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From:   Stefano Garzarella <sgarzare@redhat.com>
To:     netdev@vger.kernel.org
Cc:     virtualization@lists.linux-foundation.org,
        Dexuan Cui <decui@microsoft.com>,
        Stefan Hajnoczi <stefanha@redhat.com>,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        "David S. Miller" <davem@davemloft.net>,
        Jorgen Hansen <jhansen@vmware.com>
Subject: [PATCH net-next 5/6] vsock: use local transport when it is loaded
Date:   Tue, 19 Nov 2019 12:01:20 +0100
Message-Id: <20191119110121.14480-6-sgarzare@redhat.com>
In-Reply-To: <20191119110121.14480-1-sgarzare@redhat.com>
References: <20191119110121.14480-1-sgarzare@redhat.com>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Now that we have a transport that can handle the local communication,
we can use it when it is loaded.

A socket will use the local transport (loopback) when the remote
CID is:
- equal to VMADDR_CID_LOCAL
- or equal to transport_g2h->get_local_cid(), if transport_g2h
  is loaded (this allows us to keep the same behavior implemented
  by virtio and vmci transports)
- or equal to VMADDR_CID_HOST, if transport_g2h is not loaded

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 net/vmw_vsock/af_vsock.c | 32 ++++++++++++++++++++++++++------
 1 file changed, 26 insertions(+), 6 deletions(-)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index c9e5bad59dc1..40bbb2a17e3d 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -388,6 +388,21 @@ void vsock_enqueue_accept(struct sock *listener, struc=
t sock *connected)
 }
 EXPORT_SYMBOL_GPL(vsock_enqueue_accept);
=20
+static bool vsock_use_local_transport(unsigned int remote_cid)
+{
+=09if (!transport_local)
+=09=09return false;
+
+=09if (remote_cid =3D=3D VMADDR_CID_LOCAL)
+=09=09return true;
+
+=09if (transport_g2h) {
+=09=09return remote_cid =3D=3D transport_g2h->get_local_cid();
+=09} else {
+=09=09return remote_cid =3D=3D VMADDR_CID_HOST;
+=09}
+}
+
 static void vsock_deassign_transport(struct vsock_sock *vsk)
 {
 =09if (!vsk->transport)
@@ -404,9 +419,10 @@ static void vsock_deassign_transport(struct vsock_sock=
 *vsk)
  * (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:
- *  - remote CID <=3D VMADDR_CID_HOST will use guest->host transport;
- *  - remote CID =3D=3D local_cid (guest->host transport) will use guest->=
host
- *    transport for loopback (host->guest transports don't support loopbac=
k);
+ *  - remote CID =3D=3D VMADDR_CID_LOCAL or g2h->local_cid or VMADDR_CID_H=
OST if
+ *    g2h is not loaded, will use local transport;
+ *  - remote CID =3D=3D VMADDR_CID_HOST or VMADDR_CID_HYPERVISOR, 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)
@@ -420,9 +436,10 @@ int vsock_assign_transport(struct vsock_sock *vsk, str=
uct vsock_sock *psk)
 =09=09new_transport =3D transport_dgram;
 =09=09break;
 =09case SOCK_STREAM:
-=09=09if (remote_cid <=3D VMADDR_CID_HOST ||
-=09=09    (transport_g2h &&
-=09=09     remote_cid =3D=3D transport_g2h->get_local_cid()))
+=09=09if (vsock_use_local_transport(remote_cid))
+=09=09=09new_transport =3D transport_local;
+=09=09else if (remote_cid =3D=3D VMADDR_CID_HOST ||
+=09=09=09 remote_cid =3D=3D VMADDR_CID_HYPERVISOR)
 =09=09=09new_transport =3D transport_g2h;
 =09=09else
 =09=09=09new_transport =3D transport_h2g;
@@ -459,6 +476,9 @@ bool vsock_find_cid(unsigned int cid)
 =09if (transport_h2g && cid =3D=3D VMADDR_CID_HOST)
 =09=09return true;
=20
+=09if (transport_local && cid =3D=3D VMADDR_CID_LOCAL)
+=09=09return true;
+
 =09return false;
 }
 EXPORT_SYMBOL_GPL(vsock_find_cid);
--=20
2.21.0