Messages in this thread | | | Subject | Re: [PATCH v6 2/7] s390: ap: new vfio_ap_queue structure | From | Pierre Morel <> | Date | Thu, 28 Mar 2019 14:06:46 +0100 |
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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
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