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  * Contributions after 2012-01-13 are licensed under the terms of the
  18  * GNU GPL, version 2 or (at your option) any later version.
  19  */
  20
  21 #include "iov.h"
  22 #include "monitor.h"
  23 #include "qemu-queue.h"
  24 #include "sysbus.h"
  25 #include "trace.h"
  26 #include "virtio-serial.h"
  27
  28 /* The virtio-serial bus on top of which the ports will ride as devices */
  29 struct VirtIOSerialBus {
  30     BusState qbus;
  31
  32     /* This is the parent device that provides the bus for ports. */
  33     VirtIOSerial *vser;
  34
  35     /* The maximum number of ports that can ride on top of this bus */
  36     uint32_t max_nr_ports;
  37 };
  38
  39 struct VirtIOSerial {
  40     VirtIODevice vdev;
  41
  42     VirtQueue *c_ivq, *c_ovq;
  43     /* Arrays of ivqs and ovqs: one per port */
  44     VirtQueue **ivqs, **ovqs;
  45
  46     VirtIOSerialBus bus;
  47
  48     DeviceState *qdev;
  49
  50     QTAILQ_HEAD(, VirtIOSerialPort) ports;
  51
  52     /* bitmap for identifying active ports */
  53     uint32_t *ports_map;
  54
  55     struct virtio_console_config config;
  56 };
  57
  58 static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
  59 {
  60     VirtIOSerialPort *port;
  61
  62     if (id == VIRTIO_CONSOLE_BAD_ID) {
  63         return NULL;
  64     }
  65
  66     QTAILQ_FOREACH(port, &vser->ports, next) {
  67         if (port->id == id)
  68             return port;
  69     }
  70     return NULL;
  71 }
  72
  73 static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
  74 {
  75     VirtIOSerialPort *port;
  76
  77     QTAILQ_FOREACH(port, &vser->ports, next) {
  78         if (port->ivq == vq || port->ovq == vq)
  79             return port;
  80     }
  81     return NULL;
  82 }
  83
  84 static bool use_multiport(VirtIOSerial *vser)
  85 {
  86     return vser->vdev.guest_features & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
  87 }
  88
  89 static size_t write_to_port(VirtIOSerialPort *port,
  90                             const uint8_t *buf, size_t size)
  91 {
  92     VirtQueueElement elem;
  93     VirtQueue *vq;
  94     size_t offset;
  95
  96     vq = port->ivq;
  97     if (!virtio_queue_ready(vq)) {
  98         return 0;
  99     }
 100
 101     offset = 0;
 102     while (offset < size) {
 103         size_t len;
 104
 105         if (!virtqueue_pop(vq, &elem)) {
 106             break;
 107         }
 108
 109         len = iov_from_buf(elem.in_sg, elem.in_num,
 110                            buf + offset, 0, size - offset);
 111         offset += len;
 112
 113         virtqueue_push(vq, &elem, len);
 114     }
 115
 116     virtio_notify(&port->vser->vdev, vq);
 117     return offset;
 118 }
 119
 120 static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
 121 {
 122     VirtQueueElement elem;
 123
 124     if (!virtio_queue_ready(vq)) {
 125         return;
 126     }
 127     while (virtqueue_pop(vq, &elem)) {
 128         virtqueue_push(vq, &elem, 0);
 129     }
 130     virtio_notify(vdev, vq);
 131 }
 132
 133 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 134                                  VirtIODevice *vdev)
 135 {
 136     VirtIOSerialPortClass *vsc;
 137
 138     assert(port);
 139     assert(virtio_queue_ready(vq));
 140
 141     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 142
 143     while (!port->throttled) {
 144         unsigned int i;
 145
 146         /* Pop an elem only if we haven't left off a previous one mid-way */
 147         if (!port->elem.out_num) {
 148             if (!virtqueue_pop(vq, &port->elem)) {
 149                 break;
 150             }
 151             port->iov_idx = 0;
 152             port->iov_offset = 0;
 153         }
 154
 155         for (i = port->iov_idx; i < port->elem.out_num; i++) {
 156             size_t buf_size;
 157             ssize_t ret;
 158
 159             buf_size = port->elem.out_sg[i].iov_len - port->iov_offset;
 160             ret = vsc->have_data(port,
 161                                   port->elem.out_sg[i].iov_base
 162                                   + port->iov_offset,
 163                                   buf_size);
 164             if (ret < 0 && ret != -EAGAIN) {
 165                 /* We don't handle any other type of errors here */
 166                 abort();
 167             }
 168             if (ret == -EAGAIN || (ret >= 0 && ret < buf_size)) {
 169                 /*
 170                  * this is a temporary check until chardevs can signal to
 171                  * frontends that they are writable again. This prevents
 172                  * the console from going into throttled mode (forever)
 173                  * if virtio-console is connected to a pty without a
 174                  * listener. Otherwise the guest spins forever.
