[PATCH RFC net-next v3 0/8] virtio/vsock: support datagrams

[PATCH RFC net-next v3 0/8] virtio/vsock: support datagrams

[Bobby Eshleman]

Hey all!

This series introduces support for datagrams to virtio/vsock.

It is a spin-off (and smaller version) of this series from the summer: 
  https://lore.kernel.org/all/cover.1660362668.git.bobby.eshleman@bytedance.com/

Please note that this is an RFC and should not be merged until
associated changes are made to the virtio specification, which will
follow after discussion from this series.

This series first supports datagrams in a basic form for virtio, and
then optimizes the sendpath for all transports.

The result is a very fast datagram communication protocol that
outperforms even UDP on multi-queue virtio-net w/ vhost on a variety
of multi-threaded workload samples.

For those that are curious, some summary data comparing UDP and VSOCK
DGRAM (N=5):

	vCPUS: 16
	virtio-net queues: 16
	payload size: 4KB
	Setup: bare metal + vm (non-nested)

	UDP: 287.59 MB/s
	VSOCK DGRAM: 509.2 MB/s

Some notes about the implementation...

This datagram implementation forces datagrams to self-throttle according
to the threshold set by sk_sndbuf. It behaves similar to the credits
used by streams in its effect on throughput and memory consumption, but
it is not influenced by the receiving socket as credits are.

The device drops packets silently.

As discussed previously, this series introduces datagrams and defers
fairness to future work. See discussion in v2 for more context around
datagrams, fairness, and this implementation.

Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
---
Changes in v3:
- Support multi-transport dgram, changing logic in connect/bind
  to support VMCI case
- Support per-pkt transport lookup for sendto() case
- Fix dgram_allow() implementation
- Fix dgram feature bit number (now it is 3)
- Fix binding so dgram and connectible (cid,port) spaces are
  non-overlapping
- RCU protect transport ptr so connect() calls never leave
  a lockless read of the transport and remote_addr are always
  in sync
- Link to v2: https://lore.kernel.org/r/20230413-b4-vsock-dgram-v2-0-079cc7cee62e@bytedance.com

---
Bobby Eshleman (7):
      vsock/dgram: generalize recvmsg and drop transport->dgram_dequeue
      vsock: refactor transport lookup code
      vsock: support multi-transport datagrams
      vsock: make vsock bind reusable
      virtio/vsock: add VIRTIO_VSOCK_F_DGRAM feature bit
      virtio/vsock: support dgrams
      vsock: Add lockless sendmsg() support

Jiang Wang (1):
      tests: add vsock dgram tests

 drivers/vhost/vsock.c                   |  44 ++-
 include/linux/virtio_vsock.h            |  13 +-
 include/net/af_vsock.h                  |  53 ++-
 include/uapi/linux/virtio_vsock.h       |   2 +
 net/vmw_vsock/af_vsock.c                | 615 ++++++++++++++++++++++++++------
 net/vmw_vsock/diag.c                    |  10 +-
 net/vmw_vsock/hyperv_transport.c        |  42 ++-
 net/vmw_vsock/virtio_transport.c        |  28 +-
 net/vmw_vsock/virtio_transport_common.c | 227 +++++++++---
 net/vmw_vsock/vmci_transport.c          | 152 ++++----
 net/vmw_vsock/vsock_bpf.c               |  10 +-
 net/vmw_vsock/vsock_loopback.c          |  13 +-
 tools/testing/vsock/util.c              | 105 ++++++
 tools/testing/vsock/util.h              |   4 +
 tools/testing/vsock/vsock_test.c        | 193 ++++++++++
 15 files changed, 1259 insertions(+), 252 deletions(-)
---
base-commit: ed72bd5a6790a0c3747cb32b0427f921bd03bb71
change-id: 20230413-b4-vsock-dgram-3b6eba6a64e5

Best regards,
-- 
Bobby Eshleman <bobby.eshleman@bytedance.com>

[PATCH RFC net-next v3 1/8] vsock/dgram: generalize recvmsg and drop transport->dgram_dequeue

[Bobby Eshleman]

This commit drops the transport->dgram_dequeue callback and makes
vsock_dgram_recvmsg() generic. It also adds additional transport
callbacks for use by the generic vsock_dgram_recvmsg(), such as for
parsing skbs for CID/port which vary in format per transport.

Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
---
 drivers/vhost/vsock.c                   |  4 +-
 include/linux/virtio_vsock.h            |  3 ++
 include/net/af_vsock.h                  | 13 ++++++-
 net/vmw_vsock/af_vsock.c                | 51 ++++++++++++++++++++++++-
 net/vmw_vsock/hyperv_transport.c        | 17 +++++++--
 net/vmw_vsock/virtio_transport.c        |  4 +-
 net/vmw_vsock/virtio_transport_common.c | 18 +++++++++
 net/vmw_vsock/vmci_transport.c          | 68 +++++++++++++--------------------
 net/vmw_vsock/vsock_loopback.c          |  4 +-
 9 files changed, 132 insertions(+), 50 deletions(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 6578db78f0ae..c8201c070b4b 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -410,9 +410,11 @@ static struct virtio_transport vhost_transport = {
 		.cancel_pkt               = vhost_transport_cancel_pkt,
 
 		.dgram_enqueue            = virtio_transport_dgram_enqueue,
-		.dgram_dequeue            = virtio_transport_dgram_dequeue,
 		.dgram_bind               = virtio_transport_dgram_bind,
 		.dgram_allow              = virtio_transport_dgram_allow,
+		.dgram_get_cid		  = virtio_transport_dgram_get_cid,
+		.dgram_get_port		  = virtio_transport_dgram_get_port,
+		.dgram_get_length	  = virtio_transport_dgram_get_length,
 
 		.stream_enqueue           = virtio_transport_stream_enqueue,
 		.stream_dequeue           = virtio_transport_stream_dequeue,
diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index c58453699ee9..23521a318cf0 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -219,6 +219,9 @@ 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_dgram_get_cid(struct sk_buff *skb, unsigned int *cid);
+int virtio_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port);
+int virtio_transport_dgram_get_length(struct sk_buff *skb, size_t *len);
 
 int virtio_transport_connect(struct vsock_sock *vsk);
 
diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 0e7504a42925..7bedb9ee7e3e 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -120,11 +120,20 @@ struct vsock_transport {
 
 	/* DGRAM. */
 	int (*dgram_bind)(struct vsock_sock *, struct sockaddr_vm *);
-	int (*dgram_dequeue)(struct vsock_sock *vsk, struct msghdr *msg,
-			     size_t len, int flags);
 	int (*dgram_enqueue)(struct vsock_sock *, struct sockaddr_vm *,
 			     struct msghdr *, size_t len);
 	bool (*dgram_allow)(u32 cid, u32 port);
+	int (*dgram_get_cid)(struct sk_buff *skb, unsigned int *cid);
+	int (*dgram_get_port)(struct sk_buff *skb, unsigned int *port);
+	int (*dgram_get_length)(struct sk_buff *skb, size_t *length);
+
+	/* The number of bytes into the buffer at which the payload starts, as
+	 * first seen by the receiving socket layer. For example, if the
+	 * transport presets the skb pointers using skb_pull(sizeof(header))
+	 * than this would be zero, otherwise it would be the size of the
+	 * header.
+	 */
+	const size_t dgram_payload_offset;
 
 	/* STREAM. */
 	/* TODO: stream_bind() */
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 413407bb646c..7ec0659c6ae5 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1271,11 +1271,15 @@ static int vsock_dgram_connect(struct socket *sock,
 int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
 			size_t len, int flags)
 {
+	const struct vsock_transport *transport;
 #ifdef CONFIG_BPF_SYSCALL
 	const struct proto *prot;
 #endif
 	struct vsock_sock *vsk;
+	struct sk_buff *skb;
+	size_t payload_len;
 	struct sock *sk;
+	int err;
 
 	sk = sock->sk;
 	vsk = vsock_sk(sk);
@@ -1286,7 +1290,52 @@ int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
 		return prot->recvmsg(sk, msg, len, flags, NULL);
 #endif
 
-	return vsk->transport->dgram_dequeue(vsk, msg, len, flags);
+	if (flags & MSG_OOB || flags & MSG_ERRQUEUE)
+		return -EOPNOTSUPP;
+
+	transport = vsk->transport;
+
+	/* Retrieve the head sk_buff from the socket's receive queue. */
+	err = 0;
+	skb = skb_recv_datagram(&vsk->sk, flags, &err);
+	if (!skb)
+		return err;
+
+	err = transport->dgram_get_length(skb, &payload_len);
+	if (err)
+		goto out;
+
+	if (payload_len > len) {
+		payload_len = len;
+		msg->msg_flags |= MSG_TRUNC;
+	}
+
+	/* Place the datagram payload in the user's iovec. */
+	err = skb_copy_datagram_msg(skb, transport->dgram_payload_offset, msg, payload_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);
+		unsigned int cid, port;
+
+		err = transport->dgram_get_cid(skb, &cid);
+		if (err)
+			goto out;
+
+		err = transport->dgram_get_port(skb, &port);
+		if (err)
+			goto out;
+
+		vsock_addr_init(vm_addr, cid, port);
+		msg->msg_namelen = sizeof(*vm_addr);
+	}
+	err = payload_len;
+
+out:
+	skb_free_datagram(&vsk->sk, skb);
+	return err;
 }
 EXPORT_SYMBOL_GPL(vsock_dgram_recvmsg);
 
diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
index 7cb1a9d2cdb4..ff6e87e25fa0 100644
--- a/net/vmw_vsock/hyperv_transport.c
+++ b/net/vmw_vsock/hyperv_transport.c
@@ -556,8 +556,17 @@ static int hvs_dgram_bind(struct vsock_sock *vsk, struct sockaddr_vm *addr)
 	return -EOPNOTSUPP;
 }
 
-static int hvs_dgram_dequeue(struct vsock_sock *vsk, struct msghdr *msg,
-			     size_t len, int flags)
+static int hvs_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
+{
+	return -EOPNOTSUPP;
+}
+
+static int hvs_dgram_get_port(struct sk_buff *skb, unsigned int *port)
+{
+	return -EOPNOTSUPP;
+}
+
+static int hvs_dgram_get_length(struct sk_buff *skb, size_t *len)
 {
 	return -EOPNOTSUPP;
 }
@@ -833,7 +842,9 @@ static struct vsock_transport hvs_transport = {
 	.shutdown                 = hvs_shutdown,
 
 	.dgram_bind               = hvs_dgram_bind,
-	.dgram_dequeue            = hvs_dgram_dequeue,
+	.dgram_get_cid		  = hvs_dgram_get_cid,
+	.dgram_get_port		  = hvs_dgram_get_port,
+	.dgram_get_length	  = hvs_dgram_get_length,
 	.dgram_enqueue            = hvs_dgram_enqueue,
 	.dgram_allow              = hvs_dgram_allow,
 
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index e95df847176b..5763cdf13804 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -429,9 +429,11 @@ static struct virtio_transport virtio_transport = {
 		.cancel_pkt               = virtio_transport_cancel_pkt,
 
 		.dgram_bind               = virtio_transport_dgram_bind,
-		.dgram_dequeue            = virtio_transport_dgram_dequeue,
 		.dgram_enqueue            = virtio_transport_dgram_enqueue,
 		.dgram_allow              = virtio_transport_dgram_allow,
+		.dgram_get_cid		  = virtio_transport_dgram_get_cid,
+		.dgram_get_port		  = virtio_transport_dgram_get_port,
+		.dgram_get_length	  = virtio_transport_dgram_get_length,
 
 		.stream_dequeue           = virtio_transport_stream_dequeue,
 		.stream_enqueue           = virtio_transport_stream_enqueue,
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index e4878551f140..abd939694a1a 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -797,6 +797,24 @@ int virtio_transport_dgram_bind(struct vsock_sock *vsk,
 }
 EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind);
 
+int virtio_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
+{
+	return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_cid);
+
+int virtio_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port)
+{
+	return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_port);
+
+int virtio_transport_dgram_get_length(struct sk_buff *skb, size_t *len)
+{
+	return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_length);
+
 bool virtio_transport_dgram_allow(u32 cid, u32 port)
 {
 	return false;
diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
index b370070194fa..b6a51afb74b8 100644
--- a/net/vmw_vsock/vmci_transport.c
+++ b/net/vmw_vsock/vmci_transport.c
@@ -1731,57 +1731,40 @@ static int vmci_transport_dgram_enqueue(
 	return err - sizeof(*dg);
 }
 
-static int vmci_transport_dgram_dequeue(struct vsock_sock *vsk,
-					struct msghdr *msg, size_t len,
-					int flags)
+int vmci_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
 {
-	int err;
 	struct vmci_datagram *dg;
-	size_t payload_len;
-	struct sk_buff *skb;
 
-	if (flags & MSG_OOB || flags & MSG_ERRQUEUE)
-		return -EOPNOTSUPP;
+	dg = (struct vmci_datagram *)skb->data;
+	if (!dg)
+		return -EINVAL;
 
-	/* Retrieve the head sk_buff from the socket's receive queue. */
-	err = 0;
-	skb = skb_recv_datagram(&vsk->sk, flags, &err);
-	if (!skb)
-		return err;
+	*cid = dg->src.context;
+	return 0;
+}
+
+int vmci_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port)
+{
+	struct vmci_datagram *dg;
 
 	dg = (struct vmci_datagram *)skb->data;
 	if (!dg)
-		/* err is 0, meaning we read zero bytes. */
-		goto out;
-
-	payload_len = dg->payload_size;
-	/* Ensure the sk_buff matches the payload size claimed in the packet. */
-	if (payload_len != skb->len - sizeof(*dg)) {
-		err = -EINVAL;
-		goto out;
-	}
+		return -EINVAL;
 
-	if (payload_len > len) {
-		payload_len = len;
-		msg->msg_flags |= MSG_TRUNC;
-	}
+	*port = dg->src.resource;
+	return 0;
+}
 
-	/* Place the datagram payload in the user's iovec. */
-	err = skb_copy_datagram_msg(skb, sizeof(*dg), msg, payload_len);
-	if (err)
-		goto out;
+int vmci_transport_dgram_get_length(struct sk_buff *skb, size_t *len)
+{
+	struct vmci_datagram *dg;
 
-	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, dg->src.context, dg->src.resource);
-		msg->msg_namelen = sizeof(*vm_addr);
-	}
-	err = payload_len;
+	dg = (struct vmci_datagram *)skb->data;
+	if (!dg)
+		return -EINVAL;
 
-out:
-	skb_free_datagram(&vsk->sk, skb);
-	return err;
+	*len = dg->payload_size;
+	return 0;
 }
 
 static bool vmci_transport_dgram_allow(u32 cid, u32 port)
@@ -2040,9 +2023,12 @@ static struct vsock_transport vmci_transport = {
 	.release = vmci_transport_release,
 	.connect = vmci_transport_connect,
 	.dgram_bind = vmci_transport_dgram_bind,
-	.dgram_dequeue = vmci_transport_dgram_dequeue,
 	.dgram_enqueue = vmci_transport_dgram_enqueue,
 	.dgram_allow = vmci_transport_dgram_allow,
+	.dgram_get_cid = vmci_transport_dgram_get_cid,
+	.dgram_get_port = vmci_transport_dgram_get_port,
+	.dgram_get_length = vmci_transport_dgram_get_length,
+	.dgram_payload_offset = sizeof(struct vmci_datagram),
 	.stream_dequeue = vmci_transport_stream_dequeue,
 	.stream_enqueue = vmci_transport_stream_enqueue,
 	.stream_has_data = vmci_transport_stream_has_data,
diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c
index e3afc0c866f5..136061f622b8 100644
--- a/net/vmw_vsock/vsock_loopback.c
+++ b/net/vmw_vsock/vsock_loopback.c
@@ -63,9 +63,11 @@ static struct virtio_transport loopback_transport = {
 		.cancel_pkt               = vsock_loopback_cancel_pkt,
 
 		.dgram_bind               = virtio_transport_dgram_bind,
-		.dgram_dequeue            = virtio_transport_dgram_dequeue,
 		.dgram_enqueue            = virtio_transport_dgram_enqueue,
 		.dgram_allow              = virtio_transport_dgram_allow,
+		.dgram_get_cid		  = virtio_transport_dgram_get_cid,
+		.dgram_get_port		  = virtio_transport_dgram_get_port,
+		.dgram_get_length	  = virtio_transport_dgram_get_length,
 
 		.stream_dequeue           = virtio_transport_stream_dequeue,
 		.stream_enqueue           = virtio_transport_stream_enqueue,

-- 
2.30.2

Re: [PATCH RFC net-next v3 1/8] vsock/dgram: generalize recvmsg and drop transport->dgram_dequeue

[Simon Horman]

On Wed, May 31, 2023 at 12:35:05AM +0000, Bobby Eshleman wrote:
> This commit drops the transport->dgram_dequeue callback and makes
> vsock_dgram_recvmsg() generic. It also adds additional transport
> callbacks for use by the generic vsock_dgram_recvmsg(), such as for
> parsing skbs for CID/port which vary in format per transport.
> 
> Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>

...

> diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
> index b370070194fa..b6a51afb74b8 100644
> --- a/net/vmw_vsock/vmci_transport.c
> +++ b/net/vmw_vsock/vmci_transport.c
> @@ -1731,57 +1731,40 @@ static int vmci_transport_dgram_enqueue(
>  	return err - sizeof(*dg);
>  }
>  
> -static int vmci_transport_dgram_dequeue(struct vsock_sock *vsk,
> -					struct msghdr *msg, size_t len,
> -					int flags)
> +int vmci_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
>  {
> -	int err;
>  	struct vmci_datagram *dg;
> -	size_t payload_len;
> -	struct sk_buff *skb;
>  
> -	if (flags & MSG_OOB || flags & MSG_ERRQUEUE)
> -		return -EOPNOTSUPP;
> +	dg = (struct vmci_datagram *)skb->data;
> +	if (!dg)
> +		return -EINVAL;
>  
> -	/* Retrieve the head sk_buff from the socket's receive queue. */
> -	err = 0;
> -	skb = skb_recv_datagram(&vsk->sk, flags, &err);
> -	if (!skb)
> -		return err;
> +	*cid = dg->src.context;
> +	return 0;
> +}

Hi Bobby,

clang-16 with W=1 seems a bit unhappy about this.

  net/vmw_vsock/vmci_transport.c:1734:5: warning: no previous prototype for function 'vmci_transport_dgram_get_cid' [-Wmissing-prototypes]
  int vmci_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
      ^
  net/vmw_vsock/vmci_transport.c:1734:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
  int vmci_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
  ^
  static 
  net/vmw_vsock/vmci_transport.c:1746:5: warning: no previous prototype for function 'vmci_transport_dgram_get_port' [-Wmissing-prototypes]
  int vmci_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port)
      ^
  net/vmw_vsock/vmci_transport.c:1746:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
  int vmci_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port)
  ^
  static 
  net/vmw_vsock/vmci_transport.c:1758:5: warning: no previous prototype for function 'vmci_transport_dgram_get_length' [-Wmissing-prototypes]
  int vmci_transport_dgram_get_length(struct sk_buff *skb, size_t *len)
      ^
  net/vmw_vsock/vmci_transport.c:1758:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
  int vmci_transport_dgram_get_length(struct sk_buff *skb, size_t *len)
  ^

I see similar warnings for net/vmw_vsock/af_vsock.c in patch 4/8.

> +
> +int vmci_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port)
> +{
> +	struct vmci_datagram *dg;
>  
>  	dg = (struct vmci_datagram *)skb->data;
>  	if (!dg)
> -		/* err is 0, meaning we read zero bytes. */
> -		goto out;
> -
> -	payload_len = dg->payload_size;
> -	/* Ensure the sk_buff matches the payload size claimed in the packet. */
> -	if (payload_len != skb->len - sizeof(*dg)) {
> -		err = -EINVAL;
> -		goto out;
> -	}
> +		return -EINVAL;
>  
> -	if (payload_len > len) {
> -		payload_len = len;
> -		msg->msg_flags |= MSG_TRUNC;
> -	}
> +	*port = dg->src.resource;
> +	return 0;
> +}
>  
> -	/* Place the datagram payload in the user's iovec. */
> -	err = skb_copy_datagram_msg(skb, sizeof(*dg), msg, payload_len);
> -	if (err)
> -		goto out;
> +int vmci_transport_dgram_get_length(struct sk_buff *skb, size_t *len)
> +{
> +	struct vmci_datagram *dg;
>  
> -	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, dg->src.context, dg->src.resource);
> -		msg->msg_namelen = sizeof(*vm_addr);
> -	}
> -	err = payload_len;
> +	dg = (struct vmci_datagram *)skb->data;
> +	if (!dg)
> +		return -EINVAL;
>  
> -out:
> -	skb_free_datagram(&vsk->sk, skb);
> -	return err;
> +	*len = dg->payload_size;
> +	return 0;
>  }
>  
>  static bool vmci_transport_dgram_allow(u32 cid, u32 port)

...

