The specification says the device MUST set num_buffers to 1 if VIRTIO_NET_F_MRG_RXBUF has not been negotiated. Fixes: 41e3e42108bc ("vhost/net: enable virtio 1.0") Signed-off-by: Akihiko Odaki <akihiko.odaki@xxxxxxxxxx> --- drivers/vhost/net.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index f16279351db5..d4d97fa9cc8f 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -1107,6 +1107,7 @@ static void handle_rx(struct vhost_net *net) size_t vhost_hlen, sock_hlen; size_t vhost_len, sock_len; bool busyloop_intr = false; + bool set_num_buffers; struct socket *sock; struct iov_iter fixup; __virtio16 num_buffers; @@ -1129,6 +1130,8 @@ static void handle_rx(struct vhost_net *net) vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ? vq->log : NULL; mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF); + set_num_buffers = mergeable || + vhost_has_feature(vq, VIRTIO_F_VERSION_1); do { sock_len = vhost_net_rx_peek_head_len(net, sock->sk, @@ -1205,7 +1208,7 @@ static void handle_rx(struct vhost_net *net) /* TODO: Should check and handle checksum. */ num_buffers = cpu_to_vhost16(vq, headcount); - if (likely(mergeable) && + if (likely(set_num_buffers) && copy_to_iter(&num_buffers, sizeof num_buffers, &fixup) != sizeof num_buffers) { vq_err(vq, "Failed num_buffers write"); --- base-commit: 46a0057a5853cbdb58211c19e89ba7777dc6fd50 change-id: 20240908-v1-90fc83ff8b09 Best regards, -- Akihiko Odaki <akihiko.odaki@xxxxxxxxxx>