Merge branch 'vsock-add-multi-transports-support'

Stefano Garzarella says:

====================
vsock: add multi-transports support

Most of the patches are reviewed by Dexuan, Stefan, and Jorgen.
The following patches need reviews:
- [11/15] vsock: add multi-transports support
- [12/15] vsock/vmci: register vmci_transport only when VMCI guest/host
          are active
- [15/15] vhost/vsock: refuse CID assigned to the guest->host transport

RFC: https://patchwork.ozlabs.org/cover/1168442/
v1: https://patchwork.ozlabs.org/cover/1181986/

v1 -> v2:
- Patch 11:
    + vmci_transport: sent reset when vsock_assign_transport() fails
      [Jorgen]
    + fixed loopback in the guests, checking if the remote_addr is the
      same of transport_g2h->get_local_cid()
    + virtio_transport_common: updated space available while creating
      the new child socket during a connection request
- Patch 12:
    + removed 'features' variable in vmci_transport_init() [Stefan]
    + added a flag to register only once the host [Jorgen]
- Added patch 15 to refuse CID assigned to the guest->host transport in
  the vhost_transport

This series adds the multi-transports support to vsock, following
this proposal: https://www.spinics.net/lists/netdev/msg575792.html

With the multi-transports support, we can use VSOCK with nested VMs
(using also different hypervisors) loading both guest->host and
host->guest transports at the same time.
Before this series, vmci_transport supported this behavior but only
using VMware hypervisor on L0, L1, etc.

The first 9 patches are cleanups and preparations, maybe some of
these can go regardless of this series.

Patch 10 changes the hvs_remote_addr_init(). setting the
VMADDR_CID_HOST as remote CID instead of VMADDR_CID_ANY to make
the choice of transport to be used work properly.

Patch 11 adds multi-transports support.

Patch 12 changes a little bit the vmci_transport and the vmci driver
to register the vmci_transport only when there are active host/guest.

Patch 13 prevents the transport modules unloading while sockets are
assigned to them.

Patch 14 fixes an issue in the bind() logic discoverable only with
the new multi-transport support.

Patch 15 refuses CID assigned to the guest->host transport in the
vhost_transport.

I've tested this series with nested KVM (vsock-transport [L0,L1],
virtio-transport[L1,L2]) and with VMware (L0) + KVM (L1)
(vmci-transport [L0,L1], vhost-transport [L1], virtio-transport[L2]).

Dexuan successfully tested the RFC series on HyperV with a Linux guest.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/misc/vmw_vmci/vmci_driver.c

@@ -28,6 +28,10 @@ MODULE_PARM_DESC(disable_guest,
 static bool vmci_guest_personality_initialized;
 static bool vmci_host_personality_initialized;
 
+static DEFINE_MUTEX(vmci_vsock_mutex); /* protects vmci_vsock_transport_cb */
+static vmci_vsock_cb vmci_vsock_transport_cb;
+bool vmci_vsock_cb_host_called;
+
 /*
  * vmci_get_context_id() - Gets the current context ID.
  *
@@ -45,6 +49,69 @@ u32 vmci_get_context_id(void)
 }
 EXPORT_SYMBOL_GPL(vmci_get_context_id);
 
+/*
+ * vmci_register_vsock_callback() - Register the VSOCK vmci_transport callback.
+ *
+ * The callback will be called when the first host or guest becomes active,
+ * or if they are already active when this function is called.
+ * To unregister the callback, call this function with NULL parameter.
+ *
+ * Returns 0 on success. -EBUSY if a callback is already registered.
+ */
+int vmci_register_vsock_callback(vmci_vsock_cb callback)
+{
+	int err = 0;
+
+	mutex_lock(&vmci_vsock_mutex);
+
+	if (vmci_vsock_transport_cb && callback) {
+		err = -EBUSY;
+		goto out;
+	}
+
+	vmci_vsock_transport_cb = callback;
+
+	if (!vmci_vsock_transport_cb) {
+		vmci_vsock_cb_host_called = false;
+		goto out;
+	}
+
+	if (vmci_guest_code_active())
+		vmci_vsock_transport_cb(false);
+
+	if (vmci_host_users() > 0) {
+		vmci_vsock_cb_host_called = true;
+		vmci_vsock_transport_cb(true);
+	}
+
+out:
+	mutex_unlock(&vmci_vsock_mutex);
+	return err;
+}
+EXPORT_SYMBOL_GPL(vmci_register_vsock_callback);
+
+void vmci_call_vsock_callback(bool is_host)
+{
+	mutex_lock(&vmci_vsock_mutex);
+
+	if (!vmci_vsock_transport_cb)
+		goto out;
+
+	/* In the host, this function could be called multiple times,
+	 * but we want to register it only once.
+	 */
+	if (is_host) {
+		if (vmci_vsock_cb_host_called)
+			goto out;
+
+		vmci_vsock_cb_host_called = true;
+	}
+
+	vmci_vsock_transport_cb(is_host);
+out:
+	mutex_unlock(&vmci_vsock_mutex);
+}
+
 static int __init vmci_drv_init(void)
 {
 	int vmci_err;

drivers/misc/vmw_vmci/vmci_driver.h

@@ -36,10 +36,12 @@ extern struct pci_dev *vmci_pdev;
 
 u32 vmci_get_context_id(void);
 int vmci_send_datagram(struct vmci_datagram *dg);
+void vmci_call_vsock_callback(bool is_host);
 
 int vmci_host_init(void);
 void vmci_host_exit(void);
 bool vmci_host_code_active(void);
+int vmci_host_users(void);
 
 int vmci_guest_init(void);
 void vmci_guest_exit(void);

drivers/misc/vmw_vmci/vmci_guest.c

@@ -637,6 +637,8 @@ static int vmci_guest_probe_device(struct pci_dev *pdev,
 		  vmci_dev->iobase + VMCI_CONTROL_ADDR);
 
 	pci_set_drvdata(pdev, vmci_dev);
+
+	vmci_call_vsock_callback(false);
 	return 0;
 
 err_free_irq:

drivers/misc/vmw_vmci/vmci_host.c

@@ -108,6 +108,11 @@ bool vmci_host_code_active(void)
 	     atomic_read(&vmci_host_active_users) > 0);
 }
 
+int vmci_host_users(void)
+{
+	return atomic_read(&vmci_host_active_users);
+}
+
 /*
  * Called on open of /dev/vmci.
  */
@@ -338,6 +343,8 @@ static int vmci_host_do_init_context(struct vmci_host_dev *vmci_host_dev,
 	vmci_host_dev->ct_type = VMCIOBJ_CONTEXT;
 	atomic_inc(&vmci_host_active_users);
 
+	vmci_call_vsock_callback(true);
+
 	retval = 0;
 
 out:

drivers/vhost/vsock.c

@@ -384,6 +384,49 @@ static bool vhost_vsock_more_replies(struct vhost_vsock *vsock)
 	return val < vq->num;
 }
 
