virtio-net: Fix num_buffers for version 1

akihikodaki · mstsirkin · commit c17ad4b11bd2 · 2025-04-02T12:44:47.000-04:00
The specification says the device MUST set num_buffers to 1 if VIRTIO_NET_F_MRG_RXBUF has not been negotiated. Fixes: df91055 ("virtio-net: enable virtio 1.0") Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com> Message-Id: <20250108-buffers-v1-1-a0c85ff31aeb@daynix.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Lei Yang <leiyang@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
@@ -1999,6 +1999,8 @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
                                     offsetof(typeof(hdr),
                                              virtio_net.hdr.num_buffers),
                                     sizeof(hdr.virtio_net.hdr.num_buffers));
+            } else {
+                hdr.virtio_net.hdr.num_buffers = cpu_to_le16(1);
             }
 
             guest_offset = n->has_vnet_hdr ?

Original file line number	Diff line number	Diff line change
`@@ -1999,6 +1999,8 @@ static ssize_t virtio_net_receive_rcu(NetClientState nc, const uint8_t buf,`
`1999`	`1999`	`offsetof(typeof(hdr),`
`2000`	`2000`	`virtio_net.hdr.num_buffers),`
`2001`	`2001`	`sizeof(hdr.virtio_net.hdr.num_buffers));`
	`2002`	`+ } else {`
	`2003`	`+ hdr.virtio_net.hdr.num_buffers = cpu_to_le16(1);`
`2002`	`2004`	`}`
`2003`	`2005`
`2004`	`2006`	`guest_offset = n->has_vnet_hdr ?`