net: Add is_vhost_user flag to vhost_net struct

Introduce a boolean is_vhost_user field to the vhost_net
structure. This flag is initialized during vhost_net_init based
on whether the backend is vhost-user.

This refactoring simplifies checks for vhost-user specific behavior,
replacing direct comparisons of 'net->nc->info->type' with the new
flag. It improves readability and encapsulates the backend type
information directly within the vhost_net instance.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

hw/net/vhost_net.c

@@ -246,6 +246,7 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
     net->feature_bits = options->feature_bits;
     net->save_acked_features = options->save_acked_features;
     net->max_tx_queue_size = options->max_tx_queue_size;
+    net->is_vhost_user = options->is_vhost_user;
 
     net->dev.max_queues = 1;
     net->dev.vqs = net->vqs;
@@ -440,7 +441,7 @@ int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,
          * because vhost user doesn't interrupt masking/unmasking
          * properly.
          */
-        if (net->nc->info->type == NET_CLIENT_DRIVER_VHOST_USER) {
+        if (net->is_vhost_user) {
             dev->use_guest_notifier_mask = false;
         }
      }

hw/net/virtio-net.c

@@ -691,12 +691,14 @@ default_value:
 static int peer_attach(VirtIONet *n, int index)
 {
     NetClientState *nc = qemu_get_subqueue(n->nic, index);
+    struct vhost_net *net;
 
     if (!nc->peer) {
         return 0;
     }
 
-    if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_USER) {
+    net = get_vhost_net(nc->peer);
+    if (net && net->is_vhost_user) {
         vhost_net_set_vring_enable(nc->peer, 1);
     }
 
@@ -714,12 +716,14 @@ static int peer_attach(VirtIONet *n, int index)
 static int peer_detach(VirtIONet *n, int index)
 {
     NetClientState *nc = qemu_get_subqueue(n->nic, index);
+    struct vhost_net *net;
 
     if (!nc->peer) {
         return 0;
     }
 
-    if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_USER) {
+    net = get_vhost_net(nc->peer);
+    if (net && net->is_vhost_user) {
         vhost_net_set_vring_enable(nc->peer, 0);
     }
 

include/hw/virtio/vhost.h

@@ -147,6 +147,7 @@ struct vhost_net {
     const int *feature_bits;
     int max_tx_queue_size;
     SaveAcketFeatures *save_acked_features;
+    bool is_vhost_user;
     NetClientState *nc;
 };
 

include/net/vhost_net.h

@@ -17,6 +17,7 @@ typedef struct VhostNetOptions {
     unsigned int nvqs;
     const int *feature_bits;
     int max_tx_queue_size;
+    bool is_vhost_user;
     GetAckedFeatures *get_acked_features;
     SaveAcketFeatures *save_acked_features;
     void *opaque;

net/tap.c

@@ -747,6 +747,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
         options.get_acked_features = NULL;
         options.save_acked_features = NULL;
         options.max_tx_queue_size = 0;
+        options.is_vhost_user = false;
 
         s->vhost_net = vhost_net_init(&options);
         if (!s->vhost_net) {

net/vhost-user.c

@@ -141,6 +141,7 @@ static int vhost_user_start(int queues, NetClientState *ncs[],
         options.max_tx_queue_size = VIRTQUEUE_MAX_SIZE;
         options.get_acked_features = vhost_user_get_acked_features;
         options.save_acked_features = vhost_user_save_acked_features;
+        options.is_vhost_user = true;
 
         net = vhost_net_init(&options);
         if (!net) {

net/vhost-vdpa.c

@@ -205,6 +205,7 @@ static int vhost_vdpa_add(NetClientState *ncs, void *be,
     options.get_acked_features = NULL;
     options.save_acked_features = NULL;
     options.max_tx_queue_size = VIRTQUEUE_MAX_SIZE;
+    options.is_vhost_user = false;
 
     net = vhost_net_init(&options);
     if (!net) {