev_set_drvdata(&queue->ap_dev.device, q);
> >   	q->apqn = queue->qid;
> >   	q->saved_isc = VFIO_AP_ISC_INVALID;
> > +	vfio_ap_mdev_for_queue(q);
> >   	hash_add(matrix_dev->qtable, &q->qnode, q->apqn);
> >   	mutex_unlock(&matrix_dev->lock);
> >   
> In general, looks sane.