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>

1 files changed, 53 insertions, 49 deletions

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 9f57736fe15e..dde392b91bb3 100644
--- a/drivers/vhost/vsock.c
+++ b/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);