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>
---
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
