Am 08.06.2016 um 08:39 schrieb Jason Wang: > > > On 2016年06月07日 21:00, Peter Lieven wrote: >> commit fefe2a78 accidently dropped the code path for injecting >> raw packets. This feature is needed for sending gratuitous ARPs >> after an incoming migration has completed. The result is increased >> network downtime for vservers where the network card is not virtio-net >> with the VIRTIO_NET_F_GUEST_ANNOUNCE feature. >> >> Fixes: fefe2a78abde932e0f340b21bded2c86def1d242 >> Cc: qemu-sta...@nongnu.org >> Cc: hongyang.y...@easystack.cn >> Signed-off-by: Peter Lieven <p...@kamp.de> >> --- >> v1->v2: assert that only raw packets with a plain buffer come in. [Paolo] >> >> net/net.c | 10 +++++++++- >> 1 file changed, 9 insertions(+), 1 deletion(-) >> >> diff --git a/net/net.c b/net/net.c >> index 5f3e5a9..5e1b5fa 100644 >> --- a/net/net.c >> +++ b/net/net.c >> @@ -714,6 +714,11 @@ ssize_t qemu_deliver_packet_iov(NetClientState *sender, >> NetClientState *nc = opaque; >> int ret; >> + /* we currently only support sending raw packets via >> qemu_send_packet_raw. >> + * If we want generic raw iov support we need to implement something >> like >> + * .receive_raw_iov in NetClientInfo first. */ >> + assert(!(flags & QEMU_NET_PACKET_FLAG_RAW) || iovcnt == 1); >> + >> if (nc->link_down) { >> return iov_size(iov, iovcnt); >> } >> @@ -722,7 +727,10 @@ ssize_t qemu_deliver_packet_iov(NetClientState *sender, >> return 0; >> } >> - if (nc->info->receive_iov) { >> + if (flags & QEMU_NET_PACKET_FLAG_RAW && nc->info->receive_raw) { >> + /* this is required for qemu_announce_self() */ >> + ret = nc->info->receive_raw(nc, iov[0].iov_base, iov[0].iov_len); >> + } else if (nc->info->receive_iov) { >> ret = nc->info->receive_iov(nc, iov, iovcnt); >> } else { >> ret = nc_sendv_compat(nc, iov, iovcnt, flags); > > We still have raw packet support in nv_sendv_compat, can we use it? (and then > there's no need for the assert above).
Okay, so Version 1 of the patch is more appropiate. I would either use V1 or revert fefe2a78. The issue is quite serious for live migration. Peter