+static struct virtio_transport vhost_transport = {
+	.transport = {
+		.module                   = THIS_MODULE,
+
+		.get_local_cid            = vhost_transport_get_local_cid,
+
+		.init                     = virtio_transport_do_socket_init,
+		.destruct                 = virtio_transport_destruct,
+		.release                  = virtio_transport_release,
+		.connect                  = virtio_transport_connect,
+		.shutdown                 = virtio_transport_shutdown,
+		.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,
+
+		.stream_enqueue           = virtio_transport_stream_enqueue,
+		.stream_dequeue           = virtio_transport_stream_dequeue,
+		.stream_has_data          = virtio_transport_stream_has_data,
+		.stream_has_space         = virtio_transport_stream_has_space,
+		.stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
+		.stream_is_active         = virtio_transport_stream_is_active,
+		.stream_allow             = virtio_transport_stream_allow,
+
+		.notify_poll_in           = virtio_transport_notify_poll_in,
+		.notify_poll_out          = virtio_transport_notify_poll_out,
+		.notify_recv_init         = virtio_transport_notify_recv_init,
+		.notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
+		.notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
+		.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
+		.notify_send_init         = virtio_transport_notify_send_init,
+		.notify_send_pre_block    = virtio_transport_notify_send_pre_block,
+		.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
+		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
+		.notify_buffer_size       = virtio_transport_notify_buffer_size,
+
+	},
+
+	.send_pkt = vhost_transport_send_pkt,
+};
+
 static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
 {
 	struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
@@ -438,7 +481,7 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
 
 		/* Only accept correctly addressed packets */
 		if (le64_to_cpu(pkt->hdr.src_cid) == vsock->guest_cid)
-			virtio_transport_recv_pkt(pkt);
+			virtio_transport_recv_pkt(&vhost_transport, pkt);
 		else
 			virtio_transport_free_pkt(pkt);
 
@@ -675,6 +718,12 @@ static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u64 guest_cid)
 	if (guest_cid > U32_MAX)
 		return -EINVAL;
 
+	/* Refuse if CID is assigned to the guest->host transport (i.e. nested
+	 * VM), to make the loopback work.
+	 */
+	if (vsock_find_cid(guest_cid))
+		return -EADDRINUSE;
+
 	/* Refuse if CID is already in use */
 	mutex_lock(&vhost_vsock_mutex);
 	other = vhost_vsock_get(guest_cid);
@@ -786,57 +835,12 @@ static struct miscdevice vhost_vsock_misc = {
 	.fops = &vhost_vsock_fops,
 };
 
-static struct virtio_transport vhost_transport = {
-	.transport = {
-		.get_local_cid            = vhost_transport_get_local_cid,
-
-		.init                     = virtio_transport_do_socket_init,
-		.destruct                 = virtio_transport_destruct,
-		.release                  = virtio_transport_release,
-		.connect                  = virtio_transport_connect,
-		.shutdown                 = virtio_transport_shutdown,
-		.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,
-
-		.stream_enqueue           = virtio_transport_stream_enqueue,
-		.stream_dequeue           = virtio_transport_stream_dequeue,
-		.stream_has_data          = virtio_transport_stream_has_data,
-		.stream_has_space         = virtio_transport_stream_has_space,
-		.stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
-		.stream_is_active         = virtio_transport_stream_is_active,
-		.stream_allow             = virtio_transport_stream_allow,
-
-		.notify_poll_in           = virtio_transport_notify_poll_in,
-		.notify_poll_out          = virtio_transport_notify_poll_out,
-		.notify_recv_init         = virtio_transport_notify_recv_init,
-		.notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
-		.notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
-		.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
-		.notify_send_init         = virtio_transport_notify_send_init,
-		.notify_send_pre_block    = virtio_transport_notify_send_pre_block,
-		.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
-		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
-
-		.set_buffer_size          = virtio_transport_set_buffer_size,
-		.set_min_buffer_size      = virtio_transport_set_min_buffer_size,
-		.set_max_buffer_size      = virtio_transport_set_max_buffer_size,
-		.get_buffer_size          = virtio_transport_get_buffer_size,
-		.get_min_buffer_size      = virtio_transport_get_min_buffer_size,
-		.get_max_buffer_size      = virtio_transport_get_max_buffer_size,
-	},
-
-	.send_pkt = vhost_transport_send_pkt,
-};
-
 static int __init vhost_vsock_init(void)
 {
 	int ret;
 
-	ret = vsock_core_init(&vhost_transport.transport);
+	ret = vsock_core_register(&vhost_transport.transport,
+				  VSOCK_TRANSPORT_F_H2G);
 	if (ret < 0)
 		return ret;
 	return misc_register(&vhost_vsock_misc);
@@ -845,7 +849,7 @@ static int __init vhost_vsock_init(void)
 static void __exit vhost_vsock_exit(void)
 {
 	misc_deregister(&vhost_vsock_misc);
-	vsock_core_exit();
+	vsock_core_unregister(&vhost_transport.transport);
 };
 
 module_init(vhost_vsock_init);

include/linux/virtio_vsock.h

@@ -7,9 +7,6 @@
 #include <net/sock.h>
 #include <net/af_vsock.h>
 
-#define VIRTIO_VSOCK_DEFAULT_MIN_BUF_SIZE	128
-#define VIRTIO_VSOCK_DEFAULT_BUF_SIZE		(1024 * 256)
-#define VIRTIO_VSOCK_DEFAULT_MAX_BUF_SIZE	(1024 * 256)
 #define VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE	(1024 * 4)
 #define VIRTIO_VSOCK_MAX_BUF_SIZE		0xFFFFFFFFUL
 #define VIRTIO_VSOCK_MAX_PKT_BUF_SIZE		(1024 * 64)
@@ -25,11 +22,6 @@ enum {
 struct virtio_vsock_sock {
 	struct vsock_sock *vsk;
 
-	/* Protected by lock_sock(sk_vsock(trans->vsk)) */
-	u32 buf_size;
-	u32 buf_size_min;
-	u32 buf_size_max;
-
 	spinlock_t tx_lock;
 	spinlock_t rx_lock;
 
@@ -92,12 +84,6 @@ s64 virtio_transport_stream_has_space(struct vsock_sock *vsk);
 
 int virtio_transport_do_socket_init(struct vsock_sock *vsk,
 				 struct vsock_sock *psk);
-u64 virtio_transport_get_buffer_size(struct vsock_sock *vsk);
-u64 virtio_transport_get_min_buffer_size(struct vsock_sock *vsk);
-u64 virtio_transport_get_max_buffer_size(struct vsock_sock *vsk);
-void virtio_transport_set_buffer_size(struct vsock_sock *vsk, u64 val);
-void virtio_transport_set_min_buffer_size(struct vsock_sock *vsk, u64 val);
-void virtio_transport_set_max_buffer_size(struct vsock_sock *vs, u64 val);
 int
 virtio_transport_notify_poll_in(struct vsock_sock *vsk,
 				size_t target,
@@ -124,6 +110,7 @@ int virtio_transport_notify_send_pre_enqueue(struct vsock_sock *vsk,
 	struct vsock_transport_send_notify_data *data);
 int virtio_transport_notify_send_post_enqueue(struct vsock_sock *vsk,
 	ssize_t written, struct vsock_transport_send_notify_data *data);
+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);
@@ -150,7 +137,8 @@ virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
 
 void virtio_transport_destruct(struct vsock_sock *vsk);
 
