1 files changed, 258 insertions, 48 deletions

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index d219070..29e850a 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -74,6 +74,22 @@ static int move_iovec_hdr(struct iovec *from, struct iovec *to,
 	}
 	return seg;
 }
+/* Copy iovec entries for len bytes from iovec. */
+static void copy_iovec_hdr(const struct iovec *from, struct iovec *to,
+			   size_t len, int iovcount)
+{
+	int seg = 0;
+	size_t size;
+	while (len && seg < iovcount) {
+		size = min(from->iov_len, len);
+		to->iov_base = from->iov_base;
+		to->iov_len = size;
+		len -= size;
+		++from;
+		++to;
+		++seg;
+	}
+}
 
 /* Caller must have TX VQ lock */
 static void tx_poll_stop(struct vhost_net *net)
@@ -129,7 +145,7 @@ static void handle_tx(struct vhost_net *net)
 
 	if (wmem < sock->sk->sk_sndbuf / 2)
 		tx_poll_stop(net);
-	hdr_size = vq->hdr_size;
+	hdr_size = vq->vhost_hlen;
 
 	for (;;) {
 		head = vhost_get_vq_desc(&net->dev, vq, vq->iov,
@@ -172,7 +188,7 @@ static void handle_tx(struct vhost_net *net)
 		/* TODO: Check specific error and bomb out unless ENOBUFS? */
 		err = sock->ops->sendmsg(NULL, sock, &msg, len);
 		if (unlikely(err < 0)) {
-			vhost_discard_vq_desc(vq);
+			vhost_discard_vq_desc(vq, 1);
 			tx_poll_start(net, sock);
 			break;
 		}
@@ -191,9 +207,82 @@ static void handle_tx(struct vhost_net *net)
 	unuse_mm(net->dev.mm);
 }
 
+static int peek_head_len(struct sock *sk)
+{
+	struct sk_buff *head;
+	int len = 0;
+
+	lock_sock(sk);
+	head = skb_peek(&sk->sk_receive_queue);
+	if (head)
+		len = head->len;
+	release_sock(sk);
+	return len;
+}
+
+/* This is a multi-buffer version of vhost_get_desc, that works if
+ *	vq has read descriptors only.
+ * @vq		- the relevant virtqueue
+ * @datalen	- data length we'll be reading
+ * @iovcount	- returned count of io vectors we fill
+ * @log		- vhost log
+ * @log_num	- log offset
+ *	returns number of buffer heads allocated, negative on error
+ */
+static int get_rx_bufs(struct vhost_virtqueue *vq,
+		       struct vring_used_elem *heads,
+		       int datalen,
+		       unsigned *iovcount,
+		       struct vhost_log *log,
+		       unsigned *log_num)
+{
+	unsigned int out, in;
+	int seg = 0;
+	int headcount = 0;
+	unsigned d;
+	int r, nlogs = 0;
+
+	while (datalen > 0) {
+		if (unlikely(headcount >= VHOST_NET_MAX_SG)) {
+			r = -ENOBUFS;
+			goto err;
+		}
+		d = vhost_get_vq_desc(vq->dev, vq, vq->iov + seg,
+				      ARRAY_SIZE(vq->iov) - seg, &out,
+				      &in, log, log_num);
+		if (d == vq->num) {
+			r = 0;
+			goto err;
+		}
+		if (unlikely(out || in <= 0)) {
+			vq_err(vq, "unexpected descriptor format for RX: "
+				"out %d, in %d\n", out, in);
+			r = -EINVAL;
+			goto err;
+		}
+		if (unlikely(log)) {
+			nlogs += *log_num;
+			log += *log_num;
+		}
+		heads[headcount].id = d;
+		heads[headcount].len = iov_length(vq->iov + seg, in);
+		datalen -= heads[headcount].len;
+		++headcount;
+		seg += in;
+	}
+	heads[headcount - 1].len += datalen;
+	*iovcount = seg;
+	if (unlikely(log))
+		*log_num = nlogs;
+	return headcount;
+err:
+	vhost_discard_vq_desc(vq, headcount);
+	return r;
+}
+
 /* Expects to be always run from workqueue - which acts as
  * read-size critical section for our kind of RCU. */
-static void handle_rx(struct vhost_net *net)
+static void handle_rx_big(struct vhost_net *net)
 {
 	struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
 	unsigned out, in, log, s;
@@ -223,7 +312,7 @@ static void handle_rx(struct vhost_net *net)
 	use_mm(net->dev.mm);
 	mutex_lock(&vq->mutex);
 	vhost_disable_notify(vq);
-	hdr_size = vq->hdr_size;
+	hdr_size = vq->vhost_hlen;
 
