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, we forbid receiving packets in generic net code when
VM is not running. Also, when the runstate changes back to running,
we definitely need to flush queues to get packets flowing again.
Here we implement this in the net layer:
(1) Judge the vm runstate in qemu_can_send_packet
(2) Add a member 'VMChangeStateEntry *vmstate' to struct NICState,
Which will listen for VM runstate changes.
(3) Register a handler function for VMstate change.
When vm changes back to running, we flush all queues in the callback function.
(4) Remove checking vm state in virtio_net_can_receive
Signed-off-by: zhanghailiang<address@hidden>
---
v3:
- change the 'vmstate' to 'vm_running'
v2:
- remove the superfluous check of nc->received_disabled
---
hw/net/virtio-net.c | 4 ----
include/net/net.h | 2 ++
net/net.c | 31 +++++++++++++++++++++++++++++++
3 files changed, 33 insertions(+), 4 deletions(-)