-void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt);
+void virtio_transport_recv_pkt(struct virtio_transport *t,
+			       struct virtio_vsock_pkt *pkt);
 void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt);
 void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct virtio_vsock_pkt *pkt);
 u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 wanted);

include/linux/vm_sockets.h

-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * VMware vSockets Driver
- *
- * Copyright (C) 2007-2013 VMware, Inc. All rights reserved.
- */
-
-#ifndef _VM_SOCKETS_H
-#define _VM_SOCKETS_H
-
-#include <uapi/linux/vm_sockets.h>
-
-int vm_sockets_get_local_cid(void);
-
-#endif /* _VM_SOCKETS_H */

include/linux/vmw_vmci_api.h

@@ -19,6 +19,7 @@
 struct msghdr;
 typedef void (vmci_device_shutdown_fn) (void *device_registration,
 					void *user_data);
+typedef void (*vmci_vsock_cb) (bool is_host);
 
 int vmci_datagram_create_handle(u32 resource_id, u32 flags,
 				vmci_datagram_recv_cb recv_cb,
@@ -37,6 +38,7 @@ int vmci_doorbell_destroy(struct vmci_handle handle);
 int vmci_doorbell_notify(struct vmci_handle handle, u32 priv_flags);
 u32 vmci_get_context_id(void);
 bool vmci_is_context_owner(u32 context_id, kuid_t uid);
+int vmci_register_vsock_callback(vmci_vsock_cb callback);
 
 int vmci_event_subscribe(u32 event,
 			 vmci_event_cb callback, void *callback_data,

include/net/af_vsock.h

@@ -10,7 +10,7 @@
 
 #include <linux/kernel.h>
 #include <linux/workqueue.h>
-#include <linux/vm_sockets.h>
+#include <uapi/linux/vm_sockets.h>
 
 #include "vsock_addr.h"
 
@@ -27,6 +27,7 @@ extern spinlock_t vsock_table_lock;
 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;
 	/* Links for the global tables of bound and connected sockets. */
@@ -64,16 +65,18 @@ struct vsock_sock {
 	bool sent_request;
 	bool ignore_connecting_rst;
 
+	/* Protected by lock_sock(sk) */
+	u64 buffer_size;
+	u64 buffer_min_size;
+	u64 buffer_max_size;
+
 	/* Private to transport. */
 	void *trans;
 };
 
 s64 vsock_stream_has_data(struct vsock_sock *vsk);
 s64 vsock_stream_has_space(struct vsock_sock *vsk);
-struct sock *__vsock_create(struct net *net,
-			    struct socket *sock,
-			    struct sock *parent,
-			    gfp_t priority, unsigned short type, int kern);
+struct sock *vsock_create_connected(struct sock *parent);
 
 /**** TRANSPORT ****/
 
@@ -88,7 +91,17 @@ struct vsock_transport_send_notify_data {
 	u64 data2; /* Transport-defined. */
 };
 
+/* Transport features flags */
+/* Transport provides host->guest communication */
+#define VSOCK_TRANSPORT_F_H2G		0x00000001
+/* Transport provides guest->host communication */
+#define VSOCK_TRANSPORT_F_G2H		0x00000002
+/* Transport provides DGRAM communication */
+#define VSOCK_TRANSPORT_F_DGRAM		0x00000004
+
 struct vsock_transport {
+	struct module *module;
+
 	/* Initialize/tear-down socket. */
 	int (*init)(struct vsock_sock *, struct vsock_sock *);
 	void (*destruct)(struct vsock_sock *);
@@ -139,33 +152,23 @@ struct vsock_transport {
 		struct vsock_transport_send_notify_data *);
 	int (*notify_send_post_enqueue)(struct vsock_sock *, ssize_t,
 		struct vsock_transport_send_notify_data *);
+	/* sk_lock held by the caller */
+	void (*notify_buffer_size)(struct vsock_sock *, u64 *);
 
 	/* Shutdown. */
 	int (*shutdown)(struct vsock_sock *, int);
 
-	/* Buffer sizes. */
-	void (*set_buffer_size)(struct vsock_sock *, u64);
-	void (*set_min_buffer_size)(struct vsock_sock *, u64);
-	void (*set_max_buffer_size)(struct vsock_sock *, u64);
-	u64 (*get_buffer_size)(struct vsock_sock *);
-	u64 (*get_min_buffer_size)(struct vsock_sock *);
-	u64 (*get_max_buffer_size)(struct vsock_sock *);
-
 	/* Addressing. */
 	u32 (*get_local_cid)(void);
 };
 
 /**** CORE ****/
 
-int __vsock_core_init(const struct vsock_transport *t, struct module *owner);
-static inline int vsock_core_init(const struct vsock_transport *t)
-{
-	return __vsock_core_init(t, THIS_MODULE);
-}
-void vsock_core_exit(void);
+int vsock_core_register(const struct vsock_transport *t, int features);
+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(void);
+const struct vsock_transport *vsock_core_get_transport(struct vsock_sock *vsk);
 
 /**** UTILS ****/
 
@@ -193,6 +196,8 @@ struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
 					 struct sockaddr_vm *dst);
 void vsock_remove_sock(struct vsock_sock *vsk);
 void vsock_for_each_connected_socket(void (*fn)(struct sock *sk));
+int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk);
+bool vsock_find_cid(unsigned int cid);
 
 /**** TAP ****/
 

include/net/vsock_addr.h

@@ -8,7 +8,7 @@
 #ifndef _VSOCK_ADDR_H_
 #define _VSOCK_ADDR_H_
 
-#include <linux/vm_sockets.h>
+#include <uapi/linux/vm_sockets.h>
 
 void vsock_addr_init(struct sockaddr_vm *addr, u32 cid, u32 port);
 int vsock_addr_validate(const struct sockaddr_vm *addr);

net/vmw_vsock/hyperv_transport.c

@@ -165,6 +165,8 @@ static const guid_t srv_id_template =
 	GUID_INIT(0x00000000, 0xfacb, 0x11e6, 0xbd, 0x58,
 		  0x64, 0x00, 0x6a, 0x79, 0x86, 0xd3);
 
+static bool hvs_check_transport(struct vsock_sock *vsk);
+
 static bool is_valid_srv_id(const guid_t *id)
 {
 	return !memcmp(&id->b[4], &srv_id_template.b[4], sizeof(guid_t) - 4);
@@ -188,7 +190,8 @@ static void hvs_remote_addr_init(struct sockaddr_vm *remote,
 	static u32 host_ephemeral_port = MIN_HOST_EPHEMERAL_PORT;
 	struct sock *sk;
 
-	vsock_addr_init(remote, VMADDR_CID_ANY, VMADDR_PORT_ANY);
+	/* Remote peer is always the host */
+	vsock_addr_init(remote, VMADDR_CID_HOST, VMADDR_PORT_ANY);
 
 	while (1) {
 		/* Wrap around ? */
@@ -360,13 +363,24 @@ static void hvs_open_connection(struct vmbus_channel *chan)
 		if (sk->sk_ack_backlog >= sk->sk_max_ack_backlog)
 			goto out;
 
-		new = __vsock_create(sock_net(sk), NULL, sk, GFP_KERNEL,
-				     sk->sk_type, 0);
+		new = vsock_create_connected(sk);
 		if (!new)
 			goto out;
 
 		new->sk_state = TCP_SYN_SENT;
 		vnew = vsock_sk(new);
+
+		hvs_addr_init(&vnew->local_addr, if_type);
+		hvs_remote_addr_init(&vnew->remote_addr, &vnew->local_addr);
+
+		ret = vsock_assign_transport(vnew, vsock_sk(sk));
+		/* Transport assigned (looking at remote_addr) must be the
+		 * same where we received the request.
+		 */
+		if (ret || !hvs_check_transport(vnew)) {
+			sock_put(new);
+			goto out;
+		}
 		hvs_new = vnew->trans;
 		hvs_new->chan = chan;
 	} else {
@@ -430,9 +444,6 @@ static void hvs_open_connection(struct vmbus_channel *chan)
 		new->sk_state = TCP_ESTABLISHED;
 		sk_acceptq_added(sk);
 