 	vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ?
 		vq->log : NULL;
@@ -270,14 +359,14 @@ static void handle_rx(struct vhost_net *net)
 					 len, MSG_DONTWAIT | MSG_TRUNC);
 		/* TODO: Check specific error and bomb out unless EAGAIN? */
 		if (err < 0) {
-			vhost_discard_vq_desc(vq);
+			vhost_discard_vq_desc(vq, 1);
 			break;
 		}
 		/* TODO: Should check and handle checksum. */
 		if (err > len) {
 			pr_debug("Discarded truncated rx packet: "
 				 " len %d > %zd\n", err, len);
-			vhost_discard_vq_desc(vq);
+			vhost_discard_vq_desc(vq, 1);
 			continue;
 		}
 		len = err;
@@ -302,54 +391,175 @@ static void handle_rx(struct vhost_net *net)
 	unuse_mm(net->dev.mm);
 }
 
-static void handle_tx_kick(struct work_struct *work)
+/* Expects to be always run from workqueue - which acts as
+ * read-size critical section for our kind of RCU. */
+static void handle_rx_mergeable(struct vhost_net *net)
 {
-	struct vhost_virtqueue *vq;
-	struct vhost_net *net;
-	vq = container_of(work, struct vhost_virtqueue, poll.work);
-	net = container_of(vq->dev, struct vhost_net, dev);
+	struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
+	unsigned uninitialized_var(in), log;
+	struct vhost_log *vq_log;
+	struct msghdr msg = {
+		.msg_name = NULL,
+		.msg_namelen = 0,
+		.msg_control = NULL, /* FIXME: get and handle RX aux data. */
+		.msg_controllen = 0,
+		.msg_iov = vq->iov,
+		.msg_flags = MSG_DONTWAIT,
+	};
+
+	struct virtio_net_hdr_mrg_rxbuf hdr = {
+		.hdr.flags = 0,
+		.hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE
+	};
+
+	size_t total_len = 0;
+	int err, headcount;
+	size_t vhost_hlen, sock_hlen;
+	size_t vhost_len, sock_len;
+	struct socket *sock = rcu_dereference(vq->private_data);
+	if (!sock || skb_queue_empty(&sock->sk->sk_receive_queue))
+		return;
+
+	use_mm(net->dev.mm);
+	mutex_lock(&vq->mutex);
+	vhost_disable_notify(vq);
+	vhost_hlen = vq->vhost_hlen;
+	sock_hlen = vq->sock_hlen;
+
+	vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ?
+		vq->log : NULL;
+
+	while ((sock_len = peek_head_len(sock->sk))) {
+		sock_len += sock_hlen;
+		vhost_len = sock_len + vhost_hlen;
+		headcount = get_rx_bufs(vq, vq->heads, vhost_len,
+					&in, vq_log, &log);
+		/* On error, stop handling until the next kick. */
+		if (unlikely(headcount < 0))
+			break;
+		/* OK, now we need to know about added descriptors. */
+		if (!headcount) {
+			if (unlikely(vhost_enable_notify(vq))) {
+				/* They have slipped one in as we were
+				 * doing that: check again. */
+				vhost_disable_notify(vq);
+				continue;
+			}
+			/* Nothing new?  Wait for eventfd to tell us
+			 * they refilled. */
+			break;
+		}
+		/* We don't need to be notified again. */
+		if (unlikely((vhost_hlen)))
+			/* Skip header. TODO: support TSO. */
+			move_iovec_hdr(vq->iov, vq->hdr, vhost_hlen, in);