Re: [PATCH RFC net-next v3 1/8] vsock/dgram: generalize recvmsg and drop transport->dgram_dequeue

[Bobby Eshleman]

On Wed, May 31, 2023 at 05:56:48PM +0200, Simon Horman wrote:
> On Wed, May 31, 2023 at 12:35:05AM +0000, Bobby Eshleman wrote:
> > This commit drops the transport->dgram_dequeue callback and makes
> > vsock_dgram_recvmsg() generic. It also adds additional transport
> > callbacks for use by the generic vsock_dgram_recvmsg(), such as for
> > parsing skbs for CID/port which vary in format per transport.
> > 
> > Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
> 
> ...
> 
> > diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
> > index b370070194fa..b6a51afb74b8 100644
> > --- a/net/vmw_vsock/vmci_transport.c
> > +++ b/net/vmw_vsock/vmci_transport.c
> > @@ -1731,57 +1731,40 @@ static int vmci_transport_dgram_enqueue(
> >  	return err - sizeof(*dg);
> >  }
> >  
> > -static int vmci_transport_dgram_dequeue(struct vsock_sock *vsk,
> > -					struct msghdr *msg, size_t len,
> > -					int flags)
> > +int vmci_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
> >  {
> > -	int err;
> >  	struct vmci_datagram *dg;
> > -	size_t payload_len;
> > -	struct sk_buff *skb;
> >  
> > -	if (flags & MSG_OOB || flags & MSG_ERRQUEUE)
> > -		return -EOPNOTSUPP;
> > +	dg = (struct vmci_datagram *)skb->data;
> > +	if (!dg)
> > +		return -EINVAL;
> >  
> > -	/* Retrieve the head sk_buff from the socket's receive queue. */
> > -	err = 0;
> > -	skb = skb_recv_datagram(&vsk->sk, flags, &err);
> > -	if (!skb)
> > -		return err;
> > +	*cid = dg->src.context;
> > +	return 0;
> > +}
> 
> Hi Bobby,
> 
> clang-16 with W=1 seems a bit unhappy about this.
> 
>   net/vmw_vsock/vmci_transport.c:1734:5: warning: no previous prototype for function 'vmci_transport_dgram_get_cid' [-Wmissing-prototypes]
>   int vmci_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
>       ^
>   net/vmw_vsock/vmci_transport.c:1734:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
>   int vmci_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
>   ^
>   static 
>   net/vmw_vsock/vmci_transport.c:1746:5: warning: no previous prototype for function 'vmci_transport_dgram_get_port' [-Wmissing-prototypes]
>   int vmci_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port)
>       ^
>   net/vmw_vsock/vmci_transport.c:1746:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
>   int vmci_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port)
>   ^
>   static 
>   net/vmw_vsock/vmci_transport.c:1758:5: warning: no previous prototype for function 'vmci_transport_dgram_get_length' [-Wmissing-prototypes]
>   int vmci_transport_dgram_get_length(struct sk_buff *skb, size_t *len)
>       ^
>   net/vmw_vsock/vmci_transport.c:1758:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
>   int vmci_transport_dgram_get_length(struct sk_buff *skb, size_t *len)
>   ^
> 
> I see similar warnings for net/vmw_vsock/af_vsock.c in patch 4/8.
> 
> > +
> > +int vmci_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port)
> > +{
> > +	struct vmci_datagram *dg;
> >  
> >  	dg = (struct vmci_datagram *)skb->data;
> >  	if (!dg)
> > -		/* err is 0, meaning we read zero bytes. */
> > -		goto out;
> > -
> > -	payload_len = dg->payload_size;
> > -	/* Ensure the sk_buff matches the payload size claimed in the packet. */
> > -	if (payload_len != skb->len - sizeof(*dg)) {
> > -		err = -EINVAL;
> > -		goto out;
> > -	}
> > +		return -EINVAL;
> >  
> > -	if (payload_len > len) {
> > -		payload_len = len;
> > -		msg->msg_flags |= MSG_TRUNC;
> > -	}
> > +	*port = dg->src.resource;
> > +	return 0;
> > +}
> >  
> > -	/* Place the datagram payload in the user's iovec. */
> > -	err = skb_copy_datagram_msg(skb, sizeof(*dg), msg, payload_len);
> > -	if (err)
> > -		goto out;
> > +int vmci_transport_dgram_get_length(struct sk_buff *skb, size_t *len)
> > +{
> > +	struct vmci_datagram *dg;
> >  
> > -	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, dg->src.context, dg->src.resource);
> > -		msg->msg_namelen = sizeof(*vm_addr);
> > -	}
> > -	err = payload_len;
> > +	dg = (struct vmci_datagram *)skb->data;
> > +	if (!dg)
> > +		return -EINVAL;
> >  
> > -out:
> > -	skb_free_datagram(&vsk->sk, skb);
> > -	return err;
> > +	*len = dg->payload_size;
> > +	return 0;
> >  }
> >  
> >  static bool vmci_transport_dgram_allow(u32 cid, u32 port)
> 
> ...

Thanks for the review! Your feedback from both emails will be
incorporated in the next rev (with C=1 and W=1 output clearing).

Thanks again,
Bobby

[PATCH RFC net-next v3 2/8] vsock: refactor transport lookup code

[Bobby Eshleman]

Introduce new reusable function vsock_connectible_lookup_transport()
that performs the transport lookup logic.

No functional change intended.

Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
---
 net/vmw_vsock/af_vsock.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 7ec0659c6ae5..67dd9d78272d 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -422,6 +422,22 @@ static void vsock_deassign_transport(struct vsock_sock *vsk)
 	vsk->transport = NULL;
 }
 
+static const struct vsock_transport *
+vsock_connectible_lookup_transport(unsigned int cid, __u8 flags)
+{
+	const struct vsock_transport *transport;
+
+	if (vsock_use_local_transport(cid))
+		transport = transport_local;
+	else if (cid <= VMADDR_CID_HOST || !transport_h2g ||
+		 (flags & VMADDR_FLAG_TO_HOST))
+		transport = transport_g2h;
+	else
+		transport = transport_h2g;
+
+	return transport;
+}
+
 /* Assign a transport to a socket and call the .init transport callback.
  *
  * Note: for connection oriented socket this must be called when vsk->remote_addr
@@ -462,13 +478,8 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
 		break;
 	case SOCK_STREAM:
 	case SOCK_SEQPACKET:
-		if (vsock_use_local_transport(remote_cid))
-			new_transport = transport_local;
-		else if (remote_cid <= VMADDR_CID_HOST || !transport_h2g ||
-			 (remote_flags & VMADDR_FLAG_TO_HOST))
-			new_transport = transport_g2h;
-		else
-			new_transport = transport_h2g;
+		new_transport = vsock_connectible_lookup_transport(remote_cid,
+								   remote_flags);
 		break;
 	default:
 		return -ESOCKTNOSUPPORT;

-- 
2.30.2

[PATCH RFC net-next v3 3/8] vsock: support multi-transport datagrams

[Bobby Eshleman]

This patch adds support for multi-transport datagrams.

This includes:
- Per-packet lookup of transports when using sendto(sockaddr_vm)
- Selecting H2G or G2H transport using VMADDR_FLAG_TO_HOST and CID in
  sockaddr_vm

To preserve backwards compatibility with VMCI, some important changes
were made. The "transport_dgram" / VSOCK_TRANSPORT_F_DGRAM is changed to
be used for all dgrams if it has been registered / is non-NULL.
Otherwise, the normal h2g/g2h transports are used. It makes more
intuitive sense to eliminate transport_dgram and simply use
transport_{h2g,g2h} since there is nothing preventing any of these
transports from support datagrams. But "transport_dgram" had
to be retained to prevent breaking VMCI:

1) VMCI datagrams appear to function outside of the h2g/g2h
   paradigm. When the vmci transport becomes online, it registers itself
   with the DGRAM feature, but not H2G/G2H. Only later when the
   transport has more information about its environment does it register
   H2G or G2H. In the case that a datagram socket becomes active
   after DGRAM registration but before G2H/H2G registration, the
   "transport_dgram" transport needs to be used.

2) VMCI seems to require special message be sent by the transport when a
   datagram socket calls bind(). Under the h2g/g2h model, the transport
   is selected using the remote_addr which is set by connect(). At
   bind time there is no remote_addr because often no connect() has been
   called yet: the transport is null. Therefore, with a null transport
   there doesn't seem to be any good way for a datagram socket a tell the
   VMCI transport that it has just had bind() called upon it.

Therefore, to preserve backwards compatibility, his patch follows this
rule: if transport_dgram exists, all datagram socket traffic must use
it. Otherwise, use the normal logic to determine whether or not to use
H2G or G2H.

In the case of other transports like virtio, they may simply only
register H2G or G2H to a transport (but not DGRAM!) to support multi-transport and
nesting.

Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
---
 drivers/vhost/vsock.c                   |  1 -
 include/linux/virtio_vsock.h            |  2 -
 net/vmw_vsock/af_vsock.c                | 75 +++++++++++++++++++++++++--------
 net/vmw_vsock/hyperv_transport.c        |  6 ---
 net/vmw_vsock/virtio_transport.c        |  1 -
 net/vmw_vsock/virtio_transport_common.c |  7 ---
 net/vmw_vsock/vsock_loopback.c          |  1 -
 7 files changed, 57 insertions(+), 36 deletions(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index c8201c070b4b..8f0082da5e70 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -410,7 +410,6 @@ static struct virtio_transport vhost_transport = {
 		.cancel_pkt               = vhost_transport_cancel_pkt,
 
 		.dgram_enqueue            = virtio_transport_dgram_enqueue,
-		.dgram_bind               = virtio_transport_dgram_bind,
 		.dgram_allow              = virtio_transport_dgram_allow,
 		.dgram_get_cid		  = virtio_transport_dgram_get_cid,
 		.dgram_get_port		  = virtio_transport_dgram_get_port,
diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index 23521a318cf0..73afa09f4585 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -216,8 +216,6 @@ void virtio_transport_notify_buffer_size(struct vsock_sock *vsk, u64 *val);
 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_dgram_get_cid(struct sk_buff *skb, unsigned int *cid);
 int virtio_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port);
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 67dd9d78272d..578272a987be 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -438,6 +438,15 @@ vsock_connectible_lookup_transport(unsigned int cid, __u8 flags)
 	return transport;
 }
 
+static const struct vsock_transport *
+vsock_dgram_lookup_transport(unsigned int cid, __u8 flags)
+{
+	if (transport_dgram)
+		return transport_dgram;
+
+	return vsock_connectible_lookup_transport(cid, flags);
+}
+
 /* Assign a transport to a socket and call the .init transport callback.
  *
  * Note: for connection oriented socket this must be called when vsk->remote_addr
@@ -474,7 +483,8 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
 
 	switch (sk->sk_type) {
 	case SOCK_DGRAM:
-		new_transport = transport_dgram;
+		new_transport = vsock_dgram_lookup_transport(remote_cid,
+							     remote_flags);
 		break;
 	case SOCK_STREAM:
 	case SOCK_SEQPACKET:
@@ -691,6 +701,9 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
 static int __vsock_bind_dgram(struct vsock_sock *vsk,
 			      struct sockaddr_vm *addr)
 {
+	if (!vsk->transport || !vsk->transport->dgram_bind)
+		return -EINVAL;
+
 	return vsk->transport->dgram_bind(vsk, addr);
 }
 
@@ -1172,19 +1185,24 @@ static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
 
 	lock_sock(sk);
 
-	transport = vsk->transport;
-
-	err = vsock_auto_bind(vsk);
-	if (err)
-		goto out;
-
-
 	/* If the provided message contains an address, use that.  Otherwise
 	 * fall back on the socket's remote handle (if it has been connected).
 	 */
 	if (msg->msg_name &&
 	    vsock_addr_cast(msg->msg_name, msg->msg_namelen,
 			    &remote_addr) == 0) {
+		transport = vsock_dgram_lookup_transport(remote_addr->svm_cid,
+							 remote_addr->svm_flags);
+		if (!transport) {
+			err = -EINVAL;
+			goto out;
+		}
+
+		if (!try_module_get(transport->module)) {
+			err = -ENODEV;
+			goto out;
+		}
+
 		/* Ensure this address is of the right type and is a valid
 		 * destination.
 		 */
@@ -1193,11 +1211,27 @@ static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
 			remote_addr->svm_cid = transport->get_local_cid();
 
 		if (!vsock_addr_bound(remote_addr)) {
+			module_put(transport->module);
+			err = -EINVAL;
+			goto out;
+		}
+
+		if (!transport->dgram_allow(remote_addr->svm_cid,
+					    remote_addr->svm_port)) {
+			module_put(transport->module);
 			err = -EINVAL;
 			goto out;
 		}
+
+		err = transport->dgram_enqueue(vsk, remote_addr, msg, len);
+		module_put(transport->module);
 	} else if (sock->state == SS_CONNECTED) {
 		remote_addr = &vsk->remote_addr;
+		transport = vsk->transport;
+
+		err = vsock_auto_bind(vsk);
+		if (err)
+			goto out;
 
 		if (remote_addr->svm_cid == VMADDR_CID_ANY)
 			remote_addr->svm_cid = transport->get_local_cid();
@@ -1205,23 +1239,23 @@ static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
 		/* XXX Should connect() or this function ensure remote_addr is
 		 * bound?
 		 */
-		if (!vsock_addr_bound(&vsk->remote_addr)) {
+		if (!vsock_addr_bound(remote_addr)) {
 			err = -EINVAL;
 			goto out;
 		}
-	} else {
-		err = -EINVAL;
-		goto out;
-	}
 
-	if (!transport->dgram_allow(remote_addr->svm_cid,
-				    remote_addr->svm_port)) {
+		if (!transport->dgram_allow(remote_addr->svm_cid,
+					    remote_addr->svm_port)) {
+			err = -EINVAL;
+			goto out;
+		}
+
+		err = transport->dgram_enqueue(vsk, remote_addr, msg, len);
+	} else {
 		err = -EINVAL;
 		goto out;
 	}
 
-	err = transport->dgram_enqueue(vsk, remote_addr, msg, len);
-
 out:
 	release_sock(sk);
 	return err;
@@ -1255,13 +1289,18 @@ static int vsock_dgram_connect(struct socket *sock,
 	if (err)
 		goto out;
 
+	memcpy(&vsk->remote_addr, remote_addr, sizeof(vsk->remote_addr));
+
+	err = vsock_assign_transport(vsk, NULL);
+	if (err)
+		goto out;
+
 	if (!vsk->transport->dgram_allow(remote_addr->svm_cid,
 					 remote_addr->svm_port)) {
 		err = -EINVAL;
 		goto out;
 	}
 
-	memcpy(&vsk->remote_addr, remote_addr, sizeof(vsk->remote_addr));
 	sock->state = SS_CONNECTED;
 
 	/* sock map disallows redirection of non-TCP sockets with sk_state !=
diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
index ff6e87e25fa0..c00bc5da769a 100644
--- a/net/vmw_vsock/hyperv_transport.c
+++ b/net/vmw_vsock/hyperv_transport.c
@@ -551,11 +551,6 @@ static void hvs_destruct(struct vsock_sock *vsk)
 	kfree(hvs);
 }
 
-static int hvs_dgram_bind(struct vsock_sock *vsk, struct sockaddr_vm *addr)
-{
-	return -EOPNOTSUPP;
-}
-
 static int hvs_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
 {
 	return -EOPNOTSUPP;
@@ -841,7 +836,6 @@ static struct vsock_transport hvs_transport = {
 	.connect                  = hvs_connect,
 	.shutdown                 = hvs_shutdown,
 
-	.dgram_bind               = hvs_dgram_bind,
 	.dgram_get_cid		  = hvs_dgram_get_cid,
 	.dgram_get_port		  = hvs_dgram_get_port,
 	.dgram_get_length	  = hvs_dgram_get_length,
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 5763cdf13804..1b7843a7779a 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -428,7 +428,6 @@ static struct virtio_transport virtio_transport = {
 		.shutdown                 = virtio_transport_shutdown,
 		.cancel_pkt               = virtio_transport_cancel_pkt,
 
-		.dgram_bind               = virtio_transport_dgram_bind,
 		.dgram_enqueue            = virtio_transport_dgram_enqueue,
 		.dgram_allow              = virtio_transport_dgram_allow,
 		.dgram_get_cid		  = virtio_transport_dgram_get_cid,
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index abd939694a1a..5e9bccb21869 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -790,13 +790,6 @@ bool virtio_transport_stream_allow(u32 cid, u32 port)
 }
 EXPORT_SYMBOL_GPL(virtio_transport_stream_allow);
 
-int virtio_transport_dgram_bind(struct vsock_sock *vsk,
-				struct sockaddr_vm *addr)
-{
-	return -EOPNOTSUPP;
-}
-EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind);
-
 int virtio_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
 {
 	return -EOPNOTSUPP;
diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c
index 136061f622b8..7b0a5030e555 100644
--- a/net/vmw_vsock/vsock_loopback.c
+++ b/net/vmw_vsock/vsock_loopback.c
@@ -62,7 +62,6 @@ static struct virtio_transport loopback_transport = {
 		.shutdown                 = virtio_transport_shutdown,
 		.cancel_pkt               = vsock_loopback_cancel_pkt,
 
-		.dgram_bind               = virtio_transport_dgram_bind,
 		.dgram_enqueue            = virtio_transport_dgram_enqueue,
 		.dgram_allow              = virtio_transport_dgram_allow,
 		.dgram_get_cid		  = virtio_transport_dgram_get_cid,

-- 
2.30.2

[PATCH RFC net-next v3 4/8] vsock: make vsock bind reusable

[Bobby Eshleman]

This commit makes the bind table management functions in vsock usable
for different bind tables. For use by datagrams in a future patch.

Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
---
 net/vmw_vsock/af_vsock.c | 46 +++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 39 insertions(+), 7 deletions(-)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 578272a987be..ed02a5592e43 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -230,11 +230,12 @@ static void __vsock_remove_connected(struct vsock_sock *vsk)
 	sock_put(&vsk->sk);
 }
 
-static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
+struct sock *vsock_find_bound_socket_common(struct sockaddr_vm *addr,
+					    struct list_head *bind_table)
 {
 	struct vsock_sock *vsk;
 
-	list_for_each_entry(vsk, vsock_bound_sockets(addr), bound_table) {
+	list_for_each_entry(vsk, bind_table, bound_table) {
 		if (vsock_addr_equals_addr(addr, &vsk->local_addr))
 			return sk_vsock(vsk);
 
@@ -247,6 +248,11 @@ static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
 	return NULL;
 }
 
+static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
+{
+	return vsock_find_bound_socket_common(addr, vsock_bound_sockets(addr));
+}
+
 static struct sock *__vsock_find_connected_socket(struct sockaddr_vm *src,
 						  struct sockaddr_vm *dst)
 {
@@ -643,12 +649,17 @@ static void vsock_pending_work(struct work_struct *work)
 
 /**** SOCKET OPERATIONS ****/
 
-static int __vsock_bind_connectible(struct vsock_sock *vsk,
-				    struct sockaddr_vm *addr)
+int vsock_bind_common(struct vsock_sock *vsk,
+		      struct sockaddr_vm *addr,
+		      struct list_head *bind_table,
+		      size_t table_size)
 {
 	static u32 port;
 	struct sockaddr_vm new_addr;
 
+	if (table_size < VSOCK_HASH_SIZE)
+		return -1;
+
 	if (!port)
 		port = get_random_u32_above(LAST_RESERVED_PORT);
 
@@ -664,7 +675,8 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
 
 			new_addr.svm_port = port++;
 
-			if (!__vsock_find_bound_socket(&new_addr)) {
+			if (!vsock_find_bound_socket_common(&new_addr,
+							    &bind_table[VSOCK_HASH(addr)])) {
 				found = true;
 				break;
 			}
@@ -681,7 +693,8 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
 			return -EACCES;
 		}
 
-		if (__vsock_find_bound_socket(&new_addr))
+		if (vsock_find_bound_socket_common(&new_addr,
+						   &bind_table[VSOCK_HASH(addr)]))
 			return -EADDRINUSE;
 	}
 
@@ -693,11 +706,30 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
 	 * by AF_UNIX.
 	 */
 	__vsock_remove_bound(vsk);
-	__vsock_insert_bound(vsock_bound_sockets(&vsk->local_addr), vsk);
+	__vsock_insert_bound(&bind_table[VSOCK_HASH(&vsk->local_addr)], vsk);
 
 	return 0;
 }
 
+static int __vsock_bind_connectible(struct vsock_sock *vsk,
+				    struct sockaddr_vm *addr)
+{
+	return vsock_bind_common(vsk, addr, vsock_bind_table, VSOCK_HASH_SIZE + 1);
+}
+
+int vsock_bind_stream(struct vsock_sock *vsk,
+		      struct sockaddr_vm *addr)
+{
+	int retval;
+
+	spin_lock_bh(&vsock_table_lock);
+	retval = __vsock_bind_connectible(vsk, addr);
+	spin_unlock_bh(&vsock_table_lock);
+
+	return retval;
+}
+EXPORT_SYMBOL(vsock_bind_stream);
+
 static int __vsock_bind_dgram(struct vsock_sock *vsk,
 			      struct sockaddr_vm *addr)
 {

-- 
2.30.2

[PATCH RFC net-next v3 5/8] virtio/vsock: add VIRTIO_VSOCK_F_DGRAM feature bit

[Bobby Eshleman]

This commit adds a feature bit for virtio vsock to support datagrams.

Signed-off-by: Jiang Wang <jiang.wang@bytedance.com>
Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
---
 include/uapi/linux/virtio_vsock.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/uapi/linux/virtio_vsock.h b/include/uapi/linux/virtio_vsock.h
index 64738838bee5..772487c66f9d 100644
--- a/include/uapi/linux/virtio_vsock.h
+++ b/include/uapi/linux/virtio_vsock.h
@@ -40,6 +40,7 @@
 
 /* The feature bitmap for virtio vsock */
 #define VIRTIO_VSOCK_F_SEQPACKET	1	/* SOCK_SEQPACKET supported */
+#define VIRTIO_VSOCK_F_DGRAM		3	/* Host support dgram vsock */
 
 struct virtio_vsock_config {
 	__le64 guest_cid;

-- 
2.30.2

[PATCH RFC net-next v3 6/8] virtio/vsock: support dgrams

[Bobby Eshleman]

This commit adds support for datagrams over virtio/vsock.

Message boundaries are preserved on a per-skb and per-vq entry basis.
Messages are copied in whole from the user to an SKB, which in turn is
added to the scatterlist for the virtqueue in whole for the device.
Messages do not straddle skbs and they do not straddle packets.
Messages may be truncated by the receiving user if their buffer is
shorter than the message.

Other properties of vsock datagrams:
- Datagrams self-throttle at the per-socket sk_sndbuf threshold.
- The same virtqueue is used as is used for streams and seqpacket flows
- Credits are not used for datagrams
- Packets are dropped silently by the device, which means the virtqueue
  will still get kicked even during high packet loss, so long as the
  socket does not exceed sk_sndbuf.

Future work might include finding a way to reduce the virtqueue kick
rate for datagram flows with high packet loss.

Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
---
 drivers/vhost/vsock.c                   |  27 +++-
 include/linux/virtio_vsock.h            |   5 +-
 include/net/af_vsock.h                  |   1 +
 include/uapi/linux/virtio_vsock.h       |   1 +
 net/vmw_vsock/af_vsock.c                |  41 ++++++-
 net/vmw_vsock/virtio_transport.c        |  23 +++-
 net/vmw_vsock/virtio_transport_common.c | 210 ++++++++++++++++++++++++--------
 net/vmw_vsock/vsock_loopback.c          |   8 +-
 8 files changed, 253 insertions(+), 63 deletions(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 8f0082da5e70..159c1a22c1a8 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -32,7 +32,8 @@
 enum {
 	VHOST_VSOCK_FEATURES = VHOST_FEATURES |
 			       (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
-			       (1ULL << VIRTIO_VSOCK_F_SEQPACKET)
+			       (1ULL << VIRTIO_VSOCK_F_SEQPACKET) |
+			       (1ULL << VIRTIO_VSOCK_F_DGRAM)
 };
 
 enum {
@@ -56,6 +57,7 @@ struct vhost_vsock {
 	atomic_t queued_replies;
 
 	u32 guest_cid;
+	bool dgram_allow;
 	bool seqpacket_allow;
 };
 
@@ -394,6 +396,7 @@ static bool vhost_vsock_more_replies(struct vhost_vsock *vsock)
 	return val < vq->num;
 }
 
+static bool vhost_transport_dgram_allow(u32 cid, u32 port);
 static bool vhost_transport_seqpacket_allow(u32 remote_cid);
 
 static struct virtio_transport vhost_transport = {
@@ -410,10 +413,11 @@ static struct virtio_transport vhost_transport = {
 		.cancel_pkt               = vhost_transport_cancel_pkt,
 
 		.dgram_enqueue            = virtio_transport_dgram_enqueue,
-		.dgram_allow              = virtio_transport_dgram_allow,
+		.dgram_allow              = vhost_transport_dgram_allow,
 		.dgram_get_cid		  = virtio_transport_dgram_get_cid,
 		.dgram_get_port		  = virtio_transport_dgram_get_port,
 		.dgram_get_length	  = virtio_transport_dgram_get_length,
+		.dgram_payload_offset	  = 0,
 
 		.stream_enqueue           = virtio_transport_stream_enqueue,
 		.stream_dequeue           = virtio_transport_stream_dequeue,
@@ -446,6 +450,22 @@ static struct virtio_transport vhost_transport = {
 	.send_pkt = vhost_transport_send_pkt,
 };
 
+static bool vhost_transport_dgram_allow(u32 cid, u32 port)
+{
+	struct vhost_vsock *vsock;
+	bool dgram_allow = false;
+
+	rcu_read_lock();
+	vsock = vhost_vsock_get(cid);
+
+	if (vsock)
+		dgram_allow = vsock->dgram_allow;
+
+	rcu_read_unlock();
+
+	return dgram_allow;
+}
+
 static bool vhost_transport_seqpacket_allow(u32 remote_cid)
 {
 	struct vhost_vsock *vsock;
@@ -802,6 +822,9 @@ static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features)
 	if (features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET))
 		vsock->seqpacket_allow = true;
 
+	if (features & (1ULL << VIRTIO_VSOCK_F_DGRAM))
+		vsock->dgram_allow = true;
+
 	for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
 		vq = &vsock->vqs[i];
 		mutex_lock(&vq->mutex);
diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index 73afa09f4585..237ca87a2ecd 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -216,7 +216,6 @@ void virtio_transport_notify_buffer_size(struct vsock_sock *vsk, u64 *val);
 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);
-bool virtio_transport_dgram_allow(u32 cid, u32 port);
 int virtio_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid);
 int virtio_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port);
 int virtio_transport_dgram_get_length(struct sk_buff *skb, size_t *len);
@@ -247,4 +246,8 @@ void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit);
 void virtio_transport_deliver_tap_pkt(struct sk_buff *skb);
 int virtio_transport_purge_skbs(void *vsk, struct sk_buff_head *list);
 int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t read_actor);
+void virtio_transport_init_dgram_bind_tables(void);
+int virtio_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid);
+int virtio_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port);
+int virtio_transport_dgram_get_length(struct sk_buff *skb, size_t *len);
 #endif /* _LINUX_VIRTIO_VSOCK_H */
diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 7bedb9ee7e3e..c115e655b4f5 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -225,6 +225,7 @@ void vsock_for_each_connected_socket(struct vsock_transport *transport,
 				     void (*fn)(struct sock *sk));
 int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk);
 bool vsock_find_cid(unsigned int cid);
+struct sock *vsock_find_bound_dgram_socket(struct sockaddr_vm *addr);
 
 /**** TAP ****/
 
diff --git a/include/uapi/linux/virtio_vsock.h b/include/uapi/linux/virtio_vsock.h
index 772487c66f9d..2cad35e39a61 100644
--- a/include/uapi/linux/virtio_vsock.h
+++ b/include/uapi/linux/virtio_vsock.h
@@ -70,6 +70,7 @@ struct virtio_vsock_hdr {
 enum virtio_vsock_type {
 	VIRTIO_VSOCK_TYPE_STREAM = 1,
 	VIRTIO_VSOCK_TYPE_SEQPACKET = 2,
+	VIRTIO_VSOCK_TYPE_DGRAM = 3,
 };
 
 enum virtio_vsock_op {
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index ed02a5592e43..e8c70069d77d 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -180,6 +180,10 @@ struct list_head vsock_connected_table[VSOCK_HASH_SIZE];
 EXPORT_SYMBOL_GPL(vsock_connected_table);
 DEFINE_SPINLOCK(vsock_table_lock);
 EXPORT_SYMBOL_GPL(vsock_table_lock);
+struct list_head vsock_dgram_bind_table[VSOCK_HASH_SIZE];
+EXPORT_SYMBOL_GPL(vsock_dgram_bind_table);
+DEFINE_SPINLOCK(vsock_dgram_table_lock);
+EXPORT_SYMBOL_GPL(vsock_dgram_table_lock);
 
 /* Autobind this socket to the local address if necessary. */
 static int vsock_auto_bind(struct vsock_sock *vsk)
@@ -202,6 +206,9 @@ static void vsock_init_tables(void)
 
 	for (i = 0; i < ARRAY_SIZE(vsock_connected_table); i++)
 		INIT_LIST_HEAD(&vsock_connected_table[i]);
+
+	for (i = 0; i < ARRAY_SIZE(vsock_dgram_bind_table); i++)
+		INIT_LIST_HEAD(&vsock_dgram_bind_table[i]);
 }
 
 static void __vsock_insert_bound(struct list_head *list,
@@ -248,6 +255,23 @@ struct sock *vsock_find_bound_socket_common(struct sockaddr_vm *addr,
 	return NULL;
 }
 
+struct sock *
+vsock_find_bound_dgram_socket(struct sockaddr_vm *addr)
+{
+	struct sock *sk;
+
+	spin_lock_bh(&vsock_dgram_table_lock);
+	sk = vsock_find_bound_socket_common(addr,
+					    &vsock_dgram_bind_table[VSOCK_HASH(addr)]);
+	if (sk)
+		sock_hold(sk);
+
+	spin_unlock_bh(&vsock_dgram_table_lock);
+
+	return sk;
+}
+EXPORT_SYMBOL_GPL(vsock_find_bound_dgram_socket);
+
 static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
 {
 	return vsock_find_bound_socket_common(addr, vsock_bound_sockets(addr));
@@ -730,11 +754,18 @@ int vsock_bind_stream(struct vsock_sock *vsk,
 }
 EXPORT_SYMBOL(vsock_bind_stream);
 
-static int __vsock_bind_dgram(struct vsock_sock *vsk,
-			      struct sockaddr_vm *addr)
+static int vsock_bind_dgram(struct vsock_sock *vsk,
+			    struct sockaddr_vm *addr)
 {
-	if (!vsk->transport || !vsk->transport->dgram_bind)
-		return -EINVAL;
+	if (!vsk->transport || !vsk->transport->dgram_bind) {
+		int retval;
+		spin_lock_bh(&vsock_dgram_table_lock);
+		retval = vsock_bind_common(vsk, addr, vsock_dgram_bind_table,
+					   VSOCK_HASH_SIZE);
+		spin_unlock_bh(&vsock_dgram_table_lock);
+
+		return retval;
+	}
 
 	return vsk->transport->dgram_bind(vsk, addr);
 }
@@ -765,7 +796,7 @@ static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr)
 		break;
 
 	case SOCK_DGRAM:
-		retval = __vsock_bind_dgram(vsk, addr);
+		retval = vsock_bind_dgram(vsk, addr);
 		break;
 
 	default:
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 1b7843a7779a..7160a3104218 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -63,6 +63,7 @@ struct virtio_vsock {
 
 	u32 guest_cid;
 	bool seqpacket_allow;
+	bool dgram_allow;
 };
 
 static u32 virtio_transport_get_local_cid(void)
@@ -413,6 +414,7 @@ static void virtio_vsock_rx_done(struct virtqueue *vq)
 	queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 }
 
+static bool virtio_transport_dgram_allow(u32 cid, u32 port);
 static bool virtio_transport_seqpacket_allow(u32 remote_cid);
 
 static struct virtio_transport virtio_transport = {
@@ -465,6 +467,21 @@ static struct virtio_transport virtio_transport = {
 	.send_pkt = virtio_transport_send_pkt,
 };
 
+static bool virtio_transport_dgram_allow(u32 cid, u32 port)
+{
+	struct virtio_vsock *vsock;
+	bool dgram_allow;
+
+	dgram_allow = false;
+	rcu_read_lock();
+	vsock = rcu_dereference(the_virtio_vsock);
+	if (vsock)
+		dgram_allow = vsock->dgram_allow;
+	rcu_read_unlock();
+
+	return dgram_allow;
+}
+
 static bool virtio_transport_seqpacket_allow(u32 remote_cid)
 {
 	struct virtio_vsock *vsock;
@@ -658,6 +675,9 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
 	if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))
 		vsock->seqpacket_allow = true;
 
+	if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_DGRAM))
+		vsock->dgram_allow = true;
+
 	vdev->priv = vsock;
 
 	ret = virtio_vsock_vqs_init(vsock);
@@ -750,7 +770,8 @@ static struct virtio_device_id id_table[] = {
 };
 
 static unsigned int features[] = {
-	VIRTIO_VSOCK_F_SEQPACKET
+	VIRTIO_VSOCK_F_SEQPACKET,
+	VIRTIO_VSOCK_F_DGRAM
 };
 
 static struct virtio_driver virtio_vsock_driver = {
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 5e9bccb21869..ab4af21c4f3f 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -37,6 +37,35 @@ virtio_transport_get_ops(struct vsock_sock *vsk)
 	return container_of(t, struct virtio_transport, transport);
 }
 
+/* Requires info->msg and info->vsk */
+static struct sk_buff *
+virtio_transport_sock_alloc_send_skb(struct virtio_vsock_pkt_info *info, unsigned int size,
+				     gfp_t mask, int *err)
+{
+	struct sk_buff *skb;
+	struct sock *sk;
+	int noblock;
+
+	if (size < VIRTIO_VSOCK_SKB_HEADROOM) {
+		*err = -EINVAL;
+		return NULL;
+	}
+
+	if (info->msg)
+		noblock = info->msg->msg_flags & MSG_DONTWAIT;
+	else
+		noblock = 1;
+
+	sk = sk_vsock(info->vsk);
+	sk->sk_allocation = mask;
+	skb = sock_alloc_send_skb(sk, size, noblock, err);
+	if (!skb)
+		return NULL;
+
+	skb_reserve(skb, VIRTIO_VSOCK_SKB_HEADROOM);
+	return skb;
+}
+
 /* Returns a new packet on success, otherwise returns NULL.
  *
  * If NULL is returned, errp is set to a negative errno.
@@ -47,7 +76,8 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
 			   u32 src_cid,
 			   u32 src_port,
 			   u32 dst_cid,
-			   u32 dst_port)
+			   u32 dst_port,
+			   int *errp)
 {
 	const size_t skb_len = VIRTIO_VSOCK_SKB_HEADROOM + len;
 	struct virtio_vsock_hdr *hdr;
@@ -55,9 +85,21 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
 	void *payload;
 	int err;
 
-	skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL);
-	if (!skb)
+	/* dgrams do not use credits, self-throttle according to sk_sndbuf
+	 * using sock_alloc_send_skb. This helps avoid triggering the OOM.
+	 */
+	if (info->vsk && info->type == VIRTIO_VSOCK_TYPE_DGRAM) {
+		skb = virtio_transport_sock_alloc_send_skb(info, skb_len, GFP_KERNEL, &err);
+	} else {
+		skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL);
+		if (!skb)
+			err = -ENOMEM;
+	}
+
+	if (!skb) {
+		*errp = err;
 		return NULL;
+	}
 
 	hdr = virtio_vsock_hdr(skb);
 	hdr->type	= cpu_to_le16(info->type);
@@ -102,6 +144,7 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
 	return skb;
 
 out:
+	*errp = err;
 	kfree_skb(skb);
 	return NULL;
 }
@@ -183,7 +226,9 @@ EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt);
 
 static u16 virtio_transport_get_type(struct sock *sk)
 {
-	if (sk->sk_type == SOCK_STREAM)
+	if (sk->sk_type == SOCK_DGRAM)
+		return VIRTIO_VSOCK_TYPE_DGRAM;
+	else if (sk->sk_type == SOCK_STREAM)
 		return VIRTIO_VSOCK_TYPE_STREAM;
 	else
 		return VIRTIO_VSOCK_TYPE_SEQPACKET;
@@ -239,11 +284,10 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
 
 		skb = virtio_transport_alloc_skb(info, skb_len,
 						 src_cid, src_port,
-						 dst_cid, dst_port);
-		if (!skb) {
-			ret = -ENOMEM;
+						 dst_cid, dst_port,
+						 &ret);
+		if (!skb)
 			break;
-		}
 
 		virtio_transport_inc_tx_pkt(vvs, skb);
 
@@ -583,14 +627,30 @@ virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,
 }
 EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_enqueue);
 
-int
-virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
-			       struct msghdr *msg,
-			       size_t len, int flags)
+int virtio_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
 {
-	return -EOPNOTSUPP;
+	*cid = le64_to_cpu(virtio_vsock_hdr(skb)->src_cid);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_cid);
+
+int virtio_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port)
+{
+	*port = le32_to_cpu(virtio_vsock_hdr(skb)->src_port);
+	return 0;
 }
-EXPORT_SYMBOL_GPL(virtio_transport_dgram_dequeue);
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_port);
+
+int virtio_transport_dgram_get_length(struct sk_buff *skb, size_t *len)
+{
+	/* The device layer must have already moved the data ptr beyond the
+	 * header for skb->len to be correct.
+	 */
+	WARN_ON(skb->data == skb->head);
+	*len = skb->len;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_length);
 
 s64 virtio_transport_stream_has_data(struct vsock_sock *vsk)
 {
@@ -790,30 +850,6 @@ bool virtio_transport_stream_allow(u32 cid, u32 port)
 }
 EXPORT_SYMBOL_GPL(virtio_transport_stream_allow);
 
-int virtio_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid)
-{
-	return -EOPNOTSUPP;
-}
-EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_cid);
-
-int virtio_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port)
-{
-	return -EOPNOTSUPP;
-}
-EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_port);
-
-int virtio_transport_dgram_get_length(struct sk_buff *skb, size_t *len)
-{
-	return -EOPNOTSUPP;
-}
-EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_length);
-
-bool virtio_transport_dgram_allow(u32 cid, u32 port)
-{
-	return false;
-}
-EXPORT_SYMBOL_GPL(virtio_transport_dgram_allow);
-
 int virtio_transport_connect(struct vsock_sock *vsk)
 {
 	struct virtio_vsock_pkt_info info = {
@@ -846,7 +882,34 @@ virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
 			       struct msghdr *msg,
 			       size_t dgram_len)
 {
-	return -EOPNOTSUPP;
+	const struct virtio_transport *t_ops;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_RW,
+		.msg = msg,
+		.vsk = vsk,
+		.type = VIRTIO_VSOCK_TYPE_DGRAM,
+	};
+	u32 src_cid, src_port;
+	struct sk_buff *skb;
+	int err;
+
+	if (dgram_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE)
+		return -EMSGSIZE;
+
+	t_ops = virtio_transport_get_ops(vsk);
+	src_cid = t_ops->transport.get_local_cid();
+	src_port = vsk->local_addr.svm_port;
+
+	skb = virtio_transport_alloc_skb(&info, dgram_len,
+					 src_cid, src_port,
+					 remote_addr->svm_cid,
+					 remote_addr->svm_port,
+					 &err);
+
+	if (!skb)
+		return err;
+
+	return t_ops->send_pkt(skb);
 }
 EXPORT_SYMBOL_GPL(virtio_transport_dgram_enqueue);
 