-		hvs_addr_init(&vnew->local_addr, if_type);
-		hvs_remote_addr_init(&vnew->remote_addr, &vnew->local_addr);
-
 		hvs_new->vm_srv_id = *if_type;
 		hvs_new->host_srv_id = *if_instance;
 
@@ -845,37 +856,9 @@ int hvs_notify_send_post_enqueue(struct vsock_sock *vsk, ssize_t written,
 	return 0;
 }
 
-static void hvs_set_buffer_size(struct vsock_sock *vsk, u64 val)
-{
-	/* Ignored. */
-}
-
-static void hvs_set_min_buffer_size(struct vsock_sock *vsk, u64 val)
-{
-	/* Ignored. */
-}
-
-static void hvs_set_max_buffer_size(struct vsock_sock *vsk, u64 val)
-{
-	/* Ignored. */
-}
-
-static u64 hvs_get_buffer_size(struct vsock_sock *vsk)
-{
-	return -ENOPROTOOPT;
-}
-
-static u64 hvs_get_min_buffer_size(struct vsock_sock *vsk)
-{
-	return -ENOPROTOOPT;
-}
-
-static u64 hvs_get_max_buffer_size(struct vsock_sock *vsk)
-{
-	return -ENOPROTOOPT;
-}
-
 static struct vsock_transport hvs_transport = {
+	.module                   = THIS_MODULE,
+
 	.get_local_cid            = hvs_get_local_cid,
 
 	.init                     = hvs_sock_init,
@@ -908,14 +891,13 @@ static struct vsock_transport hvs_transport = {
 	.notify_send_pre_enqueue  = hvs_notify_send_pre_enqueue,
 	.notify_send_post_enqueue = hvs_notify_send_post_enqueue,
 
-	.set_buffer_size          = hvs_set_buffer_size,
-	.set_min_buffer_size      = hvs_set_min_buffer_size,
-	.set_max_buffer_size      = hvs_set_max_buffer_size,
-	.get_buffer_size          = hvs_get_buffer_size,
-	.get_min_buffer_size      = hvs_get_min_buffer_size,
-	.get_max_buffer_size      = hvs_get_max_buffer_size,
 };
 
+static bool hvs_check_transport(struct vsock_sock *vsk)
+{
+	return vsk->transport == &hvs_transport;
+}
+
 static int hvs_probe(struct hv_device *hdev,
 		     const struct hv_vmbus_device_id *dev_id)
 {
@@ -964,7 +946,7 @@ static int __init hvs_init(void)
 	if (ret != 0)
 		return ret;
 
-	ret = vsock_core_init(&hvs_transport);
+	ret = vsock_core_register(&hvs_transport, VSOCK_TRANSPORT_F_G2H);
 	if (ret) {
 		vmbus_driver_unregister(&hvs_drv);
 		return ret;
@@ -975,7 +957,7 @@ static int __init hvs_init(void)
 
 static void __exit hvs_exit(void)
 {
-	vsock_core_exit();
+	vsock_core_unregister(&hvs_transport);
 	vmbus_driver_unregister(&hvs_drv);
 }
 

net/vmw_vsock/virtio_transport.c

@@ -86,33 +86,6 @@ static u32 virtio_transport_get_local_cid(void)
 	return ret;
 }
 
-static void virtio_transport_loopback_work(struct work_struct *work)
-{
-	struct virtio_vsock *vsock =
-		container_of(work, struct virtio_vsock, loopback_work);
-	LIST_HEAD(pkts);
-
-	spin_lock_bh(&vsock->loopback_list_lock);
-	list_splice_init(&vsock->loopback_list, &pkts);
-	spin_unlock_bh(&vsock->loopback_list_lock);
-
-	mutex_lock(&vsock->rx_lock);
-
-	if (!vsock->rx_run)
-		goto out;
-
-	while (!list_empty(&pkts)) {
-		struct virtio_vsock_pkt *pkt;
-
-		pkt = list_first_entry(&pkts, struct virtio_vsock_pkt, list);
-		list_del_init(&pkt->list);
-
-		virtio_transport_recv_pkt(pkt);
-	}
-out:
-	mutex_unlock(&vsock->rx_lock);
-}
-
 static int virtio_transport_send_pkt_loopback(struct virtio_vsock *vsock,
 					      struct virtio_vsock_pkt *pkt)
 {
@@ -370,59 +343,6 @@ static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
 	return val < virtqueue_get_vring_size(vq);
 }
 
-static void virtio_transport_rx_work(struct work_struct *work)
-{
-	struct virtio_vsock *vsock =
-		container_of(work, struct virtio_vsock, rx_work);
-	struct virtqueue *vq;
-
-	vq = vsock->vqs[VSOCK_VQ_RX];
-
-	mutex_lock(&vsock->rx_lock);
-
-	if (!vsock->rx_run)
-		goto out;
-
-	do {
-		virtqueue_disable_cb(vq);
-		for (;;) {
-			struct virtio_vsock_pkt *pkt;
-			unsigned int len;
-
-			if (!virtio_transport_more_replies(vsock)) {
-				/* Stop rx until the device processes already
-				 * pending replies.  Leave rx virtqueue
-				 * callbacks disabled.
-				 */
-				goto out;
-			}
-
-			pkt = virtqueue_get_buf(vq, &len);
-			if (!pkt) {
-				break;
-			}
-
-			vsock->rx_buf_nr--;
-
-			/* Drop short/long packets */
-			if (unlikely(len < sizeof(pkt->hdr) ||
-				     len > sizeof(pkt->hdr) + pkt->len)) {
-				virtio_transport_free_pkt(pkt);
-				continue;
-			}
-
-			pkt->len = len - sizeof(pkt->hdr);
-			virtio_transport_deliver_tap_pkt(pkt);
-			virtio_transport_recv_pkt(pkt);
-		}
-	} while (!virtqueue_enable_cb(vq));
-
-out:
-	if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
-		virtio_vsock_rx_fill(vsock);
-	mutex_unlock(&vsock->rx_lock);
-}
-
 /* event_lock must be held */
 static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
 				       struct virtio_vsock_event *event)
@@ -542,6 +462,8 @@ static void virtio_vsock_rx_done(struct virtqueue *vq)
 
 static struct virtio_transport virtio_transport = {
 	.transport = {
+		.module                   = THIS_MODULE,
+
 		.get_local_cid            = virtio_transport_get_local_cid,
 
 		.init                     = virtio_transport_do_socket_init,
@@ -574,18 +496,92 @@ static struct virtio_transport virtio_transport = {
 		.notify_send_pre_block    = virtio_transport_notify_send_pre_block,
 		.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
 		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
-
-		.set_buffer_size          = virtio_transport_set_buffer_size,
-		.set_min_buffer_size      = virtio_transport_set_min_buffer_size,
-		.set_max_buffer_size      = virtio_transport_set_max_buffer_size,
-		.get_buffer_size          = virtio_transport_get_buffer_size,
-		.get_min_buffer_size      = virtio_transport_get_min_buffer_size,
-		.get_max_buffer_size      = virtio_transport_get_max_buffer_size,
+		.notify_buffer_size       = virtio_transport_notify_buffer_size,
 	},
 