+		else
+			/* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF:
+			 * needed because sendmsg can modify msg_iov. */
+			copy_iovec_hdr(vq->iov, vq->hdr, sock_hlen, in);
+		msg.msg_iovlen = in;
+		err = sock->ops->recvmsg(NULL, sock, &msg,
+					 sock_len, MSG_DONTWAIT | MSG_TRUNC);
+		/* Userspace might have consumed the packet meanwhile:
+		 * it's not supposed to do this usually, but might be hard
+		 * to prevent. Discard data we got (if any) and keep going. */
+		if (unlikely(err != sock_len)) {
+			pr_debug("Discarded rx packet: "
+				 " len %d, expected %zd\n", err, sock_len);
+			vhost_discard_vq_desc(vq, headcount);
+			continue;
+		}
+		if (unlikely(vhost_hlen) &&
+		    memcpy_toiovecend(vq->hdr, (unsigned char *)&hdr, 0,
+				      vhost_hlen)) {
+			vq_err(vq, "Unable to write vnet_hdr at addr %p\n",
+			       vq->iov->iov_base);
+			break;
+		}
+		/* TODO: Should check and handle checksum. */
+		if (vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF) &&
+		    memcpy_toiovecend(vq->hdr, (unsigned char *)&headcount,
+				      offsetof(typeof(hdr), num_buffers),
+				      sizeof hdr.num_buffers)) {
+			vq_err(vq, "Failed num_buffers write");
+			vhost_discard_vq_desc(vq, headcount);
+			break;
+		}
+		vhost_add_used_and_signal_n(&net->dev, vq, vq->heads,
+					    headcount);
+		if (unlikely(vq_log))
+			vhost_log_write(vq, vq_log, log, vhost_len);
+		total_len += vhost_len;
+		if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
+			vhost_poll_queue(&vq->poll);
+			break;
+		}
+	}
+
+	mutex_unlock(&vq->mutex);
+	unuse_mm(net->dev.mm);
+}
+
+static void handle_rx(struct vhost_net *net)
+{
+	if (vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF))
+		handle_rx_mergeable(net);
+	else
+		handle_rx_big(net);
+}
+
+static void handle_tx_kick(struct vhost_work *work)
+{
+	struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
+						  poll.work);
+	struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
+
 	handle_tx(net);
 }
 
-static void handle_rx_kick(struct work_struct *work)
+static void handle_rx_kick(struct vhost_work *work)
 {
-	struct vhost_virtqueue *vq;
-	struct vhost_net *net;
-	vq = container_of(work, struct vhost_virtqueue, poll.work);
-	net = container_of(vq->dev, struct vhost_net, dev);
+	struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
+						  poll.work);
+	struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
+
 	handle_rx(net);
 }
 
-static void handle_tx_net(struct work_struct *work)
+static void handle_tx_net(struct vhost_work *work)
 {
-	struct vhost_net *net;
-	net = container_of(work, struct vhost_net, poll[VHOST_NET_VQ_TX].work);
+	struct vhost_net *net = container_of(work, struct vhost_net,
+					     poll[VHOST_NET_VQ_TX].work);
 	handle_tx(net);
 }
 
