Linux Virtualization - Dec 2015 - [PATCH v2 0/5] Add virtio transport for AF_VSOCK

v2:
 * Rebased onto Linux v4.4-rc2
 * vhost: Refuse to assign reserved CIDs
 * vhost: Refuse guest CID if already in use
 * vhost: Only accept correctly addressed packets (no spoofing!)
 * vhost: Support flexible rx/tx descriptor layout
 * vhost: Add missing total_tx_buf decrement
 * virtio_transport: Fix total_tx_buf accounting
 * virtio_transport: Add virtio_transport global mutex to prevent races
 * common: Notify other side of SOCK_STREAM disconnect (fixes shutdown
   semantics)
 * common: Avoid recursive mutex_lock(tx_lock) for write_space (fixes deadlock)
 * common: Define VIRTIO_VSOCK_TYPE_STREAM/DGRAM hardware interface constants
 * common: Define VIRTIO_VSOCK_SHUTDOWN_RCV/SEND hardware interface constants
 * common: Fix peer_buf_alloc inheritance on child socket

This patch series adds a virtio transport for AF_VSOCK (net/vmw_vsock/).
AF_VSOCK is designed for communication between virtual machines and
hypervisors.  It is currently only implemented for VMware's VMCI transport.

This series implements the proposed virtio-vsock device specification from
here:
http://comments.gmane.org/gmane.comp.emulators.virtio.devel/855

Most of the work was done by Asias He and Gerd Hoffmann a while back.  I have
picked up the series again.

The QEMU userspace changes are here:
https://github.com/stefanha/qemu/commits/vsock

Why virtio-vsock?
-----------------
Guest<->host communication is currently done over the virtio-serial
device.
This makes it hard to port sockets API-based applications and is limited to
static ports.

virtio-vsock uses the sockets API so that applications can rely on familiar
SOCK_STREAM and SOCK_DGRAM semantics.  Applications on the host can easily
connect to guest agents because the sockets API allows multiple connections to
a listen socket (unlike virtio-serial).  This simplifies the guest<->host
communication and eliminates the need for extra processes on the host to
arbitrate virtio-serial ports.

Overview
--------
This series adds 3 pieces:

1. virtio_transport_common.ko - core virtio vsock code that uses vsock.ko

2. virtio_transport.ko - guest driver

3. drivers/vhost/vsock.ko - host driver

Howto
-----
The following kernel options are needed:
  CONFIG_VSOCKETS=y
  CONFIG_VIRTIO_VSOCKETS=y
  CONFIG_VIRTIO_VSOCKETS_COMMON=y
  CONFIG_VHOST_VSOCK=m

Launch QEMU as follows:
  # qemu ... -device vhost-vsock-pci,id=vhost-vsock-pci0,guest-cid=3

Guest and host can communicate via AF_VSOCK sockets.  The host's CID
(address)
is 2 and the guest is automatically assigned a CID (use VMADDR_CID_ANY (-1) to
bind to it).

Status
------
There are a few design changes I'd like to make to the virtio-vsock device:

1. The 3-way handshake isn't necessary over a reliable transport
(virtqueue).
   Spoofing packets is also impossible so the security aspects of the 3-way
   handshake (including syn cookie) add nothing.  The next version will have a
   single operation to establish a connection.

2. Credit-based flow control doesn't work for SOCK_DGRAM since multiple
clients
   can transmit to the same listen socket.  There is no way for the clients to
   coordinate buffer space with each other fairly.  The next version will drop
   credit-based flow control for SOCK_DGRAM and only rely on best-effort
   delivery.  SOCK_STREAM still has guaranteed delivery.

3. In the next version only the host will be able to establish connections
   (i.e. to connect to a guest agent).  This is for security reasons since
   there is currently no ability to provide host services only to certain
   guests.  This also matches how AF_VSOCK works on modern VMware hypervisors.

Asias He (5):
  VSOCK: Introduce vsock_find_unbound_socket and
    vsock_bind_dgram_generic
  VSOCK: Introduce virtio-vsock-common.ko
  VSOCK: Introduce virtio-vsock.ko
  VSOCK: Introduce vhost-vsock.ko
  VSOCK: Add Makefile and Kconfig

 drivers/vhost/Kconfig                   |    4 +
 drivers/vhost/Kconfig.vsock             |    7 +
 drivers/vhost/Makefile                  |    4 +
 drivers/vhost/vsock.c                   |  631 +++++++++++++++
 drivers/vhost/vsock.h                   |    4 +
 include/linux/virtio_vsock.h            |  209 +++++
 include/net/af_vsock.h                  |    2 +
 include/uapi/linux/virtio_ids.h         |    1 +
 include/uapi/linux/virtio_vsock.h       |   89 +++
 net/vmw_vsock/Kconfig                   |   18 +
 net/vmw_vsock/Makefile                  |    2 +
 net/vmw_vsock/af_vsock.c                |   70 ++
 net/vmw_vsock/virtio_transport.c        |  466 +++++++++++
 net/vmw_vsock/virtio_transport_common.c | 1272 +++++++++++++++++++++++++++++++
 14 files changed, 2779 insertions(+)
 create mode 100644 drivers/vhost/Kconfig.vsock
 create mode 100644 drivers/vhost/vsock.c
 create mode 100644 drivers/vhost/vsock.h
 create mode 100644 include/linux/virtio_vsock.h
 create mode 100644 include/uapi/linux/virtio_vsock.h
 create mode 100644 net/vmw_vsock/virtio_transport.c
 create mode 100644 net/vmw_vsock/virtio_transport_common.c

-- 
2.5.0

From: Asias He <asias at redhat.com>

Signed-off-by: Asias He <asias at redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha at redhat.com>
---
 include/net/af_vsock.h   |  2 ++
 net/vmw_vsock/af_vsock.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+)

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index e9eb2d6..a0c8fa2 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -175,8 +175,10 @@ void vsock_insert_connected(struct vsock_sock *vsk);
 void vsock_remove_bound(struct vsock_sock *vsk);
 void vsock_remove_connected(struct vsock_sock *vsk);
 struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr);
+struct sock *vsock_find_unbound_socket(struct sockaddr_vm *addr);
 struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
 					 struct sockaddr_vm *dst);
 void vsock_for_each_connected_socket(void (*fn)(struct sock *sk));
+int vsock_bind_dgram_generic(struct vsock_sock *vsk, struct sockaddr_vm *addr);
 
 #endif /* __AF_VSOCK_H__ */
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 7fd1220..77247a2 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -223,6 +223,17 @@ static struct sock *__vsock_find_bound_socket(struct
sockaddr_vm *addr)
 	return NULL;
 }
 
+static struct sock *__vsock_find_unbound_socket(struct sockaddr_vm *addr)
+{
+	struct vsock_sock *vsk;
+
+	list_for_each_entry(vsk, vsock_unbound_sockets, bound_table)
+		if (addr->svm_port == vsk->local_addr.svm_port)
+			return sk_vsock(vsk);
+
+	return NULL;
+}
+
 static struct sock *__vsock_find_connected_socket(struct sockaddr_vm *src,
 						  struct sockaddr_vm *dst)
 {
@@ -298,6 +309,21 @@ struct sock *vsock_find_bound_socket(struct sockaddr_vm
*addr)
 }
 EXPORT_SYMBOL_GPL(vsock_find_bound_socket);
 
+struct sock *vsock_find_unbound_socket(struct sockaddr_vm *addr)
+{
+	struct sock *sk;
+
+	spin_lock_bh(&vsock_table_lock);
+	sk = __vsock_find_unbound_socket(addr);
+	if (sk)
+		sock_hold(sk);
+
+	spin_unlock_bh(&vsock_table_lock);
+
+	return sk;
+}
+EXPORT_SYMBOL_GPL(vsock_find_unbound_socket);
+
 struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
 					 struct sockaddr_vm *dst)
 {
@@ -532,6 +558,50 @@ static int __vsock_bind_stream(struct vsock_sock *vsk,
 	return 0;
 }
 
+int vsock_bind_dgram_generic(struct vsock_sock *vsk, struct sockaddr_vm *addr)
+{
+	static u32 port = LAST_RESERVED_PORT + 1;
+	struct sockaddr_vm new_addr;
+
+	vsock_addr_init(&new_addr, addr->svm_cid, addr->svm_port);
+
+	if (addr->svm_port == VMADDR_PORT_ANY) {
+		bool found = false;
+		unsigned int i;
+
+		for (i = 0; i < MAX_PORT_RETRIES; i++) {
+			if (port <= LAST_RESERVED_PORT)
+				port = LAST_RESERVED_PORT + 1;
+
+			new_addr.svm_port = port++;
+
+			if (!__vsock_find_unbound_socket(&new_addr)) {
+				found = true;
+				break;
+			}
+		}
+
+		if (!found)
+			return -EADDRNOTAVAIL;
+	} else {
+		/* If port is in reserved range, ensure caller
+		 * has necessary privileges.
+		 */
+		if (addr->svm_port <= LAST_RESERVED_PORT &&
+		    !capable(CAP_NET_BIND_SERVICE)) {
+			return -EACCES;
+		}
+
+		if (__vsock_find_unbound_socket(&new_addr))
+			return -EADDRINUSE;
+	}
+
+	vsock_addr_init(&vsk->local_addr, new_addr.svm_cid, new_addr.svm_port);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vsock_bind_dgram_generic);
+
 static int __vsock_bind_dgram(struct vsock_sock *vsk,
 			      struct sockaddr_vm *addr)
 {
-- 
2.5.0

From: Asias He <asias at redhat.com>

This module contains the common code and header files for the following
virtio-vsock and virtio-vhost kernel modules.

Signed-off-by: Asias He <asias at redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha at redhat.com>
---
v2:
 * Fix peer_buf_alloc inheritance on child socket
 * Notify other side of SOCK_STREAM disconnect (fixes shutdown
   semantics)
 * Avoid recursive mutex_lock(tx_lock) for write_space (fixes deadlock)
 * Define VIRTIO_VSOCK_TYPE_STREAM/DGRAM hardware interface constants
 * Define VIRTIO_VSOCK_SHUTDOWN_RCV/SEND hardware interface constants
---
 include/linux/virtio_vsock.h            |  209 +++++
 include/uapi/linux/virtio_ids.h         |    1 +
 include/uapi/linux/virtio_vsock.h       |   89 +++
 net/vmw_vsock/virtio_transport_common.c | 1272 +++++++++++++++++++++++++++++++
 4 files changed, 1571 insertions(+)
 create mode 100644 include/linux/virtio_vsock.h
 create mode 100644 include/uapi/linux/virtio_vsock.h
 create mode 100644 net/vmw_vsock/virtio_transport_common.c

diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
new file mode 100644
index 0000000..a5f3ecc
--- /dev/null
+++ b/include/linux/virtio_vsock.h
@@ -0,0 +1,209 @@
+/*
+ * This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
+ * anyone can use the definitions to implement compatible drivers/servers:
+ *
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * Copyright (C) Red Hat, Inc., 2013-2015
+ * Copyright (C) Asias He <asias at redhat.com>, 2013
+ * Copyright (C) Stefan Hajnoczi <stefanha at redhat.com>, 2015
+ */
+
+#ifndef _LINUX_VIRTIO_VSOCK_H
+#define _LINUX_VIRTIO_VSOCK_H
+
+#include <uapi/linux/virtio_vsock.h>
+#include <linux/socket.h>
+#include <net/sock.h>
+
+#define VIRTIO_VSOCK_DEFAULT_MIN_BUF_SIZE	128
+#define VIRTIO_VSOCK_DEFAULT_BUF_SIZE		(1024 * 256)
+#define VIRTIO_VSOCK_DEFAULT_MAX_BUF_SIZE	(1024 * 256)
+#define VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE	(1024 * 4)
+#define VIRTIO_VSOCK_MAX_BUF_SIZE		0xFFFFFFFFUL
+#define VIRTIO_VSOCK_MAX_PKT_BUF_SIZE		(1024 * 64)
+#define VIRTIO_VSOCK_MAX_TX_BUF_SIZE		(1024 * 1024 * 16)
+#define VIRTIO_VSOCK_MAX_DGRAM_SIZE		(1024 * 64)
+
+struct vsock_transport_recv_notify_data;
+struct vsock_transport_send_notify_data;
+struct sockaddr_vm;
+struct vsock_sock;
+
+enum {
+	VSOCK_VQ_CTRL	= 0,
+	VSOCK_VQ_RX	= 1, /* for host to guest data */
+	VSOCK_VQ_TX	= 2, /* for guest to host data */
+	VSOCK_VQ_MAX	= 3,
+};
+
+/* virtio transport socket state */
+struct virtio_transport {
+	struct virtio_transport_pkt_ops	*ops;
+	struct vsock_sock *vsk;
+
+	u32 buf_size;
+	u32 buf_size_min;
+	u32 buf_size_max;
+
+	struct mutex tx_lock;
+	struct mutex rx_lock;
+
+	struct list_head rx_queue;
+	u32 rx_bytes;
+
+	/* Protected by trans->tx_lock */
+	u32 tx_cnt;
+	u32 buf_alloc;
+	u32 peer_fwd_cnt;
+	u32 peer_buf_alloc;
+	/* Protected by trans->rx_lock */
+	u32 fwd_cnt;
+
+	/* Protected by sk_lock */
+	u16 dgram_id;
+	struct list_head incomplete_dgrams; /* dgram fragments */
+};
+
+struct virtio_vsock_pkt {
+	struct virtio_vsock_hdr	hdr;
+	struct virtio_transport	*trans;
+	struct work_struct work;
+	struct list_head list;
+	void *buf;
+	u32 len;
+	u32 off;
+};
+
+struct virtio_vsock_pkt_info {
+	u32 remote_cid, remote_port;
+	struct msghdr *msg;
+	u32 pkt_len;
+	u16 type;
+	u16 op;
+	u32 flags;
+	u16 dgram_id;
+	u16 dgram_len;
+};
+
+struct virtio_transport_pkt_ops {
+	int (*send_pkt)(struct vsock_sock *vsk,
+			struct virtio_vsock_pkt_info *info);
+};
+
+void virtio_vsock_dumppkt(const char *func,
+			  const struct virtio_vsock_pkt *pkt);
+
+struct sock *
+virtio_transport_get_pending(struct sock *listener,
+			     struct virtio_vsock_pkt *pkt);
+struct virtio_vsock_pkt *
+virtio_transport_alloc_pkt(struct vsock_sock *vsk,
+			   struct virtio_vsock_pkt_info *info,
+			   size_t len,
+			   u32 src_cid,
+			   u32 src_port,
+			   u32 dst_cid,
+			   u32 dst_port);
+ssize_t
+virtio_transport_stream_dequeue(struct vsock_sock *vsk,
+				struct msghdr *msg,
+				size_t len,
+				int type);
+int
+virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
+			       struct msghdr *msg,
+			       size_t len, int flags);
+
+s64 virtio_transport_stream_has_data(struct vsock_sock *vsk);
+s64 virtio_transport_stream_has_space(struct vsock_sock *vsk);
+
+int virtio_transport_do_socket_init(struct vsock_sock *vsk,
+				 struct vsock_sock *psk);
+u64 virtio_transport_get_buffer_size(struct vsock_sock *vsk);
+u64 virtio_transport_get_min_buffer_size(struct vsock_sock *vsk);
+u64 virtio_transport_get_max_buffer_size(struct vsock_sock *vsk);
+void virtio_transport_set_buffer_size(struct vsock_sock *vsk, u64 val);
+void virtio_transport_set_min_buffer_size(struct vsock_sock *vsk, u64 val);
+void virtio_transport_set_max_buffer_size(struct vsock_sock *vs, u64 val);
+int
+virtio_transport_notify_poll_in(struct vsock_sock *vsk,
+				size_t target,
+				bool *data_ready_now);
+int
+virtio_transport_notify_poll_out(struct vsock_sock *vsk,
+				 size_t target,
+				 bool *space_available_now);
+
+int virtio_transport_notify_recv_init(struct vsock_sock *vsk,
+	size_t target, struct vsock_transport_recv_notify_data *data);
+int virtio_transport_notify_recv_pre_block(struct vsock_sock *vsk,
+	size_t target, struct vsock_transport_recv_notify_data *data);
+int virtio_transport_notify_recv_pre_dequeue(struct vsock_sock *vsk,
+	size_t target, struct vsock_transport_recv_notify_data *data);
+int virtio_transport_notify_recv_post_dequeue(struct vsock_sock *vsk,
+	size_t target, ssize_t copied, bool data_read,
+	struct vsock_transport_recv_notify_data *data);
+int virtio_transport_notify_send_init(struct vsock_sock *vsk,
+	struct vsock_transport_send_notify_data *data);
+int virtio_transport_notify_send_pre_block(struct vsock_sock *vsk,
+	struct vsock_transport_send_notify_data *data);
+int virtio_transport_notify_send_pre_enqueue(struct vsock_sock *vsk,
+	struct vsock_transport_send_notify_data *data);
+int virtio_transport_notify_send_post_enqueue(struct vsock_sock *vsk,
+	ssize_t written, struct vsock_transport_send_notify_data *data);
+
+u64 virtio_transport_stream_rcvhiwat(struct vsock_sock *vsk);
+bool virtio_transport_stream_is_active(struct vsock_sock *vsk);
+bool virtio_transport_stream_allow(u32 cid, u32 port);
+int virtio_transport_dgram_bind(struct vsock_sock *vsk,
+				struct sockaddr_vm *addr);
+bool virtio_transport_dgram_allow(u32 cid, u32 port);
+
+int virtio_transport_connect(struct vsock_sock *vsk);
+
+int virtio_transport_shutdown(struct vsock_sock *vsk, int mode);
+
+void virtio_transport_release(struct vsock_sock *vsk);
+
+ssize_t
+virtio_transport_stream_enqueue(struct vsock_sock *vsk,
+				struct msghdr *msg,
+				size_t len);
+int
+virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
+			       struct sockaddr_vm *remote_addr,
+			       struct msghdr *msg,
+			       size_t len);
+
+void virtio_transport_destruct(struct vsock_sock *vsk);
+
+void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt);
+void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt);
+void virtio_transport_inc_tx_pkt(struct virtio_vsock_pkt *pkt);
+void virtio_transport_dec_tx_pkt(struct virtio_vsock_pkt *pkt);
+u32 virtio_transport_get_credit(struct virtio_transport *trans, u32 wanted);
+void virtio_transport_put_credit(struct virtio_transport *trans, u32 credit);
+#endif /* _LINUX_VIRTIO_VSOCK_H */
diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h
index 77925f5..16dcf5d 100644
--- a/include/uapi/linux/virtio_ids.h
+++ b/include/uapi/linux/virtio_ids.h
@@ -39,6 +39,7 @@
 #define VIRTIO_ID_9P		9 /* 9p virtio console */
 #define VIRTIO_ID_RPROC_SERIAL 11 /* virtio remoteproc serial link */
 #define VIRTIO_ID_CAIF	       12 /* Virtio caif */
+#define VIRTIO_ID_VSOCK        13 /* virtio vsock transport */
 #define VIRTIO_ID_GPU          16 /* virtio GPU */
 #define VIRTIO_ID_INPUT        18 /* virtio input */
 
