To map the guest memory while it is migrating we need to create the
iova_tree, as long as the destination uses x-svq=on. Checking to not
override it.

The function vhost_vdpa_net_client_stop clear it if the device is
stopped. If the guest starts the device again, the iova tree is
recreated by vhost_vdpa_net_data_start_first or vhost_vdpa_net_cvq_start
if needed, so old behavior is kept.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 net/vhost-vdpa.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 3fb209cd35..a37de7860e 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -341,7 +341,9 @@ static void vhost_vdpa_net_data_start_first(VhostVDPAState *s)
 
     migration_add_notifier(&s->migration_state,
                            vdpa_net_migration_state_notifier);
-    if (v->shadow_vqs_enabled) {
+
+    /* iova_tree may be initialized by vhost_vdpa_net_load_setup */
+    if (v->shadow_vqs_enabled && !v->shared->iova_tree) {
         v->shared->iova_tree = vhost_iova_tree_new(v->shared->iova_range.first,
                                                    v->shared->iova_range.last);
     }
-- 
2.39.3