Messages in this thread | | | Subject | Re: [PATCH v2 1/7] s390: vfio-ap: wait for queue empty on queue reset | From | Pierre Morel <> | Date | Mon, 6 May 2019 08:41:05 +0200 |
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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 ?
> + 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.
> + 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
> 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.
> @@ -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.
> /* > * 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.
>
-- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany
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