diff --git a/include/uapi/linux/virtio_vsock.h
b/include/uapi/linux/virtio_vsock.h
new file mode 100644
index 0000000..8cf9b56
--- /dev/null
+++ b/include/uapi/linux/virtio_vsock.h
@@ -0,0 +1,89 @@
+/*
+ * This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
+ * anyone can use the definitions to implement compatible drivers/servers:
+ *
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * Copyright (C) Red Hat, Inc., 2013-2015
+ * Copyright (C) Asias He <asias at redhat.com>, 2013
+ * Copyright (C) Stefan Hajnoczi <stefanha at redhat.com>, 2015
+ */
+
+#ifndef _UAPI_LINUX_VIRTIO_VSOCK_H
+#define _UAPI_LINUX_VIRTIO_VOSCK_H
+
+#include <linux/types.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+
+struct virtio_vsock_config {
+	__le32 guest_cid;
+	__le32 max_virtqueue_pairs;
+};
+
+struct virtio_vsock_hdr {
+	__le32	src_cid;
+	__le32	src_port;
+	__le32	dst_cid;
+	__le32	dst_port;
+	__le32	len;
+	__le16	type;		/* enum virtio_vsock_type */
+	__le16	op;		/* enum virtio_vsock_op */
+	__le32	flags;
+	__le32	buf_alloc;
+	__le32	fwd_cnt;
+};
+
+enum virtio_vsock_type {
+	VIRTIO_VSOCK_TYPE_STREAM = 1,
+	VIRTIO_VSOCK_TYPE_DGRAM = 2,
+};
+
+enum virtio_vsock_op {
+	VIRTIO_VSOCK_OP_INVALID = 0,
+
+	/* Connect operations */
+	VIRTIO_VSOCK_OP_REQUEST = 1,
+	VIRTIO_VSOCK_OP_RESPONSE = 2,
+	VIRTIO_VSOCK_OP_ACK = 3,
+	VIRTIO_VSOCK_OP_RST = 4,
+	VIRTIO_VSOCK_OP_SHUTDOWN = 5,
+
+	/* To send payload */
+	VIRTIO_VSOCK_OP_RW = 6,
+
+	/* Tell the peer our credit info */
+	VIRTIO_VSOCK_OP_CREDIT_UPDATE = 7,
+	/* Request the peer to send the credit info to us */
+	VIRTIO_VSOCK_OP_CREDIT_REQUEST = 8,
+};
+
+/* VIRTIO_VSOCK_OP_SHUTDOWN flags values */
+enum virtio_vsock_shutdown {
+	VIRTIO_VSOCK_SHUTDOWN_RCV = 1,
+	VIRTIO_VSOCK_SHUTDOWN_SEND = 2,
+};
+
+#endif /* _UAPI_LINUX_VIRTIO_VSOCK_H */
diff --git a/net/vmw_vsock/virtio_transport_common.c
b/net/vmw_vsock/virtio_transport_common.c
new file mode 100644
index 0000000..28f790d
--- /dev/null
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -0,0 +1,1272 @@
+/*
+ * common code for virtio vsock
+ *
+ * Copyright (C) 2013-2015 Red Hat, Inc.
+ * Author: Asias He <asias at redhat.com>
+ *         Stefan Hajnoczi <stefanha at redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ */
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/list.h>
+#include <linux/virtio.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_vsock.h>
+#include <linux/random.h>
+#include <linux/cryptohash.h>
+
+#include <net/sock.h>
+#include <net/af_vsock.h>
+
+#define COOKIEBITS 24
+#define COOKIEMASK (((u32)1 << COOKIEBITS) - 1)
+#define VSOCK_TIMEOUT_INIT 4
+
+#define SHA_MESSAGE_WORDS 16
+#define SHA_VSOCK_WORDS 5
+
+static u32 vsockcookie_secret[2][SHA_MESSAGE_WORDS - SHA_VSOCK_WORDS +
+				 SHA_DIGEST_WORDS];
+
+static DEFINE_PER_CPU(__u32[SHA_MESSAGE_WORDS + SHA_DIGEST_WORDS +
+		      SHA_WORKSPACE_WORDS], vsock_cookie_scratch);
+
+static u32 cookie_hash(u32 saddr, u32 daddr, u16 sport, u16 dport,
+		       u32 count, int c)
+{
+	__u32 *tmp = this_cpu_ptr(vsock_cookie_scratch);
+
+	memcpy(tmp + SHA_VSOCK_WORDS, vsockcookie_secret[c],
+	       sizeof(vsockcookie_secret[c]));
+	tmp[0] = saddr;
+	tmp[1] = daddr;
+	tmp[2] = sport;
+	tmp[3] = dport;
+	tmp[4] = count;
+	sha_transform(tmp + SHA_MESSAGE_WORDS, (__u8 *)tmp,
+		      tmp + SHA_MESSAGE_WORDS + SHA_DIGEST_WORDS);
+
+	return tmp[17];
+}
+
+static u32
+virtio_vsock_secure_cookie(u32 saddr, u32 daddr, u32 sport, u32 dport,
+			   u32 count)
+{
+	u32 h1, h2;
+
+	h1 = cookie_hash(saddr, daddr, sport, dport, 0, 0);
+	h2 = cookie_hash(saddr, daddr, sport, dport, count, 1);
+
+	return h1 + (count << COOKIEBITS) + (h2 & COOKIEMASK);
+}
+
+static u32
+virtio_vsock_check_cookie(u32 saddr, u32 daddr, u32 sport, u32 dport,
+			  u32 count, u32 cookie, u32 maxdiff)
+{
+	u32 diff;
+	u32 ret;
+
+	cookie -= cookie_hash(saddr, daddr, sport, dport, 0, 0);
+
+	diff = (count - (cookie >> COOKIEBITS)) & ((u32)-1 >>
COOKIEBITS);
+	pr_debug("%s: diff=%x\n", __func__, diff);
+	if (diff >= maxdiff)
+		return (u32)-1;
+
+	ret = (cookie -
+		cookie_hash(saddr, daddr, sport, dport, count - diff, 1))
+		& COOKIEMASK;
+	pr_debug("%s: ret=%x\n", __func__, diff);
+
+	return ret;
+}
+
+void virtio_vsock_dumppkt(const char *func,  const struct virtio_vsock_pkt
*pkt)
+{
+	pr_debug("%s: pkt=%p, op=%d, len=%d, %d:%d---%d:%d, len=%d\n",
+		 func, pkt,
+		 le16_to_cpu(pkt->hdr.op),
+		 le32_to_cpu(pkt->hdr.len),
+		 le32_to_cpu(pkt->hdr.src_cid),
+		 le32_to_cpu(pkt->hdr.src_port),
+		 le32_to_cpu(pkt->hdr.dst_cid),
+		 le32_to_cpu(pkt->hdr.dst_port),
+		 pkt->len);
+}
+EXPORT_SYMBOL_GPL(virtio_vsock_dumppkt);
+
+struct virtio_vsock_pkt *
+virtio_transport_alloc_pkt(struct vsock_sock *vsk,
+			   struct virtio_vsock_pkt_info *info,
+			   size_t len,
+			   u32 src_cid,
+			   u32 src_port,
+			   u32 dst_cid,
+			   u32 dst_port)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt *pkt;
+	int err;
+
+	BUG_ON(!trans);
+
+	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
+	if (!pkt)
+		return NULL;
+
+	pkt->hdr.type		= cpu_to_le16(info->type);
+	pkt->hdr.op		= cpu_to_le16(info->op);
+	pkt->hdr.src_cid	= cpu_to_le32(src_cid);
+	pkt->hdr.src_port	= cpu_to_le32(src_port);
+	pkt->hdr.dst_cid	= cpu_to_le32(dst_cid);
+	pkt->hdr.dst_port	= cpu_to_le32(dst_port);
+	pkt->hdr.flags		= cpu_to_le32(info->flags);
+	pkt->len		= len;
+	pkt->trans		= trans;
+	if (info->type == VIRTIO_VSOCK_TYPE_DGRAM)
+		pkt->hdr.len	= cpu_to_le32(len + (info->dgram_len << 16));
+	else if (info->type == VIRTIO_VSOCK_TYPE_STREAM)
+		pkt->hdr.len	= cpu_to_le32(len);
+
+	if (info->msg && len > 0) {
+		pkt->buf = kmalloc(len, GFP_KERNEL);
+		if (!pkt->buf)
+			goto out_pkt;
+		err = memcpy_from_msg(pkt->buf, info->msg, len);
+		if (err)
+			goto out;
+	}
+
+	return pkt;
+
+out:
+	kfree(pkt->buf);
+out_pkt:
+	kfree(pkt);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_alloc_pkt);
+
+struct sock *
+virtio_transport_get_pending(struct sock *listener,
+			     struct virtio_vsock_pkt *pkt)
+{
+	struct vsock_sock *vlistener;
+	struct vsock_sock *vpending;
+	struct sockaddr_vm src;
+	struct sockaddr_vm dst;
+	struct sock *pending;
+
+	vsock_addr_init(&src, le32_to_cpu(pkt->hdr.src_cid),
le32_to_cpu(pkt->hdr.src_port));
+	vsock_addr_init(&dst, le32_to_cpu(pkt->hdr.dst_cid),
le32_to_cpu(pkt->hdr.dst_port));
+
+	vlistener = vsock_sk(listener);
+	list_for_each_entry(vpending, &vlistener->pending_links,
+			    pending_links) {
+		if (vsock_addr_equals_addr(&src, &vpending->remote_addr)
&&
+		    vsock_addr_equals_addr(&dst, &vpending->local_addr)) {
+			pending = sk_vsock(vpending);
+			sock_hold(pending);
+			return pending;
+		}
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_get_pending);
+
+static void virtio_transport_inc_rx_pkt(struct virtio_vsock_pkt *pkt)
+{
+	pkt->trans->rx_bytes += pkt->len;
+}
+
+static void virtio_transport_dec_rx_pkt(struct virtio_vsock_pkt *pkt)
+{
+	pkt->trans->rx_bytes -= pkt->len;
+	pkt->trans->fwd_cnt += pkt->len;
+}
+
+void virtio_transport_inc_tx_pkt(struct virtio_vsock_pkt *pkt)
+{
+	mutex_lock(&pkt->trans->tx_lock);
+	pkt->hdr.fwd_cnt = cpu_to_le32(pkt->trans->fwd_cnt);
+	pkt->hdr.buf_alloc = cpu_to_le32(pkt->trans->buf_alloc);
+	mutex_unlock(&pkt->trans->tx_lock);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_inc_tx_pkt);
+
+void virtio_transport_dec_tx_pkt(struct virtio_vsock_pkt *pkt)
+{
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dec_tx_pkt);
+
+u32 virtio_transport_get_credit(struct virtio_transport *trans, u32 credit)
+{
+	u32 ret;
+
+	mutex_lock(&trans->tx_lock);
+	ret = trans->peer_buf_alloc - (trans->tx_cnt - trans->peer_fwd_cnt);
+	if (ret > credit)
+		ret = credit;
+	trans->tx_cnt += ret;
+	mutex_unlock(&trans->tx_lock);
+
+	pr_debug("%s: ret=%d, buf_alloc=%d, peer_buf_alloc=%d,"
+		 "tx_cnt=%d, fwd_cnt=%d, peer_fwd_cnt=%d\n", __func__,
+		 ret, trans->buf_alloc, trans->peer_buf_alloc,
+		 trans->tx_cnt, trans->fwd_cnt, trans->peer_fwd_cnt);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_get_credit);
+
+void virtio_transport_put_credit(struct virtio_transport *trans, u32 credit)
+{
+	mutex_lock(&trans->tx_lock);
+	trans->tx_cnt -= credit;
+	mutex_unlock(&trans->tx_lock);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_put_credit);
+
+static int virtio_transport_send_credit_update(struct vsock_sock *vsk, int
type, struct virtio_vsock_hdr *hdr)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_CREDIT_UPDATE,
+		.type = type,
+	};
+
+	if (hdr && type == VIRTIO_VSOCK_TYPE_DGRAM) {
+		info.remote_cid = le32_to_cpu(hdr->src_cid);
+		info.remote_port = le32_to_cpu(hdr->src_port);
+	}
+
+	pr_debug("%s: sk=%p send_credit_update\n", __func__, vsk);
+	return trans->ops->send_pkt(vsk, &info);
+}
+
+static int virtio_transport_send_credit_request(struct vsock_sock *vsk, int
type)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_CREDIT_REQUEST,
+		.type = type,
+	};
+
+	pr_debug("%s: sk=%p send_credit_request\n", __func__, vsk);
+	return trans->ops->send_pkt(vsk, &info);
+}
+
+static ssize_t
+virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
+				   struct msghdr *msg,
+				   size_t len)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt *pkt;
+	size_t bytes, total = 0;
+	int err = -EFAULT;
+
+	mutex_lock(&trans->rx_lock);
+	while (total < len && trans->rx_bytes > 0  &&
+			!list_empty(&trans->rx_queue)) {
+		pkt = list_first_entry(&trans->rx_queue,
+				       struct virtio_vsock_pkt, list);
+
+		bytes = len - total;
+		if (bytes > pkt->len - pkt->off)
+			bytes = pkt->len - pkt->off;
+
+		err = memcpy_to_msg(msg, pkt->buf + pkt->off, bytes);
+		if (err)
+			goto out;
+		total += bytes;
+		pkt->off += bytes;
+		if (pkt->off == pkt->len) {
+			virtio_transport_dec_rx_pkt(pkt);
+			list_del(&pkt->list);
+			virtio_transport_free_pkt(pkt);
+		}
+	}
+	mutex_unlock(&trans->rx_lock);
+
+	/* Send a credit pkt to peer */
+	virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_STREAM,
+					    NULL);
+
+	return total;
+
+out:
+	mutex_unlock(&trans->rx_lock);
+	if (total)
+		err = total;
+	return err;
+}
+
+ssize_t
+virtio_transport_stream_dequeue(struct vsock_sock *vsk,
+				struct msghdr *msg,
+				size_t len, int flags)
+{
+	if (flags & MSG_PEEK)
+		return -EOPNOTSUPP;
+
+	return virtio_transport_stream_do_dequeue(vsk, msg, len);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_dequeue);
+
+struct dgram_skb {
+	struct list_head list;
+	struct sk_buff *skb;
+	u16 id;
+};
+
+static struct dgram_skb *dgram_id_to_skb(struct virtio_transport *trans,
+					 u16 id)
+{
+	struct dgram_skb *dgram_skb;
+
+	list_for_each_entry(dgram_skb, &trans->incomplete_dgrams, list) {
+		if (dgram_skb->id == id)
+			return dgram_skb;
+	}
+
+	return NULL;
+}
+
+static void
+virtio_transport_recv_dgram(struct sock *sk,
+			    struct virtio_vsock_pkt *pkt)
+{
+	struct sk_buff *skb = NULL;
+	struct vsock_sock *vsk;
+	struct virtio_transport *trans;
+	size_t size;
+	u16 dgram_id, pkt_off, dgram_len, pkt_len;
+	u32 flags, len;
+	struct dgram_skb *dgram_skb;
+
+	vsk = vsock_sk(sk);
+	trans = vsk->trans;
+
+	/* len:   dgram_len | pkt_len */
+	len = le32_to_cpu(pkt->hdr.len);
+	dgram_len = len >> 16;
+	pkt_len = len & 0xFFFF;
+
+	/* flags: dgram_id  | pkt_off */
+	flags = le32_to_cpu(pkt->hdr.flags);
+	dgram_id = flags >> 16;
+	pkt_off = flags & 0xFFFF;
+
+	pr_debug("%s: dgram_len=%d, pkt_len=%d, id=%d, off=%d\n", __func__,
+		 dgram_len, pkt_len, dgram_id, pkt_off);
+
+	dgram_skb = dgram_id_to_skb(trans, dgram_id);
+	if (dgram_skb) {
+		/* This pkt is for a existing dgram */
+		skb = dgram_skb->skb;
+		pr_debug("%s:found skb\n", __func__);
+	}
+
+	/* Packet payload must be within datagram bounds */
