diff options
| -rw-r--r-- | drivers/s390/crypto/vfio_ap_ops.c | 124 |
1 files changed, 85 insertions, 39 deletions
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c index dcd36d427b86..fd0f0f241197 100644 --- a/drivers/s390/crypto/vfio_ap_ops.c +++ b/drivers/s390/crypto/vfio_ap_ops.c @@ -125,6 +125,72 @@ static inline void release_update_locks_for_mdev(struct ap_matrix_mdev *matrix_m } /** + * get_update_locks_by_apqn: Find the mdev to which an APQN is assigned and + * acquire the locks required to update the APCB of + * the KVM guest to which the mdev is attached. + * + * @apqn: the APQN of a queue device. + * + * The proper locking order is: + * 1. matrix_dev->guests_lock: required to use the KVM pointer to update a KVM + * guest's APCB. + * 2. matrix_mdev->kvm->lock: required to update a guest's APCB + * 3. matrix_dev->mdevs_lock: required to access data stored in a matrix_mdev + * + * Note: If @apqn is not assigned to a matrix_mdev, the matrix_mdev->kvm->lock + * will not be taken. + * + * Return: the ap_matrix_mdev object to which @apqn is assigned or NULL if @apqn + * is not assigned to an ap_matrix_mdev. + */ +static struct ap_matrix_mdev *get_update_locks_by_apqn(int apqn) +{ + struct ap_matrix_mdev *matrix_mdev; + + mutex_lock(&matrix_dev->guests_lock); + + list_for_each_entry(matrix_mdev, &matrix_dev->mdev_list, node) { + if (test_bit_inv(AP_QID_CARD(apqn), matrix_mdev->matrix.apm) && + test_bit_inv(AP_QID_QUEUE(apqn), matrix_mdev->matrix.aqm)) { + if (matrix_mdev->kvm) + mutex_lock(&matrix_mdev->kvm->lock); + + mutex_lock(&matrix_dev->mdevs_lock); + + return matrix_mdev; + } + } + + mutex_lock(&matrix_dev->mdevs_lock); + + return NULL; +} + +/** + * get_update_locks_for_queue: get the locks required to update the APCB of the + * KVM guest to which the matrix mdev linked to a + * vfio_ap_queue object is attached. + * + * @q: a pointer to a vfio_ap_queue object. + * + * The proper locking order is: + * 1. q->matrix_dev->guests_lock: required to use the KVM pointer to update a + * KVM guest's APCB. + * 2. q->matrix_mdev->kvm->lock: required to update a guest's APCB + * 3. matrix_dev->mdevs_lock: required to access data stored in matrix_mdev + * + * Note: if @queue is not linked to an ap_matrix_mdev object, the KVM lock + * will not be taken. + */ +static inline void get_update_locks_for_queue(struct vfio_ap_queue *q) +{ + mutex_lock(&matrix_dev->guests_lock); + if (q->matrix_mdev && q->matrix_mdev->kvm) + mutex_lock(&q->matrix_mdev->kvm->lock); + mutex_lock(&matrix_dev->mdevs_lock); +} + +/** * vfio_ap_mdev_get_queue - retrieve a queue with a specific APQN from a * hash table of queues assigned to a matrix mdev * @matrix_mdev: the matrix mdev @@ -622,21 +688,17 @@ static int vfio_ap_mdev_probe(struct mdev_device *mdev) matrix_mdev->pqap_hook = handle_pqap; vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->shadow_apcb); hash_init(matrix_mdev->qtable.queues); - dev_set_drvdata(&mdev->dev, matrix_mdev); - mutex_lock(&matrix_dev->mdevs_lock); - list_add(&matrix_mdev->node, &matrix_dev->mdev_list); - mutex_unlock(&matrix_dev->mdevs_lock); ret = vfio_register_emulated_iommu_dev(&matrix_mdev->vdev); if (ret) goto