vdpa: check for iova tree initialized at net_client_start

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.

Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
Message-Id: <20250522145839.59974-2-jonah.palmer@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 7ca8b46eee779ddd0e1318ec91dc2c5b5a82759a..decb82686838ecd6b6301a4431ac44e48a63ac18 100644 (file)
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -366,7 +366,9 @@ 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);
     }