+	if (pkt_len > VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE)
+		goto drop;
+	if (pkt_len > dgram_len)
+		goto drop;
+	if (pkt_off > dgram_len)
+		goto drop;
+	if (dgram_len - pkt_off < pkt_len)
+		goto drop;
+
+	if (!skb) {
+		/* This pkt is for a new dgram */
+		pr_debug("%s:create skb\n", __func__);
+
+		size = sizeof(pkt->hdr) + dgram_len;
+		/* Attach the packet to the socket's receive queue as an sk_buff. */
+		dgram_skb = kzalloc(sizeof(struct dgram_skb), GFP_ATOMIC);
+		if (!dgram_skb)
+			goto drop;
+
+		skb = alloc_skb(size, GFP_ATOMIC);
+		if (!skb) {
+			kfree(dgram_skb);
+			dgram_skb = NULL;
+			goto drop;
+		}
+		dgram_skb->id = dgram_id;
+		dgram_skb->skb = skb;
+		list_add_tail(&dgram_skb->list, &trans->incomplete_dgrams);
+
+		/* sk_receive_skb() will do a sock_put(), so hold here. */
+		sock_hold(sk);
+		skb_put(skb, size);
+		memcpy(skb->data, &pkt->hdr, sizeof(pkt->hdr));
+	}
+
+	memcpy(skb->data + sizeof(pkt->hdr) + pkt_off, pkt->buf, pkt_len);
+
+	pr_debug("%s:C, off=%d, pkt_len=%d, dgram_len=%d\n", __func__,
+		 pkt_off, pkt_len, dgram_len);
+
+	/* We are done with this dgram */
+	if (pkt_off + pkt_len == dgram_len) {
+		pr_debug("%s:dgram_id=%d is done\n", __func__, dgram_id);
+		list_del(&dgram_skb->list);
+		kfree(dgram_skb);
+		sk_receive_skb(sk, skb, 0);
+	}
+	virtio_transport_free_pkt(pkt);
+	return;
+
+drop:
+	if (dgram_skb) {
+		list_del(&dgram_skb->list);
+		kfree(dgram_skb);
+		kfree_skb(skb);
+		sock_put(sk);
+	}
+	virtio_transport_free_pkt(pkt);
+}
+
+int
+virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
+			       struct msghdr *msg,
+			       size_t len, int flags)
+{
+	struct virtio_vsock_hdr *hdr;
+	struct sk_buff *skb;
+	int noblock;
+	int err;
+	int dgram_len;
+
+	noblock = flags & MSG_DONTWAIT;
+
+	if (flags & MSG_OOB || flags & MSG_ERRQUEUE)
+		return -EOPNOTSUPP;
+
+	/* Retrieve the head sk_buff from the socket's receive queue. */
+	err = 0;
+	skb = skb_recv_datagram(&vsk->sk, flags, noblock, &err);
+	if (err)
+		return err;
+	if (!skb)
+		return -EAGAIN;
+
+	hdr = (struct virtio_vsock_hdr *)skb->data;
+	if (!hdr)
+		goto out;
+
+	dgram_len = le32_to_cpu(hdr->len) >> 16;
+	/* Place the datagram payload in the user's iovec. */
+	err = skb_copy_datagram_msg(skb, sizeof(*hdr), msg, dgram_len);
+	if (err)
+		goto out;
+
+	if (msg->msg_name) {
+		/* Provide the address of the sender. */
+		DECLARE_SOCKADDR(struct sockaddr_vm *, vm_addr, msg->msg_name);
+		vsock_addr_init(vm_addr, le32_to_cpu(hdr->src_cid),
le32_to_cpu(hdr->src_port));
+		msg->msg_namelen = sizeof(*vm_addr);
+	}
+	err = dgram_len;
+
+	/* Send a credit pkt to peer */
+	virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_DGRAM, hdr);
+
+	pr_debug("%s:done, recved =%d\n", __func__, dgram_len);
+out:
+	skb_free_datagram(&vsk->sk, skb);
+	return err;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_dequeue);
+
+s64 virtio_transport_stream_has_data(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+	s64 bytes;
+
+	mutex_lock(&trans->rx_lock);
+	bytes = trans->rx_bytes;
+	mutex_unlock(&trans->rx_lock);
+
+	return bytes;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_has_data);
+
+static s64 virtio_transport_has_space(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+	s64 bytes;
+
+	bytes = trans->peer_buf_alloc - (trans->tx_cnt -
trans->peer_fwd_cnt);
+	if (bytes < 0)
+		bytes = 0;
+
+	return bytes;
+}
+
+s64 virtio_transport_stream_has_space(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+	s64 bytes;
+
+	mutex_lock(&trans->tx_lock);
+	bytes = virtio_transport_has_space(vsk);
+	mutex_unlock(&trans->tx_lock);
+
+	pr_debug("%s: bytes=%lld\n", __func__, bytes);
+
+	return bytes;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_has_space);
+
+int virtio_transport_do_socket_init(struct vsock_sock *vsk,
+				    struct vsock_sock *psk)
+{
+	struct virtio_transport *trans;
+
+	trans = kzalloc(sizeof(*trans), GFP_KERNEL);
+	if (!trans)
+		return -ENOMEM;
+
+	vsk->trans = trans;
+	trans->vsk = vsk;
+	if (psk) {
+		struct virtio_transport *ptrans = psk->trans;
+		trans->buf_size	= ptrans->buf_size;
+		trans->buf_size_min = ptrans->buf_size_min;
+		trans->buf_size_max = ptrans->buf_size_max;
+		trans->peer_buf_alloc = ptrans->peer_buf_alloc;
+	} else {
+		trans->buf_size = VIRTIO_VSOCK_DEFAULT_BUF_SIZE;
+		trans->buf_size_min = VIRTIO_VSOCK_DEFAULT_MIN_BUF_SIZE;
+		trans->buf_size_max = VIRTIO_VSOCK_DEFAULT_MAX_BUF_SIZE;
+	}
+
+	trans->buf_alloc = trans->buf_size;
+
+	pr_debug("%s: trans->buf_alloc=%d\n", __func__,
trans->buf_alloc);
+
+	mutex_init(&trans->rx_lock);
+	mutex_init(&trans->tx_lock);
+	INIT_LIST_HEAD(&trans->rx_queue);
+	INIT_LIST_HEAD(&trans->incomplete_dgrams);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_do_socket_init);
+
+u64 virtio_transport_get_buffer_size(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	return trans->buf_size;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_get_buffer_size);
+
+u64 virtio_transport_get_min_buffer_size(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	return trans->buf_size_min;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_get_min_buffer_size);
+
+u64 virtio_transport_get_max_buffer_size(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	return trans->buf_size_max;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_get_max_buffer_size);
+
+void virtio_transport_set_buffer_size(struct vsock_sock *vsk, u64 val)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
+		val = VIRTIO_VSOCK_MAX_BUF_SIZE;
+	if (val < trans->buf_size_min)
+		trans->buf_size_min = val;
+	if (val > trans->buf_size_max)
+		trans->buf_size_max = val;
+	trans->buf_size = val;
+	trans->buf_alloc = val;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_set_buffer_size);
+
+void virtio_transport_set_min_buffer_size(struct vsock_sock *vsk, u64 val)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
+		val = VIRTIO_VSOCK_MAX_BUF_SIZE;
+	if (val > trans->buf_size)
+		trans->buf_size = val;
+	trans->buf_size_min = val;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_set_min_buffer_size);
+
+void virtio_transport_set_max_buffer_size(struct vsock_sock *vsk, u64 val)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
+		val = VIRTIO_VSOCK_MAX_BUF_SIZE;
+	if (val < trans->buf_size)
+		trans->buf_size = val;
+	trans->buf_size_max = val;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_set_max_buffer_size);
+
+int
+virtio_transport_notify_poll_in(struct vsock_sock *vsk,
+				size_t target,
+				bool *data_ready_now)
+{
+	if (vsock_stream_has_data(vsk))
+		*data_ready_now = true;
+	else
+		*data_ready_now = false;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_in);
+
+int
+virtio_transport_notify_poll_out(struct vsock_sock *vsk,
+				 size_t target,
+				 bool *space_avail_now)
+{
+	s64 free_space;
+
+	free_space = vsock_stream_has_space(vsk);
+	if (free_space > 0)
+		*space_avail_now = true;
+	else if (free_space == 0)
+		*space_avail_now = false;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_out);
+
+int virtio_transport_notify_recv_init(struct vsock_sock *vsk,
+	size_t target, struct vsock_transport_recv_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_init);
+
+int virtio_transport_notify_recv_pre_block(struct vsock_sock *vsk,
+	size_t target, struct vsock_transport_recv_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_block);
+
+int virtio_transport_notify_recv_pre_dequeue(struct vsock_sock *vsk,
+	size_t target, struct vsock_transport_recv_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_dequeue);
+
+int virtio_transport_notify_recv_post_dequeue(struct vsock_sock *vsk,
+	size_t target, ssize_t copied, bool data_read,
+	struct vsock_transport_recv_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_post_dequeue);
+
+int virtio_transport_notify_send_init(struct vsock_sock *vsk,
+	struct vsock_transport_send_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_send_init);
+
+int virtio_transport_notify_send_pre_block(struct vsock_sock *vsk,
+	struct vsock_transport_send_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_block);
+
+int virtio_transport_notify_send_pre_enqueue(struct vsock_sock *vsk,
+	struct vsock_transport_send_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_enqueue);
+
+int virtio_transport_notify_send_post_enqueue(struct vsock_sock *vsk,
+	ssize_t written, struct vsock_transport_send_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_send_post_enqueue);
+
+u64 virtio_transport_stream_rcvhiwat(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	return trans->buf_size;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_rcvhiwat);
+
+bool virtio_transport_stream_is_active(struct vsock_sock *vsk)
+{
+	return true;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_is_active);
+
+bool virtio_transport_stream_allow(u32 cid, u32 port)
+{
+	return true;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_allow);
+
+int virtio_transport_dgram_bind(struct vsock_sock *vsk,
+				struct sockaddr_vm *addr)
+{
+	return vsock_bind_dgram_generic(vsk, addr);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind);
+
+bool virtio_transport_dgram_allow(u32 cid, u32 port)
+{
+	return true;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_allow);
+
+int virtio_transport_connect(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_REQUEST,
+		.type = VIRTIO_VSOCK_TYPE_STREAM,
+	};
+
+	pr_debug("%s: vsk=%p send_request\n", __func__, vsk);
+	return trans->ops->send_pkt(vsk, &info);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_connect);
+
+int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_SHUTDOWN,
+		.type = VIRTIO_VSOCK_TYPE_STREAM,
+		.flags = (mode & RCV_SHUTDOWN ?
+			  VIRTIO_VSOCK_SHUTDOWN_RCV : 0) |
+			 (mode & SEND_SHUTDOWN ?
+			  VIRTIO_VSOCK_SHUTDOWN_SEND : 0),
+	};
+
+	pr_debug("%s: vsk=%p: send_shutdown\n", __func__, vsk);
+	return trans->ops->send_pkt(vsk, &info);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_shutdown);
+
+void virtio_transport_release(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct sock *sk = &vsk->sk;
+	struct dgram_skb *dgram_skb;
+	struct dgram_skb *dgram_skb_tmp;
+
+	pr_debug("%s: vsk=%p\n", __func__, vsk);
+
+	/* Tell other side to terminate connection */
+	if (sk->sk_type == SOCK_STREAM && sk->sk_state == SS_CONNECTED)
{
+		virtio_transport_shutdown(vsk, SHUTDOWN_MASK);
+	}
+
+	/* Free incomplete dgrams */
+	lock_sock(sk);
+	list_for_each_entry_safe(dgram_skb, dgram_skb_tmp,
+				 &trans->incomplete_dgrams, list) {
+		list_del(&dgram_skb->list);
+		kfree_skb(dgram_skb->skb);
+		kfree(dgram_skb);
+		sock_put(sk); /* held in virtio_transport_recv_dgram() */
+	}
+	release_sock(sk);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_release);
+
+int
+virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
+			       struct sockaddr_vm *remote_addr,
+			       struct msghdr *msg,
+			       size_t dgram_len)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_RW,
+		.type = VIRTIO_VSOCK_TYPE_DGRAM,
+		.msg = msg,
+	};
+	size_t total_written = 0, pkt_off = 0, written;
+	u16 dgram_id;
+
+	/* The max size of a single dgram we support is 64KB */
+	if (dgram_len > VIRTIO_VSOCK_MAX_DGRAM_SIZE)
+		return -EMSGSIZE;
+
+	info.dgram_len = dgram_len;
+	vsk->remote_addr = *remote_addr;
+
+	dgram_id = trans->dgram_id++;
+
+	/* TODO: To optimize, if we have enough credit to send the pkt already,
+	 * do not ask the peer to send credit to use  */
+	virtio_transport_send_credit_request(vsk, VIRTIO_VSOCK_TYPE_DGRAM);
+
+	while (total_written < dgram_len) {
+		info.pkt_len = dgram_len - total_written;
+		info.flags = dgram_id << 16 | pkt_off;