 	.send_pkt = virtio_transport_send_pkt,
 };
 
+static void virtio_transport_loopback_work(struct work_struct *work)
+{
+	struct virtio_vsock *vsock =
+		container_of(work, struct virtio_vsock, loopback_work);
+	LIST_HEAD(pkts);
+
+	spin_lock_bh(&vsock->loopback_list_lock);
+	list_splice_init(&vsock->loopback_list, &pkts);
+	spin_unlock_bh(&vsock->loopback_list_lock);
+
+	mutex_lock(&vsock->rx_lock);
+
+	if (!vsock->rx_run)
+		goto out;
+
+	while (!list_empty(&pkts)) {
+		struct virtio_vsock_pkt *pkt;
+
+		pkt = list_first_entry(&pkts, struct virtio_vsock_pkt, list);
+		list_del_init(&pkt->list);
+
+		virtio_transport_recv_pkt(&virtio_transport, pkt);
+	}
+out:
+	mutex_unlock(&vsock->rx_lock);
+}
+
+static void virtio_transport_rx_work(struct work_struct *work)
+{
+	struct virtio_vsock *vsock =
+		container_of(work, struct virtio_vsock, rx_work);
+	struct virtqueue *vq;
+
+	vq = vsock->vqs[VSOCK_VQ_RX];
+
+	mutex_lock(&vsock->rx_lock);
+
+	if (!vsock->rx_run)
+		goto out;
+
+	do {
+		virtqueue_disable_cb(vq);
+		for (;;) {
+			struct virtio_vsock_pkt *pkt;
+			unsigned int len;
+
+			if (!virtio_transport_more_replies(vsock)) {
+				/* Stop rx until the device processes already
+				 * pending replies.  Leave rx virtqueue
+				 * callbacks disabled.
+				 */
+				goto out;
+			}
+
+			pkt = virtqueue_get_buf(vq, &len);
+			if (!pkt) {
+				break;
+			}
+
+			vsock->rx_buf_nr--;
+
+			/* Drop short/long packets */
+			if (unlikely(len < sizeof(pkt->hdr) ||
+				     len > sizeof(pkt->hdr) + pkt->len)) {
+				virtio_transport_free_pkt(pkt);
+				continue;
+			}
+
+			pkt->len = len - sizeof(pkt->hdr);
+			virtio_transport_deliver_tap_pkt(pkt);
+			virtio_transport_recv_pkt(&virtio_transport, pkt);
+		}
+	} while (!virtqueue_enable_cb(vq));
+
+out:
+	if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
+		virtio_vsock_rx_fill(vsock);
+	mutex_unlock(&vsock->rx_lock);
+}
+
 static int virtio_vsock_probe(struct virtio_device *vdev)
 {
 	vq_callback_t *callbacks[] = {
@@ -776,7 +772,8 @@ static int __init virtio_vsock_init(void)
 	if (!virtio_vsock_workqueue)
 		return -ENOMEM;
 
-	ret = vsock_core_init(&virtio_transport.transport);
+	ret = vsock_core_register(&virtio_transport.transport,
+				  VSOCK_TRANSPORT_F_G2H);
 	if (ret)
 		goto out_wq;
 
@@ -787,7 +784,7 @@ static int __init virtio_vsock_init(void)
 	return 0;
 
 out_vci:
-	vsock_core_exit();
+	vsock_core_unregister(&virtio_transport.transport);
 out_wq:
 	destroy_workqueue(virtio_vsock_workqueue);
 	return ret;
@@ -796,7 +793,7 @@ static int __init virtio_vsock_init(void)
 static void __exit virtio_vsock_exit(void)
 {
 	unregister_virtio_driver(&virtio_vsock_driver);
-	vsock_core_exit();
+	vsock_core_unregister(&virtio_transport.transport);
 	destroy_workqueue(virtio_vsock_workqueue);
 }
 

net/vmw_vsock/virtio_transport_common.c

@@ -29,9 +29,10 @@
 /* Threshold for detecting small packets to copy */
 #define GOOD_COPY_LEN  128
 
-static const struct virtio_transport *virtio_transport_get_ops(void)
+static const struct virtio_transport *
+virtio_transport_get_ops(struct vsock_sock *vsk)
 {
-	const struct vsock_transport *t = vsock_core_get_transport();
+	const struct vsock_transport *t = vsock_core_get_transport(vsk);
 
 	return container_of(t, struct virtio_transport, transport);
 }
@@ -168,7 +169,7 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
 	struct virtio_vsock_pkt *pkt;
 	u32 pkt_len = info->pkt_len;
 
-	src_cid = vm_sockets_get_local_cid();
+	src_cid = virtio_transport_get_ops(vsk)->transport.get_local_cid();
 	src_port = vsk->local_addr.svm_port;
 	if (!info->remote_cid) {
 		dst_cid	= vsk->remote_addr.svm_cid;
@@ -201,7 +202,7 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
 
 	virtio_transport_inc_tx_pkt(vvs, pkt);
 
-	return virtio_transport_get_ops()->send_pkt(pkt);
+	return virtio_transport_get_ops(vsk)->send_pkt(pkt);
 }
 
 static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,
@@ -452,20 +453,16 @@ int virtio_transport_do_socket_init(struct vsock_sock *vsk,
 
 	vsk->trans = vvs;
 	vvs->vsk = vsk;
-	if (psk) {
+	if (psk && psk->trans) {
 		struct virtio_vsock_sock *ptrans = psk->trans;
 
-		vvs->buf_size	= ptrans->buf_size;
-		vvs->buf_size_min = ptrans->buf_size_min;
-		vvs->buf_size_max = ptrans->buf_size_max;
 		vvs->peer_buf_alloc = ptrans->peer_buf_alloc;
-	} else {
-		vvs->buf_size = VIRTIO_VSOCK_DEFAULT_BUF_SIZE;
-		vvs->buf_size_min = VIRTIO_VSOCK_DEFAULT_MIN_BUF_SIZE;
-		vvs->buf_size_max = VIRTIO_VSOCK_DEFAULT_MAX_BUF_SIZE;
 	}
 
-	vvs->buf_alloc = vvs->buf_size;
+	if (vsk->buffer_size > VIRTIO_VSOCK_MAX_BUF_SIZE)
+		vsk->buffer_size = VIRTIO_VSOCK_MAX_BUF_SIZE;
+
+	vvs->buf_alloc = vsk->buffer_size;
 
 	spin_lock_init(&vvs->rx_lock);
 	spin_lock_init(&vvs->tx_lock);
@@ -475,71 +472,20 @@ int virtio_transport_do_socket_init(struct vsock_sock *vsk,
 }
 EXPORT_SYMBOL_GPL(virtio_transport_do_socket_init);
 
-u64 virtio_transport_get_buffer_size(struct vsock_sock *vsk)
-{
-	struct virtio_vsock_sock *vvs = vsk->trans;
-
-	return vvs->buf_size;
-}
-EXPORT_SYMBOL_GPL(virtio_transport_get_buffer_size);
-
-u64 virtio_transport_get_min_buffer_size(struct vsock_sock *vsk)
+/* sk_lock held by the caller */
+void virtio_transport_notify_buffer_size(struct vsock_sock *vsk, u64 *val)
 {
 	struct virtio_vsock_sock *vvs = vsk->trans;
 
