+static int
+vhost_user_set_postcopy_advise(struct virtio_net **pdev,
+ struct VhostUserMsg *msg,
+ int main_fd __rte_unused)
+{
+ struct virtio_net *dev = *pdev;
+#ifdef RTE_LIBRTE_VHOST_POSTCOPY
+ struct uffdio_api api_struct;
+
+ dev->postcopy_ufd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
+
+ if (dev->postcopy_ufd == -1) {
+ RTE_LOG(ERR, VHOST_CONFIG, "Userfaultfd not available: %s\n",
+ strerror(errno));
+ return VH_RESULT_ERR;
+ }
+ api_struct.api = UFFD_API;
+ api_struct.features = 0;
+ if (ioctl(dev->postcopy_ufd, UFFDIO_API, &api_struct)) {
+ RTE_LOG(ERR, VHOST_CONFIG, "UFFDIO_API ioctl failure: %s\n",
+ strerror(errno));
+ close(dev->postcopy_ufd);
+ dev->postcopy_ufd = -1;
+ return VH_RESULT_ERR;
+ }
+ msg->fds[0] = dev->postcopy_ufd;
+ msg->fd_num = 1;
+
+ return VH_RESULT_REPLY;
+#else
+ dev->postcopy_ufd = -1;
+ msg->fd_num = 0;
+
+ return VH_RESULT_ERR;
+#endif
+}
+