@@ -903,6 +966,7 @@ static int virtio_transport_reset_no_sock(const struct virtio_transport *t,
 		.reply = true,
 	};
 	struct sk_buff *reply;
+	int err;
 
 	/* Send RST only if the original pkt is not a RST pkt */
 	if (le16_to_cpu(hdr->op) == VIRTIO_VSOCK_OP_RST)
@@ -915,9 +979,10 @@ static int virtio_transport_reset_no_sock(const struct virtio_transport *t,
 					   le64_to_cpu(hdr->dst_cid),
 					   le32_to_cpu(hdr->dst_port),
 					   le64_to_cpu(hdr->src_cid),
-					   le32_to_cpu(hdr->src_port));
+					   le32_to_cpu(hdr->src_port),
+					   &err);
 	if (!reply)
-		return -ENOMEM;
+		return err;
 
 	return t->send_pkt(reply);
 }
@@ -1137,6 +1202,25 @@ virtio_transport_recv_enqueue(struct vsock_sock *vsk,
 		kfree_skb(skb);
 }
 
+/* This function takes ownership of the skb.
+ *
+ * It either places the skb on the sk_receive_queue or frees it.
+ */
+static int
+virtio_transport_recv_dgram(struct sock *sk, struct sk_buff *skb)
+{
+	int err;
+
+	err = sock_queue_rcv_skb(sk, skb);
+	if (err < 0) {
+		kfree_skb(skb);
+		return err;
+	}
+
+	sk->sk_data_ready(sk);
+	return 0;
+}
+
 static int
 virtio_transport_recv_connected(struct sock *sk,
 				struct sk_buff *skb)
@@ -1300,7 +1384,8 @@ virtio_transport_recv_listen(struct sock *sk, struct sk_buff *skb,
 static bool virtio_transport_valid_type(u16 type)
 {
 	return (type == VIRTIO_VSOCK_TYPE_STREAM) ||
-	       (type == VIRTIO_VSOCK_TYPE_SEQPACKET);
+	       (type == VIRTIO_VSOCK_TYPE_SEQPACKET) ||
+	       (type == VIRTIO_VSOCK_TYPE_DGRAM);
 }
 
 /* We are under the virtio-vsock's vsock->rx_lock or vhost-vsock's vq->mutex
@@ -1314,40 +1399,52 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
 	struct vsock_sock *vsk;
 	struct sock *sk;
 	bool space_available;
+	u16 type;
 
 	vsock_addr_init(&src, le64_to_cpu(hdr->src_cid),
 			le32_to_cpu(hdr->src_port));
 	vsock_addr_init(&dst, le64_to_cpu(hdr->dst_cid),
 			le32_to_cpu(hdr->dst_port));
 
+	type = le16_to_cpu(hdr->type);
+
 	trace_virtio_transport_recv_pkt(src.svm_cid, src.svm_port,
 					dst.svm_cid, dst.svm_port,
 					le32_to_cpu(hdr->len),
-					le16_to_cpu(hdr->type),
+					type,
 					le16_to_cpu(hdr->op),
 					le32_to_cpu(hdr->flags),
 					le32_to_cpu(hdr->buf_alloc),
 					le32_to_cpu(hdr->fwd_cnt));
 
-	if (!virtio_transport_valid_type(le16_to_cpu(hdr->type))) {
+	if (!virtio_transport_valid_type(type)) {
 		(void)virtio_transport_reset_no_sock(t, skb);
 		goto free_pkt;
 	}
 
-	/* The socket must be in connected or bound table
-	 * otherwise send reset back
+	/* For stream/seqpacket, the socket must be in connected or bound table
+	 * otherwise send reset back.
+	 *
+	 * For datagrams, no reset is sent back.
 	 */
 	sk = vsock_find_connected_socket(&src, &dst);
 	if (!sk) {
-		sk = vsock_find_bound_socket(&dst);
-		if (!sk) {
-			(void)virtio_transport_reset_no_sock(t, skb);
-			goto free_pkt;
+		if (type == VIRTIO_VSOCK_TYPE_DGRAM) {
+			sk = vsock_find_bound_dgram_socket(&dst);
+			if (!sk)
+				goto free_pkt;
+		} else {
+			sk = vsock_find_bound_socket(&dst);
+			if (!sk) {
+				(void)virtio_transport_reset_no_sock(t, skb);
+				goto free_pkt;
+			}
 		}
 	}
 
-	if (virtio_transport_get_type(sk) != le16_to_cpu(hdr->type)) {
-		(void)virtio_transport_reset_no_sock(t, skb);
+	if (virtio_transport_get_type(sk) != type) {
+		if (type != VIRTIO_VSOCK_TYPE_DGRAM)
+			(void)virtio_transport_reset_no_sock(t, skb);
 		sock_put(sk);
 		goto free_pkt;
 	}
@@ -1363,12 +1460,18 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
 
 	/* Check if sk has been closed before lock_sock */
 	if (sock_flag(sk, SOCK_DONE)) {
-		(void)virtio_transport_reset_no_sock(t, skb);
+		if (type != VIRTIO_VSOCK_TYPE_DGRAM)
+			(void)virtio_transport_reset_no_sock(t, skb);
 		release_sock(sk);
 		sock_put(sk);
 		goto free_pkt;
 	}
 
+	if (sk->sk_type == SOCK_DGRAM) {
+		virtio_transport_recv_dgram(sk, skb);
+		goto out;
+	}
+
 	space_available = virtio_transport_space_update(sk, skb);
 
 	/* Update CID in case it has changed after a transport reset event */
@@ -1400,6 +1503,7 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
 		break;
 	}
 
+out:
 	release_sock(sk);
 
 	/* Release refcnt obtained when we fetched this socket out of the
diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c
index 7b0a5030e555..53eccd714567 100644
--- a/net/vmw_vsock/vsock_loopback.c
+++ b/net/vmw_vsock/vsock_loopback.c
@@ -47,6 +47,7 @@ static int vsock_loopback_cancel_pkt(struct vsock_sock *vsk)
 	return 0;
 }
 
+static bool vsock_loopback_dgram_allow(u32 cid, u32 port);
 static bool vsock_loopback_seqpacket_allow(u32 remote_cid);
 
 static struct virtio_transport loopback_transport = {
@@ -63,7 +64,7 @@ static struct virtio_transport loopback_transport = {
 		.cancel_pkt               = vsock_loopback_cancel_pkt,
 
 		.dgram_enqueue            = virtio_transport_dgram_enqueue,
-		.dgram_allow              = virtio_transport_dgram_allow,
+		.dgram_allow              = vsock_loopback_dgram_allow,
 		.dgram_get_cid		  = virtio_transport_dgram_get_cid,
 		.dgram_get_port		  = virtio_transport_dgram_get_port,
 		.dgram_get_length	  = virtio_transport_dgram_get_length,
@@ -99,6 +100,11 @@ static struct virtio_transport loopback_transport = {
 	.send_pkt = vsock_loopback_send_pkt,
 };
 
+static bool vsock_loopback_dgram_allow(u32 cid, u32 port)
+{
+	return true;
+}
+
 static bool vsock_loopback_seqpacket_allow(u32 remote_cid)
 {
 	return true;

-- 
2.30.2

Re: [PATCH RFC net-next v3 6/8] virtio/vsock: support dgrams

[Simon Horman]

+ Dan Carpenter

On Wed, May 31, 2023 at 12:35:10AM +0000, Bobby Eshleman wrote:
> This commit adds support for datagrams over virtio/vsock.
> 
> Message boundaries are preserved on a per-skb and per-vq entry basis.
> Messages are copied in whole from the user to an SKB, which in turn is
> added to the scatterlist for the virtqueue in whole for the device.
> Messages do not straddle skbs and they do not straddle packets.
> Messages may be truncated by the receiving user if their buffer is
> shorter than the message.
> 
> Other properties of vsock datagrams:
> - Datagrams self-throttle at the per-socket sk_sndbuf threshold.
> - The same virtqueue is used as is used for streams and seqpacket flows
> - Credits are not used for datagrams
> - Packets are dropped silently by the device, which means the virtqueue
>   will still get kicked even during high packet loss, so long as the
>   socket does not exceed sk_sndbuf.
> 
> Future work might include finding a way to reduce the virtqueue kick
> rate for datagram flows with high packet loss.
> 
> Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>

...

Hi Bobby,

some feedback from my side.

> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c

...

> @@ -730,11 +754,18 @@ int vsock_bind_stream(struct vsock_sock *vsk,
>  }
>  EXPORT_SYMBOL(vsock_bind_stream);
>  
> -static int __vsock_bind_dgram(struct vsock_sock *vsk,
> -			      struct sockaddr_vm *addr)
> +static int vsock_bind_dgram(struct vsock_sock *vsk,
> +			    struct sockaddr_vm *addr)
>  {
> -	if (!vsk->transport || !vsk->transport->dgram_bind)
> -		return -EINVAL;
> +	if (!vsk->transport || !vsk->transport->dgram_bind) {
> +		int retval;

nit: blank line here

> +		spin_lock_bh(&vsock_dgram_table_lock);
> +		retval = vsock_bind_common(vsk, addr, vsock_dgram_bind_table,
> +					   VSOCK_HASH_SIZE);
> +		spin_unlock_bh(&vsock_dgram_table_lock);
> +
> +		return retval;
> +	}
>  
>  	return vsk->transport->dgram_bind(vsk, addr);
>  }

...

> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c

...

> @@ -47,7 +76,8 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
>  			   u32 src_cid,
>  			   u32 src_port,
>  			   u32 dst_cid,
> -			   u32 dst_port)
> +			   u32 dst_port,
> +			   int *errp)
>  {
>  	const size_t skb_len = VIRTIO_VSOCK_SKB_HEADROOM + len;
>  	struct virtio_vsock_hdr *hdr;
> @@ -55,9 +85,21 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
>  	void *payload;
>  	int err;
>  
> -	skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL);
> -	if (!skb)
> +	/* dgrams do not use credits, self-throttle according to sk_sndbuf
> +	 * using sock_alloc_send_skb. This helps avoid triggering the OOM.
> +	 */
> +	if (info->vsk && info->type == VIRTIO_VSOCK_TYPE_DGRAM) {
> +		skb = virtio_transport_sock_alloc_send_skb(info, skb_len, GFP_KERNEL, &err);
> +	} else {
> +		skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL);
> +		if (!skb)
> +			err = -ENOMEM;
> +	}
> +
> +	if (!skb) {
> +		*errp = err;
>  		return NULL;
> +	}
>  
>  	hdr = virtio_vsock_hdr(skb);
>  	hdr->type	= cpu_to_le16(info->type);
> @@ -102,6 +144,7 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,

Smatch that err may not be initialised in the out label below.

Just above this context the following appears:

	if (info->vsk && !skb_set_owner_sk_safe(skb, sk_vsock(info->vsk))) {
		WARN_ONCE(1, "failed to allocate skb on vsock socket with sk_refcnt == 0\n");
		goto out;
	}

So I wonder if in that case err may not be initialised.

>  	return skb;
>  
>  out:
> +	*errp = err;
>  	kfree_skb(skb);
>  	return NULL;
>  }

...

Re: [PATCH RFC net-next v3 6/8] virtio/vsock: support dgrams

[Dan Carpenter]

On Wed, May 31, 2023 at 06:09:11PM +0200, Simon Horman wrote:
> > @@ -102,6 +144,7 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
> 
> Smatch that err may not be initialised in the out label below.
> 
> Just above this context the following appears:
> 
> 	if (info->vsk && !skb_set_owner_sk_safe(skb, sk_vsock(info->vsk))) {
> 		WARN_ONCE(1, "failed to allocate skb on vsock socket with sk_refcnt == 0\n");
> 		goto out;
> 	}
> 
> So I wonder if in that case err may not be initialised.
> 

Yep, exactly right.  I commented out the goto and it silenced the
warning.  I also initialized err to zero at the start hoping that it
would trigger a different warning but it didn't.  :(

regards,
dan carpenter


> >  	return skb;
> >  
> >  out:
> > +	*errp = err;
> >  	kfree_skb(skb);
> >  	return NULL;
> >  }

Re: [PATCH RFC net-next v3 6/8] virtio/vsock: support dgrams

[Bobby Eshleman]

On Wed, May 31, 2023 at 09:13:04PM +0300, Dan Carpenter wrote:
> On Wed, May 31, 2023 at 06:09:11PM +0200, Simon Horman wrote:
> > > @@ -102,6 +144,7 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
> > 
> > Smatch that err may not be initialised in the out label below.
> > 
> > Just above this context the following appears:
> > 
> > 	if (info->vsk && !skb_set_owner_sk_safe(skb, sk_vsock(info->vsk))) {
> > 		WARN_ONCE(1, "failed to allocate skb on vsock socket with sk_refcnt == 0\n");
> > 		goto out;
> > 	}
> > 
> > So I wonder if in that case err may not be initialised.
> > 
> 
> Yep, exactly right.  I commented out the goto and it silenced the
> warning.  I also initialized err to zero at the start hoping that it
> would trigger a different warning but it didn't.  :(
> 
> regards,
> dan carpenter
> 

Thanks for checking that Dan. Fixed in the next rev.

Best,
Bobby

[PATCH RFC net-next v3 7/8] vsock: Add lockless sendmsg() support

[Bobby Eshleman]

Because the dgram sendmsg() path for AF_VSOCK acquires the socket lock
it does not scale when many senders share a socket.

Prior to this patch the socket lock is used to protect both reads and
writes to the local_addr, remote_addr, transport, and buffer size
variables of a vsock socket. What follows are the new protection schemes
for these fields that ensure a race-free and usually lock-free
multi-sender sendmsg() path for vsock dgrams.

- local_addr
    local_addr changes as a result of binding a socket. The write path
    for local_addr is bind() and various vsock_auto_bind() call sites.
    After a socket has been bound via vsock_auto_bind() or bind(), subsequent
    calls to bind()/vsock_auto_bind() do not write to local_addr again. bind()
    rejects the user request and vsock_auto_bind() early exits.
    Therefore, the local addr can not change while a parallel thread is
    in sendmsg() and lock-free reads of local addr in sendmsg() are safe.
    Change: only acquire lock for auto-binding as-needed in sendmsg().

- buffer size variables
    Not used by dgram, so they do not need protection. No change.

- remote_addr and transport
    Because a remote_addr update may result in a changed transport, but we
    would like to be able to read these two fields lock-free but coherently
    in the vsock send path, this patch packages these two fields into a new
    struct vsock_remote_info that is referenced by an RCU-protected pointer.

    Writes are synchronized as usual by the socket lock. Reads only take
    place in RCU read-side critical sections. When remote_addr or transport
    is updated, a new remote info is allocated. Old readers still see the
    old coherent remote_addr/transport pair, and new readers will refer to
    the new coherent. The coherency between remote_addr and transport
    previously provided by the socket lock alone is now also preserved by
    RCU, except with the highly-scalable lock-free read-side.

Helpers are introduced for accessing and updating the new pointer.

The new structure is contains an rcu_head so that kfree_rcu() can be
used. This removes the need of writers to use synchronize_rcu() after
freeing old structures which is simply more efficient and reduces code
churn where remote_addr/transport are already being updated inside RCU
read-side sections.

Only virtio has been tested, but updates were necessary to the VMCI and
hyperv code. Unfortunately the author does not have access to
VMCI/hyperv systems so those changes are untested.

Perf Tests (results from patch v2)
vCPUS: 16
Threads: 16
Payload: 4KB
Test Runs: 5
Type: SOCK_DGRAM

Before: 245.2 MB/s
After: 509.2 MB/s (+107%)

Notably, on the same test system, vsock dgram even outperforms
multi-threaded UDP over virtio-net with vhost and MQ support enabled.

Throughput metrics for single-threaded SOCK_DGRAM and
single/multi-threaded SOCK_STREAM showed no statistically signficant
throughput changes (lowest p-value reaching 0.27), with the range of the
mean difference ranging between -5% to +1%.

Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
---
 drivers/vhost/vsock.c                   |  12 +-
 include/linux/virtio_vsock.h            |   3 +-
 include/net/af_vsock.h                  |  39 ++-
 net/vmw_vsock/af_vsock.c                | 451 +++++++++++++++++++++++++-------
 net/vmw_vsock/diag.c                    |  10 +-
 net/vmw_vsock/hyperv_transport.c        |  27 +-
 net/vmw_vsock/virtio_transport_common.c |  32 ++-
 net/vmw_vsock/vmci_transport.c          |  84 ++++--
 net/vmw_vsock/vsock_bpf.c               |  10 +-
 9 files changed, 518 insertions(+), 150 deletions(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 159c1a22c1a8..b027a780d333 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -297,13 +297,17 @@ static int
 vhost_transport_cancel_pkt(struct vsock_sock *vsk)
 {
 	struct vhost_vsock *vsock;
+	unsigned int cid;
 	int cnt = 0;
 	int ret = -ENODEV;
 
 	rcu_read_lock();
+	ret = vsock_remote_addr_cid(vsk, &cid);
+	if (ret < 0)
+		goto out;
 
 	/* Find the vhost_vsock according to guest context id  */
-	vsock = vhost_vsock_get(vsk->remote_addr.svm_cid);
+	vsock = vhost_vsock_get(cid);
 	if (!vsock)
 		goto out;
 
@@ -706,6 +710,10 @@ static void vhost_vsock_flush(struct vhost_vsock *vsock)
 static void vhost_vsock_reset_orphans(struct sock *sk)
 {
 	struct vsock_sock *vsk = vsock_sk(sk);
+	unsigned int cid;
+
+	if (vsock_remote_addr_cid(vsk, &cid) < 0)
+		return;
 
 	/* vmci_transport.c doesn't take sk_lock here either.  At least we're
 	 * under vsock_table_lock so the sock cannot disappear while we're
@@ -713,7 +721,7 @@ static void vhost_vsock_reset_orphans(struct sock *sk)
 	 */
 
 	/* If the peer is still valid, no need to reset connection */
-	if (vhost_vsock_get(vsk->remote_addr.svm_cid))
+	if (vhost_vsock_get(cid))
 		return;
 
 	/* If the close timeout is pending, let it expire.  This avoids races
diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index 237ca87a2ecd..97656e83606f 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -231,7 +231,8 @@ virtio_transport_stream_enqueue(struct vsock_sock *vsk,
 				struct msghdr *msg,
 				size_t len);
 int
-virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
+virtio_transport_dgram_enqueue(const struct vsock_transport *transport,
+			       struct vsock_sock *vsk,
 			       struct sockaddr_vm *remote_addr,
 			       struct msghdr *msg,
 			       size_t len);
diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index c115e655b4f5..84f2a9700ebd 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -25,12 +25,17 @@ extern spinlock_t vsock_table_lock;
 #define vsock_sk(__sk)    ((struct vsock_sock *)__sk)
 #define sk_vsock(__vsk)   (&(__vsk)->sk)
 
+struct vsock_remote_info {
+	struct sockaddr_vm addr;
+	struct rcu_head rcu;
+	const struct vsock_transport *transport;
+};
+
 struct vsock_sock {
 	/* sk must be the first member. */
 	struct sock sk;
-	const struct vsock_transport *transport;
 	struct sockaddr_vm local_addr;
-	struct sockaddr_vm remote_addr;
+	struct vsock_remote_info * __rcu remote_info;
 	/* Links for the global tables of bound and connected sockets. */
 	struct list_head bound_table;
 	struct list_head connected_table;
@@ -120,8 +125,8 @@ struct vsock_transport {
 
 	/* DGRAM. */
 	int (*dgram_bind)(struct vsock_sock *, struct sockaddr_vm *);
-	int (*dgram_enqueue)(struct vsock_sock *, struct sockaddr_vm *,
-			     struct msghdr *, size_t len);
+	int (*dgram_enqueue)(const struct vsock_transport *, struct vsock_sock *,
+			     struct sockaddr_vm *, struct msghdr *, size_t len);
 	bool (*dgram_allow)(u32 cid, u32 port);
 	int (*dgram_get_cid)(struct sk_buff *skb, unsigned int *cid);
 	int (*dgram_get_port)(struct sk_buff *skb, unsigned int *port);
@@ -196,6 +201,17 @@ void vsock_core_unregister(const struct vsock_transport *t);
 /* The transport may downcast this to access transport-specific functions */
 const struct vsock_transport *vsock_core_get_transport(struct vsock_sock *vsk);
 
