[PATCH 16/40] vdpa: indicate SVQ switching via flag

[Si-Wei Liu <si-wei.liu@oracle.com>]

svq_switching indicates the case where SVQ mode change
is on going. Positive (1) means switching from the
normal passthrough mode to SVQ mode, and negative (-1)
meaning switch SVQ back to the passthrough; zero (0)
indicates that there's no SVQ mode switch taking place.

Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
---
 net/vhost-vdpa.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 7b8f047..04718b2 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -320,6 +320,7 @@ static void vhost_vdpa_net_log_global_enable(VhostVDPAState *s, bool enable)
     data_queue_pairs = n->multiqueue ? n->max_queue_pairs : 1;
     cvq = virtio_vdev_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) ?
                                   n->max_ncs - n->max_queue_pairs : 0;
+    v->shared->svq_switching = enable ? 1 : -1;
     /*
      * TODO: vhost_net_stop does suspend, get_base and reset. We can be smarter
      * in the future and resume the device if read-only operations between
@@ -332,6 +333,7 @@ static void vhost_vdpa_net_log_global_enable(VhostVDPAState *s, bool enable)
     if (unlikely(r < 0)) {
         error_report("unable to start vhost net: %s(%d)", g_strerror(-r), -r);
     }
+    v->shared->svq_switching = 0;
 }
 
 static void vdpa_net_migration_state_notifier(Notifier *notifier, void *data)
-- 
1.8.3.1