[Qemu-devel] [PATCH 1/3] net: Forbid dealing with packets when VM is not running

[zhanghailiang <zhang.zhanghailiang@huawei.com>]

For all NICs(except virtio-net) emulated by qemu,
Such as e1000, rtl8139, pcnet and ne2k_pci,
Qemu can still receive packets when VM is not running.

If this happened in *migration's* last PAUSE VM stage,
The new dirty RAM related to the packets will be missed,
And this will lead serious network fault in VM.

To avoid this, do things like virtio-net, and forbid receiving packets
in generic net code when VM is not running.

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
---
 include/net/net.h | 1 +
 net/net.c         | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/include/net/net.h b/include/net/net.h
index ed594f9..312f728 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -8,6 +8,7 @@
 #include "net/queue.h"
 #include "migration/vmstate.h"
 #include "qapi-types.h"
+#include "sysemu/sysemu.h"
 
 #define MAX_QUEUE_NUM 1024
 
diff --git a/net/net.c b/net/net.c
index 6d930ea..5bb2821 100644
--- a/net/net.c
+++ b/net/net.c
@@ -452,6 +452,12 @@ void qemu_set_vnet_hdr_len(NetClientState *nc, int len)
 
 int qemu_can_send_packet(NetClientState *sender)
 {
+    int vmstat = runstate_is_running();
+
+    if (!vmstat) {
+        return 0;
+    }
+
     if (!sender->peer) {
         return 1;
     }
-- 
1.7.12.4