diff options
Diffstat (limited to 'drivers/s390/crypto/vfio_ap_ops.c')
| -rw-r--r-- | drivers/s390/crypto/vfio_ap_ops.c | 71 |
1 files changed, 59 insertions, 12 deletions
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c index 20f779dd8ab9..dcd36d427b86 100644 --- a/drivers/s390/crypto/vfio_ap_ops.c +++ b/drivers/s390/crypto/vfio_ap_ops.c @@ -78,6 +78,53 @@ static inline void release_update_locks_for_kvm(struct kvm *kvm) } /** + * get_update_locks_for_mdev: Acquire the locks required to dynamically update a + * KVM guest's APCB in the proper order. + * + * @matrix_mdev: a pointer to a struct ap_matrix_mdev object containing the AP + * configuration data to use to update a KVM guest's APCB. + * + * 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 @matrix_mdev is NULL or is not attached to a KVM guest, the KVM + * lock will not be taken. + */ +static inline void get_update_locks_for_mdev(struct ap_matrix_mdev *matrix_mdev) +{ + mutex_lock(&matrix_dev->guests_lock); + if (matrix_mdev && matrix_mdev->kvm) + mutex_lock(&matrix_mdev->kvm->lock); + mutex_lock(&matrix_dev->mdevs_lock); +} + +/** + * release_update_locks_for_mdev: Release the locks used to dynamically update a + * KVM guest's APCB in the proper order. + * + * @matrix_mdev: a pointer to a struct ap_matrix_mdev object containing the AP + * configuration data to use to update a KVM guest's APCB. + * + * The proper unlocking order is: + * 1. matrix_dev->mdevs_lock + * 2. matrix_mdev->kvm->lock + * 3. matrix_dev->guests_lock + * + * Note: If @matrix_mdev is NULL or is not attached to a KVM guest, the KVM + * lock will not be released. + */ +static inline void release_update_locks_for_mdev(struct ap_matrix_mdev *matrix_mdev) +{ + mutex_unlock(&matrix_dev->mdevs_lock); + if (matrix_mdev && matrix_mdev->kvm) + mutex_unlock(&matrix_mdev->kvm->lock); + mutex_unlock(&matrix_dev->guests_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 @@ -832,7 +879,7 @@ static ssize_t assign_adapter_store(struct device *dev, struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev); - mutex_lock(&matrix_dev->mdevs_lock); + get_update_locks_for_mdev(matrix_mdev); /* If the KVM guest is running, disallow assignment of adapter */ if (matrix_mdev->kvm) { @@ -864,7 +911,7 @@ static ssize_t assign_adapter_store(struct device *dev, matrix_mdev->matrix.aqm, matrix_mdev); ret = count; done: - mutex_unlock(&matrix_dev->mdevs_lock); + release_update_locks_for_mdev(matrix_mdev); return ret; } @@ -907,7 +954,7 @@ static ssize_t unassign_adapter_store(struct device *dev, unsigned long apid; struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev); - mutex_lock(&matrix_dev->mdevs_lock); + get_update_locks_for_mdev(matrix_mdev); /* If the KVM guest is running, disallow unassignment of adapter */ if (matrix_mdev->kvm) { @@ -932,7 +979,7 @@ static ssize_t unassign_adapter_store(struct device *dev, ret = count; done: - mutex_unlock(&matrix_dev->mdevs_lock); + release_update_locks_for_mdev(matrix_mdev); return ret; } static DEVICE_ATTR_WO(unassign_adapter); @@ -987,7 +1034,7 @@ static ssize_t assign_domain_store(struct device *dev, struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev); unsigned long max_apqi = matrix_mdev->matrix.aqm_max; - mutex_lock(&matrix_dev->mdevs_lock); + get_update_locks_for_mdev(matrix_mdev); /* If the KVM guest is running, disallow assignment of domain */ if (matrix_mdev->kvm) { @@ -1018,7 +1065,7 @@ static ssize_t assign_domain_store(struct device *dev, matrix_mdev); ret = count; done: - mutex_unlock(&matrix_dev->mdevs_lock); + release_update_locks_for_mdev(matrix_mdev); return ret; } @@ -1061,7 +1108,7 @@ static ssize_t unassign_domain_store(struct device *dev, unsigned long apqi; struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev); - mutex_lock(&matrix_dev->mdevs_lock); + get_update_locks_for_mdev(matrix_mdev); /* If the KVM guest is running, disallow unassignment of domain */ if (matrix_mdev->kvm) { @@ -1087,7 +1134,7 @@ static ssize_t unassign_domain_store(struct device *dev, ret = count; done: - mutex_unlock(&matrix_dev->mdevs_lock); + release_update_locks_for_mdev(matrix_mdev); return ret; } static DEVICE_ATTR_WO(unassign_domain); @@ -1114,7 +1161,7 @@ static ssize_t assign_control_domain_store(struct device *dev, unsigned long id; struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev); - mutex_lock(&matrix_dev->mdevs_lock); + get_update_locks_for_mdev(matrix_mdev); /* If the KVM guest is running, disallow assignment of control domain */ if (matrix_mdev->kvm) { @@ -1140,7 +1187,7 @@ static ssize_t assign_control_domain_store(struct device *dev, vfio_ap_mdev_filter_cdoms(matrix_mdev); ret = count; done: - mutex_unlock(&matrix_dev->mdevs_lock); + release_update_locks_for_mdev(matrix_mdev); return ret; } static DEVICE_ATTR_WO(assign_control_domain); @@ -1168,7 +1215,7 @@ static ssize_t unassign_control_domain_store(struct device *dev, struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev); unsigned long max_domid = matrix_mdev->matrix.adm_max; - mutex_lock(&matrix_dev->mdevs_lock); + get_update_locks_for_mdev(matrix_mdev); /* If a KVM guest is running, disallow unassignment of control domain */ if (matrix_mdev->kvm) { @@ -1191,7 +1238,7 @@ static ssize_t unassign_control_domain_store(struct device *dev, ret = count; done: - mutex_unlock(&matrix_dev->mdevs_lock); + release_update_locks_for_mdev(matrix_mdev); return ret; } static DEVICE_ATTR_WO(unassign_control_domain); |