static int ahci_populate_sglist(AHCIDevice *ad, QEMUSGList *sglist) { AHCICmdHdr *cmd = ad->cur_cmd; uint32_t opts = le32_to_cpu(cmd->opts); uint64_t prdt_addr = le64_to_cpu(cmd->tbl_addr) + 0x80; int sglist_alloc_hint = opts >> AHCI_CMD_HDR_PRDT_LEN; dma_addr_t prdt_len = (sglist_alloc_hint * sizeof(AHCI_SG)); dma_addr_t real_prdt_len = prdt_len; uint8_t *prdt; int i; int r = 0; if (!sglist_alloc_hint) { DPRINTF(ad->port_no, "no sg list given by guest: 0x%08x\n", opts); return -1; } /* map PRDT */ if (!(prdt = dma_memory_map(ad->hba->dma, prdt_addr, &prdt_len, DMA_DIRECTION_TO_DEVICE))){ DPRINTF(ad->port_no, "map failed\n"); return -1; } if (prdt_len < real_prdt_len) { DPRINTF(ad->port_no, "mapped less than expected\n"); r = -1; goto out; } /* Get entries in the PRDT, init a qemu sglist accordingly */ if (sglist_alloc_hint > 0) { AHCI_SG *tbl = (AHCI_SG *)prdt; qemu_sglist_init(sglist, sglist_alloc_hint, ad->hba->dma); for (i = 0; i < sglist_alloc_hint; i++) { /* flags_size is zero-based */ qemu_sglist_add(sglist, le64_to_cpu(tbl[i].addr), le32_to_cpu(tbl[i].flags_size) + 1); } } out: dma_memory_unmap(ad->hba->dma, prdt, prdt_len, DMA_DIRECTION_TO_DEVICE, prdt_len); return r; }