static int ahci_dma_prepare_buf(IDEDMA *dma, int is_write) { AHCIDevice *ad = DO_UPCAST(AHCIDevice, dma, dma); IDEState *s = &ad->port.ifs[0]; ahci_populate_sglist(ad, &s->sg); s->io_buffer_size = s->sg.size; DPRINTF(ad->port_no, "len=%#x\n", s->io_buffer_size); return s->io_buffer_size != 0; }