+		written = trans->ops->send_pkt(vsk, &info);
+		if (written < 0)
+			return -ENOMEM;
+		if (written == 0) {
+			/* TODO: if written = 0, we need a sleep & wakeup
+			 * instead of sleep */
+			pr_debug("%s: SHOULD WAIT written==0", __func__);
+			msleep(10);
+		}
+		total_written += written;
+		pkt_off += written;
+		pr_debug("%s:id=%d, dgram_len=%zu, off=%zu, total_written=%zu,
written=%zu\n",
+			  __func__, dgram_id, dgram_len, pkt_off, total_written, written);
+	}
+
+	return dgram_len;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_enqueue);
+
+ssize_t
+virtio_transport_stream_enqueue(struct vsock_sock *vsk,
+				struct msghdr *msg,
+				size_t len)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_RW,
+		.type = VIRTIO_VSOCK_TYPE_STREAM,
+		.msg = msg,
+		.pkt_len = len,
+	};
+
+	return trans->ops->send_pkt(vsk, &info);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_enqueue);
+
+void virtio_transport_destruct(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	pr_debug("%s: vsk=%p\n", __func__, vsk);
+	kfree(trans);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_destruct);
+
+static int virtio_transport_send_ack(struct vsock_sock *vsk, u32 cookie)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_ACK,
+		.type = VIRTIO_VSOCK_TYPE_STREAM,
+		.flags = cpu_to_le32(cookie),
+	};
+
+	pr_debug("%s: sk=%p send_offer\n", __func__, vsk);
+	return trans->ops->send_pkt(vsk, &info);
+}
+
+static int virtio_transport_send_reset(struct vsock_sock *vsk,
+				       struct virtio_vsock_pkt *pkt)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_RST,
+		.type = VIRTIO_VSOCK_TYPE_STREAM,
+	};
+
+	pr_debug("%s\n", __func__);
+
+	/* Send RST only if the original pkt is not a RST pkt */
+	if (le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_RST)
+		return 0;
+
+	return trans->ops->send_pkt(vsk, &info);
+}
+
+static int
+virtio_transport_recv_connecting(struct sock *sk,
+				 struct virtio_vsock_pkt *pkt)
+{
+	struct vsock_sock *vsk = vsock_sk(sk);
+	int err;
+	int skerr;
+	u32 cookie;
+
+	pr_debug("%s: vsk=%p\n", __func__, vsk);
+	switch (le16_to_cpu(pkt->hdr.op)) {
+	case VIRTIO_VSOCK_OP_RESPONSE:
+		cookie = le32_to_cpu(pkt->hdr.flags);
+		pr_debug("%s: got RESPONSE and send ACK, cookie=%x\n", __func__,
cookie);
+		err = virtio_transport_send_ack(vsk, cookie);
+		if (err < 0) {
+			skerr = -err;
+			goto destroy;
+		}
+		sk->sk_state = SS_CONNECTED;
+		sk->sk_socket->state = SS_CONNECTED;
+		vsock_insert_connected(vsk);
+		sk->sk_state_change(sk);
+		break;
+	case VIRTIO_VSOCK_OP_INVALID:
+		pr_debug("%s: got invalid\n", __func__);
+		break;
+	case VIRTIO_VSOCK_OP_RST:
+		pr_debug("%s: got rst\n", __func__);
+		skerr = ECONNRESET;
+		err = 0;
+		goto destroy;
+	default:
+		pr_debug("%s: got def\n", __func__);
+		skerr = EPROTO;
+		err = -EINVAL;
+		goto destroy;
+	}
+	return 0;
+
+destroy:
+	virtio_transport_send_reset(vsk, pkt);
+	sk->sk_state = SS_UNCONNECTED;
+	sk->sk_err = skerr;
+	sk->sk_error_report(sk);
+	return err;
+}
+
+static int
+virtio_transport_recv_connected(struct sock *sk,
+				struct virtio_vsock_pkt *pkt)
+{
+	struct vsock_sock *vsk = vsock_sk(sk);
+	struct virtio_transport *trans = vsk->trans;
+	int err = 0;
+
+	switch (le16_to_cpu(pkt->hdr.op)) {
+	case VIRTIO_VSOCK_OP_RW:
+		pkt->len = le32_to_cpu(pkt->hdr.len);
+		pkt->off = 0;
+		pkt->trans = trans;
+
+		mutex_lock(&trans->rx_lock);
+		virtio_transport_inc_rx_pkt(pkt);
+		list_add_tail(&pkt->list, &trans->rx_queue);
+		mutex_unlock(&trans->rx_lock);
+
+		sk->sk_data_ready(sk);
+		return err;
+	case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
+		sk->sk_write_space(sk);
+		break;
+	case VIRTIO_VSOCK_OP_SHUTDOWN:
+		pr_debug("%s: got shutdown\n", __func__);
+		if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SHUTDOWN_RCV)
+			vsk->peer_shutdown |= RCV_SHUTDOWN;
+		if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SHUTDOWN_SEND)
+			vsk->peer_shutdown |= SEND_SHUTDOWN;
+		if (le32_to_cpu(pkt->hdr.flags))
+			sk->sk_state_change(sk);
+		break;
+	case VIRTIO_VSOCK_OP_RST:
+		pr_debug("%s: got rst\n", __func__);
+		sock_set_flag(sk, SOCK_DONE);
+		vsk->peer_shutdown = SHUTDOWN_MASK;
+		if (vsock_stream_has_data(vsk) <= 0)
+			sk->sk_state = SS_DISCONNECTING;
+		sk->sk_state_change(sk);
+		break;
+	default:
+		err = -EINVAL;
+		break;
+	}
+
+	virtio_transport_free_pkt(pkt);
+	return err;
+}
+
+static int
+virtio_transport_send_response(struct vsock_sock *vsk,
+			       struct virtio_vsock_pkt *pkt)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_RESPONSE,
+		.type = VIRTIO_VSOCK_TYPE_STREAM,
+		.remote_cid = le32_to_cpu(pkt->hdr.src_cid),
+		.remote_port = le32_to_cpu(pkt->hdr.src_port),
+	};
+	u32 cookie;
+
+	cookie = virtio_vsock_secure_cookie(le32_to_cpu(pkt->hdr.src_cid),
+					    le32_to_cpu(pkt->hdr.dst_cid),
+					    le32_to_cpu(pkt->hdr.src_port),
+					    le32_to_cpu(pkt->hdr.dst_port),
+					    jiffies / (HZ * 60));
+	info.flags = cpu_to_le32(cookie);
+
+	pr_debug("%s: send_response, cookie=%x\n", __func__,
le32_to_cpu(cookie));
+
+	return trans->ops->send_pkt(vsk, &info);
+}
+
+/* Handle server socket */
+static int
+virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt)
+{
+	struct vsock_sock *vsk = vsock_sk(sk);
+	struct vsock_sock *vpending;
+	struct sock *pending;
+	int err;
+	u32 cookie;
+
+	switch (le16_to_cpu(pkt->hdr.op)) {
+	case VIRTIO_VSOCK_OP_REQUEST:
+		err = virtio_transport_send_response(vsk, pkt);
+		if (err < 0) {
+			// FIXME vsk should be vpending
+			virtio_transport_send_reset(vsk, pkt);
+			return err;
+		}
+		break;
+	case VIRTIO_VSOCK_OP_ACK:
+		cookie = le32_to_cpu(pkt->hdr.flags);
+		err = virtio_vsock_check_cookie(le32_to_cpu(pkt->hdr.src_cid),
+						le32_to_cpu(pkt->hdr.dst_cid),
+						le32_to_cpu(pkt->hdr.src_port),
+						le32_to_cpu(pkt->hdr.dst_port),
+						jiffies / (HZ * 60),
+						le32_to_cpu(pkt->hdr.flags),
+						VSOCK_TIMEOUT_INIT);
+		pr_debug("%s: cookie=%x, err=%d\n", __func__, cookie, err);
+		if (err)
+			return err;
+
+		/* So no pending socket are responsible for this pkt, create one */
+		pr_debug("%s: create pending\n", __func__);
+		pending = __vsock_create(sock_net(sk), NULL, sk, GFP_KERNEL,
+				sk->sk_type, 0);
+		if (!pending) {
+			virtio_transport_send_reset(vsk, pkt);
+			return -ENOMEM;
+		}
+		sk->sk_ack_backlog++;
+		pending->sk_state = SS_CONNECTING;
+
+		vpending = vsock_sk(pending);
+		vsock_addr_init(&vpending->local_addr,
le32_to_cpu(pkt->hdr.dst_cid),
+				le32_to_cpu(pkt->hdr.dst_port));
+		vsock_addr_init(&vpending->remote_addr,
le32_to_cpu(pkt->hdr.src_cid),
+				le32_to_cpu(pkt->hdr.src_port));
+		vsock_add_pending(sk, pending);
+
+		pr_debug("%s: get pending\n", __func__);
+		pending = virtio_transport_get_pending(sk, pkt);
+		vpending = vsock_sk(pending);
+		lock_sock(pending);
+		switch (pending->sk_state) {
+			case SS_CONNECTING:
+				if (le16_to_cpu(pkt->hdr.op) != VIRTIO_VSOCK_OP_ACK) {
+					pr_debug("%s: op=%d != OP_ACK\n", __func__,
+						 le16_to_cpu(pkt->hdr.op));
+					virtio_transport_send_reset(vpending, pkt);
+					pending->sk_err = EPROTO;
+					pending->sk_state = SS_UNCONNECTED;
+					sock_put(pending);
+				} else {
+					pending->sk_state = SS_CONNECTED;
+					vsock_insert_connected(vpending);
+
+					vsock_remove_pending(sk, pending);
+					vsock_enqueue_accept(sk, pending);
+
+					sk->sk_data_ready(sk);
+				}
+				err = 0;
+				break;
+			default:
+				pr_debug("%s: sk->sk_ack_backlog=%d\n", __func__,
+						sk->sk_ack_backlog);
+				virtio_transport_send_reset(vpending, pkt);
+				err = -EINVAL;
+				break;
+		}
+		if (err < 0)
+			vsock_remove_pending(sk, pending);
+		release_sock(pending);
+
+		/* Release refcnt obtained in virtio_transport_get_pending */
+		sock_put(pending);
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static void virtio_transport_space_update(struct sock *sk,
+					  struct virtio_vsock_pkt *pkt)
+{
+	struct vsock_sock *vsk = vsock_sk(sk);
+	struct virtio_transport *trans = vsk->trans;
+	bool space_available;
+
+	/* buf_alloc and fwd_cnt is always included in the hdr */
+	mutex_lock(&trans->tx_lock);
+	trans->peer_buf_alloc = le32_to_cpu(pkt->hdr.buf_alloc);
+	trans->peer_fwd_cnt = le32_to_cpu(pkt->hdr.fwd_cnt);
+	space_available = virtio_transport_has_space(vsk);
+	mutex_unlock(&trans->tx_lock);
+
+	if (space_available)
+		sk->sk_write_space(sk);
+}
+
+/* We are under the virtio-vsock's vsock->rx_lock or
+ * vhost-vsock's vq->mutex lock */
+void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt)
+{
+	struct virtio_transport *trans;
+	struct sockaddr_vm src, dst;
+	struct vsock_sock *vsk;
+	struct sock *sk;
+
+	vsock_addr_init(&src, le32_to_cpu(pkt->hdr.src_cid),
le32_to_cpu(pkt->hdr.src_port));
+	vsock_addr_init(&dst, le32_to_cpu(pkt->hdr.dst_cid),
le32_to_cpu(pkt->hdr.dst_port));
+
+	virtio_vsock_dumppkt(__func__, pkt);
+
+	if (le16_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_DGRAM) {
+		sk = vsock_find_unbound_socket(&dst);
+		if (!sk)
+			goto free_pkt;
+
+		vsk = vsock_sk(sk);
+		trans = vsk->trans;
+		BUG_ON(!trans);
+
+		virtio_transport_space_update(sk, pkt);
+
+		lock_sock(sk);
+		switch (le16_to_cpu(pkt->hdr.op)) {
+		case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
+			virtio_transport_free_pkt(pkt);
+			break;
+		case VIRTIO_VSOCK_OP_CREDIT_REQUEST:
+			virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_DGRAM,
+							    &pkt->hdr);
+			virtio_transport_free_pkt(pkt);
+			break;
+		case VIRTIO_VSOCK_OP_RW:
+			virtio_transport_recv_dgram(sk, pkt);
+			break;
+		default:
+			virtio_transport_free_pkt(pkt);
+			break;
+		}
+		release_sock(sk);
+
+		/* Release refcnt obtained when we fetched this socket out of
+		 * the unbound list.
+		 */
+		sock_put(sk);
+		return;
+	} else if (le16_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_STREAM) {
+		/* The socket must be in connected or bound table
+		 * otherwise send reset back
+		 */
+		sk = vsock_find_connected_socket(&src, &dst);
+		if (!sk) {
+			sk = vsock_find_bound_socket(&dst);
+			if (!sk) {
+				pr_debug("%s: can not find bound_socket\n", __func__);
+				virtio_vsock_dumppkt(__func__, pkt);
+				/* Ignore this pkt instead of sending reset back */
+				/* TODO send a RST unless this packet is a RST (to avoid infinite loops) */
+				goto free_pkt;
+			}
+		}
+
+		vsk = vsock_sk(sk);
+		trans = vsk->trans;
+		BUG_ON(!trans);
+
+		virtio_transport_space_update(sk, pkt);
+
+		lock_sock(sk);
+		switch (sk->sk_state) {
+		case VSOCK_SS_LISTEN:
+			virtio_transport_recv_listen(sk, pkt);
+			virtio_transport_free_pkt(pkt);
+			break;
+		case SS_CONNECTING:
+			virtio_transport_recv_connecting(sk, pkt);
+			virtio_transport_free_pkt(pkt);
+			break;
+		case SS_CONNECTED:
+			virtio_transport_recv_connected(sk, pkt);
+			break;
+		default:
+			virtio_transport_free_pkt(pkt);
+			break;
+		}
+		release_sock(sk);
+
+		/* Release refcnt obtained when we fetched this socket out of the
+		 * bound or connected list.
+		 */
+		sock_put(sk);
+	}
+	return;
+
+free_pkt:
+	virtio_transport_free_pkt(pkt);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_recv_pkt);
+
+void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt)
+{
+	kfree(pkt->buf);
+	kfree(pkt);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_free_pkt);
+
+static int __init virtio_vsock_common_init(void)
+{
+	get_random_bytes(vsockcookie_secret, sizeof(vsockcookie_secret));
+	return 0;
+}
+
+static void __exit virtio_vsock_common_exit(void)
+{
+}
+
+module_init(virtio_vsock_common_init);
+module_exit(virtio_vsock_common_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Asias He");
+MODULE_DESCRIPTION("common code for virtio vsock");
-- 
2.5.0