 175                  * We can revert this if
 176                  * 1: chardevs can notify frondends
 177                  * 2: the guest driver does not spin in these cases
 178                  */
 179                 if (!vsc->is_console) {
 180                     virtio_serial_throttle_port(port, true);
 181                 }
 182                 port->iov_idx = i;
 183                 if (ret > 0) {
 184                     port->iov_offset += ret;
 185                 }
 186                 break;
 187             }
 188             port->iov_offset = 0;
 189         }
 190         if (port->throttled) {
 191             break;
 192         }
 193         virtqueue_push(vq, &port->elem, 0);
 194         port->elem.out_num = 0;
 195     }
 196     virtio_notify(vdev, vq);
 197 }
 198
 199 static void flush_queued_data(VirtIOSerialPort *port)
 200 {
 201     assert(port);
 202
 203     if (!virtio_queue_ready(port->ovq)) {
 204         return;
 205     }
 206     do_flush_queued_data(port, port->ovq, &port->vser->vdev);
 207 }
 208
 209 static size_t send_control_msg(VirtIOSerialPort *port, void *buf, size_t len)
 210 {
 211     VirtQueueElement elem;
 212     VirtQueue *vq;
 213     struct virtio_console_control *cpkt;
 214
 215     vq = port->vser->c_ivq;
 216     if (!virtio_queue_ready(vq)) {
 217         return 0;
 218     }
 219     if (!virtqueue_pop(vq, &elem)) {
 220         return 0;
 221     }
 222
 223     cpkt = (struct virtio_console_control *)buf;
 224     stl_p(&cpkt->id, port->id);
 225     memcpy(elem.in_sg[0].iov_base, buf, len);
 226
 227     virtqueue_push(vq, &elem, len);
 228     virtio_notify(&port->vser->vdev, vq);
 229     return len;
 230 }
 231
 232 static size_t send_control_event(VirtIOSerialPort *port, uint16_t event,
 233                                  uint16_t value)
 234 {
 235     struct virtio_console_control cpkt;
 236
 237     stw_p(&cpkt.event, event);
 238     stw_p(&cpkt.value, value);
 239
 240     trace_virtio_serial_send_control_event(port->id, event, value);
 241     return send_control_msg(port, &cpkt, sizeof(cpkt));
 242 }
 243
 244 /* Functions for use inside qemu to open and read from/write to ports */
 245 int virtio_serial_open(VirtIOSerialPort *port)
 246 {
 247     /* Don't allow opening an already-open port */
 248     if (port->host_connected) {
 249         return 0;
 250     }
 251     /* Send port open notification to the guest */
 252     port->host_connected = true;
 253     send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
 254
 255     return 0;
 256 }
 257
 258 int virtio_serial_close(VirtIOSerialPort *port)
 259 {
 260     port->host_connected = false;
 261     /*
 262      * If there's any data the guest sent which the app didn't
 263      * consume, reset the throttling flag and discard the data.
 264      */
 265     port->throttled = false;
 266     discard_vq_data(port->ovq, &port->vser->vdev);
 267
 268     send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
 269
 270     return 0;
 271 }
 272
 273 /* Individual ports/apps call this function to write to the guest. */
 274 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 275                             size_t size)
 276 {
 277     if (!port || !port->host_connected || !port->guest_connected) {
 278         return 0;
 279     }
 280     return write_to_port(port, buf, size);
 281 }
 282
 283 /*
 284  * Readiness of the guest to accept data on a port.