err_list; dev_set_drvdata(&mdev->dev, matrix_mdev); + mutex_lock(&matrix_dev->mdevs_lock); + list_add(&matrix_mdev->node, &matrix_dev->mdev_list); + mutex_unlock(&matrix_dev->mdevs_lock); return 0; err_list: - mutex_lock(&matrix_dev->mdevs_lock); - list_del(&matrix_mdev->node); - mutex_unlock(&matrix_dev->mdevs_lock); vfio_uninit_group_dev(&matrix_mdev->vdev); kfree(matrix_mdev); err_dec_available: @@ -699,11 +761,13 @@ static void vfio_ap_mdev_remove(struct mdev_device *mdev) vfio_unregister_group_dev(&matrix_mdev->vdev); + mutex_lock(&matrix_dev->guests_lock); mutex_lock(&matrix_dev->mdevs_lock); vfio_ap_mdev_reset_queues(matrix_mdev); vfio_ap_mdev_unlink_fr_queues(matrix_mdev); list_del(&matrix_mdev->node); mutex_unlock(&matrix_dev->mdevs_lock); + mutex_unlock(&matrix_dev->guests_lock); vfio_uninit_group_dev(&matrix_mdev->vdev); kfree(matrix_mdev); atomic_inc(&matrix_dev->available_instances); @@ -1701,32 +1765,11 @@ void vfio_ap_mdev_unregister(void) mdev_unregister_driver(&vfio_ap_matrix_driver); } -/* - * vfio_ap_queue_link_mdev - * - * @q: The queue to link with the matrix mdev. - * - * Links @q with the matrix mdev to which the queue's APQN is assigned. - */ -static void vfio_ap_queue_link_mdev(struct vfio_ap_queue *q) -{ - unsigned long apid = AP_QID_CARD(q->apqn); - unsigned long apqi = AP_QID_QUEUE(q->apqn); - struct ap_matrix_mdev *matrix_mdev; - - list_for_each_entry(matrix_mdev, &matrix_dev->mdev_list, node) { - if (test_bit_inv(apid, matrix_mdev->matrix.apm) && - test_bit_inv(apqi, matrix_mdev->matrix.aqm)) { - vfio_ap_mdev_link_queue(matrix_mdev, q); - break; - } - } -} - int vfio_ap_mdev_probe_queue(struct ap_device *apdev) { int ret; struct vfio_ap_queue *q; + struct ap_matrix_mdev *matrix_mdev; ret = sysfs_create_group(&apdev->device.kobj, &vfio_queue_attr_group); if (ret) @@ -1736,17 +1779,18 @@ int vfio_ap_mdev_probe_queue(struct ap_device *apdev) if (!q) return -ENOMEM; - mutex_lock(&matrix_dev->mdevs_lock); q->apqn = to_ap_queue(&apdev->device)->qid; q->saved_isc = VFIO_AP_ISC_INVALID; - vfio_ap_queue_link_mdev(q); - if (q->matrix_mdev) { - vfio_ap_mdev_filter_matrix(q->matrix_mdev->matrix.apm, - q->matrix_mdev->matrix.aqm, - q->matrix_mdev); + matrix_mdev = get_update_locks_by_apqn(q->apqn); + + if (matrix_mdev) { + vfio_ap_mdev_link_queue(matrix_mdev, q); + vfio_ap_mdev_filter_matrix(matrix_mdev->matrix.apm, + matrix_mdev->matrix.aqm, + matrix_mdev); } dev_set_drvdata(&apdev->device, q); - mutex_unlock(&matrix_dev->mdevs_lock); + release_update_locks_for_mdev(matrix_mdev); return 0; } @@ -1755,12 +1799,14 @@ void vfio_ap_mdev_remove_queue(struct ap_device *apdev) { unsigned long apid; struct vfio_ap_queue *q; + struct ap_matrix_mdev *matrix_mdev; - mutex_lock(&matrix_dev->mdevs_lock); sysfs_remove_group(&apdev->device.kobj, &vfio_queue_attr_group); q = dev_get_drvdata(&apdev->device); + get_update_locks_for_queue(q); + matrix_mdev = q->matrix_mdev; - if (q->matrix_mdev) { + if (matrix_mdev) { vfio_ap_unlink_queue_fr_mdev(q); apid = AP_QID_CARD(q->apqn); @@ -1771,5 +1817,5 @@ void vfio_ap_mdev_remove_queue(struct ap_device *apdev) vfio_ap_mdev_reset_queue(q, 1); dev_set_drvdata(&apdev->device, NULL); kfree(q); - mutex_unlock(&matrix_dev->mdevs_lock); + release_update_locks_for_mdev(matrix_mdev); } |