From: Asias He <asias at redhat.com>

VM sockets virtio transport implementation. This module runs in guest
kernel.

Signed-off-by: Asias He <asias at redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha at redhat.com>
---
v2:
 * Fix total_tx_buf accounting
 * Add virtio_transport global mutex to prevent races
---
 net/vmw_vsock/virtio_transport.c | 466 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 466 insertions(+)
 create mode 100644 net/vmw_vsock/virtio_transport.c

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
new file mode 100644
index 0000000..df65dca
--- /dev/null
+++ b/net/vmw_vsock/virtio_transport.c
@@ -0,0 +1,466 @@
+/*
+ * virtio transport for vsock
+ *
+ * Copyright (C) 2013-2015 Red Hat, Inc.
+ * Author: Asias He <asias at redhat.com>
+ *         Stefan Hajnoczi <stefanha at redhat.com>
+ *
+ * Some of the code is take from Gerd Hoffmann <kraxel at
redhat.com>'s
+ * early virtio-vsock proof-of-concept bits.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ */
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/virtio.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_vsock.h>
+#include <net/sock.h>
+#include <linux/mutex.h>
+#include <net/af_vsock.h>
+
+static struct workqueue_struct *virtio_vsock_workqueue;
+static struct virtio_vsock *the_virtio_vsock;
+static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */
+static void virtio_vsock_rx_fill(struct virtio_vsock *vsock);
+
+struct virtio_vsock {
+	/* Virtio device */
+	struct virtio_device *vdev;
+	/* Virtio virtqueue */
+	struct virtqueue *vqs[VSOCK_VQ_MAX];
+	/* Wait queue for send pkt */
+	wait_queue_head_t queue_wait;
+	/* Work item to send pkt */
+	struct work_struct tx_work;
+	/* Work item to recv pkt */
+	struct work_struct rx_work;
+	/* Mutex to protect send pkt*/
+	struct mutex tx_lock;
+	/* Mutex to protect recv pkt*/
+	struct mutex rx_lock;
+	/* Number of recv buffers */
+	int rx_buf_nr;
+	/* Number of max recv buffers */
+	int rx_buf_max_nr;
+	/* Used for global tx buf limitation */
+	u32 total_tx_buf;
+	/* Guest context id, just like guest ip address */
+	u32 guest_cid;
+};
+
+static struct virtio_vsock *virtio_vsock_get(void)
+{
+	return the_virtio_vsock;
+}
+
+static u32 virtio_transport_get_local_cid(void)
+{
+	struct virtio_vsock *vsock = virtio_vsock_get();
+
+	return vsock->guest_cid;
+}
+
+static int
+virtio_transport_send_pkt(struct vsock_sock *vsk,
+			  struct virtio_vsock_pkt_info *info)
+{
+	u32 src_cid, src_port, dst_cid, dst_port;
+	int ret, in_sg = 0, out_sg = 0;
+	struct virtio_transport *trans;
+	struct virtio_vsock_pkt *pkt;
+	struct virtio_vsock *vsock;
+	struct scatterlist hdr, buf, *sgs[2];
+	struct virtqueue *vq;
+	u32 pkt_len = info->pkt_len;
+	DEFINE_WAIT(wait);
+
+	vsock = virtio_vsock_get();
+	if (!vsock)
+		return -ENODEV;
+
+	src_cid	= virtio_transport_get_local_cid();
+	src_port = vsk->local_addr.svm_port;
+	if (!info->remote_cid) {
+		dst_cid	= vsk->remote_addr.svm_cid;
+		dst_port = vsk->remote_addr.svm_port;
+	} else {
+		dst_cid = info->remote_cid;
+		dst_port = info->remote_port;
+	}
+
+	trans = vsk->trans;
+	vq = vsock->vqs[VSOCK_VQ_TX];
+
+	if (pkt_len > VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE)
+		pkt_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
+	pkt_len = virtio_transport_get_credit(trans, pkt_len);
+	/* Do not send zero length OP_RW pkt*/
+	if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
+		return pkt_len;
+
+	/* Respect global tx buf limitation */
+	mutex_lock(&vsock->tx_lock);
+	while (pkt_len + vsock->total_tx_buf > VIRTIO_VSOCK_MAX_TX_BUF_SIZE) {
+		prepare_to_wait_exclusive(&vsock->queue_wait, &wait,
+					  TASK_UNINTERRUPTIBLE);
+		mutex_unlock(&vsock->tx_lock);
+		schedule();
+		mutex_lock(&vsock->tx_lock);
+		finish_wait(&vsock->queue_wait, &wait);
+	}
+	vsock->total_tx_buf += pkt_len;
+	mutex_unlock(&vsock->tx_lock);
+
+	pkt = virtio_transport_alloc_pkt(vsk, info, pkt_len,
+					 src_cid, src_port,
+					 dst_cid, dst_port);
+	if (!pkt) {
+		mutex_lock(&vsock->tx_lock);
+		vsock->total_tx_buf -= pkt_len;
+		mutex_unlock(&vsock->tx_lock);
+		virtio_transport_put_credit(trans, pkt_len);
+		return -ENOMEM;
+	}
+
+	pr_debug("%s:info->pkt_len= %d\n", __func__, info->pkt_len);
+
+	/* Will be released in virtio_transport_send_pkt_work */
+	sock_hold(&trans->vsk->sk);
+	virtio_transport_inc_tx_pkt(pkt);
+
+	/* Put pkt in the virtqueue */
+	sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
+	sgs[out_sg++] = &hdr;
+	if (info->msg && info->pkt_len > 0) {
+		sg_init_one(&buf, pkt->buf, pkt->len);
+	        sgs[out_sg++] = &buf;
+	}
+
+	mutex_lock(&vsock->tx_lock);
+	while ((ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt,
+					GFP_KERNEL)) < 0) {
+		prepare_to_wait_exclusive(&vsock->queue_wait, &wait,
+					  TASK_UNINTERRUPTIBLE);
+		mutex_unlock(&vsock->tx_lock);
+		schedule();
+		mutex_lock(&vsock->tx_lock);
+		finish_wait(&vsock->queue_wait, &wait);
+	}
+	virtqueue_kick(vq);
+	mutex_unlock(&vsock->tx_lock);
+
+	return pkt_len;
+}
+
+static struct virtio_transport_pkt_ops virtio_ops = {
+	.send_pkt = virtio_transport_send_pkt,
+};
+
+static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
+{
+	int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
+	struct virtio_vsock_pkt *pkt;
+	struct scatterlist hdr, buf, *sgs[2];
+	struct virtqueue *vq;
+	int ret;
+
+	vq = vsock->vqs[VSOCK_VQ_RX];
+
+	do {
+		pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
+		if (!pkt) {
+			pr_debug("%s: fail to allocate pkt\n", __func__);
+			goto out;
+		}
+
+		/* TODO: use mergeable rx buffer */
+		pkt->buf = kmalloc(buf_len, GFP_KERNEL);
+		if (!pkt->buf) {
+			pr_debug("%s: fail to allocate pkt->buf\n", __func__);
+			goto err;
+		}
+
+		sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
+		sgs[0] = &hdr;
+
+		sg_init_one(&buf, pkt->buf, buf_len);
+	        sgs[1] = &buf;
+		ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);
+		if (ret)
+			goto err;
+		vsock->rx_buf_nr++;
+	} while (vq->num_free);
+	if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
+		vsock->rx_buf_max_nr = vsock->rx_buf_nr;
+out:
+	virtqueue_kick(vq);
+	return;
+err:
+	virtqueue_kick(vq);
+	virtio_transport_free_pkt(pkt);
+	return;
+}
+
+static void virtio_transport_send_pkt_work(struct work_struct *work)
+{
+	struct virtio_vsock *vsock +		container_of(work, struct virtio_vsock,
tx_work);
+	struct virtio_vsock_pkt *pkt;
+	bool added = false;
+	struct virtqueue *vq;
+	unsigned int len;
+	struct sock *sk;
+
+	vq = vsock->vqs[VSOCK_VQ_TX];
+	mutex_lock(&vsock->tx_lock);
+	do {
+		virtqueue_disable_cb(vq);
+		while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
+			sk = &pkt->trans->vsk->sk;
+			virtio_transport_dec_tx_pkt(pkt);
+			/* Release refcnt taken in virtio_transport_send_pkt */
+			sock_put(sk);
+			vsock->total_tx_buf -= pkt->len;
+			virtio_transport_free_pkt(pkt);
+			added = true;
+		}
+	} while (!virtqueue_enable_cb(vq));
+	mutex_unlock(&vsock->tx_lock);
+
+	if (added)
+		wake_up(&vsock->queue_wait);
+}
+
+static void virtio_transport_recv_pkt_work(struct work_struct *work)
+{
+	struct virtio_vsock *vsock +		container_of(work, struct virtio_vsock,
rx_work);
+	struct virtio_vsock_pkt *pkt;
+	struct virtqueue *vq;
+	unsigned int len;
+
+	vq = vsock->vqs[VSOCK_VQ_RX];
+	mutex_lock(&vsock->rx_lock);
+	do {
+		virtqueue_disable_cb(vq);
+		while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
+			pkt->len = len;
+			virtio_transport_recv_pkt(pkt);
+			vsock->rx_buf_nr--;
+		}
+	} while (!virtqueue_enable_cb(vq));
+
+	if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
+		virtio_vsock_rx_fill(vsock);
+	mutex_unlock(&vsock->rx_lock);
+}
+
+static void virtio_vsock_ctrl_done(struct virtqueue *vq)
+{
+}
+
+static void virtio_vsock_tx_done(struct virtqueue *vq)
+{
+	struct virtio_vsock *vsock = vq->vdev->priv;
+
+	if (!vsock)
+		return;
+	queue_work(virtio_vsock_workqueue, &vsock->tx_work);
+}
+
+static void virtio_vsock_rx_done(struct virtqueue *vq)
+{
+	struct virtio_vsock *vsock = vq->vdev->priv;
+
+	if (!vsock)
+		return;
+	queue_work(virtio_vsock_workqueue, &vsock->rx_work);
+}
+
+static int
+virtio_transport_socket_init(struct vsock_sock *vsk, struct vsock_sock *psk)
+{
+	struct virtio_transport *trans;
+	int ret;
+
+	ret = virtio_transport_do_socket_init(vsk, psk);
+	if (ret)
+		return ret;
+
+	trans = vsk->trans;
+	trans->ops = &virtio_ops;
+	return ret;
+}
+
+static struct vsock_transport virtio_transport = {
+	.get_local_cid            = virtio_transport_get_local_cid,
+
+	.init                     = virtio_transport_socket_init,
+	.destruct                 = virtio_transport_destruct,
+	.release                  = virtio_transport_release,
+	.connect                  = virtio_transport_connect,
+	.shutdown                 = virtio_transport_shutdown,
+
+	.dgram_bind               = virtio_transport_dgram_bind,
+	.dgram_dequeue            = virtio_transport_dgram_dequeue,
+	.dgram_enqueue            = virtio_transport_dgram_enqueue,
+	.dgram_allow              = virtio_transport_dgram_allow,
+
+	.stream_dequeue           = virtio_transport_stream_dequeue,
+	.stream_enqueue           = virtio_transport_stream_enqueue,
+	.stream_has_data          = virtio_transport_stream_has_data,
+	.stream_has_space         = virtio_transport_stream_has_space,
+	.stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
+	.stream_is_active         = virtio_transport_stream_is_active,
+	.stream_allow             = virtio_transport_stream_allow,
+
+	.notify_poll_in           = virtio_transport_notify_poll_in,
+	.notify_poll_out          = virtio_transport_notify_poll_out,
+	.notify_recv_init         = virtio_transport_notify_recv_init,
+	.notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
+	.notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
+	.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
+	.notify_send_init         = virtio_transport_notify_send_init,
+	.notify_send_pre_block    = virtio_transport_notify_send_pre_block,
+	.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
+	.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
+
+	.set_buffer_size          = virtio_transport_set_buffer_size,
+	.set_min_buffer_size      = virtio_transport_set_min_buffer_size,
+	.set_max_buffer_size      = virtio_transport_set_max_buffer_size,
+	.get_buffer_size          = virtio_transport_get_buffer_size,
+	.get_min_buffer_size      = virtio_transport_get_min_buffer_size,
+	.get_max_buffer_size      = virtio_transport_get_max_buffer_size,
+};
+
+static int virtio_vsock_probe(struct virtio_device *vdev)
+{
+	vq_callback_t *callbacks[] = {
+		virtio_vsock_ctrl_done,
+		virtio_vsock_rx_done,
+		virtio_vsock_tx_done,
+	};
+	const char *names[] = {
+		"ctrl",
+		"rx",
+		"tx",
+	};
+	struct virtio_vsock *vsock = NULL;
+	u32 guest_cid;
+	int ret;
+
+	ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
+	if (ret)
+		return ret;
+
+	/* Only one virtio-vsock device per guest is supported */
+	if (the_virtio_vsock) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
+	if (!vsock) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	vsock->vdev = vdev;
+
+	ret = vsock->vdev->config->find_vqs(vsock->vdev, VSOCK_VQ_MAX,
+					    vsock->vqs, callbacks, names);
+	if (ret < 0)
+		goto out;
+
+	vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
+			  &guest_cid, sizeof(guest_cid));
+	vsock->guest_cid = le32_to_cpu(guest_cid);
+	pr_debug("%s:guest_cid=%d\n", __func__, vsock->guest_cid);
+
+	ret = vsock_core_init(&virtio_transport);
+	if (ret < 0)
+		goto out_vqs;
+
+	vsock->rx_buf_nr = 0;
+	vsock->rx_buf_max_nr = 0;
+
+	vdev->priv = the_virtio_vsock = vsock;
+	init_waitqueue_head(&vsock->queue_wait);
+	mutex_init(&vsock->tx_lock);
+	mutex_init(&vsock->rx_lock);
+	INIT_WORK(&vsock->rx_work, virtio_transport_recv_pkt_work);
+	INIT_WORK(&vsock->tx_work, virtio_transport_send_pkt_work);
+
+	mutex_lock(&vsock->rx_lock);
+	virtio_vsock_rx_fill(vsock);
+	mutex_unlock(&vsock->rx_lock);
+
+	mutex_unlock(&the_virtio_vsock_mutex);
+	return 0;
+
+out_vqs:
+	vsock->vdev->config->del_vqs(vsock->vdev);
+out:
+	kfree(vsock);
+	mutex_unlock(&the_virtio_vsock_mutex);
+	return ret;
+}
+
+static void virtio_vsock_remove(struct virtio_device *vdev)
+{
+	struct virtio_vsock *vsock = vdev->priv;
+
+	mutex_lock(&the_virtio_vsock_mutex);
+	the_virtio_vsock = NULL;
+	vsock_core_exit();
+	mutex_unlock(&the_virtio_vsock_mutex);
+
+	kfree(vsock);
+}
+
+static struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static unsigned int features[] = {
+};
+
+static struct virtio_driver virtio_vsock_driver = {
+	.feature_table = features,
+	.feature_table_size = ARRAY_SIZE(features),
+	.driver.name = KBUILD_MODNAME,
+	.driver.owner = THIS_MODULE,
+	.id_table = id_table,
+	.probe = virtio_vsock_probe,
+	.remove = virtio_vsock_remove,
+};
+
+static int __init virtio_vsock_init(void)
+{
+	int ret;
+
+	virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
+	if (!virtio_vsock_workqueue)
+		return -ENOMEM;
+	ret = register_virtio_driver(&virtio_vsock_driver);
+	if (ret)
+		destroy_workqueue(virtio_vsock_workqueue);
+	return ret;
+}
+
+static void __exit virtio_vsock_exit(void)
+{
+	unregister_virtio_driver(&virtio_vsock_driver);
+	destroy_workqueue(virtio_vsock_workqueue);
+}
+
+module_init(virtio_vsock_init);
+module_exit(virtio_vsock_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Asias He");
+MODULE_DESCRIPTION("virtio transport for vsock");
+MODULE_DEVICE_TABLE(virtio, id_table);
-- 
2.5.0

From: Asias He <asias at redhat.com>

VM sockets vhost transport implementation. This module runs in host
kernel.

Signed-off-by: Asias He <asias at redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha at redhat.com>
---
v2:
 * Add missing total_tx_buf decrement
 * Support flexible rx/tx descriptor layout
 * Refuse to assign reserved CIDs
 * Refuse guest CID if already in use
 * Only accept correctly addressed packets
---
 drivers/vhost/vsock.c | 631 ++++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/vhost/vsock.h |   4 +
 2 files changed, 635 insertions(+)
 create mode 100644 drivers/vhost/vsock.c
 create mode 100644 drivers/vhost/vsock.h

