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 17:06:06 +0100 |
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On 28/03/2019 16:32, Tony Krowiak wrote: > On 3/28/19 9:06 AM, Pierre Morel wrote: >> 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
... >>>> +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 /* Bits 41-47 >>> must all be zeros */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. > > That is true, but if the queue is never used, there is nothing to reset.
:) OK
Regards, Pierre
-- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany
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