static struct vfio_ap_queue *vfio_ap_find_queue(int apqn);
static const struct vfio_device_ops vfio_ap_matrix_dev_ops;
+/**
+ * get_update_locks_for_kvm: Acquire the locks required to dynamically update a
+ * KVM guest's APCB in the proper order.
+ *
+ * @kvm: a pointer to a struct kvm object containing the 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. 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 @kvm is NULL, the KVM lock will not be taken.
+ */
+static inline void get_update_locks_for_kvm(struct kvm *kvm)
+{
+ mutex_lock(&matrix_dev->guests_lock);
+ if (kvm)
+ mutex_lock(&kvm->lock);
+ mutex_lock(&matrix_dev->mdevs_lock);
+}
+
+/**
+ * release_update_locks_for_kvm: Release the locks used to dynamically update a
+ * KVM guest's APCB in the proper order.
+ *
+ * @kvm: a pointer to a struct kvm object containing the KVM guest's APCB.
+ *
+ * The proper unlocking order is:
+ * 1. matrix_dev->mdevs_lock
+ * 2. kvm->lock
+ * 3. matrix_dev->guests_lock
+ *
+ * Note: If @kvm is NULL, the KVM lock will not be released.
+ */
+static inline void release_update_locks_for_kvm(struct kvm *kvm)
+{
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ if (kvm)
+ mutex_unlock(&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
kvm->arch.crypto.pqap_hook = &matrix_mdev->pqap_hook;
up_write(&kvm->arch.crypto.pqap_hook_rwsem);
- mutex_lock(&kvm->lock);
- mutex_lock(&matrix_dev->mdevs_lock);
+ get_update_locks_for_kvm(kvm);
list_for_each_entry(m, &matrix_dev->mdev_list, node) {
if (m != matrix_mdev && m->kvm == kvm) {
- mutex_unlock(&kvm->lock);
- mutex_unlock(&matrix_dev->mdevs_lock);
+ release_update_locks_for_kvm(kvm);
return -EPERM;
}
}
matrix_mdev->shadow_apcb.aqm,
matrix_mdev->shadow_apcb.adm);
- mutex_unlock(&kvm->lock);
- mutex_unlock(&matrix_dev->mdevs_lock);
+ release_update_locks_for_kvm(kvm);
}
return 0;
kvm->arch.crypto.pqap_hook = NULL;
up_write(&kvm->arch.crypto.pqap_hook_rwsem);
- mutex_lock(&kvm->lock);
- mutex_lock(&matrix_dev->mdevs_lock);
+ get_update_locks_for_kvm(kvm);
kvm_arch_crypto_clear_masks(kvm);
vfio_ap_mdev_reset_queues(matrix_mdev);
kvm_put_kvm(kvm);
matrix_mdev->kvm = NULL;
- mutex_unlock(&kvm->lock);
- mutex_unlock(&matrix_dev->mdevs_lock);
+ release_update_locks_for_kvm(kvm);
}
}