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>

3 files changed, 5 insertions, 30 deletions

diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index 07875ccc7bb5..71c81e0dc8f2 100644
--- a/include/linux/virtio_vsock.h
+++ b/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);
diff --git a/include/linux/vm_sockets.h b/include/linux/vm_sockets.h
deleted file mode 100644
index 33f1a2ecd905..000000000000
--- a/include/linux/vm_sockets.h
+++ /dev/null
@@ -1,15 +0,0 @@
-/* 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 */
diff --git a/include/linux/vmw_vmci_api.h b/include/linux/vmw_vmci_api.h
index acd9fafe4fc6..f28907345c80 100644
--- a/include/linux/vmw_vmci_api.h
+++ b/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,