Some vhost user backends are able to support live migration.
To provide this service the following features must be added:
1. Add the VIRTIO_NET_F_GUEST_ANNOUNCE capability to vhost-net when netdev
backend is vhost-user.
2. Provide a nop receive callback to vhost-user.
This callback is called by:
* qemu_announce_self after a migration to send fake RARP to avoid network
outage for peers talking to the migrated guest.
- For guest with GUEST_ANNOUNCE capabilities, guest already sends GARP
when the bit VIRTIO_NET_S_ANNOUNCE is set.
=> These packets must be discarded.
- For guest without GUEST_ANNOUNCE capabilities, migration termination
is notified when the guest sends packets.
=> These packets can be discarded.
* virtio_net_tx_bh with a dummy boot to send fake bootp/dhcp request.
BIOS guest manages virtio driver to send 4 bootp/dhcp request in case of
dummy boot.
=> These packets must be discarded.
Signed-off-by: Thibaut Collet <thibaut.col...@6wind.com>
---
hw/net/vhost_net.c | 2 ++
net/vhost-user.c | 12 ++++++++++--
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index c864237..9850520 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -85,6 +85,8 @@ 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
diff --git a/net/vhost-user.c b/net/vhost-user.c
index 93dcecd..1b1c626 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -65,6 +65,15 @@ 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)
+{
+ /* Discard the request that is received and managed by backend
+ * by an other way.
+ */
+ return size;
+}
+
static void vhost_user_cleanup(NetClientState *nc)
{
VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
@@ -90,6 +99,7 @@ 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,
@@ -143,8 +153,6 @@ 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;
qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event, s);
--
1.7.10.4
