net/virtio-user: fix protocol features advertising

When connected to a vhost-user backend, the flag
VHOST_USER_F_PROTOCOL_FEATURES is not advertised, preventing to do
multiqueue (the VHOST_USER_PROTOCOL_F_MQ protocol feature is ignored by
some backends if the VHOST_USER_F_PROTOCOL_FEATURES feature is not set).

When setting vhost-user features, advertise this flag if it was
advertised by our peer.

Fixes: 8e7561054ac7 ("net/virtio: support vhost-user protocol features")
Cc: stable@dpdk.org
Suggested-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

diff --git a/drivers/net/virtio/virtio_user/vhost_user.c b/drivers/net/virtio/virtio_user/vhost_user.c
index b93e65c..350eed4 100644 (file)
--- a/drivers/net/virtio/virtio_user/vhost_user.c
+++ b/drivers/net/virtio/virtio_user/vhost_user.c
@@ -297,13 +297,18 @@ vhost_user_sock(struct virtio_user_dev *dev,
                if (has_reply_ack)
                        msg.flags |= VHOST_USER_NEED_REPLY_MASK;
                /* Fallthrough */
-       case VHOST_USER_SET_FEATURES:
        case VHOST_USER_SET_PROTOCOL_FEATURES:
        case VHOST_USER_SET_LOG_BASE:
                msg.payload.u64 = *((__u64 *)arg);
                msg.size = sizeof(m.payload.u64);
                break;
 
+       case VHOST_USER_SET_FEATURES:
+               msg.payload.u64 = *((__u64 *)arg) | (dev->device_features &
+                       (1ULL << VHOST_USER_F_PROTOCOL_FEATURES));
+               msg.size = sizeof(m.payload.u64);
+               break;
+
        case VHOST_USER_SET_OWNER:
        case VHOST_USER_RESET_OWNER:
                break;