+static inline struct vsock_remote_info *
+vsock_core_get_remote_info(struct vsock_sock *vsk)
+{
+
+	/* vsk->remote_info may be accessed if the rcu read lock is held OR the
+	 * socket lock is held
+	 */
+	return rcu_dereference_check(vsk->remote_info,
+				     lockdep_sock_is_held(sk_vsock(vsk)));
+}
+
 /**** UTILS ****/
 
 /* vsock_table_lock must be held */
@@ -214,7 +230,7 @@ void vsock_release_pending(struct sock *pending);
 void vsock_add_pending(struct sock *listener, struct sock *pending);
 void vsock_remove_pending(struct sock *listener, struct sock *pending);
 void vsock_enqueue_accept(struct sock *listener, struct sock *connected);
-void vsock_insert_connected(struct vsock_sock *vsk);
+int 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);
@@ -223,7 +239,8 @@ struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
 void vsock_remove_sock(struct vsock_sock *vsk);
 void vsock_for_each_connected_socket(struct vsock_transport *transport,
 				     void (*fn)(struct sock *sk));
-int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk);
+int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk,
+			   struct sockaddr_vm *remote_addr);
 bool vsock_find_cid(unsigned int cid);
 struct sock *vsock_find_bound_dgram_socket(struct sockaddr_vm *addr);
 
@@ -253,4 +270,14 @@ static inline void __init vsock_bpf_build_proto(void)
 {}
 #endif
 
+/* RCU-protected remote addr helpers */
+int vsock_remote_addr_cid(struct vsock_sock *vsk, unsigned int *cid);
+int vsock_remote_addr_port(struct vsock_sock *vsk, unsigned int *port);
+int vsock_remote_addr_cid_port(struct vsock_sock *vsk, unsigned int *cid,
+			       unsigned int *port);
+int vsock_remote_addr_copy(struct vsock_sock *vsk, struct sockaddr_vm *dest);
+bool vsock_remote_addr_bound(struct vsock_sock *vsk);
+bool vsock_remote_addr_equals(struct vsock_sock *vsk, struct sockaddr_vm *other);
+int vsock_remote_addr_update_cid_port(struct vsock_sock *vsk, u32 cid, u32 port);
+
 #endif /* __AF_VSOCK_H__ */
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index e8c70069d77d..0520228d2a68 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -114,6 +114,8 @@
 static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr);
 static void vsock_sk_destruct(struct sock *sk);
 static int vsock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
+static bool vsock_use_local_transport(unsigned int remote_cid);
+static bool sock_type_connectible(u16 type);
 
 /* Protocol family. */
 struct proto vsock_proto = {
@@ -145,6 +147,147 @@ static const struct vsock_transport *transport_local;
 static DEFINE_MUTEX(vsock_register_mutex);
 
 /**** UTILS ****/
+bool vsock_remote_addr_bound(struct vsock_sock *vsk)
+{
+	struct vsock_remote_info *remote_info;
+	bool ret;
+
+	rcu_read_lock();
+	remote_info = vsock_core_get_remote_info(vsk);
+	if (!remote_info) {
+		rcu_read_unlock();
+		return false;
+	}
+
+	ret = vsock_addr_bound(&remote_info->addr);
+	rcu_read_unlock();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(vsock_remote_addr_bound);
+
+int vsock_remote_addr_copy(struct vsock_sock *vsk, struct sockaddr_vm *dest)
+{
+	struct vsock_remote_info *remote_info;
+
+	rcu_read_lock();
+	remote_info = vsock_core_get_remote_info(vsk);
+	if (!remote_info) {
+		rcu_read_unlock();
+		return -EINVAL;
+	}
+	memcpy(dest, &remote_info->addr, sizeof(*dest));
+	rcu_read_unlock();
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vsock_remote_addr_copy);
+
+int vsock_remote_addr_cid(struct vsock_sock *vsk, unsigned int *cid)
+{
+	return vsock_remote_addr_cid_port(vsk, cid, NULL);
+}
+EXPORT_SYMBOL_GPL(vsock_remote_addr_cid);
+
+int vsock_remote_addr_port(struct vsock_sock *vsk, unsigned int *port)
+{
+	return vsock_remote_addr_cid_port(vsk, NULL, port);
+}
+EXPORT_SYMBOL_GPL(vsock_remote_addr_port);
+
+int vsock_remote_addr_cid_port(struct vsock_sock *vsk, unsigned int *cid,
+			       unsigned int *port)
+{
+	struct vsock_remote_info *remote_info;
+
+	rcu_read_lock();
+	remote_info = vsock_core_get_remote_info(vsk);
+	if (!remote_info) {
+		rcu_read_unlock();
+		return -EINVAL;
+	}
+
+	if (cid)
+		*cid = remote_info->addr.svm_cid;
+	if (port)
+		*port = remote_info->addr.svm_port;
+
+	rcu_read_unlock();
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vsock_remote_addr_cid_port);
+
+/* The socket lock must be held by the caller */
+int vsock_set_remote_info(struct vsock_sock *vsk,
+			  const struct vsock_transport *transport,
+			  struct sockaddr_vm *addr)
+{
+	struct vsock_remote_info *old, *new;
+
+	if (addr || transport) {
+		new = kmalloc(sizeof(*new), GFP_KERNEL);
+		if (!new)
+			return -ENOMEM;
+
+		if (addr)
+			memcpy(&new->addr, addr, sizeof(new->addr));
+
+		if (transport)
+			new->transport = transport;
+	} else {
+		new = NULL;
+	}
+
+	old = rcu_replace_pointer(vsk->remote_info, new, lockdep_sock_is_held(sk_vsock(vsk)));
+	kfree_rcu(old, rcu);
+
+	return 0;
+}
+
+static const struct vsock_transport *
+vsock_connectible_lookup_transport(unsigned int cid, __u8 flags)
+{
+	const struct vsock_transport *transport;
+
+	if (vsock_use_local_transport(cid))
+		transport = transport_local;
+	else if (cid <= VMADDR_CID_HOST || !transport_h2g ||
+		 (flags & VMADDR_FLAG_TO_HOST))
+		transport = transport_g2h;
+	else
+		transport = transport_h2g;
+
+	return transport;
+}
+
+static const struct vsock_transport *
+vsock_dgram_lookup_transport(unsigned int cid, __u8 flags)
+{
+	if (transport_dgram)
+		return transport_dgram;
+
+	return vsock_connectible_lookup_transport(cid, flags);
+}
+
+bool vsock_remote_addr_equals(struct vsock_sock *vsk,
+			      struct sockaddr_vm *other)
+{
+	struct vsock_remote_info *remote_info;
+	bool equals;
+
+	rcu_read_lock();
+	remote_info = vsock_core_get_remote_info(vsk);
+	if (!remote_info) {
+		rcu_read_unlock();
+		return false;
+	}
+
+	equals = vsock_addr_equals_addr(&remote_info->addr, other);
+	rcu_read_unlock();
+
+	return equals;
+}
+EXPORT_SYMBOL_GPL(vsock_remote_addr_equals);
 
 /* Each bound VSocket is stored in the bind hash table and each connected
  * VSocket is stored in the connected hash table.
@@ -284,10 +427,16 @@ static struct sock *__vsock_find_connected_socket(struct sockaddr_vm *src,
 
 	list_for_each_entry(vsk, vsock_connected_sockets(src, dst),
 			    connected_table) {
-		if (vsock_addr_equals_addr(src, &vsk->remote_addr) &&
+		struct vsock_remote_info *remote_info;
+
+		rcu_read_lock();
+		remote_info = vsock_core_get_remote_info(vsk);
+		if (vsock_addr_equals_addr(src, &remote_info->addr) &&
 		    dst->svm_port == vsk->local_addr.svm_port) {
+			rcu_read_unlock();
 			return sk_vsock(vsk);
 		}
+		rcu_read_unlock();
 	}
 
 	return NULL;
@@ -300,17 +449,36 @@ static void vsock_insert_unbound(struct vsock_sock *vsk)
 	spin_unlock_bh(&vsock_table_lock);
 }
 
-void vsock_insert_connected(struct vsock_sock *vsk)
+int vsock_insert_connected(struct vsock_sock *vsk)
 {
-	struct list_head *list = vsock_connected_sockets(
-		&vsk->remote_addr, &vsk->local_addr);
+	struct list_head *list;
+	struct vsock_remote_info *remote_info;
+
+	rcu_read_lock();
+	remote_info = vsock_core_get_remote_info(vsk);
+	if (!remote_info) {
+		rcu_read_unlock();
+		return -EINVAL;
+	}
+	list = vsock_connected_sockets(&remote_info->addr, &vsk->local_addr);
+	rcu_read_unlock();
 
 	spin_lock_bh(&vsock_table_lock);
 	__vsock_insert_connected(list, vsk);
 	spin_unlock_bh(&vsock_table_lock);
+
+	return 0;
 }
 EXPORT_SYMBOL_GPL(vsock_insert_connected);
 
+void vsock_remove_dgram_bound(struct vsock_sock *vsk)
+{
+	spin_lock_bh(&vsock_dgram_table_lock);
+	if (__vsock_in_bound_table(vsk))
+		__vsock_remove_bound(vsk);
+	spin_unlock_bh(&vsock_dgram_table_lock);
+}
+
 void vsock_remove_bound(struct vsock_sock *vsk)
 {
 	spin_lock_bh(&vsock_table_lock);
@@ -362,7 +530,10 @@ EXPORT_SYMBOL_GPL(vsock_find_connected_socket);
 
 void vsock_remove_sock(struct vsock_sock *vsk)
 {
-	vsock_remove_bound(vsk);
+	if (sock_type_connectible(sk_vsock(vsk)->sk_type))
+		vsock_remove_bound(vsk);
+	else
+		vsock_remove_dgram_bound(vsk);
 	vsock_remove_connected(vsk);
 }
 EXPORT_SYMBOL_GPL(vsock_remove_sock);
@@ -378,7 +549,7 @@ void vsock_for_each_connected_socket(struct vsock_transport *transport,
 		struct vsock_sock *vsk;
 		list_for_each_entry(vsk, &vsock_connected_table[i],
 				    connected_table) {
-			if (vsk->transport != transport)
+			if (vsock_core_get_transport(vsk) != transport)
 				continue;
 
 			fn(sk_vsock(vsk));
@@ -444,59 +615,39 @@ static bool vsock_use_local_transport(unsigned int remote_cid)
 
 static void vsock_deassign_transport(struct vsock_sock *vsk)
 {
-	if (!vsk->transport)
-		return;
-
-	vsk->transport->destruct(vsk);
-	module_put(vsk->transport->module);
-	vsk->transport = NULL;
-}
-
-static const struct vsock_transport *
-vsock_connectible_lookup_transport(unsigned int cid, __u8 flags)
-{
-	const struct vsock_transport *transport;
+	struct vsock_remote_info *remote_info;
 
-	if (vsock_use_local_transport(cid))
-		transport = transport_local;
-	else if (cid <= VMADDR_CID_HOST || !transport_h2g ||
-		 (flags & VMADDR_FLAG_TO_HOST))
-		transport = transport_g2h;
-	else
-		transport = transport_h2g;
-
-	return transport;
-}
-
-static const struct vsock_transport *
-vsock_dgram_lookup_transport(unsigned int cid, __u8 flags)
-{
-	if (transport_dgram)
-		return transport_dgram;
+	remote_info = rcu_replace_pointer(vsk->remote_info, NULL,
+					  lockdep_sock_is_held(sk_vsock(vsk)));
+	if (!remote_info)
+		return;
 
-	return vsock_connectible_lookup_transport(cid, flags);
+	remote_info->transport->destruct(vsk);
+	module_put(remote_info->transport->module);
+	kfree_rcu(remote_info, rcu);
 }
 
 /* Assign a transport to a socket and call the .init transport callback.
  *
- * Note: for connection oriented socket this must be called when vsk->remote_addr
- * is set (e.g. during the connect() or when a connection request on a listener
- * socket is received).
- * The vsk->remote_addr is used to decide which transport to use:
+ * The remote_addr is used to decide which transport to use:
  *  - remote CID == VMADDR_CID_LOCAL or g2h->local_cid or VMADDR_CID_HOST if
  *    g2h is not loaded, will use local transport;
  *  - remote CID <= VMADDR_CID_HOST or h2g is not loaded or remote flags field
  *    includes VMADDR_FLAG_TO_HOST flag value, will use guest->host transport;
  *  - remote CID > VMADDR_CID_HOST will use host->guest transport;
  */
-int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
+int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk,
+			   struct sockaddr_vm *remote_addr)
 {
 	const struct vsock_transport *new_transport;
+	struct vsock_remote_info *old_info;
 	struct sock *sk = sk_vsock(vsk);
-	unsigned int remote_cid = vsk->remote_addr.svm_cid;
+	unsigned int remote_cid;
 	__u8 remote_flags;
 	int ret;
 
+	remote_cid = remote_addr->svm_cid;
+
 	/* If the packet is coming with the source and destination CIDs higher
 	 * than VMADDR_CID_HOST, then a vsock channel where all the packets are
 	 * forwarded to the host should be established. Then the host will
@@ -506,10 +657,10 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
 	 * the connect path the flag can be set by the user space application.
 	 */
 	if (psk && vsk->local_addr.svm_cid > VMADDR_CID_HOST &&
-	    vsk->remote_addr.svm_cid > VMADDR_CID_HOST)
-		vsk->remote_addr.svm_flags |= VMADDR_FLAG_TO_HOST;
+	    remote_cid > VMADDR_CID_HOST)
+		remote_addr->svm_flags |= VMADDR_FLAG_TO_HOST;
 
-	remote_flags = vsk->remote_addr.svm_flags;
+	remote_flags = remote_addr->svm_flags;
 
 	switch (sk->sk_type) {
 	case SOCK_DGRAM:
@@ -525,8 +676,9 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
 		return -ESOCKTNOSUPPORT;
 	}
 
-	if (vsk->transport) {
-		if (vsk->transport == new_transport)
+	old_info = vsock_core_get_remote_info(vsk);
+	if (old_info && old_info->transport) {
+		if (old_info->transport == new_transport)
 			return 0;
 
 		/* transport->release() must be called with sock lock acquired.
@@ -535,7 +687,7 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
 		 * function is called on a new socket which is not assigned to
 		 * any transport.
 		 */
-		vsk->transport->release(vsk);
+		old_info->transport->release(vsk);
 		vsock_deassign_transport(vsk);
 	}
 
@@ -553,13 +705,18 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
 		}
 	}
 
-	ret = new_transport->init(vsk, psk);
+	ret = vsock_set_remote_info(vsk, new_transport, remote_addr);
 	if (ret) {
 		module_put(new_transport->module);
 		return ret;
 	}
 
-	vsk->transport = new_transport;
+	ret = new_transport->init(vsk, psk);
+	if (ret) {
+		vsock_set_remote_info(vsk, NULL, NULL);
+		module_put(new_transport->module);
+		return ret;
+	}
 
 	return 0;
 }
@@ -616,12 +773,14 @@ static bool vsock_is_pending(struct sock *sk)
 
 static int vsock_send_shutdown(struct sock *sk, int mode)
 {
+	const struct vsock_transport *transport;
 	struct vsock_sock *vsk = vsock_sk(sk);
 
-	if (!vsk->transport)
+	transport = vsock_core_get_transport(vsk);
+	if (!transport)
 		return -ENODEV;
 
-	return vsk->transport->shutdown(vsk, mode);
+	return transport->shutdown(vsk, mode);
 }
 
 static void vsock_pending_work(struct work_struct *work)
@@ -757,7 +916,10 @@ EXPORT_SYMBOL(vsock_bind_stream);
 static int vsock_bind_dgram(struct vsock_sock *vsk,
 			    struct sockaddr_vm *addr)
 {
-	if (!vsk->transport || !vsk->transport->dgram_bind) {
+	const struct vsock_transport *transport;
+
+	transport = vsock_core_get_transport(vsk);
+	if (!transport || !transport->dgram_bind) {
 		int retval;
 		spin_lock_bh(&vsock_dgram_table_lock);
 		retval = vsock_bind_common(vsk, addr, vsock_dgram_bind_table,
@@ -767,7 +929,7 @@ static int vsock_bind_dgram(struct vsock_sock *vsk,
 		return retval;
 	}
 
-	return vsk->transport->dgram_bind(vsk, addr);
+	return transport->dgram_bind(vsk, addr);
 }
 
 static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr)
@@ -816,6 +978,7 @@ static struct sock *__vsock_create(struct net *net,
 				   unsigned short type,
 				   int kern)
 {
+	struct vsock_remote_info *remote_info;
 	struct sock *sk;
 	struct vsock_sock *psk;
 	struct vsock_sock *vsk;
@@ -835,7 +998,14 @@ static struct sock *__vsock_create(struct net *net,
 
 	vsk = vsock_sk(sk);
 	vsock_addr_init(&vsk->local_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
-	vsock_addr_init(&vsk->remote_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
+
+	remote_info = kmalloc(sizeof(*remote_info), GFP_KERNEL);
+	if (!remote_info) {
+		sk_free(sk);
+		return NULL;
+	}
+	vsock_addr_init(&remote_info->addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
+	rcu_assign_pointer(vsk->remote_info, remote_info);
 
 	sk->sk_destruct = vsock_sk_destruct;
 	sk->sk_backlog_rcv = vsock_queue_rcv_skb;
@@ -882,6 +1052,7 @@ static bool sock_type_connectible(u16 type)
 static void __vsock_release(struct sock *sk, int level)
 {
 	if (sk) {
+		const struct vsock_transport *transport;
 		struct sock *pending;
 		struct vsock_sock *vsk;
 
@@ -895,8 +1066,9 @@ static void __vsock_release(struct sock *sk, int level)
 		 */
 		lock_sock_nested(sk, level);
 
-		if (vsk->transport)
-			vsk->transport->release(vsk);
+		transport = vsock_core_get_transport(vsk);
+		if (transport)
+			transport->release(vsk);
 		else if (sock_type_connectible(sk->sk_type))
 			vsock_remove_sock(vsk);
 
@@ -926,8 +1098,6 @@ static void vsock_sk_destruct(struct sock *sk)
 	 * possibly register the address family with the kernel.
 	 */
 	vsock_addr_init(&vsk->local_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
-	vsock_addr_init(&vsk->remote_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
-
 	put_cred(vsk->owner);
 }
 
@@ -951,16 +1121,22 @@ EXPORT_SYMBOL_GPL(vsock_create_connected);
 
 s64 vsock_stream_has_data(struct vsock_sock *vsk)
 {
-	return vsk->transport->stream_has_data(vsk);
+	const struct vsock_transport *transport;
+
+	transport = vsock_core_get_transport(vsk);
+
+	return transport->stream_has_data(vsk);
 }
 EXPORT_SYMBOL_GPL(vsock_stream_has_data);
 
 s64 vsock_connectible_has_data(struct vsock_sock *vsk)
 {
+	const struct vsock_transport *transport;
 	struct sock *sk = sk_vsock(vsk);
 
+	transport = vsock_core_get_transport(vsk);
 	if (sk->sk_type == SOCK_SEQPACKET)
-		return vsk->transport->seqpacket_has_data(vsk);
+		return transport->seqpacket_has_data(vsk);
 	else
 		return vsock_stream_has_data(vsk);
 }
@@ -968,7 +1144,10 @@ EXPORT_SYMBOL_GPL(vsock_connectible_has_data);
 
 s64 vsock_stream_has_space(struct vsock_sock *vsk)
 {
-	return vsk->transport->stream_has_space(vsk);
+	const struct vsock_transport *transport;
+
+	transport = vsock_core_get_transport(vsk);
+	return transport->stream_has_space(vsk);
 }
 EXPORT_SYMBOL_GPL(vsock_stream_has_space);
 
