Previously there was a single instance of the timer used by
monitor triggered announces, that's OK, but when combined with the
previous change that lets you have announces for subsets of interfaces
it's a bit restrictive if you want to do different things to different
interfaces.

Add an 'id' field to the announce, and maintain a list of the
timers based on id.

This allows you to for example:
    a) Start an announce going on interface eth0 for a long time
    b) Start an announce going on interface eth1 for a long time
    c) Kill the announce on eth0 while leaving eth1 going.
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>

Allow the caller to restrict the set of interfaces that announces are
sent on.  The default is still to send on all interfaces.

e.g.

  { "execute": "announce-self", "arguments": { "initial": 50, "max": 550, "rounds": 5, "step": 50, "interfaces": ["vn2", "vn1"] } }

This doesn't affect the behaviour of migraiton announcments.

Note: There's still only one timer for the qmp command, so that
performing an 'announce-self' on one list of interfaces followed
by another 'announce-self' on another list will stop the announces
on the existing set.
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>

Add a qmp command that can trigger guest announcements.

It uses its own announce-timer instance, and parameters
passed to it explicitly in the command.

Like most qmp commands, it's in the main thread/bql, so
there's no racing with any outstanding timer.

Based on work of Germano Veit Michel <germano@redhat.com> and
                 Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>

Some network devices have a capability to do self announcements
(ex: virtio-net).  Add infrastructure that would allow devices
to expose this ability.
Signed-off-by: NVladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>

Switch the announcements to using the new announce timer.
Move the code that does it to announce.c rather than savevm
because it really has nothing to do with the actual migration.

Migration starts the announce from bh's and so they're all
in the main thread/bql, and so there's never any racing with
the timers themselves.
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>

The 'announce timer' will be used by migration, and explicit
requests for qemu to perform network announces.

Based on the work by Germano Veit Michel <germano@redhat.com>
 and Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>