vdpa: add vhost_vdpa_net_valid_svq_features

It will be reused at vdpa device start so let's extract in its own
function.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20221215113144.322011-6-eperezma@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

net/vhost-vdpa.c

@@ -107,6 +107,22 @@ VHostNetState *vhost_vdpa_get_vhost_net(NetClientState *nc)
     return s->vhost_net;
 }
 
+static bool vhost_vdpa_net_valid_svq_features(uint64_t features, Error **errp)
+{
+    uint64_t invalid_dev_features =
+        features & ~vdpa_svq_device_features &
+        /* Transport are all accepted at this point */
+        ~MAKE_64BIT_MASK(VIRTIO_TRANSPORT_F_START,
+                         VIRTIO_TRANSPORT_F_END - VIRTIO_TRANSPORT_F_START);
+
+    if (invalid_dev_features) {
+        error_setg(errp, "vdpa svq does not work with features 0x%" PRIx64,
+                   invalid_dev_features);
+    }
+
+    return !invalid_dev_features;
+}
+
 static int vhost_vdpa_net_check_device_id(struct vhost_net *net)
 {
     uint32_t device_id;
@@ -676,15 +692,7 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
     if (opts->x_svq) {
         struct vhost_vdpa_iova_range iova_range;
 
-        uint64_t invalid_dev_features =
-            features & ~vdpa_svq_device_features &
-            /* Transport are all accepted at this point */
-            ~MAKE_64BIT_MASK(VIRTIO_TRANSPORT_F_START,
-                             VIRTIO_TRANSPORT_F_END - VIRTIO_TRANSPORT_F_START);
-
-        if (invalid_dev_features) {
-            error_setg(errp, "vdpa svq does not work with features 0x%" PRIx64,
-                       invalid_dev_features);
+        if (!vhost_vdpa_net_valid_svq_features(features, errp)) {
             goto err_svq;
         }