/* Init poll structure */
void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
- __poll_t mask, struct vhost_dev *dev)
+ __poll_t mask, struct vhost_dev *dev,
+ struct vhost_virtqueue *vq)
{
init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
init_poll_funcptr(&poll->table, vhost_poll_func);
poll->mask = mask;
poll->dev = dev;
poll->wqh = NULL;
+ poll->vq = vq;
vhost_work_init(&poll->work, fn);
}
}
EXPORT_SYMBOL_GPL(vhost_poll_stop);
-void vhost_dev_flush(struct vhost_dev *dev)
+static void vhost_worker_queue(struct vhost_worker *worker,
+ struct vhost_work *work)
+{
+ if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) {
+ /* We can only add the work to the list after we're
+ * sure it was not in the list.
+ * test_and_set_bit() implies a memory barrier.
+ */
+ llist_add(&work->node, &worker->work_list);
+ vhost_task_wake(worker->vtsk);
+ }
+}
+
+bool vhost_vq_work_queue(struct vhost_virtqueue *vq, struct vhost_work *work)
+{
+ struct vhost_worker *worker;
+ bool queued = false;
+
+ rcu_read_lock();
+ worker = rcu_dereference(vq->worker);
+ if (worker) {
+ queued = true;
+ vhost_worker_queue(worker, work);
+ }
+ rcu_read_unlock();
+
+ return queued;
+}
+EXPORT_SYMBOL_GPL(vhost_vq_work_queue);
+
+void vhost_vq_flush(struct vhost_virtqueue *vq)
{
struct vhost_flush_struct flush;
- if (dev->worker.vtsk) {
- init_completion(&flush.wait_event);
- vhost_work_init(&flush.work, vhost_flush_work);
+ init_completion(&flush.wait_event);
+ vhost_work_init(&flush.work, vhost_flush_work);
- vhost_work_queue(dev, &flush.work);
+ if (vhost_vq_work_queue(vq, &flush.work))
wait_for_completion(&flush.wait_event);
- }
}
-EXPORT_SYMBOL_GPL(vhost_dev_flush);
+EXPORT_SYMBOL_GPL(vhost_vq_flush);
-void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
+/**
+ * vhost_worker_flush - flush a worker
+ * @worker: worker to flush
+ *
+ * This does not use RCU to protect the worker, so the device or worker
+ * mutex must be held.
+ */
+static void vhost_worker_flush(struct vhost_worker *worker)
{
- if (!dev->worker.vtsk)
- return;
+ struct vhost_flush_struct flush;
- if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) {
- /* We can only add the work to the list after we're
- * sure it was not in the list.
- * test_and_set_bit() implies a memory barrier.
- */
- llist_add(&work->node, &dev->worker.work_list);
- vhost_task_wake(dev->worker.vtsk);
+ init_completion(&flush.wait_event);
+ vhost_work_init(&flush.work, vhost_flush_work);
+
+ vhost_worker_queue(worker, &flush.work);
+ wait_for_completion(&flush.wait_event);
+}
+
+void vhost_dev_flush(struct vhost_dev *dev)
+{
+ struct vhost_worker *worker;
+ unsigned long i;
+
+ xa_for_each(&dev->worker_xa, i, worker) {
+ mutex_lock(&worker->mutex);
+ if (!worker->attachment_cnt) {
+ mutex_unlock(&worker->mutex);
+ continue;
+ }
+ vhost_worker_flush(worker);
+ mutex_unlock(&worker->mutex);
}
}
-EXPORT_SYMBOL_GPL(vhost_work_queue);
+EXPORT_SYMBOL_GPL(vhost_dev_flush);
/* A lockless hint for busy polling code to exit the loop */
-bool vhost_has_work(struct vhost_dev *dev)
+bool vhost_vq_has_work(struct vhost_virtqueue *vq)
{
- return !llist_empty(&dev->worker.work_list);
+ struct vhost_worker *worker;
+ bool has_work = false;
+
+ rcu_read_lock();
+ worker = rcu_dereference(vq->worker);
+ if (worker && !llist_empty(&worker->work_list))
+ has_work = true;
+ rcu_read_unlock();
+
+ return has_work;
}
-EXPORT_SYMBOL_GPL(vhost_has_work);
+EXPORT_SYMBOL_GPL(vhost_vq_has_work);
