+ if (unlikely(desc_chunck_len < sizeof(struct virtio_net_hdr))) {
+ uint64_t len = desc_chunck_len;
+ uint64_t remain = sizeof(struct virtio_net_hdr);
+ uint64_t src = desc_addr;
+ uint64_t dst = (uint64_t)(uintptr_t)&tmp_hdr;
+ uint64_t guest_addr = desc_gaddr;
+
+ /*
+ * No luck, the virtio-net header doesn't fit
+ * in a contiguous virtual area.
+ */
+ while (remain) {
+ len = remain;
+ src = vhost_iova_to_vva(dev, vq,
+ guest_addr, &len,
+ VHOST_ACCESS_RO);
+ if (unlikely(!src || !len)) {
+ error = -1;
+ goto out;
+ }
+
+ rte_memcpy((void *)(uintptr_t)dst,
+ (void *)(uintptr_t)src, len);
+
+ guest_addr += len;
+ remain -= len;
+ dst += len;
+ }
+
+ hdr = &tmp_hdr;
+ } else {
+ hdr = (struct virtio_net_hdr *)((uintptr_t)desc_addr);
+ rte_prefetch0(hdr);
+ }