-	return vvs->buf_size_min;
-}
-EXPORT_SYMBOL_GPL(virtio_transport_get_min_buffer_size);
+	if (*val > VIRTIO_VSOCK_MAX_BUF_SIZE)
+		*val = VIRTIO_VSOCK_MAX_BUF_SIZE;
 
-u64 virtio_transport_get_max_buffer_size(struct vsock_sock *vsk)
-{
-	struct virtio_vsock_sock *vvs = vsk->trans;
-
-	return vvs->buf_size_max;
-}
-EXPORT_SYMBOL_GPL(virtio_transport_get_max_buffer_size);
-
-void virtio_transport_set_buffer_size(struct vsock_sock *vsk, u64 val)
-{
-	struct virtio_vsock_sock *vvs = vsk->trans;
-
-	if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
-		val = VIRTIO_VSOCK_MAX_BUF_SIZE;
-	if (val < vvs->buf_size_min)
-		vvs->buf_size_min = val;
-	if (val > vvs->buf_size_max)
-		vvs->buf_size_max = val;
-	vvs->buf_size = val;
-	vvs->buf_alloc = val;
+	vvs->buf_alloc = *val;
 
 	virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_STREAM,
 					    NULL);
 }
-EXPORT_SYMBOL_GPL(virtio_transport_set_buffer_size);
-
-void virtio_transport_set_min_buffer_size(struct vsock_sock *vsk, u64 val)
-{
-	struct virtio_vsock_sock *vvs = vsk->trans;
-
-	if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
-		val = VIRTIO_VSOCK_MAX_BUF_SIZE;
-	if (val > vvs->buf_size)
-		vvs->buf_size = val;
-	vvs->buf_size_min = val;
-}
-EXPORT_SYMBOL_GPL(virtio_transport_set_min_buffer_size);
-
-void virtio_transport_set_max_buffer_size(struct vsock_sock *vsk, u64 val)
-{
-	struct virtio_vsock_sock *vvs = vsk->trans;
-
-	if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
-		val = VIRTIO_VSOCK_MAX_BUF_SIZE;
-	if (val < vvs->buf_size)
-		vvs->buf_size = val;
-	vvs->buf_size_max = val;
-}
-EXPORT_SYMBOL_GPL(virtio_transport_set_max_buffer_size);
+EXPORT_SYMBOL_GPL(virtio_transport_notify_buffer_size);
 
 int
 virtio_transport_notify_poll_in(struct vsock_sock *vsk,
@@ -631,9 +577,7 @@ EXPORT_SYMBOL_GPL(virtio_transport_notify_send_post_enqueue);
 
 u64 virtio_transport_stream_rcvhiwat(struct vsock_sock *vsk)
 {
-	struct virtio_vsock_sock *vvs = vsk->trans;
-
-	return vvs->buf_size;
+	return vsk->buffer_size;
 }
 EXPORT_SYMBOL_GPL(virtio_transport_stream_rcvhiwat);
 
@@ -745,9 +689,9 @@ static int virtio_transport_reset(struct vsock_sock *vsk,
 /* Normally packets are associated with a socket.  There may be no socket if an
  * attempt was made to connect to a socket that does not exist.
  */
-static int virtio_transport_reset_no_sock(struct virtio_vsock_pkt *pkt)
+static int virtio_transport_reset_no_sock(const struct virtio_transport *t,
+					  struct virtio_vsock_pkt *pkt)
 {
-	const struct virtio_transport *t;
 	struct virtio_vsock_pkt *reply;
 	struct virtio_vsock_pkt_info info = {
 		.op = VIRTIO_VSOCK_OP_RST,
@@ -767,7 +711,6 @@ static int virtio_transport_reset_no_sock(struct virtio_vsock_pkt *pkt)
 	if (!reply)
 		return -ENOMEM;
 
-	t = virtio_transport_get_ops();
 	if (!t) {
 		virtio_transport_free_pkt(reply);
 		return -ENOTCONN;
@@ -1043,13 +986,39 @@ virtio_transport_send_response(struct vsock_sock *vsk,
 	return virtio_transport_send_pkt_info(vsk, &info);
 }
 
+static bool virtio_transport_space_update(struct sock *sk,
+					  struct virtio_vsock_pkt *pkt)
+{
+	struct vsock_sock *vsk = vsock_sk(sk);
+	struct virtio_vsock_sock *vvs = vsk->trans;
+	bool space_available;
+
+	/* Listener sockets are not associated with any transport, so we are
+	 * not able to take the state to see if there is space available in the
+	 * remote peer, but since they are only used to receive requests, we
+	 * can assume that there is always space available in the other peer.
+	 */
+	if (!vvs)
+		return true;
+
+	/* buf_alloc and fwd_cnt is always included in the hdr */
+	spin_lock_bh(&vvs->tx_lock);
+	vvs->peer_buf_alloc = le32_to_cpu(pkt->hdr.buf_alloc);
+	vvs->peer_fwd_cnt = le32_to_cpu(pkt->hdr.fwd_cnt);
+	space_available = virtio_transport_has_space(vsk);
+	spin_unlock_bh(&vvs->tx_lock);
+	return space_available;
+}
+
 /* Handle server socket */
 static int
-virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt)
+virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt,
+			     struct virtio_transport *t)
 {
 	struct vsock_sock *vsk = vsock_sk(sk);
 	struct vsock_sock *vchild;
 	struct sock *child;
+	int ret;
 
 	if (le16_to_cpu(pkt->hdr.op) != VIRTIO_VSOCK_OP_REQUEST) {
 		virtio_transport_reset(vsk, pkt);
@@ -1061,8 +1030,7 @@ virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt)
 		return -ENOMEM;
 	}
 
-	child = __vsock_create(sock_net(sk), NULL, sk, GFP_KERNEL,
-			       sk->sk_type, 0);
+	child = vsock_create_connected(sk);
 	if (!child) {
 		virtio_transport_reset(vsk, pkt);
 		return -ENOMEM;
@@ -1080,6 +1048,20 @@ virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt)
 	vsock_addr_init(&vchild->remote_addr, le64_to_cpu(pkt->hdr.src_cid),
 			le32_to_cpu(pkt->hdr.src_port));
 
+	ret = vsock_assign_transport(vchild, vsk);
+	/* Transport assigned (looking at remote_addr) must be the same
+	 * where we received the request.
+	 */
+	if (ret || vchild->transport != &t->transport) {
+		release_sock(child);
+		virtio_transport_reset(vsk, pkt);
+		sock_put(child);
+		return ret;
+	}
+
+	if (virtio_transport_space_update(child, pkt))
+		child->sk_write_space(child);
+
 	vsock_insert_connected(vchild);
 	vsock_enqueue_accept(sk, child);
 	virtio_transport_send_response(vchild, pkt);
@@ -1090,26 +1072,11 @@ virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt)
 	return 0;
 }
 
