Messages in this thread | | | Subject | Re: [PATCH v4 3/7] s390: ap: associate a ap_vfio_queue and a matrix mdev | From | Tony Krowiak <> | Date | Tue, 5 Mar 2019 17:17:36 -0500 |
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On 3/3/19 9:09 PM, Halil Pasic wrote: > On Fri, 22 Feb 2019 16:29:56 +0100 > Pierre Morel <pmorel@linux.ibm.com> wrote: > >> We need to associate the ap_vfio_queue, which will hold the >> per queue information for interrupt with a matrix mediated device >> which hold the configuration and the way to the CRYCB. > [..] >> +static int vfio_ap_get_all_domains(struct ap_matrix_mdev *matrix_mdev, int apid) >> +{ >> + int apqi, apqn; >> + int ret = 0; >> + struct vfio_ap_queue *q; >> + struct list_head q_list; >> + >> + INIT_LIST_HEAD(&q_list); >> + >> + for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, AP_DOMAINS) { >> + apqn = AP_MKQID(apid, apqi); >> + q = vfio_ap_get_queue(apqn, &matrix_dev->free_list); >> + if (!q) { >> + ret = -EADDRNOTAVAIL; >> + goto rewind; >> + } >> + if (q->matrix_mdev) { >> + ret = -EADDRINUSE; > > You tried to get the q from matrix_dev->free_list thus modulo races > q->matrix_mdev should be 0. This change breaks the error codes in a > sense that it becomes impossible to provoke EADDRINUSE (the proper > error code for taken by another matrix_mdev).
I don't understand what you are saying here. AFIU, the idea here is to pull the q from the free list. If there is no q for the apqn on the free list, then that would indicate the queue has not been bound to a driver in which case the appropriate rc is EADDRNOTAVAIL. If the queue has been bound, then a check is done to see whether the queue has been associated with an mdev device. If so, the rc is -EADDRINUSE, which is also appropriate. What am I missing?
> >> + goto rewind; >> + } >> + list_move(&q->list, &q_list); >> + } >> + move_and_set(&q_list, &matrix_mdev->qlist, matrix_mdev); >> return 0; >> +rewind: >> + move_and_set(&q_list, &matrix_dev->free_list, NULL); >> + return ret; >> } >> - >> /** >> - * vfio_ap_mdev_verify_no_sharing >> + * vfio_ap_get_all_cards: >> * >> - * Verifies that the APQNs derived from the cross product of the AP adapter IDs >> - * and AP queue indexes comprising the AP matrix are not configured for another >> - * mediated device. AP queue sharing is not allowed. >> + * @matrix_mdev: the matrix mediated device for which we want to associate >> + * all available queues with a given apqi. >> + * @apqi: The apqi which associated with all defined APID of the >> + * mediated device will define a AP queue. >> * >> - * @matrix_mdev: the mediated matrix device >> + * We define a local list to put all queues we find on the matrix device >> + * free list when associating the apqi with all already defined apid for >> + * this matrix mediated device. >> * >> - * Returns 0 if the APQNs are not shared, otherwise; returns -EADDRINUSE. >> + * If we can get all the devices we roll them to the mediated device list >> + * If we get errors we unroll them to the free list. >> */ >> -static int vfio_ap_mdev_verify_no_sharing(struct ap_matrix_mdev *matrix_mdev) >> +static int vfio_ap_get_all_cards(struct ap_matrix_mdev *matrix_mdev, int apqi) >> { >> - struct ap_matrix_mdev *lstdev; >> - DECLARE_BITMAP(apm, AP_DEVICES); >> - DECLARE_BITMAP(aqm, AP_DOMAINS); >> - >> - list_for_each_entry(lstdev, &matrix_dev->mdev_list, node) { >> - if (matrix_mdev == lstdev) >> - continue; >> - >> - memset(apm, 0, sizeof(apm)); >> - memset(aqm, 0, sizeof(aqm)); >> - >> - /* >> - * We work on full longs, as we can only exclude the leftover >> - * bits in non-inverse order. The leftover is all zeros. >> - */ >> - if (!bitmap_and(apm, matrix_mdev->matrix.apm, >> - lstdev->matrix.apm, AP_DEVICES)) >> - continue; >> - >> - if (!bitmap_and(aqm, matrix_mdev->matrix.aqm, >> - lstdev->matrix.aqm, AP_DOMAINS)) >> - continue; >> - >> - return -EADDRINUSE; >> + int apid, apqn; >> + int ret = 0; >> + struct vfio_ap_queue *q; >> + struct list_head q_list; >> + struct ap_matrix_mdev *tmp = NULL; >> + >> + INIT_LIST_HEAD(&q_list); >> + >> + for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, AP_DEVICES) { >> + apqn = AP_MKQID(apid, apqi); >> + q = vfio_ap_get_queue(apqn, &matrix_dev->free_list); >> + if (!q) { >> + ret = -EADDRNOTAVAIL; >> + goto rewind; >> + } >> + if (q->matrix_mdev) { >> + ret = -EADDRINUSE; > > Same here! > > Regards, > Halil > >> + goto rewind; >> + } >> + list_move(&q->list, &q_list); >> } > > [..] >
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