+static int qemu_local_ram_load(QEMUFile *f, void *opaque,
+ uint64_t flags)
+{
+ QEMUFileLocal *s = opaque;
+ ram_addr_t addr;
+ struct iovec iov;
+ ssize_t ret = -EINVAL;
+
+ /*
+ * PIPE file descriptor will be received by another callback
+ * get_buffer.
+ */
+ if (pipefd_passed) {
+ void *host;
+ /*
+ * Extract the page address from the 8-byte record and
+ * read the page data from the pipe.
+ */
+ addr = qemu_get_be64(s->file);
+ host = qemu_get_ram_ptr(addr);
+
+ iov.iov_base = host;
+ iov.iov_len = TARGET_PAGE_SIZE;
+
+ /* The flag SPLICE_F_MOVE is introduced in kernel for the page
+ * flipping feature in QEMU, which will movie pages rather than
+ * copying, previously unused.
+ *
+ * If a move is not possible the kernel will transparently falls
+ * back to copying data.
+ *
+ * For older kernels the SPLICE_F_MOVE would be ignored and a copy
+ * would occur.
+ */
+ ret = vmsplice(s->pipefd[0], &iov, 1, SPLICE_F_MOVE);
+ if (ret == -1) {
+ if (errno != EAGAIN && errno != EINTR) {
+ fprintf(stderr, "vmsplice() load error: %s", strerror(errno));
+ return ret;
+ }
+ DPRINTF("vmsplice load error\n");
+ } else if (ret == 0) {
+ DPRINTF(stderr, "load_page: zero read\n");
+ }
+
+ DPRINTF("vmsplice (read): %zu\n", ret);
+ return ret;
+ }
+
+ return 0;
+}