Re: [Qemu-devel] [PATCH V2] net: fix qemu_announce_self not emitting packets

[Jason Wang <jasowang@redhat.com>]

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-stable@nongnu.org
> Cc: hongyang.yang@easystack.cn
> Signed-off-by: Peter Lieven <pl@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).

Thanks