On Wed, Jun 10, 2015 at 03:43:02PM +0200, Thibaut Collet wrote:
> Some vhost client/backend are able to support live migration.
> To provide this service the following features must be added:
> 1. GARP from guest after live migration:
> the VIRTIO_NET_F_GUEST_ANNOUNCE capability is added to vhost-net when
> netdev
> backend is vhost-user to let virtio-net NIC manages GARP after migration.
> 2. RARP on vhost-user:
> After a live migration RARP are automatically sent to any interfaces. A
> receive callback is added to vhost-user to catch this packet. If guest
> supports VIRTIO_NET_F_GUEST_ANNOUNCE this packet is discarded to avoid
> message duplication (already done by virtio-net NIC). For legacy guest
> without VIRTIO_NET_F_GUEST_ANNOUNCE a warning message is displayed to
> alert the user. RARP must be sent to the vhost client/backend.
>
> Signed-off-by: Thibaut Collet <thibaut.col...@6wind.com>
So let's do it gradually
patch 1. negotiate VIRTIO_NET_F_GUEST_ANNOUNCE, add empty recv
callback to make it not crash
patch 2. more tricks for legacy guests
then I can apply patch 1 straight away.
> ---
> hw/net/vhost_net.c | 15 +++++++++++++++
> include/net/vhost_net.h | 1 +
> net/vhost-user.c | 21 +++++++++++++++++++--
> 3 files changed, 35 insertions(+), 2 deletions(-)
>
> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> index 426b23e..4a42325 100644
> --- a/hw/net/vhost_net.c
> +++ b/hw/net/vhost_net.c
> @@ -82,6 +82,8 @@ static const int user_feature_bits[] = {
> VIRTIO_NET_F_CTRL_MAC_ADDR,
> VIRTIO_NET_F_CTRL_GUEST_OFFLOADS,
>
> + VIRTIO_NET_F_GUEST_ANNOUNCE,
> +
> VIRTIO_NET_F_MQ,
>
> VHOST_INVALID_FEATURE_BIT
> @@ -365,6 +367,15 @@ void vhost_net_stop(VirtIODevice *dev, NetClientState
> *ncs,
> assert(r >= 0);
> }
>
> +void vhost_net_inject_rarp(struct vhost_net *net, const uint8_t *buf, size_t
> size)
> +{
> + if ((net->dev.acked_features & (1 << VIRTIO_NET_F_GUEST_ANNOUNCE)) == 0)
> {
> + fprintf(stderr,
> + "Warning: Guest with no VIRTIO_NET_F_GUEST_ANNOUNCE support.
> RARP must be sent by vhost-user backend\n");
> + fflush(stderr);
> + }
> +}
> +
> void vhost_net_cleanup(struct vhost_net *net)
> {
> vhost_dev_cleanup(&net->dev);
> @@ -427,6 +438,10 @@ void vhost_net_stop(VirtIODevice *dev,
> {
> }
>
> +void vhost_net_inject_rarp(struct vhost_net *net, const uint8_t *buf, size_t
> size);
> +{
> +}
> +
> void vhost_net_cleanup(struct vhost_net *net)
> {
> }
> diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h
> index b1c18a3..e82a0f9 100644
> --- a/include/net/vhost_net.h
> +++ b/include/net/vhost_net.h
> @@ -20,6 +20,7 @@ bool vhost_net_query(VHostNetState *net, VirtIODevice *dev);
> int vhost_net_start(VirtIODevice *dev, NetClientState *ncs, int
> total_queues);
> void vhost_net_stop(VirtIODevice *dev, NetClientState *ncs, int
> total_queues);
>
> +void vhost_net_inject_rarp(VHostNetState *net, const uint8_t *buf, size_t
> size);
> void vhost_net_cleanup(VHostNetState *net);
>
> unsigned vhost_net_get_features(VHostNetState *net, unsigned features);
> diff --git a/net/vhost-user.c b/net/vhost-user.c
> index 8d26728..69c2313 100644
> --- a/net/vhost-user.c
> +++ b/net/vhost-user.c
> @@ -66,6 +66,24 @@ static void vhost_user_stop(VhostUserState *s)
> s->vhost_net = 0;
> }
>
> +static ssize_t vhost_user_receive(NetClientState *nc, const uint8_t *buf,
> + size_t size)
> +{
> + if (size == 60) {
> + /* Assume it is a RARP request sent automatically after a
> + * live migration */
> + /* The RARP must be sent if guest does not support
> + * VIRTIO_NET_F_GUEST_ANNOUNCE */
> + VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
> +
> + vhost_net_inject_rarp(s->vhost_net, buf, size);
> + } else {
> + fprintf(stderr,"Vhost user receives unexpected packets\n");
> + fflush(stderr);
> + }
> + return size;
> +}
> +
> static void vhost_user_cleanup(NetClientState *nc)
> {
> VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
> @@ -91,6 +109,7 @@ static bool vhost_user_has_ufo(NetClientState *nc)
> static NetClientInfo net_vhost_user_info = {
> .type = NET_CLIENT_OPTIONS_KIND_VHOST_USER,
> .size = sizeof(VhostUserState),
> + .receive = vhost_user_receive,
> .cleanup = vhost_user_cleanup,
> .has_vnet_hdr = vhost_user_has_vnet_hdr,
> .has_ufo = vhost_user_has_ufo,
> @@ -147,8 +166,6 @@ static int net_vhost_user_init(NetClientState *peer,
> const char *device,
>
> s = DO_UPCAST(VhostUserState, nc, nc);
>
> - /* We don't provide a receive callback */
> - s->nc.receive_disabled = 1;
> s->chr = chr;
> s->nc.queue_index = i;
>
> --
> 1.7.10.4
