vhost/net: Set num_buffers for virtio 1.0

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@daynix.com>
Message-Id: <20240915-v1-v1-1-f10d2cb5e759@daynix.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 9ad37c0121890ee5b756ca71c31ec00d8f097707..b9b9e9d40951856d881d77ac74331d914473cd56 100644 (file)
--- 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");