 285  * Returns max. data the guest can receive
 286  */
 287 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 288 {
 289     VirtQueue *vq = port->ivq;
 290
 291     if (!virtio_queue_ready(vq) ||
 292         !(port->vser->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 293         virtio_queue_empty(vq)) {
 294         return 0;
 295     }
 296     if (use_multiport(port->vser) && !port->guest_connected) {
 297         return 0;
 298     }
 299
 300     if (virtqueue_avail_bytes(vq, 4096, 0)) {
 301         return 4096;
 302     }
 303     if (virtqueue_avail_bytes(vq, 1, 0)) {
 304         return 1;
 305     }
 306     return 0;
 307 }
 308
 309 static void flush_queued_data_bh(void *opaque)
 310 {
 311     VirtIOSerialPort *port = opaque;
 312
 313     flush_queued_data(port);
 314 }
 315
 316 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 317 {
 318     if (!port) {
 319         return;
 320     }
 321
 322     trace_virtio_serial_throttle_port(port->id, throttle);
 323     port->throttled = throttle;
 324     if (throttle) {
 325         return;
 326     }
 327     qemu_bh_schedule(port->bh);
 328 }
 329
 330 /* Guest wants to notify us of some event */
 331 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 332 {
 333     struct VirtIOSerialPort *port;
 334     VirtIOSerialPortClass *vsc;
 335     struct virtio_console_control cpkt, *gcpkt;
 336     uint8_t *buffer;
 337     size_t buffer_len;
 338
 339     gcpkt = buf;
 340
 341     if (len < sizeof(cpkt)) {
 342         /* The guest sent an invalid control packet */
 343         return;
 344     }
 345
 346     cpkt.event = lduw_p(&gcpkt->event);
 347     cpkt.value = lduw_p(&gcpkt->value);
 348
 349     trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 350
 351     if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 352         if (!cpkt.value) {
 353             error_report("virtio-serial-bus: Guest failure in adding device %s",
 354                          vser->bus.qbus.name);
 355             return;
 356         }
 357         /*
 358          * The device is up, we can now tell the device about all the
 359          * ports we have here.
 360          */
 361         QTAILQ_FOREACH(port, &vser->ports, next) {
 362             send_control_event(port, VIRTIO_CONSOLE_PORT_ADD, 1);
 363         }
 364         return;
 365     }
 366
 367     port = find_port_by_id(vser, ldl_p(&gcpkt->id));
 368     if (!port) {
 369         error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 370                      ldl_p(&gcpkt->id), vser->bus.qbus.name);
 371         return;
 372     }
 373
 374     trace_virtio_serial_handle_control_message_port(port->id);
 375
 376     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 377
 378     switch(cpkt.event) {
 379     case VIRTIO_CONSOLE_PORT_READY:
 380         if (!cpkt.value) {
 381             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 382                          port->id, vser->bus.qbus.name);
 383             break;
 384         }
 385         /*
 386          * Now that we know the guest asked for the port name, we're
 387          * sure the guest has initialised whatever state is necessary
 388          * for this port. Now's a good time to let the guest know if
 389          * this port is a console port so that the guest can hook it
 390          * up to hvc.
 391          */
 392         if (vsc->is_console) {
 393             send_control_event(port, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 394         }
 395
 396         if (port->name) {
 397             stw_p(&cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 398             stw_p(&cpkt.value, 1);
 399
 400             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 401             buffer = g_malloc(buffer_len);
 402
 403             memcpy(buffer, &cpkt, sizeof(cpkt));
 404             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 405             buffer[buffer_len - 1] = 0;
 406
 407             send_control_msg(port, buffer, buffer_len);
 408             g_free(buffer);
 409         }
 410
 411         if (port->host_connected) {
 412             send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
 413         }
 414
 415         /*
 416          * When the guest has asked us for this information it means
 417          * the guest is all setup and has its virtqueues
 418          * initialised. If some app is interested in knowing about
 419          * this event, let it know.