-static bool virtio_transport_space_update(struct sock *sk,
-					  struct virtio_vsock_pkt *pkt)
-{
-	struct vsock_sock *vsk = vsock_sk(sk);
-	struct virtio_vsock_sock *vvs = vsk->trans;
-	bool space_available;
-
-	/* buf_alloc and fwd_cnt is always included in the hdr */
-	spin_lock_bh(&vvs->tx_lock);
-	vvs->peer_buf_alloc = le32_to_cpu(pkt->hdr.buf_alloc);
-	vvs->peer_fwd_cnt = le32_to_cpu(pkt->hdr.fwd_cnt);
-	space_available = virtio_transport_has_space(vsk);
-	spin_unlock_bh(&vvs->tx_lock);
-	return space_available;
-}
-
 /* We are under the virtio-vsock's vsock->rx_lock or vhost-vsock's vq->mutex
  * lock.
  */
-void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt)
+void virtio_transport_recv_pkt(struct virtio_transport *t,
+			       struct virtio_vsock_pkt *pkt)
 {
 	struct sockaddr_vm src, dst;
 	struct vsock_sock *vsk;
@@ -1131,7 +1098,7 @@ void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt)
 					le32_to_cpu(pkt->hdr.fwd_cnt));
 
 	if (le16_to_cpu(pkt->hdr.type) != VIRTIO_VSOCK_TYPE_STREAM) {
-		(void)virtio_transport_reset_no_sock(pkt);
+		(void)virtio_transport_reset_no_sock(t, pkt);
 		goto free_pkt;
 	}
 
@@ -1142,7 +1109,7 @@ void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt)
 	if (!sk) {
 		sk = vsock_find_bound_socket(&dst);
 		if (!sk) {
-			(void)virtio_transport_reset_no_sock(pkt);
+			(void)virtio_transport_reset_no_sock(t, pkt);
 			goto free_pkt;
 		}
 	}
@@ -1161,7 +1128,7 @@ void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt)
 
 	switch (sk->sk_state) {
 	case TCP_LISTEN:
-		virtio_transport_recv_listen(sk, pkt);
+		virtio_transport_recv_listen(sk, pkt, t);
 		virtio_transport_free_pkt(pkt);
 		break;
 	case TCP_SYN_SENT:
@@ -1179,6 +1146,7 @@ void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt)
 		virtio_transport_free_pkt(pkt);
 		break;
 	}
+
 	release_sock(sk);
 
 	/* Release refcnt obtained when we fetched this socket out of the

net/vmw_vsock/vmci_transport.c

@@ -57,6 +57,7 @@ static bool vmci_transport_old_proto_override(bool *old_pkt_proto);
 static u16 vmci_transport_new_proto_supported_versions(void);
 static bool vmci_transport_proto_to_notify_struct(struct sock *sk, u16 *proto,
 						  bool old_pkt_proto);
+static bool vmci_check_transport(struct vsock_sock *vsk);
 
 struct vmci_transport_recv_pkt_info {
 	struct work_struct work;
@@ -74,15 +75,6 @@ static u32 vmci_transport_qp_resumed_sub_id = VMCI_INVALID_ID;
 
 static int PROTOCOL_OVERRIDE = -1;
 
-#define VMCI_TRANSPORT_DEFAULT_QP_SIZE_MIN   128
-#define VMCI_TRANSPORT_DEFAULT_QP_SIZE       262144
-#define VMCI_TRANSPORT_DEFAULT_QP_SIZE_MAX   262144
-
-/* The default peer timeout indicates how long we will wait for a peer response
- * to a control message.
- */
-#define VSOCK_DEFAULT_CONNECT_TIMEOUT (2 * HZ)
-
 /* Helper function to convert from a VMCI error code to a VSock error code. */
 
 static s32 vmci_transport_error_to_vsock_error(s32 vmci_error)
@@ -1013,8 +1005,7 @@ static int vmci_transport_recv_listen(struct sock *sk,
 		return -ECONNREFUSED;
 	}
 
-	pending = __vsock_create(sock_net(sk), NULL, sk, GFP_KERNEL,
-				 sk->sk_type, 0);
+	pending = vsock_create_connected(sk);
 	if (!pending) {
 		vmci_transport_send_reset(sk, pkt);
 		return -ENOMEM;
@@ -1027,14 +1018,24 @@ static int vmci_transport_recv_listen(struct sock *sk,
 	vsock_addr_init(&vpending->remote_addr, pkt->dg.src.context,
 			pkt->src_port);
 
+	err = vsock_assign_transport(vpending, vsock_sk(sk));
+	/* Transport assigned (looking at remote_addr) must be the same
+	 * where we received the request.
+	 */
+	if (err || !vmci_check_transport(vpending)) {
+		vmci_transport_send_reset(sk, pkt);
+		sock_put(pending);
+		return err;
+	}
+
 	/* If the proposed size fits within our min/max, accept it. Otherwise
 	 * propose our own size.
 	 */
-	if (pkt->u.size >= vmci_trans(vpending)->queue_pair_min_size &&
-	    pkt->u.size <= vmci_trans(vpending)->queue_pair_max_size) {
+	if (pkt->u.size >= vpending->buffer_min_size &&
+	    pkt->u.size <= vpending->buffer_max_size) {
 		qp_size = pkt->u.size;
 	} else {
-		qp_size = vmci_trans(vpending)->queue_pair_size;
+		qp_size = vpending->buffer_size;
 	}
 
 	/* Figure out if we are using old or new requests based on the
@@ -1103,7 +1104,7 @@ static int vmci_transport_recv_listen(struct sock *sk,
 	pending->sk_state = TCP_SYN_SENT;
 	vmci_trans(vpending)->produce_size =
 		vmci_trans(vpending)->consume_size = qp_size;
-	vmci_trans(vpending)->queue_pair_size = qp_size;
+	vpending->buffer_size = qp_size;
 
 	vmci_trans(vpending)->notify_ops->process_request(pending);
 
@@ -1397,8 +1398,8 @@ static int vmci_transport_recv_connecting_client_negotiate(
 	vsk->ignore_connecting_rst = false;
 
 	/* Verify that we're OK with the proposed queue pair size */
-	if (pkt->u.size < vmci_trans(vsk)->queue_pair_min_size ||
-	    pkt->u.size > vmci_trans(vsk)->queue_pair_max_size) {
+	if (pkt->u.size < vsk->buffer_min_size ||
+	    pkt->u.size > vsk->buffer_max_size) {
 		err = -EINVAL;
 		goto destroy;
 	}
@@ -1503,8 +1504,7 @@ vmci_transport_recv_connecting_client_invalid(struct sock *sk,
 		vsk->sent_request = false;
 		vsk->ignore_connecting_rst = true;
 
-		err = vmci_transport_send_conn_request(
-			sk, vmci_trans(vsk)->queue_pair_size);
+		err = vmci_transport_send_conn_request(sk, vsk->buffer_size);
 		if (err < 0)
 			err = vmci_transport_error_to_vsock_error(err);
 		else
@@ -1588,21 +1588,6 @@ static int vmci_transport_socket_init(struct vsock_sock *vsk,
 	INIT_LIST_HEAD(&vmci_trans(vsk)->elem);
 	vmci_trans(vsk)->sk = &vsk->sk;
 	spin_lock_init(&vmci_trans(vsk)->lock);
-	if (psk) {
-		vmci_trans(vsk)->queue_pair_size =
-			vmci_trans(psk)->queue_pair_size;
-		vmci_trans(vsk)->queue_pair_min_size =
-			vmci_trans(psk)->queue_pair_min_size;
-		vmci_trans(vsk)->queue_pair_max_size =
-			vmci_trans(psk)->queue_pair_max_size;
-	} else {
-		vmci_trans(vsk)->queue_pair_size =
-			VMCI_TRANSPORT_DEFAULT_QP_SIZE;
-		vmci_trans(vsk)->queue_pair_min_size =
-			 VMCI_TRANSPORT_DEFAULT_QP_SIZE_MIN;
-		vmci_trans(vsk)->queue_pair_max_size =
-			VMCI_TRANSPORT_DEFAULT_QP_SIZE_MAX;
-	}
 
