From 954773230484f5afeb675e9ff814c97e54e69e17 Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Mon, 22 Nov 2010 19:52:19 +0200
Subject: [PATCH] virtio-net: don't dma while vm is stopped

DMA into memory while VM is stopped makes it
hard to debug migration (consequitive saves
result in different files).
Fixing this completely is a large effort,
this patch does this for virtio-net.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio-net.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index 1d61f191b6..43a2b3daf0 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -424,6 +424,9 @@ static void virtio_net_handle_rx(VirtIODevice *vdev, VirtQueue *vq)
 static int virtio_net_can_receive(VLANClientState *nc)
 {
     VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque;
+    if (!n->vm_running) {
+        return 0;
+    }
 
     if (!virtio_queue_ready(n->rx_vq) ||
         !(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))