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
new file mode 100644
index 0000000..65b1cf8
--- /dev/null
+++ b/drivers/vhost/vsock.c
@@ -0,0 +1,631 @@
+/*
+ * vhost transport for vsock
+ *
+ * Copyright (C) 2013-2015 Red Hat, Inc.
+ * Author: Asias He <asias at redhat.com>
+ *         Stefan Hajnoczi <stefanha at redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ */
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <net/sock.h>
+#include <linux/virtio_vsock.h>
+#include <linux/vhost.h>
+
+#include <net/af_vsock.h>
+#include "vhost.h"
+#include "vsock.h"
+
+#define VHOST_VSOCK_DEFAULT_HOST_CID	2
+
+static int vhost_transport_socket_init(struct vsock_sock *vsk,
+				       struct vsock_sock *psk);
+
+enum {
+	VHOST_VSOCK_FEATURES = VHOST_FEATURES,
+};
+
+/* Used to track all the vhost_vsock instances on the system. */
+static LIST_HEAD(vhost_vsock_list);
+static DEFINE_MUTEX(vhost_vsock_mutex);
+
+struct vhost_vsock_virtqueue {
+	struct vhost_virtqueue vq;
+};
+
+struct vhost_vsock {
+	/* Vhost device */
+	struct vhost_dev dev;
+	/* Vhost vsock virtqueue*/
+	struct vhost_vsock_virtqueue vqs[VSOCK_VQ_MAX];
+	/* Link to global vhost_vsock_list*/
+	struct list_head list;
+	/* Head for pkt from host to guest */
+	struct list_head send_pkt_list;
+	/* Work item to send pkt */
+	struct vhost_work send_pkt_work;
+	/* Wait queue for send pkt */
+	wait_queue_head_t queue_wait;
+	/* Used for global tx buf limitation */
+	u32 total_tx_buf;
+	/* Guest contex id this vhost_vsock instance handles */
+	u32 guest_cid;
+};
+
+static u32 vhost_transport_get_local_cid(void)
+{
+	u32 cid = VHOST_VSOCK_DEFAULT_HOST_CID;
+	return cid;
+}
+
+static struct vhost_vsock *vhost_vsock_get(u32 guest_cid)
+{
+	struct vhost_vsock *vsock;
+
+	mutex_lock(&vhost_vsock_mutex);
+	list_for_each_entry(vsock, &vhost_vsock_list, list) {
+		if (vsock->guest_cid == guest_cid) {
+			mutex_unlock(&vhost_vsock_mutex);
+			return vsock;
+		}
+	}
+	mutex_unlock(&vhost_vsock_mutex);
+
+	return NULL;
+}
+
+static void
+vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
+			    struct vhost_virtqueue *vq)
+{
+	bool added = false;
+
+	mutex_lock(&vq->mutex);
+	vhost_disable_notify(&vsock->dev, vq);
+	for (;;) {
+		struct virtio_vsock_pkt *pkt;
+		struct iov_iter iov_iter;
+		unsigned out, in;
+		struct sock *sk;
+		size_t nbytes;
+		size_t len;
+		int head;
+
+		if (list_empty(&vsock->send_pkt_list)) {
+			vhost_enable_notify(&vsock->dev, vq);
+			break;
+		}
+
+		head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
+					 &out, &in, NULL, NULL);
+		pr_debug("%s: head = %d\n", __func__, head);
+		if (head < 0)
+			break;
+
+		if (head == vq->num) {
+			if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
+				vhost_disable_notify(&vsock->dev, vq);
+				continue;
+			}
+			break;
+		}
+
+		pkt = list_first_entry(&vsock->send_pkt_list,
+				       struct virtio_vsock_pkt, list);
+		list_del_init(&pkt->list);
+
+		if (out) {
+			virtio_transport_free_pkt(pkt);
+			vq_err(vq, "Expected 0 output buffers, got %u\n", out);
+			break;
+		}
+
+		len = iov_length(&vq->iov[out], in);
+		iov_iter_init(&iov_iter, READ, &vq->iov[out], in, len);
+
+		nbytes = copy_to_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
+		if (nbytes != sizeof(pkt->hdr)) {
+			virtio_transport_free_pkt(pkt);
+			vq_err(vq, "Faulted on copying pkt hdr\n");
+			break;
+		}
+
+		nbytes = copy_to_iter(pkt->buf, pkt->len, &iov_iter);
+		if (nbytes != pkt->len) {
+			virtio_transport_free_pkt(pkt);
+			vq_err(vq, "Faulted on copying pkt buf\n");
+			break;
+		}
+
+		vhost_add_used(vq, head, pkt->len); /* TODO should this be
sizeof(pkt->hdr) + pkt->len? */
+		added = true;
+
+		virtio_transport_dec_tx_pkt(pkt);
+		vsock->total_tx_buf -= pkt->len;
+
+		sk = sk_vsock(pkt->trans->vsk);
+		/* Release refcnt taken in vhost_transport_send_pkt */
+		sock_put(sk);
+
+		virtio_transport_free_pkt(pkt);
+	}
+	if (added)
+		vhost_signal(&vsock->dev, vq);
+	mutex_unlock(&vq->mutex);
+
+	if (added)
+		wake_up(&vsock->queue_wait);
+}
+
+static void vhost_transport_send_pkt_work(struct vhost_work *work)
+{
+	struct vhost_virtqueue *vq;
+	struct vhost_vsock *vsock;
+
+	vsock = container_of(work, struct vhost_vsock, send_pkt_work);
+	vq = &vsock->vqs[VSOCK_VQ_RX].vq;
+
+	vhost_transport_do_send_pkt(vsock, vq);
+}
+
+static int
+vhost_transport_send_pkt(struct vsock_sock *vsk,
+			 struct virtio_vsock_pkt_info *info)
+{
+	u32 src_cid, src_port, dst_cid, dst_port;
+	struct virtio_transport *trans;
+	struct virtio_vsock_pkt *pkt;
+	struct vhost_virtqueue *vq;
+	struct vhost_vsock *vsock;
+	u32 pkt_len = info->pkt_len;
+	DEFINE_WAIT(wait);
+
+	src_cid = vhost_transport_get_local_cid();
+	src_port = vsk->local_addr.svm_port;
+	if (!info->remote_cid) {
+		dst_cid	= vsk->remote_addr.svm_cid;
+		dst_port = vsk->remote_addr.svm_port;
+	} else {
+		dst_cid = info->remote_cid;
+		dst_port = info->remote_port;
+	}
+
+	/* Find the vhost_vsock according to guest context id  */
+	vsock = vhost_vsock_get(dst_cid);
+	if (!vsock)
+		return -ENODEV;
+
+	trans = vsk->trans;
+	vq = &vsock->vqs[VSOCK_VQ_RX].vq;
+
+	/* we can send less than pkt_len bytes */
+	if (pkt_len > VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE)
+		pkt_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
+
+	/* virtio_transport_get_credit might return less than pkt_len credit */
+	pkt_len = virtio_transport_get_credit(trans, pkt_len);
+
+	/* Do not send zero length OP_RW pkt*/
+	if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
+		return pkt_len;
+
+	/* Respect global tx buf limitation */
+	mutex_lock(&vq->mutex);
+	while (pkt_len + vsock->total_tx_buf > VIRTIO_VSOCK_MAX_TX_BUF_SIZE) {
+		prepare_to_wait_exclusive(&vsock->queue_wait, &wait,
+					  TASK_UNINTERRUPTIBLE);
+		mutex_unlock(&vq->mutex);
+		schedule();
+		mutex_lock(&vq->mutex);
+		finish_wait(&vsock->queue_wait, &wait);
+	}
+	vsock->total_tx_buf += pkt_len;
+	mutex_unlock(&vq->mutex);
+
+	pkt = virtio_transport_alloc_pkt(vsk, info, pkt_len,
+					 src_cid, src_port,
+					 dst_cid, dst_port);
+	if (!pkt) {
+		mutex_lock(&vq->mutex);
+		vsock->total_tx_buf -= pkt_len;
+		mutex_unlock(&vq->mutex);
+		virtio_transport_put_credit(trans, pkt_len);
+		return -ENOMEM;
+	}
+
+	pr_debug("%s:info->pkt_len= %d\n", __func__, pkt_len);
+	/* Released in vhost_transport_do_send_pkt */
+	sock_hold(&trans->vsk->sk);
+	virtio_transport_inc_tx_pkt(pkt);
+
+	/* Queue it up in vhost work */
+	mutex_lock(&vq->mutex);
+	list_add_tail(&pkt->list, &vsock->send_pkt_list);
+	vhost_work_queue(&vsock->dev, &vsock->send_pkt_work);
+	mutex_unlock(&vq->mutex);
+
+	return pkt_len;
+}
+
+static struct virtio_transport_pkt_ops vhost_ops = {
+	.send_pkt = vhost_transport_send_pkt,
+};
+
+static struct virtio_vsock_pkt *
+vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq,
+		      unsigned int out, unsigned int in)
+{
+	struct virtio_vsock_pkt *pkt;
+	struct iov_iter iov_iter;
+	size_t nbytes;
+	size_t len;
+
+	if (in != 0) {
+		vq_err(vq, "Expected 0 input buffers, got %u\n", in);
+		return NULL;
+	}
+
+	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
+	if (!pkt)
+		return NULL;
+
+	len = iov_length(vq->iov, out);
+	iov_iter_init(&iov_iter, WRITE, vq->iov, out, len);
+
+	nbytes = copy_from_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
+	if (nbytes != sizeof(pkt->hdr)) {
+		vq_err(vq, "Expected %zu bytes for pkt->hdr, got %zu bytes\n",
+		       sizeof(pkt->hdr), nbytes);
+		kfree(pkt);
+		return NULL;
+	}
+
+	if (le16_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_DGRAM)
+		pkt->len = le32_to_cpu(pkt->hdr.len) & 0XFFFF;
+	else if (le16_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_STREAM)
+		pkt->len = le32_to_cpu(pkt->hdr.len);
+
+	/* No payload */
+	if (!pkt->len)
+		return pkt;
+
+	/* The pkt is too big */
+	if (pkt->len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) {
+		kfree(pkt);
+		return NULL;
+	}
+
+	pkt->buf = kmalloc(pkt->len, GFP_KERNEL);
+	if (!pkt->buf) {
+		kfree(pkt);
+		return NULL;
+	}
+
+	nbytes = copy_from_iter(pkt->buf, pkt->len, &iov_iter);
+	if (nbytes != pkt->len) {
+		vq_err(vq, "Expected %u byte payload, got %zu bytes\n",
+		       pkt->len, nbytes);
+		virtio_transport_free_pkt(pkt);
+		return NULL;
+	}
+
+	return pkt;
+}
+
+static void vhost_vsock_handle_ctl_kick(struct vhost_work *work)
+{
+	struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
+						  poll.work);
+	struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
+						 dev);
+
+	pr_debug("%s vq=%p, vsock=%p\n", __func__, vq, vsock);
+}
+
+static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
+{
+	struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
+						  poll.work);
+	struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
+						 dev);
+	struct virtio_vsock_pkt *pkt;
+	int head;
+	unsigned int out, in;
+	bool added = false;
+	u32 len;
+
+	mutex_lock(&vq->mutex);
+	vhost_disable_notify(&vsock->dev, vq);
+	for (;;) {
+		head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
+					 &out, &in, NULL, NULL);
+		if (head < 0)
+			break;
+
+		if (head == vq->num) {
+			if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
+				vhost_disable_notify(&vsock->dev, vq);
+				continue;
+			}
+			break;
+		}
+
+		pkt = vhost_vsock_alloc_pkt(vq, out, in);
+		if (!pkt) {
+			vq_err(vq, "Faulted on pkt\n");
+			continue;
+		}
+
+		len = pkt->len;
+
+		/* Only accept correctly addressed packets */
+		if (le32_to_cpu(pkt->hdr.src_cid) == vsock->guest_cid &&
+		    le32_to_cpu(pkt->hdr.dst_cid) == vhost_transport_get_local_cid())
+			virtio_transport_recv_pkt(pkt);
+		else
+			virtio_transport_free_pkt(pkt);
+
+		vhost_add_used(vq, head, len);
+		added = true;
+	}
+	if (added)
+		vhost_signal(&vsock->dev, vq);
+	mutex_unlock(&vq->mutex);
+}
+
+static void vhost_vsock_handle_rx_kick(struct vhost_work *work)
+{
+	struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
+						poll.work);
+	struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
+						 dev);
+
+	vhost_transport_do_send_pkt(vsock, vq);
+}
+
+static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
+{
+	struct vhost_virtqueue **vqs;
+	struct vhost_vsock *vsock;
+	int ret;
+
+	vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
+	if (!vsock)
+		return -ENOMEM;
+
+	pr_debug("%s:vsock=%p\n", __func__, vsock);
+
+	vqs = kmalloc(VSOCK_VQ_MAX * sizeof(*vqs), GFP_KERNEL);
+	if (!vqs) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	vqs[VSOCK_VQ_CTRL] = &vsock->vqs[VSOCK_VQ_CTRL].vq;
+	vqs[VSOCK_VQ_TX] = &vsock->vqs[VSOCK_VQ_TX].vq;
+	vqs[VSOCK_VQ_RX] = &vsock->vqs[VSOCK_VQ_RX].vq;
+	vsock->vqs[VSOCK_VQ_CTRL].vq.handle_kick = vhost_vsock_handle_ctl_kick;
+	vsock->vqs[VSOCK_VQ_TX].vq.handle_kick = vhost_vsock_handle_tx_kick;
+	vsock->vqs[VSOCK_VQ_RX].vq.handle_kick = vhost_vsock_handle_rx_kick;
+
+	vhost_dev_init(&vsock->dev, vqs, VSOCK_VQ_MAX);
+
+	file->private_data = vsock;
+	init_waitqueue_head(&vsock->queue_wait);
+	INIT_LIST_HEAD(&vsock->send_pkt_list);
+	vhost_work_init(&vsock->send_pkt_work, vhost_transport_send_pkt_work);
+
+	mutex_lock(&vhost_vsock_mutex);
+	list_add_tail(&vsock->list, &vhost_vsock_list);
+	mutex_unlock(&vhost_vsock_mutex);
+	return 0;
+
+out:
+	kfree(vsock);
+	return ret;
+}
+
+static void vhost_vsock_flush(struct vhost_vsock *vsock)
+{
+	int i;
+
+	for (i = 0; i < VSOCK_VQ_MAX; i++)
+		vhost_poll_flush(&vsock->vqs[i].vq.poll);
+	vhost_work_flush(&vsock->dev, &vsock->send_pkt_work);
+}
+
+static int vhost_vsock_dev_release(struct inode *inode, struct file *file)
+{
+	struct vhost_vsock *vsock = file->private_data;
+
+	mutex_lock(&vhost_vsock_mutex);
+	list_del(&vsock->list);
+	mutex_unlock(&vhost_vsock_mutex);
+
+	vhost_dev_stop(&vsock->dev);
+	vhost_vsock_flush(vsock);
+	vhost_dev_cleanup(&vsock->dev, false);
+	kfree(vsock->dev.vqs);
+	kfree(vsock);
+	return 0;
+}
+
+static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u32 guest_cid)
+{
+	struct vhost_vsock *other;
+
+	/* Refuse reserved CIDs */
+	if (guest_cid <= VMADDR_CID_HOST) {
+		return -EINVAL;
+	}
+
+	/* Refuse if CID is already in use */
+	other = vhost_vsock_get(guest_cid);
+	if (other && other != vsock) {
+		return -EADDRINUSE;
+	}
+
+	mutex_lock(&vhost_vsock_mutex);
+	vsock->guest_cid = guest_cid;
+	pr_debug("%s:guest_cid=%d\n", __func__, guest_cid);
+	mutex_unlock(&vhost_vsock_mutex);
+
+	return 0;
+}
+
+static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features)
+{
+	struct vhost_virtqueue *vq;
+	int i;
+
+	if (features & ~VHOST_VSOCK_FEATURES)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&vsock->dev.mutex);
+	if ((features & (1 << VHOST_F_LOG_ALL)) &&
+	    !vhost_log_access_ok(&vsock->dev)) {
+		mutex_unlock(&vsock->dev.mutex);
+		return -EFAULT;
+	}
+
+	for (i = 0; i < VSOCK_VQ_MAX; i++) {
+		vq = &vsock->vqs[i].vq;
+		mutex_lock(&vq->mutex);
+		vq->acked_features = features;
+		mutex_unlock(&vq->mutex);
+	}
+	mutex_unlock(&vsock->dev.mutex);
+	return 0;
+}
+
+static long vhost_vsock_dev_ioctl(struct file *f, unsigned int ioctl,
+				  unsigned long arg)
+{
+	struct vhost_vsock *vsock = f->private_data;
+	void __user *argp = (void __user *)arg;
+	u64 __user *featurep = argp;
+	u32 __user *cidp = argp;
+	u32 guest_cid;
+	u64 features;
+	int r;
+
+	switch (ioctl) {
+	case VHOST_VSOCK_SET_GUEST_CID:
+		if (get_user(guest_cid, cidp))
+			return -EFAULT;
+		return vhost_vsock_set_cid(vsock, guest_cid);
+	case VHOST_GET_FEATURES:
+		features = VHOST_VSOCK_FEATURES;
+		if (copy_to_user(featurep, &features, sizeof(features)))
+			return -EFAULT;
+		return 0;
+	case VHOST_SET_FEATURES:
+		if (copy_from_user(&features, featurep, sizeof(features)))
+			return -EFAULT;
+		return vhost_vsock_set_features(vsock, features);
+	default:
+		mutex_lock(&vsock->dev.mutex);
+		r = vhost_dev_ioctl(&vsock->dev, ioctl, argp);
+		if (r == -ENOIOCTLCMD)
+			r = vhost_vring_ioctl(&vsock->dev, ioctl, argp);
+		else
+			vhost_vsock_flush(vsock);
+		mutex_unlock(&vsock->dev.mutex);
+		return r;
+	}
+}
+
+static const struct file_operations vhost_vsock_fops = {
+	.owner          = THIS_MODULE,
+	.open           = vhost_vsock_dev_open,
+	.release        = vhost_vsock_dev_release,
+	.llseek		= noop_llseek,
+	.unlocked_ioctl = vhost_vsock_dev_ioctl,
+};
+
+static struct miscdevice vhost_vsock_misc = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "vhost-vsock",
+	.fops = &vhost_vsock_fops,
+};
+
+static int
+vhost_transport_socket_init(struct vsock_sock *vsk, struct vsock_sock *psk)
+{
+	struct virtio_transport *trans;
+	int ret;
+
+	ret = virtio_transport_do_socket_init(vsk, psk);
+	if (ret)
+		return ret;
+
+	trans = vsk->trans;
+	trans->ops = &vhost_ops;
+
+	return ret;
+}
+
+static struct vsock_transport vhost_transport = {
+	.get_local_cid            = vhost_transport_get_local_cid,
+
+	.init                     = vhost_transport_socket_init,
+	.destruct                 = virtio_transport_destruct,
+	.release                  = virtio_transport_release,
+	.connect                  = virtio_transport_connect,
+	.shutdown                 = virtio_transport_shutdown,
+
+	.dgram_enqueue            = virtio_transport_dgram_enqueue,
+	.dgram_dequeue            = virtio_transport_dgram_dequeue,
+	.dgram_bind               = virtio_transport_dgram_bind,
+	.dgram_allow              = virtio_transport_dgram_allow,
+
+	.stream_enqueue           = virtio_transport_stream_enqueue,
+	.stream_dequeue           = virtio_transport_stream_dequeue,
+	.stream_has_data          = virtio_transport_stream_has_data,
+	.stream_has_space         = virtio_transport_stream_has_space,
+	.stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
+	.stream_is_active         = virtio_transport_stream_is_active,
+	.stream_allow             = virtio_transport_stream_allow,
+
+	.notify_poll_in           = virtio_transport_notify_poll_in,
+	.notify_poll_out          = virtio_transport_notify_poll_out,
+	.notify_recv_init         = virtio_transport_notify_recv_init,
+	.notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
+	.notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
+	.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
+	.notify_send_init         = virtio_transport_notify_send_init,
+	.notify_send_pre_block    = virtio_transport_notify_send_pre_block,
+	.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
+	.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
+
+	.set_buffer_size          = virtio_transport_set_buffer_size,
+	.set_min_buffer_size      = virtio_transport_set_min_buffer_size,
+	.set_max_buffer_size      = virtio_transport_set_max_buffer_size,
+	.get_buffer_size          = virtio_transport_get_buffer_size,
+	.get_min_buffer_size      = virtio_transport_get_min_buffer_size,
+	.get_max_buffer_size      = virtio_transport_get_max_buffer_size,
+};
+
+static int __init vhost_vsock_init(void)
+{
+	int ret;
+
+	ret = vsock_core_init(&vhost_transport);
+	if (ret < 0)
+		return ret;
+	return misc_register(&vhost_vsock_misc);
+};
+
+static void __exit vhost_vsock_exit(void)
+{
+	misc_deregister(&vhost_vsock_misc);
+	vsock_core_exit();
+};
+
+module_init(vhost_vsock_init);
+module_exit(vhost_vsock_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Asias He");
+MODULE_DESCRIPTION("vhost transport for vsock ");
diff --git a/drivers/vhost/vsock.h b/drivers/vhost/vsock.h
new file mode 100644
index 0000000..0ddb107
--- /dev/null
+++ b/drivers/vhost/vsock.h
@@ -0,0 +1,4 @@
+#ifndef VHOST_VSOCK_H
+#define VHOST_VSOCK_H
+#define VHOST_VSOCK_SET_GUEST_CID _IOW(VHOST_VIRTIO, 0x60, __u32)
+#endif
-- 
2.5.0

From: Asias He <asias at redhat.com>

Enable virtio-vsock and vhost-vsock.

