static void virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb) { uint32_t type; struct iovec *iov = req->elem->out_sg; unsigned out_num = req->elem->out_num; if (req->elem->out_num < 1 || req->elem->in_num < 1) { error_report("virtio-blk missing headers"); exit(1); } if (req->elem->out_sg[0].iov_len < sizeof(req->out) || req->elem->in_sg[req->elem->in_num - 1].iov_len < sizeof(*req->in)) { error_report("virtio-blk header not in correct element"); exit(1); } if (unlikely(iov_to_buf(iov, out_num, 0, &req->out, sizeof(req->out)) != sizeof(req->out))) { error_report("virtio-blk request outhdr too short"); exit(1); } iov_discard_front(&iov, &out_num, sizeof(req->out)); req->in = (void *)req->elem->in_sg[req->elem->in_num - 1].iov_base; type = ldl_p(&req->out.type); if (type & VIRTIO_BLK_T_FLUSH) { virtio_blk_handle_flush(req, mrb); } else if (type & VIRTIO_BLK_T_SCSI_CMD) { virtio_blk_handle_scsi(req); } else if (type & VIRTIO_BLK_T_GET_ID) { VirtIOBlock *s = req->dev; /* * NB: per existing s/n string convention the string is * terminated by '\0' only when shorter than buffer. */ strncpy(req->elem->in_sg[0].iov_base, s->blk.serial ? s->blk.serial : "", MIN(req->elem->in_sg[0].iov_len, VIRTIO_BLK_ID_BYTES)); virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); virtio_blk_free_request(req); } else if (type & VIRTIO_BLK_T_OUT) { qemu_iovec_init_external(&req->qiov, &req->elem->out_sg[1], req->elem->out_num - 1); virtio_blk_handle_write(req, mrb); } else if (type == VIRTIO_BLK_T_IN || type == VIRTIO_BLK_T_BARRIER) { /* VIRTIO_BLK_T_IN is 0, so we can't just & it. */ qemu_iovec_init_external(&req->qiov, &req->elem->in_sg[0], req->elem->in_num - 1); virtio_blk_handle_read(req); } else { virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP); virtio_blk_free_request(req); } }