static int32_t virtio_net_flush_tx(VirtIONetQueue *q) { VirtIONet *n = q->n; VirtIODevice *vdev = VIRTIO_DEVICE(n); VirtQueueElement elem; int32_t num_packets = 0; int queue_index = vq2q(virtio_get_queue_index(q->tx_vq)); if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) { return num_packets; } if (q->async_tx.elem.out_num) { virtio_queue_set_notification(q->tx_vq, 0); return num_packets; } while (virtqueue_pop(q->tx_vq, &elem)) { ssize_t ret; unsigned int out_num = elem.out_num; struct iovec *out_sg = &elem.out_sg[0]; struct iovec sg[VIRTQUEUE_MAX_SIZE], sg2[VIRTQUEUE_MAX_SIZE + 1]; struct virtio_net_hdr_mrg_rxbuf mhdr; if (out_num < 1) { error_report("virtio-net header not in first element"); exit(1); } if (n->has_vnet_hdr) { if (iov_to_buf(out_sg, out_num, 0, &mhdr, n->guest_hdr_len) < n->guest_hdr_len) { error_report("virtio-net header incorrect"); exit(1); } if (virtio_needs_swap(vdev)) { virtio_net_hdr_swap(vdev, (void *) &mhdr); sg2[0].iov_base = &mhdr; sg2[0].iov_len = n->guest_hdr_len; out_num = iov_copy(&sg2[1], ARRAY_SIZE(sg2) - 1, out_sg, out_num, n->guest_hdr_len, -1); if (out_num == VIRTQUEUE_MAX_SIZE) { goto drop; } out_num += 1; out_sg = sg2; } } /* * If host wants to see the guest header as is, we can * pass it on unchanged. Otherwise, copy just the parts * that host is interested in. */ assert(n->host_hdr_len <= n->guest_hdr_len); if (n->host_hdr_len != n->guest_hdr_len) { unsigned sg_num = iov_copy(sg, ARRAY_SIZE(sg), out_sg, out_num, 0, n->host_hdr_len); sg_num += iov_copy(sg + sg_num, ARRAY_SIZE(sg) - sg_num, out_sg, out_num, n->guest_hdr_len, -1); out_num = sg_num; out_sg = sg; } ret = qemu_sendv_packet_async(qemu_get_subqueue(n->nic, queue_index), out_sg, out_num, virtio_net_tx_complete); if (ret == 0) { virtio_queue_set_notification(q->tx_vq, 0); q->async_tx.elem = elem; return -EBUSY; } drop: virtqueue_push(q->tx_vq, &elem, 0); virtio_notify(vdev, q->tx_vq); if (++num_packets >= n->tx_burst) { break; } } return num_packets; }