[Qemu-devel] [RFC 3/4] vhost-net: Add new MTU feature support

[Maxime Coquelin <maxime.coquelin@redhat.com>]

If VHOST_USER_F_MTU feature is negociated, vhost-net makes the
advised MTU available to virtio-net through a vhost_net_get_mtu()
call.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Aaron Conole <aconole@redhat.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 hw/net/vhost_net.c      | 11 +++++++++++
 include/net/vhost_net.h |  2 ++
 2 files changed, 13 insertions(+)

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index f2d49ad..21057d6 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -74,6 +74,7 @@ static const int user_feature_bits[] = {
     VIRTIO_NET_F_HOST_ECN,
     VIRTIO_NET_F_HOST_UFO,
     VIRTIO_NET_F_MRG_RXBUF,
+    VIRTIO_NET_F_MTU,
 
     /* This bit implies RARP isn't sent by QEMU out of band */
     VIRTIO_NET_F_GUEST_ANNOUNCE,
@@ -435,6 +436,11 @@ int vhost_set_vring_enable(NetClientState *nc, int enable)
     return 0;
 }
 
+uint64_t vhost_net_get_mtu(struct vhost_net *net)
+{
+    return net->dev.mtu;
+}
+
 #else
 uint64_t vhost_net_get_max_queues(VHostNetState *net)
 {
@@ -501,4 +507,9 @@ int vhost_set_vring_enable(NetClientState *nc, int enable)
 {
     return 0;
 }
+
+uint64_t vhost_net_get_mtu(struct vhost_net *net)
+{
+    return 0;
+}
 #endif
diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h
index 5a08eff..37de17b 100644
--- a/include/net/vhost_net.h
+++ b/include/net/vhost_net.h
@@ -35,4 +35,6 @@ int vhost_set_vring_enable(NetClientState * nc, int enable);
 
 uint64_t vhost_net_get_acked_features(VHostNetState *net);
 
+uint64_t vhost_net_get_mtu(struct vhost_net *net);
+
 #endif
-- 
2.7.4