Re: [PATCH v2 6/6] s390/vfio-ap: do not reset queue removed from host config

["Jason J. Herne" <jjherne@linux.ibm.com>]

On 12/12/23 4:25 PM, Tony Krowiak wrote:
> When a queue is unbound from the vfio_ap device driver, it is reset to
> ensure its crypto data is not leaked when it is bound to another device
> driver. If the queue is unbound due to the fact that the adapter or domain
> was removed from the host's AP configuration, then attempting to reset it
> will fail with response code 01 (APID not valid) getting returned from the
> reset command. Let's ensure that the queue is assigned to the host's
> configuration before resetting it.
> 
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> Fixes: eeb386aeb5b7 ("s390/vfio-ap: handle config changed and scan complete notification")
> Cc: <stable@vger.kernel.org>
> ---
>   drivers/s390/crypto/vfio_ap_ops.c | 14 ++++++++++++--
>   1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index e014108067dc..84decb0d5c97 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -2197,6 +2197,8 @@ void vfio_ap_mdev_remove_queue(struct ap_device *apdev)
>   	q = dev_get_drvdata(&apdev->device);
>   	get_update_locks_for_queue(q);
>   	matrix_mdev = q->matrix_mdev;
> +	apid = AP_QID_CARD(q->apqn);
> +	apqi = AP_QID_QUEUE(q->apqn);
>   
>   	if (matrix_mdev) {
>   		/* If the queue is assigned to the guest's AP configuration */
> @@ -2214,8 +2216,16 @@ void vfio_ap_mdev_remove_queue(struct ap_device *apdev)
>   		}
>   	}
>   
> -	vfio_ap_mdev_reset_queue(q);
> -	flush_work(&q->reset_work);
> +	/*
> +	 * If the queue is not in the host's AP configuration, then resetting
> +	 * it will fail with response code 01, (APQN not valid); so, let's make
> +	 * sure it is in the host's config.
> +	 */
> +	if (test_bit_inv(apid, (unsigned long *)matrix_dev->info.apm) &&
> +	    test_bit_inv(apqi, (unsigned long *)matrix_dev->info.aqm)) {
> +		vfio_ap_mdev_reset_queue(q);
> +		flush_work(&q->reset_work);
> +	}
>   
>   done:
>   	if (matrix_mdev)

Reviewed-by: Jason J. Herne <jjherne@linux.ibm.com>