[Qemu-devel] [PATCH] vhost-user: fix VIRTIO_NET_F_MRG_RXBUF negotiation

[damarion]

From: Damjan Marion <address@hidden>

Header length check should happen only if backend is kernel. For user
backend there is no reason to reset this bit.

vhost-user code does not define .has_vnet_hdr_len so
VIRTIO_NET_F_MRG_RXBUF cannot be negotiated even if both sides
support it.

Signed-off-by: Damjan Marion <address@hidden>
---
 hw/net/vhost_net.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index f87c798..9d1172a 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -162,11 +162,11 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
     if (r < 0) {
         goto fail;
     }
-    if (!qemu_has_vnet_hdr_len(options->net_backend,
-                               sizeof(struct virtio_net_hdr_mrg_rxbuf))) {
-        net->dev.features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);
-    }
     if (backend_kernel) {
+        if (!qemu_has_vnet_hdr_len(options->net_backend,
+                               sizeof(struct virtio_net_hdr_mrg_rxbuf))) {
+            net->dev.features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);
+        }
         if (~net->dev.features & net->dev.backend_features) {
             fprintf(stderr, "vhost lacks feature mask %" PRIu64
                    " for backend\n",
-- 
1.9.1