void vhost_poll_queue(struct vhost_poll *poll)
{
- vhost_work_queue(poll->dev, &poll->work);
+ vhost_vq_work_queue(poll->vq, &poll->work);
}
EXPORT_SYMBOL_GPL(vhost_poll_queue);
vq->busyloop_timeout = 0;
vq->umem = NULL;
vq->iotlb = NULL;
+ rcu_assign_pointer(vq->worker, NULL);
vhost_vring_call_reset(&vq->call_ctx);
__vhost_vq_meta_reset(vq);
}
dev->umem = NULL;
dev->iotlb = NULL;
dev->mm = NULL;
- memset(&dev->worker, 0, sizeof(dev->worker));
- init_llist_head(&dev->worker.work_list);
dev->iov_limit = iov_limit;
dev->weight = weight;
dev->byte_weight = byte_weight;
INIT_LIST_HEAD(&dev->read_list);
INIT_LIST_HEAD(&dev->pending_list);
spin_lock_init(&dev->iotlb_lock);
-
+ xa_init_flags(&dev->worker_xa, XA_FLAGS_ALLOC);
for (i = 0; i < dev->nvqs; ++i) {
vq = dev->vqs[i];
vhost_vq_reset(dev, vq);
if (vq->handle_kick)
vhost_poll_init(&vq->poll, vq->handle_kick,
- EPOLLIN, dev);
+ EPOLLIN, dev, vq);
}
}
EXPORT_SYMBOL_GPL(vhost_dev_init);
dev->mm = NULL;
}
-static void vhost_worker_free(struct vhost_dev *dev)
+static void vhost_worker_destroy(struct vhost_dev *dev,
+ struct vhost_worker *worker)
+{
+ if (!worker)
+ return;
+
+ WARN_ON(!llist_empty(&worker->work_list));
+ xa_erase(&dev->worker_xa, worker->id);
+ vhost_task_stop(worker->vtsk);
+ kfree(worker);
+}
+
+static void vhost_workers_free(struct vhost_dev *dev)
{
- if (!dev->worker.vtsk)
+ struct vhost_worker *worker;
+ unsigned long i;
+
+ if (!dev->use_worker)
return;
- WARN_ON(!llist_empty(&dev->worker.work_list));
- vhost_task_stop(dev->worker.vtsk);
- dev->worker.kcov_handle = 0;
- dev->worker.vtsk = NULL;
+ for (i = 0; i < dev->nvqs; i++)
+ rcu_assign_pointer(dev->vqs[i]->worker, NULL);
+ /*
+ * Free the default worker we created and cleanup workers userspace
+ * created but couldn't clean up (it forgot or crashed).
+ */
+ xa_for_each(&dev->worker_xa, i, worker)
+ vhost_worker_destroy(dev, worker);
+ xa_destroy(&dev->worker_xa);
}
-static int vhost_worker_create(struct vhost_dev *dev)
+static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev)
{
+ struct vhost_worker *worker;
struct vhost_task *vtsk;
char name[TASK_COMM_LEN];
+ int ret;
+ u32 id;
+
+ worker = kzalloc(sizeof(*worker), GFP_KERNEL_ACCOUNT);
+ if (!worker)
+ return NULL;
snprintf(name, sizeof(name), "vhost-%d", current->pid);
- vtsk = vhost_task_create(vhost_worker, &dev->worker, name);
+ vtsk = vhost_task_create(vhost_worker, worker, name);
if (!vtsk)
- return -ENOMEM;
+ goto free_worker;
+
+ mutex_init(&worker->mutex);
+ init_llist_head(&worker->work_list);
+ worker->kcov_handle = kcov_common_handle();
+ worker->vtsk = vtsk;
- dev->worker.kcov_handle = kcov_common_handle();
- dev->worker.vtsk = vtsk;
vhost_task_start(vtsk);
+
+ ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b, GFP_KERNEL);
+ if (ret < 0)
+ goto stop_worker;
+ worker->id = id;
+
+ return worker;
+
+stop_worker:
+ vhost_task_stop(vtsk);
+free_worker:
+ kfree(worker);
+ return NULL;
+}
+
+/* Caller must have device mutex */
+static void __vhost_vq_attach_worker(struct vhost_virtqueue *vq,
+ struct vhost_worker *worker)
+{
+ struct vhost_worker *old_worker;
+
+ old_worker = rcu_dereference_check(vq->worker,
+ lockdep_is_held(&vq->dev->mutex));
+
+ mutex_lock(&worker->mutex);
+ worker->attachment_cnt++;
+ mutex_unlock(&worker->mutex);
+ rcu_assign_pointer(vq->worker, worker);
+
+ if (!old_worker)
+ return;
+ /*
+ * Take the worker mutex to make sure we see the work queued from
+ * device wide flushes which doesn't use RCU for execution.