 	return 0;
 }
@@ -1818,8 +1803,7 @@ static int vmci_transport_connect(struct vsock_sock *vsk)
 
 	if (vmci_transport_old_proto_override(&old_pkt_proto) &&
 		old_pkt_proto) {
-		err = vmci_transport_send_conn_request(
-			sk, vmci_trans(vsk)->queue_pair_size);
+		err = vmci_transport_send_conn_request(sk, vsk->buffer_size);
 		if (err < 0) {
 			sk->sk_state = TCP_CLOSE;
 			return err;
@@ -1827,8 +1811,7 @@ static int vmci_transport_connect(struct vsock_sock *vsk)
 	} else {
 		int supported_proto_versions =
 			vmci_transport_new_proto_supported_versions();
-		err = vmci_transport_send_conn_request2(
-				sk, vmci_trans(vsk)->queue_pair_size,
+		err = vmci_transport_send_conn_request2(sk, vsk->buffer_size,
 				supported_proto_versions);
 		if (err < 0) {
 			sk->sk_state = TCP_CLOSE;
@@ -1881,46 +1864,6 @@ static bool vmci_transport_stream_is_active(struct vsock_sock *vsk)
 	return !vmci_handle_is_invalid(vmci_trans(vsk)->qp_handle);
 }
 
-static u64 vmci_transport_get_buffer_size(struct vsock_sock *vsk)
-{
-	return vmci_trans(vsk)->queue_pair_size;
-}
-
-static u64 vmci_transport_get_min_buffer_size(struct vsock_sock *vsk)
-{
-	return vmci_trans(vsk)->queue_pair_min_size;
-}
-
-static u64 vmci_transport_get_max_buffer_size(struct vsock_sock *vsk)
-{
-	return vmci_trans(vsk)->queue_pair_max_size;
-}
-
-static void vmci_transport_set_buffer_size(struct vsock_sock *vsk, u64 val)
-{
-	if (val < vmci_trans(vsk)->queue_pair_min_size)
-		vmci_trans(vsk)->queue_pair_min_size = val;
-	if (val > vmci_trans(vsk)->queue_pair_max_size)
-		vmci_trans(vsk)->queue_pair_max_size = val;
-	vmci_trans(vsk)->queue_pair_size = val;
-}
-
-static void vmci_transport_set_min_buffer_size(struct vsock_sock *vsk,
-					       u64 val)
-{
-	if (val > vmci_trans(vsk)->queue_pair_size)
-		vmci_trans(vsk)->queue_pair_size = val;
-	vmci_trans(vsk)->queue_pair_min_size = val;
-}
-
-static void vmci_transport_set_max_buffer_size(struct vsock_sock *vsk,
-					       u64 val)
-{
-	if (val < vmci_trans(vsk)->queue_pair_size)
-		vmci_trans(vsk)->queue_pair_size = val;
-	vmci_trans(vsk)->queue_pair_max_size = val;
-}
-
 static int vmci_transport_notify_poll_in(
 	struct vsock_sock *vsk,
 	size_t target,
@@ -2076,7 +2019,8 @@ static u32 vmci_transport_get_local_cid(void)
 	return vmci_get_context_id();
 }
 
-static const struct vsock_transport vmci_transport = {
+static struct vsock_transport vmci_transport = {
+	.module = THIS_MODULE,
 	.init = vmci_transport_socket_init,
 	.destruct = vmci_transport_destruct,
 	.release = vmci_transport_release,
@@ -2103,15 +2047,26 @@ static const struct vsock_transport vmci_transport = {
 	.notify_send_pre_enqueue = vmci_transport_notify_send_pre_enqueue,
 	.notify_send_post_enqueue = vmci_transport_notify_send_post_enqueue,
 	.shutdown = vmci_transport_shutdown,
-	.set_buffer_size = vmci_transport_set_buffer_size,
-	.set_min_buffer_size = vmci_transport_set_min_buffer_size,
-	.set_max_buffer_size = vmci_transport_set_max_buffer_size,
-	.get_buffer_size = vmci_transport_get_buffer_size,
-	.get_min_buffer_size = vmci_transport_get_min_buffer_size,
-	.get_max_buffer_size = vmci_transport_get_max_buffer_size,
 	.get_local_cid = vmci_transport_get_local_cid,
 };
 
+static bool vmci_check_transport(struct vsock_sock *vsk)
+{
+	return vsk->transport == &vmci_transport;
+}
+
+void vmci_vsock_transport_cb(bool is_host)
+{
+	int features;
+
+	if (is_host)
+		features = VSOCK_TRANSPORT_F_H2G;
+	else
+		features = VSOCK_TRANSPORT_F_G2H;
+
+	vsock_core_register(&vmci_transport, features);
+}
+
 static int __init vmci_transport_init(void)
 {
 	int err;
@@ -2128,7 +2083,6 @@ static int __init vmci_transport_init(void)
 		pr_err("Unable to create datagram handle. (%d)\n", err);
 		return vmci_transport_error_to_vsock_error(err);
 	}
-
 	err = vmci_event_subscribe(VMCI_EVENT_QP_RESUMED,
 				   vmci_transport_qp_resumed_cb,
 				   NULL, &vmci_transport_qp_resumed_sub_id);
@@ -2139,12 +2093,21 @@ static int __init vmci_transport_init(void)
 		goto err_destroy_stream_handle;
 	}
 
-	err = vsock_core_init(&vmci_transport);
+	/* Register only with dgram feature, other features (H2G, G2H) will be
+	 * registered when the first host or guest becomes active.
+	 */
+	err = vsock_core_register(&vmci_transport, VSOCK_TRANSPORT_F_DGRAM);
 	if (err < 0)
 		goto err_unsubscribe;
 
+	err = vmci_register_vsock_callback(vmci_vsock_transport_cb);
+	if (err < 0)
+		goto err_unregister;
+
 	return 0;
 
+err_unregister:
+	vsock_core_unregister(&vmci_transport);
 err_unsubscribe:
 	vmci_event_unsubscribe(vmci_transport_qp_resumed_sub_id);
 err_destroy_stream_handle:
@@ -2170,7 +2133,8 @@ static void __exit vmci_transport_exit(void)
 		vmci_transport_qp_resumed_sub_id = VMCI_INVALID_ID;
 	}
 
-	vsock_core_exit();
+	vmci_register_vsock_callback(NULL);
+	vsock_core_unregister(&vmci_transport);
 }
 module_exit(vmci_transport_exit);
 

net/vmw_vsock/vmci_transport.h

@@ -108,9 +108,6 @@ struct vmci_transport {
 	struct vmci_qp *qpair;
 	u64 produce_size;
 	u64 consume_size;
-	u64 queue_pair_size;
-	u64 queue_pair_min_size;
-	u64 queue_pair_max_size;
 	u32 detach_sub_id;
 	union vmci_transport_notify notify;
 	const struct vmci_transport_notify_ops *notify_ops;

net/vmw_vsock/vmci_transport_notify.h

@@ -11,7 +11,6 @@
 #include <linux/types.h>
 #include <linux/vmw_vmci_defs.h>
 #include <linux/vmw_vmci_api.h>
-#include <linux/vm_sockets.h>
 
 #include "vmci_transport.h"