• Stefano Garzarella's avatar
    vsock: add multi-transports support · c0cfa2d8
    Stefano Garzarella authored
    This patch adds the support of multiple transports in the
    VSOCK core.
    
    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.
    
    Major changes:
    - vsock core module can be loaded regardless of the transports
    - vsock_core_init() and vsock_core_exit() are renamed to
      vsock_core_register() and vsock_core_unregister()
    - vsock_core_register() has a feature parameter (H2G, G2H, DGRAM)
      to identify which directions the transport can handle and if it's
      support DGRAM (only vmci)
    - each stream socket is assigned to a transport when the remote CID
      is set (during the connect() or when we receive a connection request
      on a listener socket).
      The remote CID is used to decide which transport to use:
      - remote CID <= VMADDR_CID_HOST will use guest->host transport;
      - remote CID == local_cid (guest->host transport) will use guest->host
        transport for loopback (host->guest transports don't support loopback);
      - remote CID > VMADDR_CID_HOST will use host->guest transport;
    - listener sockets are not bound to any transports since no transport
      operations are done on it. In this way we can create a listener
      socket, also if the transports are not loaded or with VMADDR_CID_ANY
      to listen on all transports.
    - DGRAM sockets are handled as before, since only the vmci_transport
      provides this feature.
    Signed-off-by: default avatarStefano Garzarella <sgarzare@redhat.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    c0cfa2d8
virtio_transport_common.c 27.9 KB