+ */
+ mutex_lock(&old_worker->mutex);
+ old_worker->attachment_cnt--;
+ /*
+ * We don't want to call synchronize_rcu for every vq during setup
+ * because it will slow down VM startup. If we haven't done
+ * VHOST_SET_VRING_KICK and not done the driver specific
+ * SET_ENDPOINT/RUNNUNG then we can skip the sync since there will
+ * not be any works queued for scsi and net.
+ */
+ mutex_lock(&vq->mutex);
+ if (!vhost_vq_get_backend(vq) && !vq->kick) {
+ mutex_unlock(&vq->mutex);
+ mutex_unlock(&old_worker->mutex);
+ /*
+ * vsock can queue anytime after VHOST_VSOCK_SET_GUEST_CID.
+ * Warn if it adds support for multiple workers but forgets to
+ * handle the early queueing case.
+ */
+ WARN_ON(!old_worker->attachment_cnt &&
+ !llist_empty(&old_worker->work_list));
+ return;
+ }
+ mutex_unlock(&vq->mutex);
+
+ /* Make sure new vq queue/flush/poll calls see the new worker */
+ synchronize_rcu();
+ /* Make sure whatever was queued gets run */
+ vhost_worker_flush(old_worker);
+ mutex_unlock(&old_worker->mutex);
+}
+
+ /* Caller must have device mutex */
+static int vhost_vq_attach_worker(struct vhost_virtqueue *vq,
+ struct vhost_vring_worker *info)
+{
+ unsigned long index = info->worker_id;
+ struct vhost_dev *dev = vq->dev;
+ struct vhost_worker *worker;
+
+ if (!dev->use_worker)
+ return -EINVAL;
+
+ worker = xa_find(&dev->worker_xa, &index, UINT_MAX, XA_PRESENT);
+ if (!worker || worker->id != info->worker_id)
+ return -ENODEV;
+
+ __vhost_vq_attach_worker(vq, worker);
+ return 0;
+}
+
+/* Caller must have device mutex */
+static int vhost_new_worker(struct vhost_dev *dev,
+ struct vhost_worker_state *info)
+{
+ struct vhost_worker *worker;
+
+ worker = vhost_worker_create(dev);
+ if (!worker)
+ return -ENOMEM;
+
+ info->worker_id = worker->id;
+ return 0;
+}
+
+/* Caller must have device mutex */
+static int vhost_free_worker(struct vhost_dev *dev,
+ struct vhost_worker_state *info)
+{
+ unsigned long index = info->worker_id;
+ struct vhost_worker *worker;
+
+ worker = xa_find(&dev->worker_xa, &index, UINT_MAX, XA_PRESENT);
+ if (!worker || worker->id != info->worker_id)
+ return -ENODEV;
+
+ mutex_lock(&worker->mutex);
+ if (worker->attachment_cnt) {
+ mutex_unlock(&worker->mutex);
+ return -EBUSY;
+ }
+ mutex_unlock(&worker->mutex);
+
+ vhost_worker_destroy(dev, worker);
return 0;
}
+static int vhost_get_vq_from_user(struct vhost_dev *dev, void __user *argp,
+ struct vhost_virtqueue **vq, u32 *id)
+{
+ u32 __user *idxp = argp;
+ u32 idx;
+ long r;
+
+ r = get_user(idx, idxp);
+ if (r < 0)
+ return r;
+
+ if (idx >= dev->nvqs)
+ return -ENOBUFS;
+
+ idx = array_index_nospec(idx, dev->nvqs);
+
+ *vq = dev->vqs[idx];
+ *id = idx;
+ return 0;
+}
+
+/* Caller must have device mutex */
+long vhost_worker_ioctl(struct vhost_dev *dev, unsigned int ioctl,
+ void __user *argp)
+{
+ struct vhost_vring_worker ring_worker;
+ struct vhost_worker_state state;
+ struct vhost_worker *worker;
+ struct vhost_virtqueue *vq;
+ long ret;
+ u32 idx;
+
+ if (!dev->use_worker)
+ return -EINVAL;
+
