Messages in this thread | | | Subject | Re: [PATCH v2 1/7] s390: vfio-ap: wait for queue empty on queue reset | From | Tony Krowiak <> | Date | Mon, 6 May 2019 15:37:37 -0400 |
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On 5/6/19 2:41 AM, Pierre Morel wrote: > On 03/05/2019 23:14, 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 900b9cf20ca5..b88a2a2ba075 100644 >> --- a/drivers/s390/crypto/vfio_ap_ops.c >> +++ b/drivers/s390/crypto/vfio_ap_ops.c >> @@ -271,6 +271,32 @@ static int vfio_ap_mdev_verify_no_sharing(struct >> ap_matrix_mdev *matrix_mdev) >> return 0; >> } >> +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); > > NIT: Fall through ?
Yes
> >> + break; >> + case AP_RESPONSE_RESET_IN_PROGRESS: >> + case AP_RESPONSE_BUSY: >> + msleep(20); >> + break; >> + default: >> + pr_warn("%s: tapq err %02x: %04lx.%02lx may not be empty\n", >> + __func__, status.response_code, apid, apqi); > > I do not thing the warning sentence is appropriate: > The only possible errors here are if the AP is not available due to AP > checkstop, deconfigured AP or invalid APQN.
Right you are! I'll work on a new message.
> > >> + return; >> + } >> + } while (--retry); >> +} >> + >> /** >> * assign_adapter_store >> * >> @@ -790,15 +816,18 @@ 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) >> +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: > > Since you modify the switch, you can return for all the following cases: > AP_RESPONSE_DECONFIGURE > ..._CHECKSTOP > ..._INVALID_APQN > > > And you should wait for qempty on AP_RESET_IN_PROGRESS along with > AP_RESPONSE_NORMAL
If a queue reset is in progress, we retry the zapq. Are you saying we should wait for qempty then reissue the zapq?
> >> return 0; >> case AP_RESPONSE_RESET_IN_PROGRESS: >> case AP_RESPONSE_BUSY: > > While at modifying this function, the AP_RESPONSE_BUSY is not a valid > code for ZAPQ, you can remove this.
Okay
> >> @@ -824,7 +853,7 @@ 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); > > IMHO, since you are at changing this call, passing the apqn as parameter > would be a good simplification.
Okay.
> > > >> /* >> * Regardless whether a queue turns out to be busy, or >> * is not operational, we need to continue resetting > > Depends on why the reset failed, but this is out of scope.
I'm not sure what you mean by out of scope here, but you do make a valid point. If the response code for the zapq is AP_RESPONSE_DECONFIGURED, there is probably no sense in continuing to reset queues for that particular adapter. I'll consider a change here.
> >> > >
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