@@ -1017,6 +1196,7 @@ static int vsock_getname(struct socket *sock,
 	struct sock *sk;
 	struct vsock_sock *vsk;
 	struct sockaddr_vm *vm_addr;
+	struct vsock_remote_info *rcu_ptr;
 
 	sk = sock->sk;
 	vsk = vsock_sk(sk);
@@ -1025,11 +1205,17 @@ static int vsock_getname(struct socket *sock,
 	lock_sock(sk);
 
 	if (peer) {
+		rcu_read_lock();
 		if (sock->state != SS_CONNECTED) {
 			err = -ENOTCONN;
 			goto out;
 		}
-		vm_addr = &vsk->remote_addr;
+		rcu_ptr = vsock_core_get_remote_info(vsk);
+		if (!rcu_ptr) {
+			err = -EINVAL;
+			goto out;
+		}
+		vm_addr = &rcu_ptr->addr;
 	} else {
 		vm_addr = &vsk->local_addr;
 	}
@@ -1049,6 +1235,8 @@ static int vsock_getname(struct socket *sock,
 	err = sizeof(*vm_addr);
 
 out:
+	if (peer)
+		rcu_read_unlock();
 	release_sock(sk);
 	return err;
 }
@@ -1153,7 +1341,7 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock,
 
 		lock_sock(sk);
 
-		transport = vsk->transport;
+		transport = vsock_core_get_transport(vsk);
 
 		/* Listening sockets that have connections in their accept
 		 * queue can be read.
@@ -1224,9 +1412,11 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock,
 
 static int vsock_read_skb(struct sock *sk, skb_read_actor_t read_actor)
 {
+	const struct vsock_transport *transport;
 	struct vsock_sock *vsk = vsock_sk(sk);
 
-	return vsk->transport->read_skb(vsk, read_actor);
+	transport = vsock_core_get_transport(vsk);
+	return transport->read_skb(vsk, read_actor);
 }
 
 static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
@@ -1235,7 +1425,7 @@ static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
 	int err;
 	struct sock *sk;
 	struct vsock_sock *vsk;
-	struct sockaddr_vm *remote_addr;
+	struct sockaddr_vm stack_addr, *remote_addr;
 	const struct vsock_transport *transport;
 
 	if (msg->msg_flags & MSG_OOB)
@@ -1246,7 +1436,23 @@ static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
 	sk = sock->sk;
 	vsk = vsock_sk(sk);
 
-	lock_sock(sk);
+	/* If auto-binding is required, acquire the slock to avoid potential
+	 * race conditions. Otherwise, do not acquire the lock.
+	 *
+	 * We know that the first check of local_addr is racy (indicated by
+	 * data_race()). By acquiring the lock and then subsequently checking
+	 * again if local_addr is bound (inside vsock_auto_bind()), we can
+	 * ensure there are no real data races.
+	 *
+	 * This technique is borrowed by inet_send_prepare().
+	 */
+	if (data_race(!vsock_addr_bound(&vsk->local_addr))) {
+		lock_sock(sk);
+		err = vsock_auto_bind(vsk);
+		release_sock(sk);
+		if (err)
+			return err;
+	}
 
 	/* If the provided message contains an address, use that.  Otherwise
 	 * fall back on the socket's remote handle (if it has been connected).
@@ -1256,6 +1462,7 @@ static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
 			    &remote_addr) == 0) {
 		transport = vsock_dgram_lookup_transport(remote_addr->svm_cid,
 							 remote_addr->svm_flags);
+
 		if (!transport) {
 			err = -EINVAL;
 			goto out;
@@ -1286,18 +1493,39 @@ static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
 			goto out;
 		}
 
-		err = transport->dgram_enqueue(vsk, remote_addr, msg, len);
+		err = transport->dgram_enqueue(transport, vsk, remote_addr, msg, len);
 		module_put(transport->module);
 	} else if (sock->state == SS_CONNECTED) {
-		remote_addr = &vsk->remote_addr;
-		transport = vsk->transport;
+		struct vsock_remote_info *remote_info;
+		const struct vsock_transport *transport;
 
-		err = vsock_auto_bind(vsk);
-		if (err)
+		rcu_read_lock();
+		remote_info = vsock_core_get_remote_info(vsk);
+		if (!remote_info) {
+			err = -EINVAL;
+			rcu_read_unlock();
 			goto out;
+		}
 
-		if (remote_addr->svm_cid == VMADDR_CID_ANY)
+		transport = remote_info->transport;
+		memcpy(&stack_addr, &remote_info->addr, sizeof(stack_addr));
+		rcu_read_unlock();
+
+		remote_addr = &stack_addr;
+
+		if (remote_addr->svm_cid == VMADDR_CID_ANY) {
 			remote_addr->svm_cid = transport->get_local_cid();
+			lock_sock(sk_vsock(vsk));
+			/* Even though the CID has changed, We do not have to
+			 * look up the transport again because the local CID
+			 * will never resolve to a different transport.
+			 */
+			err = vsock_set_remote_info(vsk, transport, remote_addr);
+			release_sock(sk_vsock(vsk));
+
+			if (err)
+				goto out;
+		}
 
 		/* XXX Should connect() or this function ensure remote_addr is
 		 * bound?
@@ -1313,14 +1541,13 @@ static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
 			goto out;
 		}
 
-		err = transport->dgram_enqueue(vsk, remote_addr, msg, len);
+		err = transport->dgram_enqueue(transport, vsk, &stack_addr, msg, len);
 	} else {
 		err = -EINVAL;
 		goto out;
 	}
 
 out:
-	release_sock(sk);
 	return err;
 }
 
@@ -1331,18 +1558,22 @@ static int vsock_dgram_connect(struct socket *sock,
 	struct sock *sk;
 	struct vsock_sock *vsk;
 	struct sockaddr_vm *remote_addr;
+	const struct vsock_transport *transport;
 
 	sk = sock->sk;
 	vsk = vsock_sk(sk);
 
 	err = vsock_addr_cast(addr, addr_len, &remote_addr);
 	if (err == -EAFNOSUPPORT && remote_addr->svm_family == AF_UNSPEC) {
+		struct sockaddr_vm addr_any;
+
 		lock_sock(sk);
-		vsock_addr_init(&vsk->remote_addr, VMADDR_CID_ANY,
-				VMADDR_PORT_ANY);
+		vsock_addr_init(&addr_any, VMADDR_CID_ANY, VMADDR_PORT_ANY);
+		err = vsock_set_remote_info(vsk, vsock_core_get_transport(vsk),
+					    &addr_any);
 		sock->state = SS_UNCONNECTED;
 		release_sock(sk);
-		return 0;
+		return err;
 	} else if (err != 0)
 		return -EINVAL;
 
@@ -1352,14 +1583,13 @@ static int vsock_dgram_connect(struct socket *sock,
 	if (err)
 		goto out;
 
-	memcpy(&vsk->remote_addr, remote_addr, sizeof(vsk->remote_addr));
-
-	err = vsock_assign_transport(vsk, NULL);
+	err = vsock_assign_transport(vsk, NULL, remote_addr);
 	if (err)
 		goto out;
 
-	if (!vsk->transport->dgram_allow(remote_addr->svm_cid,
-					 remote_addr->svm_port)) {
+	transport = vsock_core_get_transport(vsk);
+	if (!transport->dgram_allow(remote_addr->svm_cid,
+				    remote_addr->svm_port)) {
 		err = -EINVAL;
 		goto out;
 	}
@@ -1406,7 +1636,9 @@ int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
 	if (flags & MSG_OOB || flags & MSG_ERRQUEUE)
 		return -EOPNOTSUPP;
 
-	transport = vsk->transport;
+	rcu_read_lock();
+	transport = vsock_core_get_transport(vsk);
+	rcu_read_unlock();
 
 	/* Retrieve the head sk_buff from the socket's receive queue. */
 	err = 0;
@@ -1474,7 +1706,7 @@ static const struct proto_ops vsock_dgram_ops = {
 
 static int vsock_transport_cancel_pkt(struct vsock_sock *vsk)
 {
-	const struct vsock_transport *transport = vsk->transport;
+	const struct vsock_transport *transport = vsock_core_get_transport(vsk);
 
 	if (!transport || !transport->cancel_pkt)
 		return -EOPNOTSUPP;
@@ -1511,6 +1743,7 @@ static int vsock_connect(struct socket *sock, struct sockaddr *addr,
 	struct sock *sk;
 	struct vsock_sock *vsk;
 	const struct vsock_transport *transport;
+	struct vsock_remote_info *remote_info;
 	struct sockaddr_vm *remote_addr;
 	long timeout;
 	DEFINE_WAIT(wait);
@@ -1548,14 +1781,20 @@ static int vsock_connect(struct socket *sock, struct sockaddr *addr,
 		}
 
 		/* Set the remote address that we are connecting to. */
-		memcpy(&vsk->remote_addr, remote_addr,
-		       sizeof(vsk->remote_addr));
-
-		err = vsock_assign_transport(vsk, NULL);
+		err = vsock_assign_transport(vsk, NULL, remote_addr);
 		if (err)
 			goto out;
 
-		transport = vsk->transport;
+		rcu_read_lock();
+		remote_info = vsock_core_get_remote_info(vsk);
+		if (!remote_info) {
+			err = -EINVAL;
+			rcu_read_unlock();
+			goto out;
+		}
+
+		transport = remote_info->transport;
+		rcu_read_unlock();
 
 		/* The hypervisor and well-known contexts do not have socket
 		 * endpoints.
@@ -1819,7 +2058,7 @@ static int vsock_connectible_setsockopt(struct socket *sock,
 
 	lock_sock(sk);
 
-	transport = vsk->transport;
+	transport = vsock_core_get_transport(vsk);
 
 	switch (optname) {
 	case SO_VM_SOCKETS_BUFFER_SIZE:
@@ -1957,7 +2196,7 @@ static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,
 
 	lock_sock(sk);
 
-	transport = vsk->transport;
+	transport = vsock_core_get_transport(vsk);
 
 	/* Callers should not provide a destination with connection oriented
 	 * sockets.
@@ -1980,7 +2219,7 @@ static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,
 		goto out;
 	}
 
-	if (!vsock_addr_bound(&vsk->remote_addr)) {
+	if (!vsock_remote_addr_bound(vsk)) {
 		err = -EDESTADDRREQ;
 		goto out;
 	}
@@ -2101,7 +2340,7 @@ static int vsock_connectible_wait_data(struct sock *sk,
 
 	vsk = vsock_sk(sk);
 	err = 0;
-	transport = vsk->transport;
+	transport = vsock_core_get_transport(vsk);
 
 	while (1) {
 		prepare_to_wait(sk_sleep(sk), wait, TASK_INTERRUPTIBLE);
@@ -2169,7 +2408,7 @@ static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg,
 	DEFINE_WAIT(wait);
 
 	vsk = vsock_sk(sk);
-	transport = vsk->transport;
+	transport = vsock_core_get_transport(vsk);
 
 	/* We must not copy less than target bytes into the user's buffer
 	 * before returning successfully, so we wait for the consume queue to
@@ -2245,7 +2484,7 @@ static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
 	DEFINE_WAIT(wait);
 
 	vsk = vsock_sk(sk);
-	transport = vsk->transport;
+	transport = vsock_core_get_transport(vsk);
 
 	timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
 
@@ -2302,7 +2541,7 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 
 	lock_sock(sk);
 
-	transport = vsk->transport;
+	transport = vsock_core_get_transport(vsk);
 
 	if (!transport || sk->sk_state != TCP_ESTABLISHED) {
 		/* Recvmsg is supposed to return 0 if a peer performs an
@@ -2369,7 +2608,7 @@ static int vsock_set_rcvlowat(struct sock *sk, int val)
 	if (val > vsk->buffer_size)
 		return -EINVAL;
 
-	transport = vsk->transport;
+	transport = vsock_core_get_transport(vsk);
 
 	if (transport && transport->set_rcvlowat)
 		return transport->set_rcvlowat(vsk, val);
@@ -2459,7 +2698,10 @@ static int vsock_create(struct net *net, struct socket *sock,
 	vsk = vsock_sk(sk);
 
 	if (sock->type == SOCK_DGRAM) {
-		ret = vsock_assign_transport(vsk, NULL);
+		struct sockaddr_vm remote_addr;
+
+		vsock_addr_init(&remote_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
+		ret = vsock_assign_transport(vsk, NULL, &remote_addr);
 		if (ret < 0) {
 			sock_put(sk);
 			return ret;
@@ -2581,7 +2823,18 @@ static void __exit vsock_exit(void)
 
 const struct vsock_transport *vsock_core_get_transport(struct vsock_sock *vsk)
 {
-	return vsk->transport;
+	const struct vsock_transport *transport;
+	struct vsock_remote_info *remote_info;
+
+	rcu_read_lock();
+	remote_info = vsock_core_get_remote_info(vsk);
+	if (!remote_info) {
+		rcu_read_unlock();
+		return NULL;
+	}
+	transport = remote_info->transport;
+	rcu_read_unlock();
+	return transport;
 }
 EXPORT_SYMBOL_GPL(vsock_core_get_transport);
 
diff --git a/net/vmw_vsock/diag.c b/net/vmw_vsock/diag.c
index a2823b1c5e28..f843bae86b32 100644
--- a/net/vmw_vsock/diag.c
+++ b/net/vmw_vsock/diag.c
@@ -15,8 +15,14 @@ static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
 			u32 portid, u32 seq, u32 flags)
 {
 	struct vsock_sock *vsk = vsock_sk(sk);
+	struct sockaddr_vm remote_addr;
 	struct vsock_diag_msg *rep;
 	struct nlmsghdr *nlh;
+	int err;
+
+	err = vsock_remote_addr_copy(vsk, &remote_addr);
+	if (err < 0)
+		return err;
 
 	nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rep),
 			flags);
@@ -36,8 +42,8 @@ static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
 	rep->vdiag_shutdown = sk->sk_shutdown;
 	rep->vdiag_src_cid = vsk->local_addr.svm_cid;
 	rep->vdiag_src_port = vsk->local_addr.svm_port;
-	rep->vdiag_dst_cid = vsk->remote_addr.svm_cid;
-	rep->vdiag_dst_port = vsk->remote_addr.svm_port;
+	rep->vdiag_dst_cid = remote_addr.svm_cid;
+	rep->vdiag_dst_port = remote_addr.svm_port;
 	rep->vdiag_ino = sock_i_ino(sk);
 
 	sock_diag_save_cookie(sk, rep->vdiag_cookie);
diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
index c00bc5da769a..84e8c64b3365 100644
--- a/net/vmw_vsock/hyperv_transport.c
+++ b/net/vmw_vsock/hyperv_transport.c
@@ -323,6 +323,8 @@ static void hvs_open_connection(struct vmbus_channel *chan)
 		goto out;
 
 	if (conn_from_host) {
+		struct sockaddr_vm remote_addr;
+
 		if (sk->sk_ack_backlog >= sk->sk_max_ack_backlog)
 			goto out;
 
@@ -336,10 +338,9 @@ static void hvs_open_connection(struct vmbus_channel *chan)
 		hvs_addr_init(&vnew->local_addr, if_type);
 
 		/* Remote peer is always the host */
-		vsock_addr_init(&vnew->remote_addr,
-				VMADDR_CID_HOST, VMADDR_PORT_ANY);
-		vnew->remote_addr.svm_port = get_port_by_srv_id(if_instance);
-		ret = vsock_assign_transport(vnew, vsock_sk(sk));
+		vsock_addr_init(&remote_addr, VMADDR_CID_HOST, get_port_by_srv_id(if_instance));
+
+		ret = vsock_assign_transport(vnew, vsock_sk(sk), &remote_addr);
 		/* Transport assigned (looking at remote_addr) must be the
 		 * same where we received the request.
 		 */
@@ -459,13 +460,18 @@ static int hvs_connect(struct vsock_sock *vsk)
 {
 	union hvs_service_id vm, host;
 	struct hvsock *h = vsk->trans;
+	int err;
 
 	vm.srv_id = srv_id_template;
 	vm.svm_port = vsk->local_addr.svm_port;
 	h->vm_srv_id = vm.srv_id;
 
 	host.srv_id = srv_id_template;
-	host.svm_port = vsk->remote_addr.svm_port;
+
+	err = vsock_remote_addr_port(vsk, &host.svm_port);
+	if (err < 0)
+		return err;
+
 	h->host_srv_id = host.srv_id;
 
 	return vmbus_send_tl_connect_request(&h->vm_srv_id, &h->host_srv_id);
@@ -566,7 +572,8 @@ static int hvs_dgram_get_length(struct sk_buff *skb, size_t *len)
 	return -EOPNOTSUPP;
 }
 
-static int hvs_dgram_enqueue(struct vsock_sock *vsk,
+static int hvs_dgram_enqueue(const struct vsock_transport *transport,
+			     struct vsock_sock *vsk,
 			     struct sockaddr_vm *remote, struct msghdr *msg,
 			     size_t dgram_len)
 {
@@ -866,7 +873,13 @@ static struct vsock_transport hvs_transport = {
 
 static bool hvs_check_transport(struct vsock_sock *vsk)
 {
-	return vsk->transport == &hvs_transport;
+	bool ret;
+
+	rcu_read_lock();
+	ret = vsock_core_get_transport(vsk) == &hvs_transport;
+	rcu_read_unlock();
+
+	return ret;
 }
 
 static int hvs_probe(struct hv_device *hdev,
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index ab4af21c4f3f..09d35c488902 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -258,8 +258,9 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
 	src_cid = t_ops->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;
+		ret = vsock_remote_addr_cid_port(vsk, &dst_cid, &dst_port);
+		if (ret < 0)
+			return ret;
 	} else {
 		dst_cid = info->remote_cid;
 		dst_port = info->remote_port;
@@ -877,12 +878,14 @@ int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
 EXPORT_SYMBOL_GPL(virtio_transport_shutdown);
 
 int
-virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
+virtio_transport_dgram_enqueue(const struct vsock_transport *transport,
+			       struct vsock_sock *vsk,
 			       struct sockaddr_vm *remote_addr,
 			       struct msghdr *msg,
 			       size_t dgram_len)
 {
-	const struct virtio_transport *t_ops;
+	const struct virtio_transport *t_ops =
+		(const struct virtio_transport *)transport;
 	struct virtio_vsock_pkt_info info = {
 		.op = VIRTIO_VSOCK_OP_RW,
 		.msg = msg,
@@ -896,7 +899,6 @@ virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
 	if (dgram_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE)
 		return -EMSGSIZE;
 
-	t_ops = virtio_transport_get_ops(vsk);
 	src_cid = t_ops->transport.get_local_cid();
 	src_port = vsk->local_addr.svm_port;
 
@@ -1120,7 +1122,9 @@ virtio_transport_recv_connecting(struct sock *sk,
 	case VIRTIO_VSOCK_OP_RESPONSE:
 		sk->sk_state = TCP_ESTABLISHED;
 		sk->sk_socket->state = SS_CONNECTED;
-		vsock_insert_connected(vsk);
+		err = vsock_insert_connected(vsk);
+		if (err)
+			goto destroy;
 		sk->sk_state_change(sk);
 		break;
 	case VIRTIO_VSOCK_OP_INVALID:
@@ -1326,6 +1330,7 @@ virtio_transport_recv_listen(struct sock *sk, struct sk_buff *skb,
 	struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
 	struct vsock_sock *vsk = vsock_sk(sk);
 	struct vsock_sock *vchild;
+	struct sockaddr_vm child_remote;
 	struct sock *child;
 	int ret;
 
@@ -1354,14 +1359,13 @@ virtio_transport_recv_listen(struct sock *sk, struct sk_buff *skb,
 	vchild = vsock_sk(child);
 	vsock_addr_init(&vchild->local_addr, le64_to_cpu(hdr->dst_cid),
 			le32_to_cpu(hdr->dst_port));
-	vsock_addr_init(&vchild->remote_addr, le64_to_cpu(hdr->src_cid),
+	vsock_addr_init(&child_remote, le64_to_cpu(hdr->src_cid),
 			le32_to_cpu(hdr->src_port));
-
-	ret = vsock_assign_transport(vchild, vsk);
+	ret = vsock_assign_transport(vchild, vsk, &child_remote);
 	/* Transport assigned (looking at remote_addr) must be the same
 	 * where we received the request.
 	 */
-	if (ret || vchild->transport != &t->transport) {
+	if (ret || vsock_core_get_transport(vchild) != &t->transport) {
 		release_sock(child);
 		virtio_transport_reset_no_sock(t, skb);
 		sock_put(child);
@@ -1371,7 +1375,13 @@ virtio_transport_recv_listen(struct sock *sk, struct sk_buff *skb,
 	if (virtio_transport_space_update(child, skb))
 		child->sk_write_space(child);
 
