Re: [PATCH v11 13/26] s390: vfio-ap: zeroize the AP queues

Christian Borntraeger
2018-09-26T19:01:15Z

On 09/26/2018 03:38 PM, Cornelia Huck wrote:
> On Tue, 25 Sep 2018 19:16:28 -0400
> Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote:
>
>> From: Tony Krowiak <akrowiak@linux.ibm.com>
>>
>> Let's call PAPQ(ZAPQ) to zeroize a queue for each queue configured
>> for a mediated matrix device when it is released.
>>
>> Zeroizing a queue resets the queue, clears all pending
>> messages for the queue entries and disables adapter interruptions
>> associated with the queue.
>>
>> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
>> Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
>> Tested-by: Michael Mueller <mimu@linux.ibm.com>
>> Tested-by: Farhan Ali <alifm@linux.ibm.com>
>> ---
>> drivers/s390/crypto/vfio_ap_ops.c | 44 +++++++++++++++++++++++++++++++
>> 1 file changed, 44 insertions(+)
>>
>> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
>> index b4f67d547493..1943e47d7d78 100644
>> --- a/drivers/s390/crypto/vfio_ap_ops.c
>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
>> @@ -816,6 +816,49 @@ static int vfio_ap_mdev_group_notifier(struct notifier_block *nb,
>> return NOTIFY_OK;
>> }
>>
>> +static int vfio_ap_mdev_reset_queue(unsigned int apid, unsigned int apqi,
>> + unsigned int retry)
>> +{
>> + struct ap_queue_status status;
>> +
>> + do {
>> + status = ap_zapq(AP_MKQID(apid, apqi));
>> + switch (status.response_code) {
>> + case AP_RESPONSE_NORMAL:
>> + return 0;
>> + case AP_RESPONSE_RESET_IN_PROGRESS:
>> + case AP_RESPONSE_BUSY:
>> + msleep(20);
>> + break;
>> + default:
>> + /* things are really broken, give up */
>> + return -EIO;
>> + }
>> + } while (retry--);
>> +
>> + return -EBUSY;
>> +}
>> +
>> +static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev)
>> +{
>> + int ret;
>> + int rc = 0;
>> + unsigned long apid, apqi;
>> + struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
>> +
>> + for_each_set_bit_inv(apid, matrix_mdev->matrix.apm,
>> + matrix_mdev->matrix.apm_max + 1) {
>> + for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm,
>> + matrix_mdev->matrix.aqm_max + 1) {
>> + ret = vfio_ap_mdev_reset_queue(apid, apqi, 1);
>
> I'd still like to see a comment here:
>
> /*
> * Regardless whether a queue turns out to be busy, or is not
> * operational, we need to continue resetting the remaining
> * queues.
> */

I added your proposal to the apv11 branch.