From: Pierre Morel <pmorel@linux.ibm.com>
To: Tony Krowiak <akrowiak@linux.ibm.com>, borntraeger@de.ibm.com
Cc: alex.williamson@redhat.com, cohuck@redhat.com,
linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org,
kvm@vger.kernel.org, frankja@linux.ibm.com, pasic@linux.ibm.com,
david@redhat.com, schwidefsky@de.ibm.com,
heiko.carstens@de.ibm.com, freude@linux.ibm.com,
mimu@linux.ibm.com
Subject: Re: [PATCH v6 2/7] s390: ap: new vfio_ap_queue structure
Date: Thu, 28 Mar 2019 14:06:46 +0100 [thread overview]
Message-ID: <1b64ad7b-2a7c-b604-1adb-af400e7be516@linux.ibm.com> (raw)
In-Reply-To: <169eec34-6397-3150-27df-9985c9e711b8@linux.ibm.com>
On 26/03/2019 21:45, Tony Krowiak wrote:
> On 3/22/19 10:43 AM, Pierre Morel wrote:
>> The AP interruptions are assigned on a queue basis and
>> the GISA structure is handled on a VM basis, so that
>> we need to add a structure we can retrieve from both side
>
> s/side/sides/
OK
>
>> holding the information we need to handle PQAP/AQIC interception
>> and setup the GISA.
>
> s/setup/set up/
OK
...snip...
>> +
>> +static int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q)
>> +{
>> + struct ap_queue_status status;
>> + int retry = 1;
>> +
>> + do {
>> + status = ap_zapq(q->apqn);
>> + 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 */
>
> I'm not sure things are necessarily broken. We could end up here if
> the AP is removed from the configuration via the SE or SCLP Deconfigure
> Adjunct Processor command.
OK, but note that it is your original comment I just moved the function
here ;)
>
>> + return -EIO;
>> + }
>> + } while (retry--);
>> +
>> + return -EBUSY;
>> +}
>> +
>> static void vfio_ap_matrix_init(struct ap_config_info *info,
>> struct ap_matrix *matrix)
>> {
>> @@ -45,6 +107,7 @@ static int vfio_ap_mdev_create(struct kobject
>> *kobj, struct mdev_device *mdev)
>> return -ENOMEM;
>> }
>> + INIT_LIST_HEAD(&matrix_mdev->qlist);
>> vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->matrix);
>> mdev_set_drvdata(mdev, matrix_mdev);
>> mutex_lock(&matrix_dev->lock);
>> @@ -113,162 +176,189 @@ static struct attribute_group
>> *vfio_ap_mdev_type_groups[] = {
>> NULL,
>> };
>> -struct vfio_ap_queue_reserved {
>> - unsigned long *apid;
>> - unsigned long *apqi;
>> - bool reserved;
>> -};
>> +static void vfio_ap_free_queue(int apqn, struct ap_matrix_mdev
>> *matrix_mdev)
>> +{
>> + struct vfio_ap_queue *q;
>> +
>> + q = vfio_ap_get_queue(apqn, &matrix_mdev->qlist);
>> + if (!q)
>> + return;
>> + q->matrix_mdev = NULL;
>> + vfio_ap_mdev_reset_queue(q);
>
> I'm wondering if it's necessary to reset the queue here. The only time
> a queue is used is when a guest using the mdev device is started. When
> that guest is terminated, the fd for the mdev device is closed and the
> mdev device's release callback is invoked. The release callback resets
> the queues assigned to the mdev device. Is it really necessary to
> reset the queue again when it is unassigned even if there would have
> been no subsequent activity?
Yes, it is necessary, the queue can be re-assigned to another guest later.
Release will only be called when unbinding the queue from the driver.
>
>> + list_move(&q->list, &matrix_dev->free_list);
>> +}
...snip...
>> + for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, AP_DEVICES) {
>> + apqn = AP_MKQID(apid, apqi);
>> + q = vfio_ap_find_queue(apqn);
>> + if (!q) {
>> + ret = -EADDRNOTAVAIL;
>> + goto rewind;
>> + }
>> + if (q->matrix_mdev) {
>
> If somebody assigns the same domain a second time, the assignment will
> fail because the matrix_mdev will already have been associated with the
> queue. I don't think it is appropriate to fail the assignment if the
It is usual to report a failure in the case the operation requested has
already be done.
But we can do as you want. Any other opinion?
> q->matrix_mdev is the same as the input matrix_mdev. This should be
> changed to:
>
> if (q->matrix_mdev != matrix_mdev)
You surely want to say: add this, not change to this. ;)
>
Thanks for commenting,
Regards,
Pierre
--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany
next prev parent reply other threads:[~2019-03-28 13:06 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-22 14:43 [PATCH v6 0/7] vfio: ap: AP Queue Interrupt Control Pierre Morel
2019-03-22 14:43 ` [PATCH v6 1/7] s390: ap: kvm: add PQAP interception for AQIC Pierre Morel
2019-03-26 18:57 ` Tony Krowiak
2019-03-27 16:06 ` Tony Krowiak
2019-03-28 12:43 ` Pierre Morel
2019-03-28 15:24 ` Tony Krowiak
2019-03-28 16:12 ` Tony Krowiak
2019-03-29 8:52 ` Pierre Morel
2019-03-29 13:02 ` Tony Krowiak
2019-03-22 14:43 ` [PATCH v6 2/7] s390: ap: new vfio_ap_queue structure Pierre Morel
2019-03-25 8:05 ` Harald Freudenberger
2019-03-28 13:12 ` Pierre Morel
2019-03-26 20:45 ` Tony Krowiak
2019-03-27 11:00 ` Harald Freudenberger
2019-03-28 12:53 ` Pierre Morel
2019-03-28 13:06 ` Pierre Morel [this message]
2019-03-28 15:32 ` Tony Krowiak
2019-03-28 16:06 ` Pierre Morel
2019-04-02 12:47 ` Pierre Morel
2019-03-22 14:43 ` [PATCH v6 3/7] s390: ap: setup relation betwen KVM and mediated device Pierre Morel
2019-03-28 16:12 ` Tony Krowiak
2019-03-28 16:27 ` Pierre Morel
2019-03-28 17:25 ` Tony Krowiak
2019-03-29 8:58 ` Pierre Morel
2019-03-29 13:06 ` Tony Krowiak
2019-03-22 14:43 ` [PATCH v6 4/7] vfio: ap: register IOMMU VFIO notifier Pierre Morel
2019-03-28 20:46 ` Tony Krowiak
2019-03-29 9:31 ` Pierre Morel
2019-03-29 13:14 ` Tony Krowiak
2019-03-22 14:43 ` [PATCH v6 5/7] s390: ap: implement PAPQ AQIC interception in kernel Pierre Morel
2019-03-22 14:43 ` [PATCH v6 6/7] s390: ap: Cleanup on removing the AP device Pierre Morel
2019-03-22 14:43 ` [PATCH v6 7/7] s390: ap: kvm: Enable PQAP/AQIC facility for the guest Pierre Morel
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