-static void handle_rx_net(struct work_struct *work)
+static void handle_rx_net(struct vhost_work *work)
 {
-	struct vhost_net *net;
-	net = container_of(work, struct vhost_net, poll[VHOST_NET_VQ_RX].work);
+	struct vhost_net *net = container_of(work, struct vhost_net,
+					     poll[VHOST_NET_VQ_RX].work);
 	handle_rx(net);
 }
 
 static int vhost_net_open(struct inode *inode, struct file *f)
 {
 	struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL);
+	struct vhost_dev *dev;
 	int r;
+
 	if (!n)
 		return -ENOMEM;
+
+	dev = &n->dev;
 	n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick;
 	n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick;
-	r = vhost_dev_init(&n->dev, n->vqs, VHOST_NET_VQ_MAX);
+	r = vhost_dev_init(dev, n->vqs, VHOST_NET_VQ_MAX);
 	if (r < 0) {
 		kfree(n);
 		return r;
 	}
 
-	vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT);
-	vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN);
+	vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev);
+	vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev);
 	n->tx_poll_state = VHOST_NET_POLL_DISABLED;
 
 	f->private_data = n;
@@ -527,13 +737,12 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
 
 	/* start polling new socket */
 	oldsock = vq->private_data;
-	if (sock == oldsock)
-		goto done;
+	if (sock != oldsock) {
+                vhost_net_disable_vq(n, vq);
+                rcu_assign_pointer(vq->private_data, sock);
+                vhost_net_enable_vq(n, vq);
+	}
 
-	vhost_net_disable_vq(n, vq);
-	rcu_assign_pointer(vq->private_data, sock);
-	vhost_net_enable_vq(n, vq);
-done:
 	mutex_unlock(&vq->mutex);
 
 	if (oldsock) {
@@ -574,9 +783,21 @@ done:
 
 static int vhost_net_set_features(struct vhost_net *n, u64 features)
 {
-	size_t hdr_size = features & (1 << VHOST_NET_F_VIRTIO_NET_HDR) ?
-		sizeof(struct virtio_net_hdr) : 0;
+	size_t vhost_hlen, sock_hlen, hdr_len;
 	int i;
+
+	hdr_len = (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ?
+			sizeof(struct virtio_net_hdr_mrg_rxbuf) :
+			sizeof(struct virtio_net_hdr);
+	if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {
+		/* vhost provides vnet_hdr */
+		vhost_hlen = hdr_len;
+		sock_hlen = 0;
+	} else {
+		/* socket provides vnet_hdr */
+		vhost_hlen = 0;
+		sock_hlen = hdr_len;
+	}
 	mutex_lock(&n->dev.mutex);
 	if ((features & (1 << VHOST_F_LOG_ALL)) &&
 	    !vhost_log_access_ok(&n->dev)) {
@@ -587,7 +808,8 @@ static int vhost_net_set_features(struct vhost_net *n, u64 features)
 	smp_wmb();
 	for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
 		mutex_lock(&n->vqs[i].mutex);
-		n->vqs[i].hdr_size = hdr_size;
+		n->vqs[i].vhost_hlen = vhost_hlen;
+		n->vqs[i].sock_hlen = sock_hlen;
 		mutex_unlock(&n->vqs[i].mutex);
 	}
 	vhost_net_flush(n);
@@ -639,7 +861,7 @@ static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl,
 }
 #endif
 
-const static struct file_operations vhost_net_fops = {
+static const struct file_operations vhost_net_fops = {
 	.owner          = THIS_MODULE,
 	.release        = vhost_net_release,
 	.unlocked_ioctl = vhost_net_ioctl,
@@ -657,25 +879,13 @@ static struct miscdevice vhost_net_misc = {
 
 static int vhost_net_init(void)
 {
-	int r = vhost_init();
-	if (r)
-		goto err_init;
-	r = misc_register(&vhost_net_misc);
-	if (r)
-		goto err_reg;
-	return 0;
-err_reg:
-	vhost_cleanup();
-err_init:
-	return r;
-
+	return misc_register(&vhost_net_misc);
 }
 module_init(vhost_net_init);
 
 static void vhost_net_exit(void)
 {
 	misc_deregister(&vhost_net_misc);
-	vhost_cleanup();
 }
 module_exit(vhost_net_exit);