+ if (!vhost_dev_has_owner(dev))
+ return -EINVAL;
+
+ ret = vhost_dev_check_owner(dev);
+ if (ret)
+ return ret;
+
+ switch (ioctl) {
+ /* dev worker ioctls */
+ case VHOST_NEW_WORKER:
+ ret = vhost_new_worker(dev, &state);
+ if (!ret && copy_to_user(argp, &state, sizeof(state)))
+ ret = -EFAULT;
+ return ret;
+ case VHOST_FREE_WORKER:
+ if (copy_from_user(&state, argp, sizeof(state)))
+ return -EFAULT;
+ return vhost_free_worker(dev, &state);
+ /* vring worker ioctls */
+ case VHOST_ATTACH_VRING_WORKER:
+ case VHOST_GET_VRING_WORKER:
+ break;
+ default:
+ return -ENOIOCTLCMD;
+ }
+
+ ret = vhost_get_vq_from_user(dev, argp, &vq, &idx);
+ if (ret)
+ return ret;
+
+ switch (ioctl) {
+ case VHOST_ATTACH_VRING_WORKER:
+ if (copy_from_user(&ring_worker, argp, sizeof(ring_worker))) {
+ ret = -EFAULT;
+ break;
+ }
+
+ ret = vhost_vq_attach_worker(vq, &ring_worker);
+ break;
+ case VHOST_GET_VRING_WORKER:
+ worker = rcu_dereference_check(vq->worker,
+ lockdep_is_held(&dev->mutex));
+ if (!worker) {
+ ret = -EINVAL;
+ break;
+ }
+
+ ring_worker.index = idx;
+ ring_worker.worker_id = worker->id;
+
+ if (copy_to_user(argp, &ring_worker, sizeof(ring_worker)))
+ ret = -EFAULT;
+ break;
+ default:
+ ret = -ENOIOCTLCMD;
+ break;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(vhost_worker_ioctl);
+
/* Caller should have device mutex */
long vhost_dev_set_owner(struct vhost_dev *dev)
{
- int err;
+ struct vhost_worker *worker;
+ int err, i;
/* Is there an owner already? */
if (vhost_dev_has_owner(dev)) {
vhost_attach_mm(dev);
- if (dev->use_worker) {
- err = vhost_worker_create(dev);
- if (err)
- goto err_worker;
- }
-
err = vhost_dev_alloc_iovecs(dev);
if (err)
goto err_iovecs;
+ if (dev->use_worker) {
+ /*
+ * This should be done last, because vsock can queue work
+ * before VHOST_SET_OWNER so it simplifies the failure path
+ * below since we don't have to worry about vsock queueing
+ * while we free the worker.
+ */
+ worker = vhost_worker_create(dev);
+ if (!worker) {
+ err = -ENOMEM;
+ goto err_worker;
+ }
+
+ for (i = 0; i < dev->nvqs; i++)
+ __vhost_vq_attach_worker(dev->vqs[i], worker);
+ }
+
return 0;
-err_iovecs:
- vhost_worker_free(dev);
+
err_worker:
+ vhost_dev_free_iovecs(dev);
+err_iovecs:
vhost_detach_mm(dev);
err_mm:
return err;
dev->iotlb = NULL;
vhost_clear_msg(dev);
wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
- vhost_worker_free(dev);
+ vhost_workers_free(dev);
vhost_detach_mm(dev);
}
EXPORT_SYMBOL_GPL(vhost_dev_cleanup);
struct file *eventfp, *filep = NULL;
bool pollstart = false, pollstop = false;
struct eventfd_ctx *ctx = NULL;
- u32 __user *idxp = argp;
struct vhost_virtqueue *vq;
struct vhost_vring_state s;
struct vhost_vring_file f;
u32 idx;
long r;
- r = get_user(idx, idxp);
+ r = vhost_get_vq_from_user(d, argp, &vq, &idx);
if (r < 0)
return r;
- if (idx >= d->nvqs)
- return -ENOBUFS;
-
- idx = array_index_nospec(idx, d->nvqs);
- vq = d->vqs[idx];
if (ioctl == VHOST_SET_VRING_NUM ||
ioctl == VHOST_SET_VRING_ADDR) {
projects / linux-2.6-block.git / blobdiff