Re: [PATCH v2 5/8] s390: vfio-ap: wait for queue empty on queue reset

Pierre Morel
2019-04-23T12:50:26Z

On 20/04/2019 23:49, Tony Krowiak wrote:
> Refactors the AP queue reset function to wait until the queue is empty
> after the PQAP(ZAPQ) instruction is executed to zero out the queue as
> required by the AP architecture.
>
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> ---
> drivers/s390/crypto/vfio_ap_ops.c | 35 ++++++++++++++++++++++++++++++++---
> 1 file changed, 32 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 091804317c5e..31ce30ee784d 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -744,15 +744,44 @@ 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)
> +static void vfio_ap_mdev_wait_for_qempty(unsigned long apid, unsigned long apqi)
> {
> struct ap_queue_status status;
> + ap_qid_t qid = AP_MKQID(apid, apqi);
> + int retry = 5;
> +
> + do {
> + status = ap_tapq(qid, NULL);
> + switch (status.response_code) {
> + case AP_RESPONSE_NORMAL:
> + if (status.queue_empty)
> + return;
> + msleep(20);
> + break;
> + case AP_RESPONSE_RESET_IN_PROGRESS:
> + case AP_RESPONSE_BUSY:
> + msleep(20);
> + break;
> + default:
> + pr_warn("%s: tapq err %02x: 0x%04x may not be empty\n",
> + __func__, status.response_code, q->apqn);

q is not defined. use qid ?

> + return;
> + }
> + } while (--retry);
> +}
> +
> +int vfio_ap_mdev_reset_queue(unsigned int apid, unsigned int apqi)
> +{
> + struct ap_queue_status status;
> + int retry = 5;
>
> do {
> status = ap_zapq(AP_MKQID(apid, apqi));
> switch (status.response_code) {
> case AP_RESPONSE_NORMAL:
> + vfio_ap_mdev_wait_for_qempty(apid, apqi);
> + return 0;
> + case AP_RESPONSE_DECONFIGURED:
> return 0;
> case AP_RESPONSE_RESET_IN_PROGRESS:
> case AP_RESPONSE_BUSY:
> @@ -778,7 +807,7 @@ static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev)
> 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);
> + ret = vfio_ap_mdev_reset_queue(apid, apqi);
> /*
> * Regardless whether a queue turns out to be busy, or
> * is not operational, we need to continue resetting
>

--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany