hw/virtio-serial-bus.c

   1 /*
   2  * A bus for connecting virtio serial and console ports
   3  *
   4  * Copyright (C) 2009, 2010 Red Hat, Inc.
   5  *
   6  * Author(s):
   7  *  Amit Shah <amit.shah@redhat.com>
   8  *
   9  * Some earlier parts are:
  10  *  Copyright IBM, Corp. 2008
  11  * authored by
  12  *  Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
  13  *
  14  * This work is licensed under the terms of the GNU GPL, version 2.  See
  15  * the COPYING file in the top-level directory.
  16  */
  17
  18 #include "iov.h"
  19 #include "monitor.h"
  20 #include "qemu-queue.h"
  21 #include "sysbus.h"
  22 #include "virtio-serial.h"
  23
  24 /* The virtio-serial bus on top of which the ports will ride as devices */
  25 struct VirtIOSerialBus {
  26     BusState qbus;
  27
  28     /* This is the parent device that provides the bus for ports. */
  29     VirtIOSerial *vser;
  30
  31     /* The maximum number of ports that can ride on top of this bus */
  32     uint32_t max_nr_ports;
  33 };
  34
  35 struct VirtIOSerial {
  36     VirtIODevice vdev;
  37
  38     VirtQueue *c_ivq, *c_ovq;
  39     /* Arrays of ivqs and ovqs: one per port */
  40     VirtQueue **ivqs, **ovqs;
  41
  42     VirtIOSerialBus bus;
  43
  44     DeviceState *qdev;
  45
  46     QTAILQ_HEAD(, VirtIOSerialPort) ports;
  47
  48     /* bitmap for identifying active ports */
  49     uint32_t *ports_map;
  50
  51     struct virtio_console_config config;
  52 };
  53
  54 static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
  55 {
  56     VirtIOSerialPort *port;
  57
  58     if (id == VIRTIO_CONSOLE_BAD_ID) {
  59         return NULL;
  60     }
  61
  62     QTAILQ_FOREACH(port, &vser->ports, next) {
  63         if (port->id == id)
  64             return port;
  65     }
  66     return NULL;
  67 }
  68
  69 static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
  70 {
  71     VirtIOSerialPort *port;
  72
  73     QTAILQ_FOREACH(port, &vser->ports, next) {
  74         if (port->ivq == vq || port->ovq == vq)
  75             return port;
  76     }
  77     return NULL;
  78 }
  79
  80 static bool use_multiport(VirtIOSerial *vser)
  81 {
  82     return vser->vdev.guest_features & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
  83 }
  84
  85 static size_t write_to_port(VirtIOSerialPort *port,
  86                             const uint8_t *buf, size_t size)
  87 {
  88     VirtQueueElement elem;
  89     VirtQueue *vq;
  90     size_t offset;
  91
  92     vq = port->ivq;
  93     if (!virtio_queue_ready(vq)) {
  94         return 0;
  95     }
  96
  97     offset = 0;
  98     while (offset < size) {
  99         size_t len;
 100
 101         if (!virtqueue_pop(vq, &elem)) {
 102             break;
 103         }
 104
 105         len = iov_from_buf(elem.in_sg, elem.in_num,
 106                            buf + offset, size - offset);
 107         offset += len;
 108
 109         virtqueue_push(vq, &elem, len);
 110     }
 111
 112     virtio_notify(&port->vser->vdev, vq);
 113     return offset;
 114 }
 115
 116 static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
 117 {
 118     VirtQueueElement elem;
 119
 120     if (!virtio_queue_ready(vq)) {
 121         return;
 122     }
 123     while (virtqueue_pop(vq, &elem)) {
 124         virtqueue_push(vq, &elem, 0);
 125     }
 126     virtio_notify(vdev, vq);
 127 }
 128
 129 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 130                                  VirtIODevice *vdev)
 131 {
 132     VirtIOSerialPortInfo *info;
 133
 134     assert(port);
 135     assert(virtio_queue_ready(vq));
 136
 137     info = DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info);
 138
 139     while (!port->throttled) {
 140         unsigned int i;
 141
 142         /* Pop an elem only if we haven't left off a previous one mid-way */
 143         if (!port->elem.out_num) {
 144             if (!virtqueue_pop(vq, &port->elem)) {
 145                 break;
 146             }
 147             port->iov_idx = 0;
 148             port->iov_offset = 0;
 149         }
 150
 151         for (i = port->iov_idx; i < port->elem.out_num; i++) {
 152             size_t buf_size;
 153             ssize_t ret;
 154
 155             buf_size = port->elem.out_sg[i].iov_len - port->iov_offset;
 156             ret = info->have_data(port,
 157                                   port->elem.out_sg[i].iov_base
 158                                   + port->iov_offset,
 159                                   buf_size);
 160             if (ret < 0 && ret != -EAGAIN) {
 161                 /* We don't handle any other type of errors here */
 162                 abort();
 163             }
 164             if (ret == -EAGAIN || (ret >= 0 && ret < buf_size)) {
 165                 virtio_serial_throttle_port(port, true);
 166                 port->iov_idx = i;
 167                 if (ret > 0) {
 168                     port->iov_offset += ret;
 169                 }
 170                 break;
 171             }
 172             port->iov_offset = 0;
 173         }
 174         if (port->throttled) {
 175             break;
 176         }
 177         virtqueue_push(vq, &port->elem, 0);
 178         port->elem.out_num = 0;
 179     }
 180     virtio_notify(vdev, vq);
 181 }
 182
 183 static void flush_queued_data(VirtIOSerialPort *port)
 184 {
 185     assert(port);
 186
 187     if (!virtio_queue_ready(port->ovq)) {
 188         return;
 189     }
 190     do_flush_queued_data(port, port->ovq, &port->vser->vdev);
 191 }
 192
 193 static size_t send_control_msg(VirtIOSerialPort *port, void *buf, size_t len)
 194 {
 195     VirtQueueElement elem;
 196     VirtQueue *vq;
 197     struct virtio_console_control *cpkt;
 198
 199     vq = port->vser->c_ivq;
 200     if (!virtio_queue_ready(vq)) {
 201         return 0;
 202     }
 203     if (!virtqueue_pop(vq, &elem)) {
 204         return 0;
 205     }
 206
 207     cpkt = (struct virtio_console_control *)buf;
 208     stl_p(&cpkt->id, port->id);
 209     memcpy(elem.in_sg[0].iov_base, buf, len);
 210
 211     virtqueue_push(vq, &elem, len);
 212     virtio_notify(&port->vser->vdev, vq);
 213     return len;
 214 }
 215
 216 static size_t send_control_event(VirtIOSerialPort *port, uint16_t event,
 217                                  uint16_t value)
 218 {
 219     struct virtio_console_control cpkt;
 220
 221     stw_p(&cpkt.event, event);
 222     stw_p(&cpkt.value, value);
 223
 224     return send_control_msg(port, &cpkt, sizeof(cpkt));
 225 }
 226
 227 /* Functions for use inside qemu to open and read from/write to ports */
 228 int virtio_serial_open(VirtIOSerialPort *port)
 229 {
 230     /* Don't allow opening an already-open port */
 231     if (port->host_connected) {
 232         return 0;
 233     }
 234     /* Send port open notification to the guest */
 235     port->host_connected = true;
 236     send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
 237
 238     return 0;
 239 }
 240
 241 int virtio_serial_close(VirtIOSerialPort *port)
 242 {
 243     port->host_connected = false;
 244     /*
 245      * If there's any data the guest sent which the app didn't
 246      * consume, reset the throttling flag and discard the data.
 247      */
 248     port->throttled = false;
 249     discard_vq_data(port->ovq, &port->vser->vdev);
 250
 251     send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
 252
 253     return 0;
 254 }
 255
 256 /* Individual ports/apps call this function to write to the guest. */
 257 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 258                             size_t size)
 259 {
 260     if (!port || !port->host_connected || !port->guest_connected) {
 261         return 0;
 262     }
 263     return write_to_port(port, buf, size);
 264 }
 265
 266 /*
 267  * Readiness of the guest to accept data on a port.
 268  * Returns max. data the guest can receive
 269  */
 270 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 271 {
 272     VirtQueue *vq = port->ivq;
 273
 274     if (!virtio_queue_ready(vq) ||
 275         !(port->vser->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 276         virtio_queue_empty(vq)) {
 277         return 0;
 278     }
 279     if (use_multiport(port->vser) && !port->guest_connected) {
 280         return 0;
 281     }
 282
 283     if (virtqueue_avail_bytes(vq, 4096, 0)) {
 284         return 4096;
 285     }
 286     if (virtqueue_avail_bytes(vq, 1, 0)) {
 287         return 1;
 288     }
 289     return 0;
 290 }
 291
 292 static void flush_queued_data_bh(void *opaque)
 293 {
 294     VirtIOSerialPort *port = opaque;
 295
 296     flush_queued_data(port);
 297 }
 298
 299 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 300 {
 301     if (!port) {
 302         return;
 303     }
 304
 305     port->throttled = throttle;
 306     if (throttle) {
 307         return;
 308     }
 309     qemu_bh_schedule(port->bh);
 310 }
 311
 312 /* Guest wants to notify us of some event */
 313 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 314 {
 315     struct VirtIOSerialPort *port;
 316     struct VirtIOSerialPortInfo *info;
 317     struct virtio_console_control cpkt, *gcpkt;
 318     uint8_t *buffer;
 319     size_t buffer_len;
 320
 321     gcpkt = buf;
 322
 323     if (len < sizeof(cpkt)) {
 324         /* The guest sent an invalid control packet */
 325         return;
 326     }
 327
 328     cpkt.event = lduw_p(&gcpkt->event);
 329     cpkt.value = lduw_p(&gcpkt->value);
 330
 331     port = find_port_by_id(vser, ldl_p(&gcpkt->id));
 332     if (!port && cpkt.event != VIRTIO_CONSOLE_DEVICE_READY)
 333         return;
 334
 335     info = DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info);
 336
 337     switch(cpkt.event) {
 338     case VIRTIO_CONSOLE_DEVICE_READY:
 339         if (!cpkt.value) {
 340             error_report("virtio-serial-bus: Guest failure in adding device %s\n",
 341                          vser->bus.qbus.name);
 342             break;
 343         }
 344         /*
 345          * The device is up, we can now tell the device about all the
 346          * ports we have here.
 347          */
 348         QTAILQ_FOREACH(port, &vser->ports, next) {
 349             send_control_event(port, VIRTIO_CONSOLE_PORT_ADD, 1);
 350         }
 351         break;
 352
 353     case VIRTIO_CONSOLE_PORT_READY:
 354         if (!cpkt.value) {
 355             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s\n",
 356                          port->id, vser->bus.qbus.name);
 357             break;
 358         }
 359         /*
 360          * Now that we know the guest asked for the port name, we're
 361          * sure the guest has initialised whatever state is necessary
 362          * for this port. Now's a good time to let the guest know if
 363          * this port is a console port so that the guest can hook it
 364          * up to hvc.
 365          */
 366         if (info->is_console) {
 367             send_control_event(port, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 368         }
 369
 370         if (port->name) {
 371             stw_p(&cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 372             stw_p(&cpkt.value, 1);
 373
 374             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 375             buffer = qemu_malloc(buffer_len);
 376
 377             memcpy(buffer, &cpkt, sizeof(cpkt));
 378             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 379             buffer[buffer_len - 1] = 0;
 380
 381             send_control_msg(port, buffer, buffer_len);
 382             qemu_free(buffer);
 383         }
 384
 385         if (port->host_connected) {
 386             send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
 387         }
 388
 389         /*
 390          * When the guest has asked us for this information it means
 391          * the guest is all setup and has its virtqueues
 392          * initialised. If some app is interested in knowing about
 393          * this event, let it know.
 394          */
 395         if (info->guest_ready) {
 396             info->guest_ready(port);
 397         }
 398         break;
 399
 400     case VIRTIO_CONSOLE_PORT_OPEN:
 401         port->guest_connected = cpkt.value;
 402         if (cpkt.value && info->guest_open) {
 403             /* Send the guest opened notification if an app is interested */
 404             info->guest_open(port);
 405         }
 406
 407         if (!cpkt.value && info->guest_close) {
 408             /* Send the guest closed notification if an app is interested */
 409             info->guest_close(port);
 410         }
 411         break;
 412     }
 413 }
 414
 415 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 416 {
 417 }
 418
 419 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 420 {
 421     VirtQueueElement elem;
 422     VirtIOSerial *vser;
 423     uint8_t *buf;
 424     size_t len;
 425
 426     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 427
 428     len = 0;
 429     buf = NULL;
 430     while (virtqueue_pop(vq, &elem)) {
 431         size_t cur_len, copied;
 432
 433         cur_len = iov_size(elem.out_sg, elem.out_num);
 434         /*
 435          * Allocate a new buf only if we didn't have one previously or
 436          * if the size of the buf differs
 437          */
 438         if (cur_len > len) {
 439             qemu_free(buf);
 440
 441             buf = qemu_malloc(cur_len);
 442             len = cur_len;
 443         }
 444         copied = iov_to_buf(elem.out_sg, elem.out_num, buf, 0, len);
 445
 446         handle_control_message(vser, buf, copied);
 447         virtqueue_push(vq, &elem, 0);
 448     }
 449     qemu_free(buf);
 450     virtio_notify(vdev, vq);
 451 }
 452
 453 /* Guest wrote something to some port. */
 454 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 455 {
 456     VirtIOSerial *vser;
 457     VirtIOSerialPort *port;
 458     VirtIOSerialPortInfo *info;
 459
 460     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 461     port = find_port_by_vq(vser, vq);
 462     info = port ? DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info) : NULL;
 463
 464     if (!port || !port->host_connected || !info->have_data) {
 465         discard_vq_data(vq, vdev);
 466         return;
 467     }
 468
 469     if (!port->throttled) {
 470         do_flush_queued_data(port, vq, vdev);
 471         return;
 472     }
 473 }
 474
 475 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 476 {
 477 }
 478
 479 static uint32_t get_features(VirtIODevice *vdev, uint32_t features)
 480 {
 481     VirtIOSerial *vser;
 482
 483     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 484
 485     if (vser->bus.max_nr_ports > 1) {
 486         features |= (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 487     }
 488     return features;
 489 }
 490
 491 /* Guest requested config info */
 492 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 493 {
 494     VirtIOSerial *vser;
 495
 496     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 497     memcpy(config_data, &vser->config, sizeof(struct virtio_console_config));
 498 }
 499
 500 static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
 501 {
 502     struct virtio_console_config config;
 503
 504     memcpy(&config, config_data, sizeof(config));
 505 }
 506
 507 static void virtio_serial_save(QEMUFile *f, void *opaque)
 508 {
 509     VirtIOSerial *s = opaque;
 510     VirtIOSerialPort *port;
 511     uint32_t nr_active_ports;
 512     unsigned int i, max_nr_ports;
 513
 514     /* The virtio device */
 515     virtio_save(&s->vdev, f);
 516
 517     /* The config space */
 518     qemu_put_be16s(f, &s->config.cols);
 519     qemu_put_be16s(f, &s->config.rows);
 520
 521     qemu_put_be32s(f, &s->config.max_nr_ports);
 522
 523     /* The ports map */
 524     max_nr_ports = tswap32(s->config.max_nr_ports);
 525     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 526         qemu_put_be32s(f, &s->ports_map[i]);
 527     }
 528
 529     /* Ports */
 530
 531     nr_active_ports = 0;
 532     QTAILQ_FOREACH(port, &s->ports, next) {
 533         nr_active_ports++;
 534     }
 535
 536     qemu_put_be32s(f, &nr_active_ports);
 537
 538     /*
 539      * Items in struct VirtIOSerialPort.
 540      */
 541     QTAILQ_FOREACH(port, &s->ports, next) {
 542         uint32_t elem_popped;
 543
 544         qemu_put_be32s(f, &port->id);
 545         qemu_put_byte(f, port->guest_connected);
 546         qemu_put_byte(f, port->host_connected);
 547
 548         elem_popped = 0;
 549         if (port->elem.out_num) {
 550             elem_popped = 1;
 551         }
 552         qemu_put_be32s(f, &elem_popped);
 553         if (elem_popped) {
 554             qemu_put_be32s(f, &port->iov_idx);
 555             qemu_put_be64s(f, &port->iov_offset);
 556
 557             qemu_put_buffer(f, (unsigned char *)&port->elem,
 558                             sizeof(port->elem));
 559         }
 560     }
 561 }
 562
 563 static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
 564 {
 565     VirtIOSerial *s = opaque;
 566     VirtIOSerialPort *port;
 567     uint32_t max_nr_ports, nr_active_ports, ports_map;
 568     unsigned int i;
 569
 570     if (version_id > 3) {
 571         return -EINVAL;
 572     }
 573
 574     /* The virtio device */
 575     virtio_load(&s->vdev, f);
 576
 577     if (version_id < 2) {
 578         return 0;
 579     }
 580
 581     /* The config space */
 582     qemu_get_be16s(f, &s->config.cols);
 583     qemu_get_be16s(f, &s->config.rows);
 584
 585     qemu_get_be32s(f, &max_nr_ports);
 586     tswap32s(&max_nr_ports);
 587     if (max_nr_ports > tswap32(s->config.max_nr_ports)) {
 588         /* Source could have had more ports than us. Fail migration. */
 589         return -EINVAL;
 590     }
 591
 592     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 593         qemu_get_be32s(f, &ports_map);
 594
 595         if (ports_map != s->ports_map[i]) {
 596             /*
 597              * Ports active on source and destination don't
 598              * match. Fail migration.
 599              */
 600             return -EINVAL;
 601         }
 602     }
 603
 604     qemu_get_be32s(f, &nr_active_ports);
 605
 606     /* Items in struct VirtIOSerialPort */
 607     for (i = 0; i < nr_active_ports; i++) {
 608         uint32_t id;
 609         bool host_connected;
 610
 611         id = qemu_get_be32(f);
 612         port = find_port_by_id(s, id);
 613         if (!port) {
 614             return -EINVAL;
 615         }
 616
 617         port->guest_connected = qemu_get_byte(f);
 618         host_connected = qemu_get_byte(f);
 619         if (host_connected != port->host_connected) {
 620             /*
 621              * We have to let the guest know of the host connection
 622              * status change
 623              */
 624             send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN,
 625                                port->host_connected);
 626         }
 627
 628         if (version_id > 2) {
 629             uint32_t elem_popped;
 630
 631             qemu_get_be32s(f, &elem_popped);
 632             if (elem_popped) {
 633                 qemu_get_be32s(f, &port->iov_idx);
 634                 qemu_get_be64s(f, &port->iov_offset);
 635
 636                 qemu_get_buffer(f, (unsigned char *)&port->elem,
 637                                 sizeof(port->elem));
 638                 virtqueue_map_sg(port->elem.in_sg, port->elem.in_addr,
 639                                  port->elem.in_num, 1);
 640                 virtqueue_map_sg(port->elem.out_sg, port->elem.out_addr,
 641                                  port->elem.out_num, 1);
 642
 643                 /*
 644                  *  Port was throttled on source machine.  Let's
 645                  *  unthrottle it here so data starts flowing again.
 646                  */
 647                 virtio_serial_throttle_port(port, false);
 648             }
 649         }
 650     }
 651     return 0;
 652 }
 653
 654 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 655
 656 static struct BusInfo virtser_bus_info = {
 657     .name      = "virtio-serial-bus",
 658     .size      = sizeof(VirtIOSerialBus),
 659     .print_dev = virtser_bus_dev_print,
 660 };
 661
 662 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 663 {
 664     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 665
 666     monitor_printf(mon, "%*s dev-prop-int: id: %u\n",
 667                    indent, "", port->id);
 668     monitor_printf(mon, "%*s dev-prop-int: guest_connected: %d\n",
 669                    indent, "", port->guest_connected);
 670     monitor_printf(mon, "%*s dev-prop-int: host_connected: %d\n",
 671                    indent, "", port->host_connected);
 672     monitor_printf(mon, "%*s dev-prop-int: throttled: %d\n",
 673                    indent, "", port->throttled);
 674 }
 675
 676 /* This function is only used if a port id is not provided by the user */
 677 static uint32_t find_free_port_id(VirtIOSerial *vser)
 678 {
 679     unsigned int i, max_nr_ports;
 680
 681     max_nr_ports = tswap32(vser->config.max_nr_ports);
 682     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 683         uint32_t map, bit;
 684
 685         map = vser->ports_map[i];
 686         bit = ffs(~map);
 687         if (bit) {
 688             return (bit - 1) + i * 32;
 689         }
 690     }
 691     return VIRTIO_CONSOLE_BAD_ID;
 692 }
 693
 694 static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 695 {
 696     unsigned int i;
 697
 698     i = port_id / 32;
 699     vser->ports_map[i] |= 1U << (port_id % 32);
 700 }
 701
 702 static void add_port(VirtIOSerial *vser, uint32_t port_id)
 703 {
 704     mark_port_added(vser, port_id);
 705
 706     send_control_event(find_port_by_id(vser, port_id),
 707                        VIRTIO_CONSOLE_PORT_ADD, 1);
 708 }
 709
 710 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 711 {
 712     VirtIOSerialPort *port;
 713     unsigned int i;
 714
 715     i = port_id / 32;
 716     vser->ports_map[i] &= ~(1U << (port_id % 32));
 717
 718     port = find_port_by_id(vser, port_id);
 719     /* Flush out any unconsumed buffers first */
 720     discard_vq_data(port->ovq, &port->vser->vdev);
 721
 722     send_control_event(port, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 723 }
 724
 725 static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
 726 {
 727     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 728     VirtIOSerialPortInfo *info = DO_UPCAST(VirtIOSerialPortInfo, qdev, base);
 729     VirtIOSerialBus *bus = DO_UPCAST(VirtIOSerialBus, qbus, qdev->parent_bus);
 730     int ret, max_nr_ports;
 731     bool plugging_port0;
 732
 733     port->vser = bus->vser;
 734     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 735
 736     /*
 737      * Is the first console port we're seeing? If so, put it up at
 738      * location 0. This is done for backward compatibility (old
 739      * kernel, new qemu).
 740      */
 741     plugging_port0 = info->is_console && !find_port_by_id(port->vser, 0);
 742
 743     if (find_port_by_id(port->vser, port->id)) {
 744         error_report("virtio-serial-bus: A port already exists at id %u\n",
 745                      port->id);
 746         return -1;
 747     }
 748
 749     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 750         if (plugging_port0) {
 751             port->id = 0;
 752         } else {
 753             port->id = find_free_port_id(port->vser);
 754             if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 755                 error_report("virtio-serial-bus: Maximum port limit for this device reached\n");
 756                 return -1;
 757             }
 758         }
 759     }
 760
 761     max_nr_ports = tswap32(port->vser->config.max_nr_ports);
 762     if (port->id >= max_nr_ports) {
 763         error_report("virtio-serial-bus: Out-of-range port id specified, max. allowed: %u\n",
 764                      max_nr_ports - 1);
 765         return -1;
 766     }
 767
 768     ret = info->init(port);
 769     if (ret) {
 770         return ret;
 771     }
 772
 773     if (!use_multiport(port->vser)) {
 774         /*
 775          * Allow writes to guest in this case; we have no way of
 776          * knowing if a guest port is connected.
 777          */
 778         port->guest_connected = true;
 779     }
 780
 781     port->elem.out_num = 0;
 782
 783     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
 784     port->ivq = port->vser->ivqs[port->id];
 785     port->ovq = port->vser->ovqs[port->id];
 786
 787     add_port(port->vser, port->id);
 788
 789     /* Send an update to the guest about this new port added */
 790     virtio_notify_config(&port->vser->vdev);
 791
 792     return ret;
 793 }
 794
 795 static int virtser_port_qdev_exit(DeviceState *qdev)
 796 {
 797     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 798     VirtIOSerialPortInfo *info = DO_UPCAST(VirtIOSerialPortInfo, qdev,
 799                                            port->dev.info);
 800     VirtIOSerial *vser = port->vser;
 801
 802     qemu_bh_delete(port->bh);
 803     remove_port(port->vser, port->id);
 804
 805     QTAILQ_REMOVE(&vser->ports, port, next);
 806
 807     if (info->exit) {
 808         info->exit(port);
 809     }
 810     return 0;
 811 }
 812
 813 void virtio_serial_port_qdev_register(VirtIOSerialPortInfo *info)
 814 {
 815     info->qdev.init = virtser_port_qdev_init;
 816     info->qdev.bus_info = &virtser_bus_info;
 817     info->qdev.exit = virtser_port_qdev_exit;
 818     info->qdev.unplug = qdev_simple_unplug_cb;
 819     qdev_register(&info->qdev);
 820 }
 821
 822 VirtIODevice *virtio_serial_init(DeviceState *dev, virtio_serial_conf *conf)
 823 {
 824     VirtIOSerial *vser;
 825     VirtIODevice *vdev;
 826     uint32_t i, max_supported_ports;
 827
 828     if (!conf->max_virtserial_ports)
 829         return NULL;
 830
 831     /* Each port takes 2 queues, and one pair is for the control queue */
 832     max_supported_ports = VIRTIO_PCI_QUEUE_MAX / 2 - 1;
 833
 834     if (conf->max_virtserial_ports > max_supported_ports) {
 835         error_report("maximum ports supported: %u", max_supported_ports);
 836         return NULL;
 837     }
 838
 839     vdev = virtio_common_init("virtio-serial", VIRTIO_ID_CONSOLE,
 840                               sizeof(struct virtio_console_config),
 841                               sizeof(VirtIOSerial));
 842
 843     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 844
 845     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
 846     qbus_create_inplace(&vser->bus.qbus, &virtser_bus_info, dev, NULL);
 847     vser->bus.qbus.allow_hotplug = 1;
 848     vser->bus.vser = vser;
 849     QTAILQ_INIT(&vser->ports);
 850
 851     vser->bus.max_nr_ports = conf->max_virtserial_ports;
 852     vser->ivqs = qemu_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 853     vser->ovqs = qemu_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 854
 855     /* Add a queue for host to guest transfers for port 0 (backward compat) */
 856     vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
 857     /* Add a queue for guest to host transfers for port 0 (backward compat) */
 858     vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
 859
 860     /* TODO: host to guest notifications can get dropped
 861      * if the queue fills up. Implement queueing in host,
 862      * this might also make it possible to reduce the control
 863      * queue size: as guest preposts buffers there,
 864      * this will save 4Kbyte of guest memory per entry. */
 865
 866     /* control queue: host to guest */
 867     vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
 868     /* control queue: guest to host */
 869     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
 870
 871     for (i = 1; i < vser->bus.max_nr_ports; i++) {
 872         /* Add a per-port queue for host to guest transfers */
 873         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
 874         /* Add a per-per queue for guest to host transfers */
 875         vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
 876     }
 877
 878     vser->config.max_nr_ports = tswap32(conf->max_virtserial_ports);
 879     vser->ports_map = qemu_mallocz(((conf->max_virtserial_ports + 31) / 32)
 880         * sizeof(vser->ports_map[0]));
 881     /*
 882      * Reserve location 0 for a console port for backward compat
 883      * (old kernel, new qemu)
 884      */
 885     mark_port_added(vser, 0);
 886
 887     vser->vdev.get_features = get_features;
 888     vser->vdev.get_config = get_config;
 889     vser->vdev.set_config = set_config;
 890
 891     vser->qdev = dev;
 892
 893     /*
 894      * Register for the savevm section with the virtio-console name
 895      * to preserve backward compat
 896      */
 897     register_savevm(dev, "virtio-console", -1, 3, virtio_serial_save,
 898                     virtio_serial_load, vser);
 899
 900     return vdev;
 901 }
 902
 903 void virtio_serial_exit(VirtIODevice *vdev)
 904 {
 905     VirtIOSerial *vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 906
 907     unregister_savevm(vser->qdev, "virtio-console", vser);
 908
 909     qemu_free(vser->ivqs);
 910     qemu_free(vser->ovqs);
 911     qemu_free(vser->ports_map);
 912
 913     virtio_cleanup(vdev);
 914 }