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

Tony Krowiak
2020-04-10T15:41:32Z

On 4/9/20 11:06 AM, Cornelia Huck wrote:
> 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).

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.
>