On Mon, Sep 01, 2014 at 07:40:18PM +0100, Stefan Hajnoczi wrote: > On Tue, Aug 26, 2014 at 04:06:17PM +0800, zhanghailiang wrote: > > 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, but > > before the end of the migration, the new receiving packets will possibly > > dirty > > parts of RAM which has been cached in *iovec*(will be sent asynchronously) > > and > > dirty parts of new RAM which will be missed. > > This will lead serious network fault in VM. > > > > To avoid this, we forbid receiving packets in generic net code when > > VM is not running. > > > > Bug reproduction steps: > > (1) Start a VM which configured at least one NIC > > (2) In VM, open several Terminal and do *Ping IP -i 0.1* > > (3) Migrate the VM repeatedly between two Hosts > > And the *PING* command in VM will very likely fail with message: > > 'Destination HOST Unreachable', the NIC in VM will stay unavailable unless > > you > > run 'service network restart' > > > > Signed-off-by: zhanghailiang <zhang.zhanghaili...@huawei.com> > > --- > > v4: > > - The action of flush queued packets is unnecessary, remove this. > > (Thanks for the help of Jason Wang and Stefan). > > > > v3: > > - change the 'vmstate' to 'vm_running' > > > > v2: > > - remove the superfluous check of nc->received_disabled > > --- > > > > net/net.c | 7 +++++++ > > 1 file changed, 7 insertions(+) > > Thanks, applied to my net tree: > https://github.com/stefanha/qemu/commits/net > > Stefan
Also please Cc: qemu-sta...@nongnu.org
