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

Cornelia Huck
2020-04-09T15:06:19Z

On Tue, 7 Apr 2020 15:20:02 -0400
Tony Krowiak <akrowiak@linux.ibm.com> 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@linux.ibm.com>
> ---
> 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).

> + *
> + * @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.

> +{
> + 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.