-	vsock_insert_connected(vchild);
+	ret = vsock_insert_connected(vchild);
+	if (ret) {
+		release_sock(child);
+		virtio_transport_reset_no_sock(t, skb);
+		sock_put(child);
+		return ret;
+	}
 	vsock_enqueue_accept(sk, child);
 	virtio_transport_send_response(vchild, skb);
 
diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
index b6a51afb74b8..b9ba6209e8fc 100644
--- a/net/vmw_vsock/vmci_transport.c
+++ b/net/vmw_vsock/vmci_transport.c
@@ -283,18 +283,25 @@ vmci_transport_send_control_pkt(struct sock *sk,
 				u16 proto,
 				struct vmci_handle handle)
 {
+	struct sockaddr_vm addr_stack;
+	struct sockaddr_vm *remote_addr = &addr_stack;
 	struct vsock_sock *vsk;
+	int err;
 
 	vsk = vsock_sk(sk);
 
 	if (!vsock_addr_bound(&vsk->local_addr))
 		return -EINVAL;
 
-	if (!vsock_addr_bound(&vsk->remote_addr))
+	if (!vsock_remote_addr_bound(vsk))
 		return -EINVAL;
 
+	err = vsock_remote_addr_copy(vsk, remote_addr);
+	if (err < 0)
+		return err;
+
 	return vmci_transport_alloc_send_control_pkt(&vsk->local_addr,
-						     &vsk->remote_addr,
+						     remote_addr,
 						     type, size, mode,
 						     wait, proto, handle);
 }
@@ -317,6 +324,7 @@ static int vmci_transport_send_reset(struct sock *sk,
 	struct sockaddr_vm *dst_ptr;
 	struct sockaddr_vm dst;
 	struct vsock_sock *vsk;
+	int err;
 
 	if (pkt->type == VMCI_TRANSPORT_PACKET_TYPE_RST)
 		return 0;
@@ -326,13 +334,16 @@ static int vmci_transport_send_reset(struct sock *sk,
 	if (!vsock_addr_bound(&vsk->local_addr))
 		return -EINVAL;
 
-	if (vsock_addr_bound(&vsk->remote_addr)) {
-		dst_ptr = &vsk->remote_addr;
+	if (vsock_remote_addr_bound(vsk)) {
+		err = vsock_remote_addr_copy(vsk, &dst);
+		if (err < 0)
+			return err;
 	} else {
 		vsock_addr_init(&dst, pkt->dg.src.context,
 				pkt->src_port);
-		dst_ptr = &dst;
 	}
+	dst_ptr = &dst;
+
 	return vmci_transport_alloc_send_control_pkt(&vsk->local_addr, dst_ptr,
 					     VMCI_TRANSPORT_PACKET_TYPE_RST,
 					     0, 0, NULL, VSOCK_PROTO_INVALID,
@@ -490,7 +501,7 @@ static struct sock *vmci_transport_get_pending(
 
 	list_for_each_entry(vpending, &vlistener->pending_links,
 			    pending_links) {
-		if (vsock_addr_equals_addr(&src, &vpending->remote_addr) &&
+		if (vsock_remote_addr_equals(vpending, &src) &&
 		    pkt->dst_port == vpending->local_addr.svm_port) {
 			pending = sk_vsock(vpending);
 			sock_hold(pending);
@@ -940,6 +951,7 @@ static void vmci_transport_recv_pkt_work(struct work_struct *work)
 static int vmci_transport_recv_listen(struct sock *sk,
 				      struct vmci_transport_packet *pkt)
 {
+	struct sockaddr_vm remote_addr;
 	struct sock *pending;
 	struct vsock_sock *vpending;
 	int err;
@@ -1015,10 +1027,10 @@ static int vmci_transport_recv_listen(struct sock *sk,
 
 	vsock_addr_init(&vpending->local_addr, pkt->dg.dst.context,
 			pkt->dst_port);
-	vsock_addr_init(&vpending->remote_addr, pkt->dg.src.context,
-			pkt->src_port);
 
-	err = vsock_assign_transport(vpending, vsock_sk(sk));
+	vsock_addr_init(&remote_addr, pkt->dg.src.context, pkt->src_port);
+
+	err = vsock_assign_transport(vpending, vsock_sk(sk), &remote_addr);
 	/* Transport assigned (looking at remote_addr) must be the same
 	 * where we received the request.
 	 */
@@ -1133,6 +1145,7 @@ vmci_transport_recv_connecting_server(struct sock *listener,
 {
 	struct vsock_sock *vpending;
 	struct vmci_handle handle;
+	unsigned int vpending_remote_cid;
 	struct vmci_qp *qpair;
 	bool is_local;
 	u32 flags;
@@ -1189,8 +1202,13 @@ vmci_transport_recv_connecting_server(struct sock *listener,
 	/* vpending->local_addr always has a context id so we do not need to
 	 * worry about VMADDR_CID_ANY in this case.
 	 */
-	is_local =
-	    vpending->remote_addr.svm_cid == vpending->local_addr.svm_cid;
+	err = vsock_remote_addr_cid(vpending, &vpending_remote_cid);
+	if (err < 0) {
+		skerr = EPROTO;
+		goto destroy;
+	}
+
+	is_local = vpending_remote_cid == vpending->local_addr.svm_cid;
 	flags = VMCI_QPFLAG_ATTACH_ONLY;
 	flags |= is_local ? VMCI_QPFLAG_LOCAL : 0;
 
@@ -1203,7 +1221,7 @@ vmci_transport_recv_connecting_server(struct sock *listener,
 					flags,
 					vmci_transport_is_trusted(
 						vpending,
-						vpending->remote_addr.svm_cid));
+						vpending_remote_cid));
 	if (err < 0) {
 		vmci_transport_send_reset(pending, pkt);
 		skerr = -err;
@@ -1277,6 +1295,8 @@ static int
 vmci_transport_recv_connecting_client(struct sock *sk,
 				      struct vmci_transport_packet *pkt)
 {
+	struct vsock_remote_info *remote_info;
+	struct sockaddr_vm *remote_addr;
 	struct vsock_sock *vsk;
 	int err;
 	int skerr;
@@ -1306,9 +1326,20 @@ vmci_transport_recv_connecting_client(struct sock *sk,
 		break;
 	case VMCI_TRANSPORT_PACKET_TYPE_NEGOTIATE:
 	case VMCI_TRANSPORT_PACKET_TYPE_NEGOTIATE2:
+		rcu_read_lock();
+		remote_info = vsock_core_get_remote_info(vsk);
+		if (!remote_info) {
+			skerr = EPROTO;
+			err = -EINVAL;
+			rcu_read_unlock();
+			goto destroy;
+		}
+
+		remote_addr = &remote_info->addr;
+
 		if (pkt->u.size == 0
-		    || pkt->dg.src.context != vsk->remote_addr.svm_cid
-		    || pkt->src_port != vsk->remote_addr.svm_port
+		    || pkt->dg.src.context != remote_addr->svm_cid
+		    || pkt->src_port != remote_addr->svm_port
 		    || !vmci_handle_is_invalid(vmci_trans(vsk)->qp_handle)
 		    || vmci_trans(vsk)->qpair
 		    || vmci_trans(vsk)->produce_size != 0
@@ -1316,9 +1347,10 @@ vmci_transport_recv_connecting_client(struct sock *sk,
 		    || vmci_trans(vsk)->detach_sub_id != VMCI_INVALID_ID) {
 			skerr = EPROTO;
 			err = -EINVAL;
-
+			rcu_read_unlock();
 			goto destroy;
 		}
+		rcu_read_unlock();
 
 		err = vmci_transport_recv_connecting_client_negotiate(sk, pkt);
 		if (err) {
@@ -1379,6 +1411,7 @@ static int vmci_transport_recv_connecting_client_negotiate(
 	int err;
 	struct vsock_sock *vsk;
 	struct vmci_handle handle;
+	unsigned int remote_cid;
 	struct vmci_qp *qpair;
 	u32 detach_sub_id;
 	bool is_local;
@@ -1449,19 +1482,23 @@ static int vmci_transport_recv_connecting_client_negotiate(
 
 	/* Make VMCI select the handle for us. */
 	handle = VMCI_INVALID_HANDLE;
-	is_local = vsk->remote_addr.svm_cid == vsk->local_addr.svm_cid;
+
+	err = vsock_remote_addr_cid(vsk, &remote_cid);
+	if (err < 0)
+		goto destroy;
+
+	is_local = remote_cid == vsk->local_addr.svm_cid;
 	flags = is_local ? VMCI_QPFLAG_LOCAL : 0;
 
 	err = vmci_transport_queue_pair_alloc(&qpair,
 					      &handle,
 					      pkt->u.size,
 					      pkt->u.size,
-					      vsk->remote_addr.svm_cid,
+					      remote_cid,
 					      flags,
 					      vmci_transport_is_trusted(
 						  vsk,
-						  vsk->
-						  remote_addr.svm_cid));
+						  remote_cid));
 	if (err < 0)
 		goto destroy;
 
@@ -1692,6 +1729,7 @@ static int vmci_transport_dgram_bind(struct vsock_sock *vsk,
 }
 
 static int vmci_transport_dgram_enqueue(
+	const struct vsock_transport *transport,
 	struct vsock_sock *vsk,
 	struct sockaddr_vm *remote_addr,
 	struct msghdr *msg,
@@ -2052,7 +2090,13 @@ static struct vsock_transport vmci_transport = {
 
 static bool vmci_check_transport(struct vsock_sock *vsk)
 {
-	return vsk->transport == &vmci_transport;
+	bool retval;
+
+	rcu_read_lock();
+	retval = vsock_core_get_transport(vsk) == &vmci_transport;
+	rcu_read_unlock();
+
+	return retval;
 }
 
 static void vmci_vsock_transport_cb(bool is_host)
diff --git a/net/vmw_vsock/vsock_bpf.c b/net/vmw_vsock/vsock_bpf.c
index a3c97546ab84..4d811c9cdf6e 100644
--- a/net/vmw_vsock/vsock_bpf.c
+++ b/net/vmw_vsock/vsock_bpf.c
@@ -148,6 +148,7 @@ static void vsock_bpf_check_needs_rebuild(struct proto *ops)
 
 int vsock_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
 {
+	const struct vsock_transport *transport;
 	struct vsock_sock *vsk;
 
 	if (restore) {
@@ -157,10 +158,15 @@ int vsock_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore
 	}
 
 	vsk = vsock_sk(sk);
-	if (!vsk->transport)
+
+	rcu_read_lock();
+	transport = vsock_core_get_transport(vsk);
+	rcu_read_unlock();
+
+	if (!transport)
 		return -ENODEV;
 
-	if (!vsk->transport->read_skb)
+	if (!transport->read_skb)
 		return -EOPNOTSUPP;
 
 	vsock_bpf_check_needs_rebuild(psock->sk_proto);

-- 
2.30.2

Re: [PATCH RFC net-next v3 7/8] vsock: Add lockless sendmsg() support

[Simon Horman]

On Wed, May 31, 2023 at 12:35:11AM +0000, Bobby Eshleman wrote:

...

Hi Bobby,

some more feedback from my side.

> Throughput metrics for single-threaded SOCK_DGRAM and
> single/multi-threaded SOCK_STREAM showed no statistically signficant

nit: s/signficant/significant/

> throughput changes (lowest p-value reaching 0.27), with the range of the
> mean difference ranging between -5% to +1%.
> 
> Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>

...

> @@ -120,8 +125,8 @@ struct vsock_transport {
>  
>  	/* DGRAM. */
>  	int (*dgram_bind)(struct vsock_sock *, struct sockaddr_vm *);
> -	int (*dgram_enqueue)(struct vsock_sock *, struct sockaddr_vm *,
> -			     struct msghdr *, size_t len);
> +	int (*dgram_enqueue)(const struct vsock_transport *, struct vsock_sock *,
> +			     struct sockaddr_vm *, struct msghdr *, size_t len);

Perhaps just a personal preference, but the arguments for these callbacks
could have names.

>  	bool (*dgram_allow)(u32 cid, u32 port);
>  	int (*dgram_get_cid)(struct sk_buff *skb, unsigned int *cid);
>  	int (*dgram_get_port)(struct sk_buff *skb, unsigned int *port);
> @@ -196,6 +201,17 @@ void vsock_core_unregister(const struct vsock_transport *t);
>  /* The transport may downcast this to access transport-specific functions */
>  const struct vsock_transport *vsock_core_get_transport(struct vsock_sock *vsk);
>  
> +static inline struct vsock_remote_info *
> +vsock_core_get_remote_info(struct vsock_sock *vsk)
> +{
> +

nit: no blank line here

> +	/* vsk->remote_info may be accessed if the rcu read lock is held OR the
> +	 * socket lock is held
> +	 */
> +	return rcu_dereference_check(vsk->remote_info,
> +				     lockdep_sock_is_held(sk_vsock(vsk)));
> +}
> +
>  /**** UTILS ****/
>  
>  /* vsock_table_lock must be held */

...

> @@ -300,17 +449,36 @@ static void vsock_insert_unbound(struct vsock_sock *vsk)
>  	spin_unlock_bh(&vsock_table_lock);
>  }
>  
> -void vsock_insert_connected(struct vsock_sock *vsk)
> +int vsock_insert_connected(struct vsock_sock *vsk)
>  {
> -	struct list_head *list = vsock_connected_sockets(
> -		&vsk->remote_addr, &vsk->local_addr);
> +	struct list_head *list;
> +	struct vsock_remote_info *remote_info;

nit: I know that this file doesn't follow the reverse xmas tree
     scheme - longest line to shortest - for local variable declarations.
     But as networking code I think it would be good towards towards
     that scheme as code is changed.

	struct vsock_remote_info *remote_info;
	struct list_head *list;

> +
> +	rcu_read_lock();
> +	remote_info = vsock_core_get_remote_info(vsk);
> +	if (!remote_info) {
> +		rcu_read_unlock();
> +		return -EINVAL;
> +	}
> +	list = vsock_connected_sockets(&remote_info->addr, &vsk->local_addr);
> +	rcu_read_unlock();
>  
>  	spin_lock_bh(&vsock_table_lock);
>  	__vsock_insert_connected(list, vsk);
>  	spin_unlock_bh(&vsock_table_lock);
> +
> +	return 0;
>  }

...

> @@ -1120,7 +1122,9 @@ virtio_transport_recv_connecting(struct sock *sk,
>  	case VIRTIO_VSOCK_OP_RESPONSE:
>  		sk->sk_state = TCP_ESTABLISHED;
>  		sk->sk_socket->state = SS_CONNECTED;
> -		vsock_insert_connected(vsk);
> +		err = vsock_insert_connected(vsk);
> +		if (err)
> +			goto destroy;

The destroy label uses skerr, but it is uninitialised here.

A W=1 or C=1 will probably tell you this.

>  		sk->sk_state_change(sk);
>  		break;
>  	case VIRTIO_VSOCK_OP_INVALID:

...

[PATCH RFC net-next v3 8/8] tests: add vsock dgram tests

[Bobby Eshleman]

From: Jiang Wang <jiang.wang@bytedance.com>

This patch adds tests for vsock datagram.

Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
Signed-off-by: Jiang Wang <jiang.wang@bytedance.com>
---
 tools/testing/vsock/util.c       | 105 +++++++++++++++++++++
 tools/testing/vsock/util.h       |   4 +
 tools/testing/vsock/vsock_test.c | 193 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 302 insertions(+)

diff --git a/tools/testing/vsock/util.c b/tools/testing/vsock/util.c
index 01b636d3039a..45e35da48b40 100644
--- a/tools/testing/vsock/util.c
+++ b/tools/testing/vsock/util.c
@@ -260,6 +260,57 @@ void send_byte(int fd, int expected_ret, int flags)
 	}
 }
 
+/* Transmit one byte and check the return value.
+ *
+ * expected_ret:
+ *  <0 Negative errno (for testing errors)
+ *   0 End-of-file
+ *   1 Success
+ */
+void sendto_byte(int fd, const struct sockaddr *dest_addr, int len, int expected_ret,
+		 int flags)
+{
+	const uint8_t byte = 'A';
+	ssize_t nwritten;
+
+	timeout_begin(TIMEOUT);
+	do {
+		nwritten = sendto(fd, &byte, sizeof(byte), flags, dest_addr,
+				  len);
+		timeout_check("write");
+	} while (nwritten < 0 && errno == EINTR);
+	timeout_end();
+
+	if (expected_ret < 0) {
+		if (nwritten != -1) {
+			fprintf(stderr, "bogus sendto(2) return value %zd\n",
+				nwritten);
+			exit(EXIT_FAILURE);
+		}
+		if (errno != -expected_ret) {
+			perror("write");
+			exit(EXIT_FAILURE);
+		}
+		return;
+	}
+
+	if (nwritten < 0) {
+		perror("write");
+		exit(EXIT_FAILURE);
+	}
+	if (nwritten == 0) {
+		if (expected_ret == 0)
+			return;
+
+		fprintf(stderr, "unexpected EOF while sending byte\n");
+		exit(EXIT_FAILURE);
+	}
+	if (nwritten != sizeof(byte)) {
+		fprintf(stderr, "bogus sendto(2) return value %zd\n", nwritten);
+		exit(EXIT_FAILURE);
+	}
+}
+
 /* Receive one byte and check the return value.
  *
  * expected_ret:
@@ -313,6 +364,60 @@ void recv_byte(int fd, int expected_ret, int flags)
 	}
 }
 
+/* Receive one byte and check the return value.
+ *
+ * expected_ret:
+ *  <0 Negative errno (for testing errors)
+ *   0 End-of-file
+ *   1 Success
+ */
+void recvfrom_byte(int fd, struct sockaddr *src_addr, socklen_t *addrlen,
+		   int expected_ret, int flags)
+{
+	uint8_t byte;
+	ssize_t nread;
+
+	timeout_begin(TIMEOUT);
+	do {
+		nread = recvfrom(fd, &byte, sizeof(byte), flags, src_addr, addrlen);
+		timeout_check("read");
+	} while (nread < 0 && errno == EINTR);
+	timeout_end();
+
+	if (expected_ret < 0) {
+		if (nread != -1) {
+			fprintf(stderr, "bogus recvfrom(2) return value %zd\n",
+				nread);
+			exit(EXIT_FAILURE);
+		}
+		if (errno != -expected_ret) {
+			perror("read");
+			exit(EXIT_FAILURE);
+		}
+		return;
+	}
+
+	if (nread < 0) {
+		perror("read");
+		exit(EXIT_FAILURE);
+	}
+	if (nread == 0) {
+		if (expected_ret == 0)
+			return;
+
+		fprintf(stderr, "unexpected EOF while receiving byte\n");
+		exit(EXIT_FAILURE);
+	}
+	if (nread != sizeof(byte)) {
+		fprintf(stderr, "bogus recvfrom(2) return value %zd\n", nread);
+		exit(EXIT_FAILURE);
+	}
+	if (byte != 'A') {
+		fprintf(stderr, "unexpected byte read %c\n", byte);
+		exit(EXIT_FAILURE);
+	}
+}
+
 /* Run test cases.  The program terminates if a failure occurs. */
 void run_tests(const struct test_case *test_cases,
 	       const struct test_opts *opts)
diff --git a/tools/testing/vsock/util.h b/tools/testing/vsock/util.h
index fb99208a95ea..6e5cd610bf05 100644
--- a/tools/testing/vsock/util.h
+++ b/tools/testing/vsock/util.h
@@ -43,7 +43,11 @@ int vsock_seqpacket_accept(unsigned int cid, unsigned int port,
 			   struct sockaddr_vm *clientaddrp);
 void vsock_wait_remote_close(int fd);
 void send_byte(int fd, int expected_ret, int flags);
+void sendto_byte(int fd, const struct sockaddr *dest_addr, int len, int expected_ret,
+		 int flags);
 void recv_byte(int fd, int expected_ret, int flags);
+void recvfrom_byte(int fd, struct sockaddr *src_addr, socklen_t *addrlen,
+		   int expected_ret, int flags);
 void run_tests(const struct test_case *test_cases,
 	       const struct test_opts *opts);
 void list_tests(const struct test_case *test_cases);
diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c
index ac1bd3ac1533..851c3d65178d 100644
--- a/tools/testing/vsock/vsock_test.c
+++ b/tools/testing/vsock/vsock_test.c
@@ -202,6 +202,113 @@ static void test_stream_server_close_server(const struct test_opts *opts)
 	close(fd);
 }
 
