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vhost user: add support of live migration

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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.collet@6wind.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Thibaut Collet <thibaut.collet@6wind.com>
This commit is contained in:
Thibaut Collet 2015-10-09 17:17:31 +02:00 committed by Michael S. Tsirkin
parent 69b32a6ce4
commit f6f56291de
2 changed files with 12 additions and 2 deletions
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2
hw/net/vhost_net.c
View File

@ -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

12
net/vhost-user.c
View File

@ -103,6 +103,15 @@ err:
return -1;
}
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);
@ -132,6 +141,7 @@ 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,
@ -182,8 +192,6 @@ static int net_vhost_user_init(NetClientState *peer, const char *device,
snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
i, chr->label);
/* We don't provide a receive callback */
nc->receive_disabled = 1;
nc->queue_index = i;
s = DO_UPCAST(VhostUserState, nc, nc);