linux-kernel - Re: [PATCH v10 03/16] s390/vfio-ap: manage link between queue struct and matrix mdev

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Message-ID: <20200825122501.624474df.cohuck@redhat.com>
Date:   Tue, 25 Aug 2020 12:25:01 +0200
From:   Cornelia Huck <cohuck@...hat.com>
To:     Tony Krowiak <akrowiak@...ux.ibm.com>
Cc:     linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, freude@...ux.ibm.com, borntraeger@...ibm.com,
        mjrosato@...ux.ibm.com, pasic@...ux.ibm.com,
        alex.williamson@...hat.com, kwankhede@...dia.com,
        fiuczy@...ux.ibm.com, frankja@...ux.ibm.com, david@...hat.com,
        imbrenda@...ux.ibm.com, hca@...ux.ibm.com, gor@...ux.ibm.com
Subject: Re: [PATCH v10 03/16] s390/vfio-ap: manage link between queue
 struct and matrix mdev

On Fri, 21 Aug 2020 15:56:03 -0400
Tony Krowiak <akrowiak@...ux.ibm.com> wrote:

> Let's create links between each queue device bound to the vfio_ap device
> driver and the matrix mdev to which the queue is assigned. The idea is to
> facilitate efficient retrieval of the objects representing the queue
> devices and matrix mdevs as well as to verify that a queue assigned to
> a matrix mdev is bound to the driver.
> 
> The links will be created as follows:
> 
>    * When the queue device is probed, if its APQN is assigned to a matrix
>      mdev, the structures representing the queue device and the matrix mdev
>      will be linked.
> 
>    * When an adapter or domain is assigned to a matrix mdev, for each new
>      APQN assigned that references a queue device bound to the vfio_ap
>      device driver, the structures representing the queue device and the
>      matrix mdev will be linked.
> 
> The links will be removed as follows:
> 
>    * When the queue device is removed, if its APQN is assigned to a matrix
>      mdev, the structures representing the queue device and the matrix mdev
>      will be unlinked.
> 
>    * When an adapter or domain is unassigned from a matrix mdev, for each
>      APQN unassigned that references a queue device bound to the vfio_ap
>      device driver, the structures representing the queue device and the
>      matrix mdev will be unlinked.
> 
> Signed-off-by: Tony Krowiak <akrowiak@...ux.ibm.com>
> ---
>  drivers/s390/crypto/vfio_ap_ops.c     | 132 +++++++++++++++++++++++++-
>  drivers/s390/crypto/vfio_ap_private.h |   2 +
>  2 files changed, 129 insertions(+), 5 deletions(-)
> 

(...)

> @@ -548,6 +557,87 @@ static int vfio_ap_mdev_verify_no_sharing(struct ap_matrix_mdev *matrix_mdev)
>  	return 0;
>  }
>  
> +enum qlink_type {

<bikeshed>I think this is less of a type, and more of an action, so
maybe call this 'qlink_action' (and the function parameter below
'action'?)</bikeshed>

> +	LINK_APID,
> +	LINK_APQI,
> +	UNLINK_APID,
> +	UNLINK_APQI,
> +};
> +
> +static void vfio_ap_mdev_link_queue(struct ap_matrix_mdev *matrix_mdev,
> +				    unsigned long apid, unsigned long apqi)
> +{
> +	struct vfio_ap_queue *q;
> +
> +	q = vfio_ap_get_queue(AP_MKQID(apid, apqi));
> +	if (q) {
> +		q->matrix_mdev = matrix_mdev;
> +		hash_add(matrix_mdev->qtable,
> +			 &q->mdev_qnode, q->apqn);
> +	}
> +}
> +
> +static void vfio_ap_mdev_unlink_queue(unsigned long apid, unsigned long apqi)
> +{
> +	struct vfio_ap_queue *q;
> +
> +	q = vfio_ap_get_queue(AP_MKQID(apid, apqi));
> +	if (q) {
> +		q->matrix_mdev = NULL;
> +		hash_del(&q->mdev_qnode);
> +	}
> +}
> +
> +/**
> + * vfio_ap_mdev_link_queues
> + *
> + * @matrix_mdev: The matrix mdev to link.
> + * @type:	 The type of @qlink_id.
> + * @qlink_id:	 The APID or APQI of the queues to link.
> + *
> + * Sets or clears the links between the queues with the specified @qlink_id
> + * and the @matrix_mdev:
> + *     @type == LINK_APID: Set the links between the @matrix_mdev and the
> + *                         queues with the specified @qlink_id (APID)
> + *     @type == LINK_APQI: Set the links between the @matrix_mdev and the
> + *                         queues with the specified @qlink_id (APQI)
> + *     @type == UNLINK_APID: Clear the links between the @matrix_mdev and the
> + *                           queues with the specified @qlink_id (APID)
> + *     @type == UNLINK_APQI: Clear the links between the @matrix_mdev and the
> + *                           queues with the specified @qlink_id (APQI)
> + */
> +static void vfio_ap_mdev_link_queues(struct ap_matrix_mdev *matrix_mdev,
> +				     enum qlink_type type,
> +				     unsigned long qlink_id)
> +{
> +	unsigned long id;
> +
> +	switch (type) {
> +	case LINK_APID:
> +		for_each_set_bit_inv(id, matrix_mdev->matrix.aqm,
> +				     matrix_mdev->matrix.aqm_max + 1)
> +			vfio_ap_mdev_link_queue(matrix_mdev, qlink_id, id);
> +		break;
> +	case UNLINK_APID:
> +		for_each_set_bit_inv(id, matrix_mdev->matrix.aqm,
> +				     matrix_mdev->matrix.aqm_max + 1)
> +			vfio_ap_mdev_unlink_queue(qlink_id, id);
> +		break;
> +	case LINK_APQI:
> +		for_each_set_bit_inv(id, matrix_mdev->matrix.apm,
> +				     matrix_mdev->matrix.apm_max + 1)
> +			vfio_ap_mdev_link_queue(matrix_mdev, id, qlink_id);
> +		break;
> +	case UNLINK_APQI:
> +		for_each_set_bit_inv(id, matrix_mdev->matrix.apm,
> +				     matrix_mdev->matrix.apm_max + 1)
> +			vfio_ap_mdev_link_queue(matrix_mdev, id, qlink_id);
> +		break;
> +	default:
> +		WARN_ON_ONCE(1);
> +	}
> +}
> +

(...)

I have not reviewed this deeply, but at a glance, it seems fine.