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Message-Id: <fde260b9-6a99-5d13-2dcc-a0ef2782f559@linux.ibm.com>
Date: Mon, 18 Feb 2019 19:36:23 +0100
From: Pierre Morel <pmorel@...ux.ibm.com>
To: Tony Krowiak <akrowiak@...ux.ibm.com>, borntraeger@...ibm.com
Cc: alex.williamson@...hat.com, cohuck@...hat.com,
linux-kernel@...r.kernel.org, linux-s390@...r.kernel.org,
kvm@...r.kernel.org, frankja@...ux.ibm.com, pasic@...ux.ibm.com,
david@...hat.com, schwidefsky@...ibm.com,
heiko.carstens@...ibm.com, freude@...ux.ibm.com, mimu@...ux.ibm.com
Subject: Re: [PATCH v3 5/9] s390: ap: tools to associate a queue to a matrix
On 15/02/2019 23:30, Tony Krowiak wrote:
> On 2/14/19 8:51 AM, Pierre Morel wrote:
>> We need tools to associate a queue and a matrix to be able
>> later to find the matrix associated with the queue for which
>> we got the APQN in the register 1 during a PQAP/AQIC instruction
>> interception.
>>
>> Signed-off-by: Pierre Morel <pmorel@...ux.ibm.com>
>> ---
>> drivers/s390/crypto/vfio_ap_ops.c | 66
>> +++++++++++++++++++++++++++++++++--
>> drivers/s390/crypto/vfio_ap_private.h | 1 +
>> 2 files changed, 64 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/s390/crypto/vfio_ap_ops.c
>> b/drivers/s390/crypto/vfio_ap_ops.c
>> index 2a52c9b..1851b24 100644
>> --- a/drivers/s390/crypto/vfio_ap_ops.c
>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
>> @@ -50,8 +50,7 @@ static int vfio_ap_check_apqn(struct device *dev,
>> void *data)
>> *
>> * Returns the pointer to the associated vfio_ap_queue
>> */
>> -static __attribute__((unused))
>> - struct vfio_ap_queue *vfio_ap_get_queue(int apqn)
>
> I don't like this, it indicates to me that this and the previous
> patch should have been squashed together. I realize your intent
> was to make the patches smaller, but I don't think this makes it
> any easier to review them. In fact, it makes it harder IMHO, because
> you have to flip back and forth between patches to fully comprehend
> the usage.
>
>> +static struct vfio_ap_queue *vfio_ap_get_queue(int apqn)
>> {
>> struct device *dev;
>> struct vfio_ap_queue *q;
>> @@ -72,7 +71,7 @@ static __attribute__((unused))
>> * put the associated device
>> *
>> */
>> -static __attribute__((unused)) void vfio_ap_put_queue(struct
>> vfio_ap_queue *q)
>
> Ditto for this.
>
>> +static void vfio_ap_put_queue(struct vfio_ap_queue *q)
>> {
>> put_device(q->dev);
>> q->dev = NULL;
>> @@ -867,6 +866,67 @@ static int vfio_ap_mdev_reset_queue(unsigned int
>> apid, unsigned int apqi,
>> return -EBUSY;
>> }
>> +/**
>> + * vfio_ap_dissociate_queues: Dissociate a matrix mediated device to
>> a queue
>> + *
>> + * Go through all bits in the AQM and APM and dissociate the queue
>> + * from the matrix device.
>> + *
>> + * No return value we are throwing the mediated device anyway.
>> + */
>> +static void vfio_ap_dissociate_queues(struct ap_matrix_mdev
>> *matrix_mdev)
>> +{
>> + unsigned long apid, apqi;
>
> The changes I recommend here are based on the comments in my
> response to patch 4.
>
>> + struct vfio_ap_queue *q;
>
> Add this:
>
> struct device *qdev;
>
>> +
>> + 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) {
>> + q = vfio_ap_get_queue(AP_MKQID(apid, apqi));
>
> Replace with:
> qdev = vfio_ap_get_queue_dev(AP_MKQID(apid, apqi);
>
>> + if (q) {
>
> Replace with:
> if (qdev) {
>
> Add this:
> q = dev_get_drvdata(qdev);
>
>> + vfio_ap_mdev_reset_queue(apid, apqi, 1);
>> + q->matrix = NULL;
>> + vfio_ap_put_queue(q);
>
> Replace with:
> put_device(qdev)
>
>> + } else
>> + pr_err("%s: no queue for %02lx.%04lx\n",
>> + __func__, apid, apqi);
>> + }
>> + }
>> +}
>> +
>> +/**
>> + * vfio_ap_associate_queues: Associate a matrix mediated device to a
>> queue
>> + *
>> + * Go through all bits in the AQM and APM and calculate the APQN, and
>> find
>> + * the matching queue to associate with the matrix device.
>> + *
>> + * In the case a queue could not be found return -ENODEV.
>> + * Otherwise return 0.
>> + */
>> +static __attribute__((unused))
>
> This indicates this patch should be squashed with the patch that
> introduces this function. Why have a patch that introduces a function
> that is not used and put and artificially specify an attribute just to
> keep the compiler from issuing a warning?
Seems to be a majority for this so... will do.
>
>> + int vfio_ap_associate_queues(struct ap_matrix_mdev *matrix_mdev)
>> +{
>
> The same as above, the changes I recommend here are based on the
> comments in my response to patch 4.
>
... will do
>> + pr_err("%s: no queue for %02lx.%04lx\n", __func__, apid, apqi);
>> + vfio_ap_dissociate_queues(matrix_mdev);
>> + return -ENODEV;
>> +}
>> static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev)
>> {
>> int ret;
>> diff --git a/drivers/s390/crypto/vfio_ap_private.h
>> b/drivers/s390/crypto/vfio_ap_private.h
>> index 081f0d7..10bc8b5 100644
>> --- a/drivers/s390/crypto/vfio_ap_private.h
>> +++ b/drivers/s390/crypto/vfio_ap_private.h
>> @@ -89,5 +89,6 @@ extern void vfio_ap_mdev_unregister(void);
>> struct vfio_ap_queue {
>> struct device *dev;
>> int apqn;
>> + struct ap_matrix_mdev *matrix;
>
> Can you rename this variable matrix_mdev?
> * That is how struct ap_matrix_mdev vars are named everywhere else
> * It prevents confusing it with naming of vars for struct ap_matrix.
Sorry, I did this but it seems to have been forgotten in a rebase.
Will do.
>
>> };
>> #endif /* _VFIO_AP_PRIVATE_H_ */
>>
>
--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany
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