+static void test_dgram_sendto_client(const struct test_opts *opts)
+{
+	union {
+		struct sockaddr sa;
+		struct sockaddr_vm svm;
+	} addr = {
+		.svm = {
+			.svm_family = AF_VSOCK,
+			.svm_port = 1234,
+			.svm_cid = opts->peer_cid,
+		},
+	};
+	int fd;
+
+	/* Wait for the server to be ready */
+	control_expectln("BIND");
+
+	fd = socket(AF_VSOCK, SOCK_DGRAM, 0);
+	if (fd < 0) {
+		perror("socket");
+		exit(EXIT_FAILURE);
+	}
+
+	sendto_byte(fd, &addr.sa, sizeof(addr.svm), 1, 0);
+
+	/* Notify the server that the client has finished */
+	control_writeln("DONE");
+
+	close(fd);
+}
+
+static void test_dgram_sendto_server(const struct test_opts *opts)
+{
+	union {
+		struct sockaddr sa;
+		struct sockaddr_vm svm;
+	} addr = {
+		.svm = {
+			.svm_family = AF_VSOCK,
+			.svm_port = 1234,
+			.svm_cid = VMADDR_CID_ANY,
+		},
+	};
+	int fd;
+	int len = sizeof(addr.sa);
+
+	fd = socket(AF_VSOCK, SOCK_DGRAM, 0);
+
+	if (bind(fd, &addr.sa, sizeof(addr.svm)) < 0) {
+		perror("bind");
+		exit(EXIT_FAILURE);
+	}
+
+	/* Notify the client that the server is ready */
+	control_writeln("BIND");
+
+	recvfrom_byte(fd, &addr.sa, &len, 1, 0);
+
+	/* Wait for the client to finish */
+	control_expectln("DONE");
+
+	close(fd);
+}
+
+static void test_dgram_connect_client(const struct test_opts *opts)
+{
+	union {
+		struct sockaddr sa;
+		struct sockaddr_vm svm;
+	} addr = {
+		.svm = {
+			.svm_family = AF_VSOCK,
+			.svm_port = 1234,
+			.svm_cid = opts->peer_cid,
+		},
+	};
+	int fd;
+	int ret;
+
+	/* Wait for the server to be ready */
+	control_expectln("BIND");
+
+	fd = socket(AF_VSOCK, SOCK_DGRAM, 0);
+	if (fd < 0) {
+		perror("bind");
+		exit(EXIT_FAILURE);
+	}
+
+	ret = connect(fd, &addr.sa, sizeof(addr.svm));
+	if (ret < 0) {
+		perror("connect");
+		exit(EXIT_FAILURE);
+	}
+
+	send_byte(fd, 1, 0);
+
+	/* Notify the server that the client has finished */
+	control_writeln("DONE");
+
+	close(fd);
+}
+
+static void test_dgram_connect_server(const struct test_opts *opts)
+{
+	test_dgram_sendto_server(opts);
+}
+
 /* With the standard socket sizes, VMCI is able to support about 100
  * concurrent stream connections.
  */
@@ -255,6 +362,77 @@ static void test_stream_multiconn_server(const struct test_opts *opts)
 		close(fds[i]);
 }
 
+static void test_dgram_multiconn_client(const struct test_opts *opts)
+{
+	int fds[MULTICONN_NFDS];
+	int i;
+	union {
+		struct sockaddr sa;
+		struct sockaddr_vm svm;
+	} addr = {
+		.svm = {
+			.svm_family = AF_VSOCK,
+			.svm_port = 1234,
+			.svm_cid = opts->peer_cid,
+		},
+	};
+
+	/* Wait for the server to be ready */
+	control_expectln("BIND");
+
+	for (i = 0; i < MULTICONN_NFDS; i++) {
+		fds[i] = socket(AF_VSOCK, SOCK_DGRAM, 0);
+		if (fds[i] < 0) {
+			perror("socket");
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	for (i = 0; i < MULTICONN_NFDS; i++)
+		sendto_byte(fds[i], &addr.sa, sizeof(addr.svm), 1, 0);
+
+	/* Notify the server that the client has finished */
+	control_writeln("DONE");
+
+	for (i = 0; i < MULTICONN_NFDS; i++)
+		close(fds[i]);
+}
+
+static void test_dgram_multiconn_server(const struct test_opts *opts)
+{
+	union {
+		struct sockaddr sa;
+		struct sockaddr_vm svm;
+	} addr = {
+		.svm = {
+			.svm_family = AF_VSOCK,
+			.svm_port = 1234,
+			.svm_cid = VMADDR_CID_ANY,
+		},
+	};
+	int fd;
+	int len = sizeof(addr.sa);
+	int i;
+
+	fd = socket(AF_VSOCK, SOCK_DGRAM, 0);
+
+	if (bind(fd, &addr.sa, sizeof(addr.svm)) < 0) {
+		perror("bind");
+		exit(EXIT_FAILURE);
+	}
+
+	/* Notify the client that the server is ready */
+	control_writeln("BIND");
+
+	for (i = 0; i < MULTICONN_NFDS; i++)
+		recvfrom_byte(fd, &addr.sa, &len, 1, 0);
+
+	/* Wait for the client to finish */
+	control_expectln("DONE");
+
+	close(fd);
+}
+
 static void test_stream_msg_peek_client(const struct test_opts *opts)
 {
 	int fd;
@@ -1128,6 +1306,21 @@ static struct test_case test_cases[] = {
 		.run_client = test_stream_virtio_skb_merge_client,
 		.run_server = test_stream_virtio_skb_merge_server,
 	},
+	{
+		.name = "SOCK_DGRAM client close",
+		.run_client = test_dgram_sendto_client,
+		.run_server = test_dgram_sendto_server,
+	},
+	{
+		.name = "SOCK_DGRAM client connect",
+		.run_client = test_dgram_connect_client,
+		.run_server = test_dgram_connect_server,
+	},
+	{
+		.name = "SOCK_DGRAM multiple connections",
+		.run_client = test_dgram_multiconn_client,
+		.run_server = test_dgram_multiconn_server,
+	},
 	{},
 };
 

-- 
2.30.2

Re: [PATCH RFC net-next v3 0/8] virtio/vsock: support datagrams

[Arseniy Krasnov]

Hello Bobby!

Thanks for this patchset, really interesting!

I applied it on head:

https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=d20dd0ea14072e8a90ff864b2c1603bd68920b4b

And tried to run ./vsock_test (client in the guest, server in the host), I had the following crash:

Control socket connected to 192.168.1.1:12345.                          
0 - SOCK_STREAM connection reset...                                     
[    8.050215] BUG: kernel NULL pointer derefer                         
[    8.050960] #PF: supervisor read access in kernel mode               
[    8.050960] #PF: error_code(0x0000) - not-present page               
[    8.050960] PGD 0 P4D 0                                              
[    8.050960] Oops: 0000 [#1] PREEMPT SMP PTI                          
[    8.050960] CPU: 0 PID: 109 Comm: vsock_test Not tainted 6.4.0-rc3-gd707c220a700
[    8.050960] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14
[    8.050960] RIP: 0010:static_key_count+0x0/0x20                      
[    8.050960] Code: 04 4c 8b 46 08 49 29 c0 4c 01 c8 4c 89 47 08 89 0e 89 56 04 4f
[    8.050960] RSP: 0018:ffffa9a1c021bdc0 EFLAGS: 00010202              
[    8.050960] RAX: ffffffffac309880 RBX: ffffffffc02fc140 RCX: 0000000000000000
[    8.050960] RDX: ffff9a5eff944600 RSI: 0000000000000000 RDI: 0000000000000000
[    8.050960] RBP: ffff9a5ec2371900 R08: ffffa9a1c021bd30 R09: ffff9a5eff98e0c0
[    8.050960] R10: 0000000000001000 R11: 0000000000000000 R12: ffffa9a1c021be80
[    8.050960] R13: 0000000000000000 R14: 0000000000000002 R15: ffff9a5ec1cfca80
[    8.050960] FS:  00007fa9bf88c5c0(0000) GS:ffff9a5efe400000(0000) knlGS:00000000
[    8.050960] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033        
[    8.050960] CR2: 0000000000000000 CR3: 00000000023e0000 CR4: 00000000000006f0
[    8.050960] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[    8.050960] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[    8.050960] Call Trace:                                              
[    8.050960]  <TASK>                                                  
[    8.050960]  once_deferred+0xd/0x30                                  
[    8.050960]  vsock_assign_transport+0xa2/0x1b0 [vsock]               
[    8.050960]  vsock_connect+0xb4/0x3a0 [vsock]                        
[    8.050960]  ? var_wake_function+0x60/0x60                           
[    8.050960]  __sys_connect+0x9e/0xd0                                 
[    8.050960]  ? _raw_spin_unlock_irq+0xe/0x30                         
[    8.050960]  ? do_setitimer+0x128/0x1f0                              
[    8.050960]  ? alarm_setitimer+0x4c/0x90                             
[    8.050960]  ? fpregs_assert_state_consistent+0x1d/0x50              
[    8.050960]  ? exit_to_user_mode_prepare+0x36/0x130                  
[    8.050960]  __x64_sys_connect+0x11/0x20                             
[    8.050960]  do_syscall_64+0x3b/0xc0                                 
[    8.050960]  entry_SYSCALL_64_after_hwframe+0x4b/0xb5                
[    8.050960] RIP: 0033:0x7fa9bf7c4d13                                 
[    8.050960] Code: 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 48
[    8.050960] RSP: 002b:00007ffdf2d96cc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000a
[    8.050960] RAX: ffffffffffffffda RBX: 0000560c305d0020 RCX: 00007fa9bf7c4d13
[    8.050960] RDX: 0000000000000010 RSI: 00007ffdf2d96ce0 RDI: 0000000000000004
[    8.050960] RBP: 0000000000000004 R08: 0000560c317dc018 R09: 0000000000000000
[    8.050960] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
[    8.050960] R13: 0000560c305ccc2d R14: 00007ffdf2d96ce0 R15: 00007ffdf2d96d70
[    8.050960]  </TASK>  


I guess crash is somewhere near:

old_info->transport->release(vsk); in vsock_assign_transport(). May be my config is wrong...

Thanks, Arseniy

Re: [PATCH RFC net-next v3 0/8] virtio/vsock: support datagrams

[Bobby Eshleman]

On Mon, Jun 05, 2023 at 11:42:06PM +0300, Arseniy Krasnov wrote:
> Hello Bobby!
> 
> Thanks for this patchset, really interesting!
> 
> I applied it on head:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=d20dd0ea14072e8a90ff864b2c1603bd68920b4b
> 
> And tried to run ./vsock_test (client in the guest, server in the host), I had the following crash:
> 
> Control socket connected to 192.168.1.1:12345.                          
> 0 - SOCK_STREAM connection reset...                                     
> [    8.050215] BUG: kernel NULL pointer derefer                         
> [    8.050960] #PF: supervisor read access in kernel mode               
> [    8.050960] #PF: error_code(0x0000) - not-present page               
> [    8.050960] PGD 0 P4D 0                                              
> [    8.050960] Oops: 0000 [#1] PREEMPT SMP PTI                          
> [    8.050960] CPU: 0 PID: 109 Comm: vsock_test Not tainted 6.4.0-rc3-gd707c220a700
> [    8.050960] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14
> [    8.050960] RIP: 0010:static_key_count+0x0/0x20                      
> [    8.050960] Code: 04 4c 8b 46 08 49 29 c0 4c 01 c8 4c 89 47 08 89 0e 89 56 04 4f
> [    8.050960] RSP: 0018:ffffa9a1c021bdc0 EFLAGS: 00010202              
> [    8.050960] RAX: ffffffffac309880 RBX: ffffffffc02fc140 RCX: 0000000000000000
> [    8.050960] RDX: ffff9a5eff944600 RSI: 0000000000000000 RDI: 0000000000000000
> [    8.050960] RBP: ffff9a5ec2371900 R08: ffffa9a1c021bd30 R09: ffff9a5eff98e0c0
> [    8.050960] R10: 0000000000001000 R11: 0000000000000000 R12: ffffa9a1c021be80
> [    8.050960] R13: 0000000000000000 R14: 0000000000000002 R15: ffff9a5ec1cfca80
> [    8.050960] FS:  00007fa9bf88c5c0(0000) GS:ffff9a5efe400000(0000) knlGS:00000000
> [    8.050960] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033        
> [    8.050960] CR2: 0000000000000000 CR3: 00000000023e0000 CR4: 00000000000006f0
> [    8.050960] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [    8.050960] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [    8.050960] Call Trace:                                              
> [    8.050960]  <TASK>                                                  
> [    8.050960]  once_deferred+0xd/0x30                                  
> [    8.050960]  vsock_assign_transport+0xa2/0x1b0 [vsock]               
> [    8.050960]  vsock_connect+0xb4/0x3a0 [vsock]                        
> [    8.050960]  ? var_wake_function+0x60/0x60                           
> [    8.050960]  __sys_connect+0x9e/0xd0                                 
> [    8.050960]  ? _raw_spin_unlock_irq+0xe/0x30                         
> [    8.050960]  ? do_setitimer+0x128/0x1f0                              
> [    8.050960]  ? alarm_setitimer+0x4c/0x90                             
> [    8.050960]  ? fpregs_assert_state_consistent+0x1d/0x50              
> [    8.050960]  ? exit_to_user_mode_prepare+0x36/0x130                  
> [    8.050960]  __x64_sys_connect+0x11/0x20                             
> [    8.050960]  do_syscall_64+0x3b/0xc0                                 
> [    8.050960]  entry_SYSCALL_64_after_hwframe+0x4b/0xb5                
> [    8.050960] RIP: 0033:0x7fa9bf7c4d13                                 
> [    8.050960] Code: 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 48
> [    8.050960] RSP: 002b:00007ffdf2d96cc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000a
> [    8.050960] RAX: ffffffffffffffda RBX: 0000560c305d0020 RCX: 00007fa9bf7c4d13
> [    8.050960] RDX: 0000000000000010 RSI: 00007ffdf2d96ce0 RDI: 0000000000000004
> [    8.050960] RBP: 0000000000000004 R08: 0000560c317dc018 R09: 0000000000000000
> [    8.050960] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> [    8.050960] R13: 0000560c305ccc2d R14: 00007ffdf2d96ce0 R15: 00007ffdf2d96d70
> [    8.050960]  </TASK>  
> 
> 
> I guess crash is somewhere near:
> 
> old_info->transport->release(vsk); in vsock_assign_transport(). May be my config is wrong...
> 
> Thanks, Arseniy

Thanks Arseniy!

I now see I broke the tests, but did't break the stream/dgram socket
utility I was using in development.

I'll track this down and include a fix in the next rev.

I should have warned this v3 is pretty under-tested. Being unsure if
some of the design choices would be accepted at all, I didn't want to
waste too much time until things were accepted at a high level.

Best,
Bobby

Re: [PATCH RFC net-next v3 0/8] virtio/vsock: support datagrams

[Arseniy Krasnov]

On 01.06.2023 00:10, Bobby Eshleman wrote:
> On Mon, Jun 05, 2023 at 11:42:06PM +0300, Arseniy Krasnov wrote:
>> Hello Bobby!
>>
>> Thanks for this patchset, really interesting!
>>
>> I applied it on head:
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=d20dd0ea14072e8a90ff864b2c1603bd68920b4b
>>
>> And tried to run ./vsock_test (client in the guest, server in the host), I had the following crash:
>>
>> Control socket connected to 192.168.1.1:12345.                          
>> 0 - SOCK_STREAM connection reset...                                     
>> [    8.050215] BUG: kernel NULL pointer derefer                         
>> [    8.050960] #PF: supervisor read access in kernel mode               
>> [    8.050960] #PF: error_code(0x0000) - not-present page               
>> [    8.050960] PGD 0 P4D 0                                              
>> [    8.050960] Oops: 0000 [#1] PREEMPT SMP PTI                          
>> [    8.050960] CPU: 0 PID: 109 Comm: vsock_test Not tainted 6.4.0-rc3-gd707c220a700
>> [    8.050960] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14
>> [    8.050960] RIP: 0010:static_key_count+0x0/0x20                      
>> [    8.050960] Code: 04 4c 8b 46 08 49 29 c0 4c 01 c8 4c 89 47 08 89 0e 89 56 04 4f
>> [    8.050960] RSP: 0018:ffffa9a1c021bdc0 EFLAGS: 00010202              
>> [    8.050960] RAX: ffffffffac309880 RBX: ffffffffc02fc140 RCX: 0000000000000000
>> [    8.050960] RDX: ffff9a5eff944600 RSI: 0000000000000000 RDI: 0000000000000000
>> [    8.050960] RBP: ffff9a5ec2371900 R08: ffffa9a1c021bd30 R09: ffff9a5eff98e0c0
>> [    8.050960] R10: 0000000000001000 R11: 0000000000000000 R12: ffffa9a1c021be80
>> [    8.050960] R13: 0000000000000000 R14: 0000000000000002 R15: ffff9a5ec1cfca80
>> [    8.050960] FS:  00007fa9bf88c5c0(0000) GS:ffff9a5efe400000(0000) knlGS:00000000
>> [    8.050960] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033        
>> [    8.050960] CR2: 0000000000000000 CR3: 00000000023e0000 CR4: 00000000000006f0
>> [    8.050960] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> [    8.050960] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> [    8.050960] Call Trace:                                              
>> [    8.050960]  <TASK>                                                  
>> [    8.050960]  once_deferred+0xd/0x30                                  
>> [    8.050960]  vsock_assign_transport+0xa2/0x1b0 [vsock]               
>> [    8.050960]  vsock_connect+0xb4/0x3a0 [vsock]                        
>> [    8.050960]  ? var_wake_function+0x60/0x60                           
>> [    8.050960]  __sys_connect+0x9e/0xd0                                 
>> [    8.050960]  ? _raw_spin_unlock_irq+0xe/0x30                         
>> [    8.050960]  ? do_setitimer+0x128/0x1f0                              
>> [    8.050960]  ? alarm_setitimer+0x4c/0x90                             
>> [    8.050960]  ? fpregs_assert_state_consistent+0x1d/0x50              
>> [    8.050960]  ? exit_to_user_mode_prepare+0x36/0x130                  
>> [    8.050960]  __x64_sys_connect+0x11/0x20                             
>> [    8.050960]  do_syscall_64+0x3b/0xc0                                 
>> [    8.050960]  entry_SYSCALL_64_after_hwframe+0x4b/0xb5                
>> [    8.050960] RIP: 0033:0x7fa9bf7c4d13                                 
>> [    8.050960] Code: 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 48
>> [    8.050960] RSP: 002b:00007ffdf2d96cc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000a
>> [    8.050960] RAX: ffffffffffffffda RBX: 0000560c305d0020 RCX: 00007fa9bf7c4d13
>> [    8.050960] RDX: 0000000000000010 RSI: 00007ffdf2d96ce0 RDI: 0000000000000004
>> [    8.050960] RBP: 0000000000000004 R08: 0000560c317dc018 R09: 0000000000000000
>> [    8.050960] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
>> [    8.050960] R13: 0000560c305ccc2d R14: 00007ffdf2d96ce0 R15: 00007ffdf2d96d70
>> [    8.050960]  </TASK>  
>>
>>
>> I guess crash is somewhere near:
>>
>> old_info->transport->release(vsk); in vsock_assign_transport(). May be my config is wrong...
>>
>> Thanks, Arseniy
> 
> Thanks Arseniy!
> 
> I now see I broke the tests, but did't break the stream/dgram socket
> utility I was using in development.
> 
> I'll track this down and include a fix in the next rev.

Great! Thanks!

Thanks, Arseniy

> 
> I should have warned this v3 is pretty under-tested. Being unsure if
> some of the design choices would be accepted at all, I didn't want to
> waste too much time until things were accepted at a high level.
> 
> Best,
> Bobby