Signed-off-by: Asias He <asias at redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha at redhat.com>
---
 drivers/vhost/Kconfig       |  4 ++++
 drivers/vhost/Kconfig.vsock |  7 +++++++
 drivers/vhost/Makefile      |  4 ++++
 net/vmw_vsock/Kconfig       | 18 ++++++++++++++++++
 net/vmw_vsock/Makefile      |  2 ++
 5 files changed, 35 insertions(+)
 create mode 100644 drivers/vhost/Kconfig.vsock

diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
index 533eaf0..81449bf 100644
--- a/drivers/vhost/Kconfig
+++ b/drivers/vhost/Kconfig
@@ -47,3 +47,7 @@ config VHOST_CROSS_ENDIAN_LEGACY
 	  adds some overhead, it is disabled by default.
 
 	  If unsure, say "N".
+
+if STAGING
+source "drivers/vhost/Kconfig.vsock"
+endif
diff --git a/drivers/vhost/Kconfig.vsock b/drivers/vhost/Kconfig.vsock
new file mode 100644
index 0000000..3491865
--- /dev/null
+++ b/drivers/vhost/Kconfig.vsock
@@ -0,0 +1,7 @@
+config VHOST_VSOCK
+	tristate "vhost virtio-vsock driver"
+	depends on VSOCKETS && EVENTFD
+	select VIRTIO_VSOCKETS_COMMON
+	default n
+	---help---
+	Say M here to enable the vhost-vsock for virtio-vsock guests
diff --git a/drivers/vhost/Makefile b/drivers/vhost/Makefile
index e0441c3..6b012b9 100644
--- a/drivers/vhost/Makefile
+++ b/drivers/vhost/Makefile
@@ -4,5 +4,9 @@ vhost_net-y := net.o
 obj-$(CONFIG_VHOST_SCSI) += vhost_scsi.o
 vhost_scsi-y := scsi.o
 
+obj-$(CONFIG_VHOST_VSOCK) += vhost_vsock.o
+vhost_vsock-y := vsock.o
+
 obj-$(CONFIG_VHOST_RING) += vringh.o
+
 obj-$(CONFIG_VHOST)	+= vhost.o
diff --git a/net/vmw_vsock/Kconfig b/net/vmw_vsock/Kconfig
index 14810ab..74e0bc8 100644
--- a/net/vmw_vsock/Kconfig
+++ b/net/vmw_vsock/Kconfig
@@ -26,3 +26,21 @@ config VMWARE_VMCI_VSOCKETS
 
 	  To compile this driver as a module, choose M here: the module
 	  will be called vmw_vsock_vmci_transport. If unsure, say N.
+
+config VIRTIO_VSOCKETS
+	tristate "virtio transport for Virtual Sockets"
+	depends on VSOCKETS && VIRTIO
+	select VIRTIO_VSOCKETS_COMMON
+	help
+	  This module implements a virtio transport for Virtual Sockets.
+
+	  Enable this transport if your Virtual Machine runs on Qemu/KVM.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called virtio_vsock_transport. If unsure, say N.
+
+config VIRTIO_VSOCKETS_COMMON
+       tristate
+       ---help---
+         This option is selected by any driver which needs to access
+         the virtio_vsock.
diff --git a/net/vmw_vsock/Makefile b/net/vmw_vsock/Makefile
index 2ce52d7..cf4c294 100644
--- a/net/vmw_vsock/Makefile
+++ b/net/vmw_vsock/Makefile
@@ -1,5 +1,7 @@
 obj-$(CONFIG_VSOCKETS) += vsock.o
 obj-$(CONFIG_VMWARE_VMCI_VSOCKETS) += vmw_vsock_vmci_transport.o
+obj-$(CONFIG_VIRTIO_VSOCKETS) += virtio_transport.o
+obj-$(CONFIG_VIRTIO_VSOCKETS_COMMON) += virtio_transport_common.o
 
 vsock-y += af_vsock.o vsock_addr.o
 
-- 
2.5.0

From: Stefan Hajnoczi <stefanha at redhat.com>
Date: Wed,  2 Dec 2015 14:43:58 +0800
> This patch series adds a virtio transport for AF_VSOCK (net/vmw_vsock/).
Series applied, thanks.

On Wed, Dec 02, 2015 at 02:43:58PM +0800, Stefan Hajnoczi
wrote:
> v2:
>  * Rebased onto Linux v4.4-rc2
>  * vhost: Refuse to assign reserved CIDs
>  * vhost: Refuse guest CID if already in use
>  * vhost: Only accept correctly addressed packets (no spoofing!)
>  * vhost: Support flexible rx/tx descriptor layout
>  * vhost: Add missing total_tx_buf decrement
>  * virtio_transport: Fix total_tx_buf accounting
>  * virtio_transport: Add virtio_transport global mutex to prevent races
>  * common: Notify other side of SOCK_STREAM disconnect (fixes shutdown
>    semantics)
>  * common: Avoid recursive mutex_lock(tx_lock) for write_space (fixes
deadlock)
>  * common: Define VIRTIO_VSOCK_TYPE_STREAM/DGRAM hardware interface
constants
>  * common: Define VIRTIO_VSOCK_SHUTDOWN_RCV/SEND hardware interface
constants
>  * common: Fix peer_buf_alloc inheritance on child socket
> 
> This patch series adds a virtio transport for AF_VSOCK (net/vmw_vsock/).
> AF_VSOCK is designed for communication between virtual machines and
> hypervisors.  It is currently only implemented for VMware's VMCI
transport.
> 
> This series implements the proposed virtio-vsock device specification from
> here:
> http://comments.gmane.org/gmane.comp.emulators.virtio.devel/855
> 
> Most of the work was done by Asias He and Gerd Hoffmann a while back.  I
have
> picked up the series again.
> 
> The QEMU userspace changes are here:
> https://github.com/stefanha/qemu/commits/vsock
> 
> Why virtio-vsock?
> -----------------
> Guest<->host communication is currently done over the virtio-serial
device.
> This makes it hard to port sockets API-based applications and is limited to
> static ports.
> 
> virtio-vsock uses the sockets API so that applications can rely on familiar
> SOCK_STREAM and SOCK_DGRAM semantics.  Applications on the host can easily
> connect to guest agents because the sockets API allows multiple connections
to
> a listen socket (unlike virtio-serial).  This simplifies the
guest<->host
> communication and eliminates the need for extra processes on the host to
> arbitrate virtio-serial ports.
> 
> Overview
> --------
> This series adds 3 pieces:
> 
> 1. virtio_transport_common.ko - core virtio vsock code that uses vsock.ko
> 
> 2. virtio_transport.ko - guest driver
> 
> 3. drivers/vhost/vsock.ko - host driver
> 
> Howto
> -----
> The following kernel options are needed:
>   CONFIG_VSOCKETS=y
>   CONFIG_VIRTIO_VSOCKETS=y
>   CONFIG_VIRTIO_VSOCKETS_COMMON=y
>   CONFIG_VHOST_VSOCK=m
> 
> Launch QEMU as follows:
>   # qemu ... -device vhost-vsock-pci,id=vhost-vsock-pci0,guest-cid=3
> 
> Guest and host can communicate via AF_VSOCK sockets.  The host's CID
(address)
> is 2 and the guest is automatically assigned a CID (use VMADDR_CID_ANY (-1)
to
> bind to it).
> 
> Status
> ------
> There are a few design changes I'd like to make to the virtio-vsock
device:
> 
> 1. The 3-way handshake isn't necessary over a reliable transport
(virtqueue).
>    Spoofing packets is also impossible so the security aspects of the 3-way
>    handshake (including syn cookie) add nothing.  The next version will
have a
>    single operation to establish a connection.
It's hard to discuss without seeing the details, but we do need to
slow down guests that are flooding host with socket creation requests.
The handshake is a simple way for hypervisor to defer
such requests until it has resources without
breaking things.
> 2. Credit-based flow control doesn't work for SOCK_DGRAM since multiple
clients
>    can transmit to the same listen socket.  There is no way for the clients
to
>    coordinate buffer space with each other fairly.  The next version will
drop
>    credit-based flow control for SOCK_DGRAM and only rely on best-effort
>    delivery.  SOCK_STREAM still has guaranteed delivery.
I suspect in the end we will need a measure of fairness even
if you drop packets. And recovering from packet loss is
hard enough that not many applications do it correctly.
I suggest disabling SOCK_DGRAM for now.
> 3. In the next version only the host will be able to establish connections
>    (i.e. to connect to a guest agent).  This is for security reasons since
>    there is currently no ability to provide host services only to certain
>    guests.  This also matches how AF_VSOCK works on modern VMware
hypervisors.

I see David merged this one already, but above planned changes are
userspace and hypervisor/guest visible.

Once this is upstream and userspace/guests start relying on it,
we'll be stuck supporting this version in addition to
whatever we really want, with no easy way to even test it.

Might it not be better to defer enabling this upstream until the interface is
finalized?

> Asias He (5):
>   VSOCK: Introduce vsock_find_unbound_socket and
>     vsock_bind_dgram_generic
>   VSOCK: Introduce virtio-vsock-common.ko
>   VSOCK: Introduce virtio-vsock.ko
>   VSOCK: Introduce vhost-vsock.ko
>   VSOCK: Add Makefile and Kconfig
> 
>  drivers/vhost/Kconfig                   |    4 +
>  drivers/vhost/Kconfig.vsock             |    7 +
>  drivers/vhost/Makefile                  |    4 +
>  drivers/vhost/vsock.c                   |  631 +++++++++++++++
>  drivers/vhost/vsock.h                   |    4 +
>  include/linux/virtio_vsock.h            |  209 +++++
>  include/net/af_vsock.h                  |    2 +
>  include/uapi/linux/virtio_ids.h         |    1 +
>  include/uapi/linux/virtio_vsock.h       |   89 +++
>  net/vmw_vsock/Kconfig                   |   18 +
>  net/vmw_vsock/Makefile                  |    2 +
>  net/vmw_vsock/af_vsock.c                |   70 ++
>  net/vmw_vsock/virtio_transport.c        |  466 +++++++++++
>  net/vmw_vsock/virtio_transport_common.c | 1272
+++++++++++++++++++++++++++++++
>  14 files changed, 2779 insertions(+)
>  create mode 100644 drivers/vhost/Kconfig.vsock
>  create mode 100644 drivers/vhost/vsock.c
>  create mode 100644 drivers/vhost/vsock.h
>  create mode 100644 include/linux/virtio_vsock.h
>  create mode 100644 include/uapi/linux/virtio_vsock.h
>  create mode 100644 net/vmw_vsock/virtio_transport.c
>  create mode 100644 net/vmw_vsock/virtio_transport_common.c
> 
> -- 
> 2.5.0

On Fri, Dec 04, 2015 at 09:45:04AM +0200, Michael S. Tsirkin
wrote:
> On Wed, Dec 02, 2015 at 02:43:58PM +0800, Stefan Hajnoczi wrote:
> > 1. The 3-way handshake isn't necessary over a reliable transport
(virtqueue).
> >    Spoofing packets is also impossible so the security aspects of the
3-way
> >    handshake (including syn cookie) add nothing.  The next version
will have a
> >    single operation to establish a connection.
> 
> It's hard to discuss without seeing the details, but we do need to
> slow down guests that are flooding host with socket creation requests.
> The handshake is a simple way for hypervisor to defer
> such requests until it has resources without
> breaking things.
I'll send an updated virtio-vsock device specification so we can discuss
it.

VMCI simply uses sk->sk_max_ack_backlog in
net/vmw_vsock/vmci_transport.c.  If backlog (from listen(2)) is maxed
out then the connection is refused.

The same would work for virtio-vsock and there is no advantage to the
3-way handshake.
> > 2. Credit-based flow control doesn't work for SOCK_DGRAM since
multiple clients
> >    can transmit to the same listen socket.  There is no way for the
clients to
> >    coordinate buffer space with each other fairly.  The next version
will drop
> >    credit-based flow control for SOCK_DGRAM and only rely on
best-effort
> >    delivery.  SOCK_STREAM still has guaranteed delivery.
> 
> I suspect in the end we will need a measure of fairness even
> if you drop packets. And recovering from packet loss is
> hard enough that not many applications do it correctly.
> I suggest disabling SOCK_DGRAM for now.
I'm not aware of a SOCK_DGRAM user at this time.  Will disable it for
now.
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