vhost: enable virtio MTU feature

This patch enables the new VIRTIO_NET_F_MTU feature,
which makes possible for the host to advise the guest
with its maximum supported MTU.

MTU value is set via QEMU parameters, either via Libvirt XML, or
directly in virtio-net device command line arguments.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>

diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
index 3c3f6a427548a4904085e87cc986aa7ffa43271c..3e87ecca07e2ac24135d39cbc4cef3acd0aca726 100644 (file)
--- a/lib/librte_vhost/vhost.c
+++ b/lib/librte_vhost/vhost.c
@@ -66,7 +66,8 @@
                                (1ULL << VIRTIO_NET_F_GUEST_CSUM) | \
                                (1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
                                (1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
-                               (1ULL << VIRTIO_RING_F_INDIRECT_DESC))
+                               (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
+                               (1ULL << VIRTIO_NET_F_MTU))
 
 uint64_t VHOST_FEATURES = VHOST_SUPPORTED_FEATURES;
 

diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index d97df1d83a085ab5c8876615931d83dd530b52f2..5c94322261e4411e70833e44369f408595bfee23 100644 (file)
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -120,6 +120,10 @@ struct vhost_virtqueue {
 #endif
 #define VHOST_MAX_QUEUE_PAIRS          0x80
 
+#ifndef VIRTIO_NET_F_MTU
+ #define VIRTIO_NET_F_MTU 3
+#endif
+
 /*
  * Define virtio 1.0 for older kernels
  */