 420          */
 421         if (vsc->guest_ready) {
 422             vsc->guest_ready(port);
 423         }
 424         break;
 425
 426     case VIRTIO_CONSOLE_PORT_OPEN:
 427         port->guest_connected = cpkt.value;
 428         if (cpkt.value && vsc->guest_open) {
 429             /* Send the guest opened notification if an app is interested */
 430             vsc->guest_open(port);
 431         }
 432
 433         if (!cpkt.value && vsc->guest_close) {
 434             /* Send the guest closed notification if an app is interested */
 435             vsc->guest_close(port);
 436         }
 437         break;
 438     }
 439 }
 440
 441 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 442 {
 443 }
 444
 445 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 446 {
 447     VirtQueueElement elem;
 448     VirtIOSerial *vser;
 449     uint8_t *buf;
 450     size_t len;
 451
 452     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 453
 454     len = 0;
 455     buf = NULL;
 456     while (virtqueue_pop(vq, &elem)) {
 457         size_t cur_len, copied;
 458
 459         cur_len = iov_size(elem.out_sg, elem.out_num);
 460         /*
 461          * Allocate a new buf only if we didn't have one previously or
 462          * if the size of the buf differs
 463          */
 464         if (cur_len > len) {
 465             g_free(buf);
 466
 467             buf = g_malloc(cur_len);
 468             len = cur_len;
 469         }
 470         copied = iov_to_buf(elem.out_sg, elem.out_num, buf, 0, len);
 471
 472         handle_control_message(vser, buf, copied);
 473         virtqueue_push(vq, &elem, 0);
 474     }
 475     g_free(buf);
 476     virtio_notify(vdev, vq);
 477 }
 478
 479 /* Guest wrote something to some port. */
 480 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 481 {
 482     VirtIOSerial *vser;
 483     VirtIOSerialPort *port;
 484
 485     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 486     port = find_port_by_vq(vser, vq);
 487
 488     if (!port || !port->host_connected) {
 489         discard_vq_data(vq, vdev);
 490         return;
 491     }
 492
 493     if (!port->throttled) {
 494         do_flush_queued_data(port, vq, vdev);
 495         return;
 496     }
 497 }
 498
 499 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 500 {
 501 }
 502
 503 static uint32_t get_features(VirtIODevice *vdev, uint32_t features)
 504 {
 505     VirtIOSerial *vser;
 506
 507     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 508
 509     if (vser->bus.max_nr_ports > 1) {
 510         features |= (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 511     }
 512     return features;
 513 }
 514
 515 /* Guest requested config info */
 516 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 517 {
 518     VirtIOSerial *vser;
 519
 520     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 521     memcpy(config_data, &vser->config, sizeof(struct virtio_console_config));
 522 }
 523
 524 static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
 525 {
 526     struct virtio_console_config config;
 527
 528     memcpy(&config, config_data, sizeof(config));
 529 }
 530
 531 static void virtio_serial_save(QEMUFile *f, void *opaque)
 532 {
 533     VirtIOSerial *s = opaque;
 534     VirtIOSerialPort *port;
 535     uint32_t nr_active_ports;
 536     unsigned int i, max_nr_ports;
 537
 538     /* The virtio device */
 539     virtio_save(&s->vdev, f);
 540
 541     /* The config space */
 542     qemu_put_be16s(f, &s->config.cols);
 543     qemu_put_be16s(f, &s->config.rows);
 544
 545     qemu_put_be32s(f, &s->config.max_nr_ports);
 546
 547     /* The ports map */
 548     max_nr_ports = tswap32(s->config.max_nr_ports);
 549     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 550         qemu_put_be32s(f, &s->ports_map[i]);
 551     }
 552
 553     /* Ports */
 554
 555     nr_active_ports = 0;
 556     QTAILQ_FOREACH(port, &s->ports, next) {
 557         nr_active_ports++;
 558     }
 559
 560     qemu_put_be32s(f, &nr_active_ports);
 561
 562     /*
 563      * Items in struct VirtIOSerialPort.
 564      */
 565     QTAILQ_FOREACH(port, &s->ports, next) {
 566         uint32_t elem_popped;
 567
 568         qemu_put_be32s(f, &port->id);
 569         qemu_put_byte(f, port->guest_connected);
 570         qemu_put_byte(f, port->host_connected);
 571
 572         elem_popped = 0;
 573         if (port->elem.out_num) {
 574             elem_popped = 1;
 575         }
 576         qemu_put_be32s(f, &elem_popped);
 577         if (elem_popped) {
 578             qemu_put_be32s(f, &port->iov_idx);
 579             qemu_put_be64s(f, &port->iov_offset);
 580
 581             qemu_put_buffer(f, (unsigned char *)&port->elem,
 582                             sizeof(port->elem));
 583         }
 584     }
 585 }
 586
 587 static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
 588 {
 589     VirtIOSerial *s = opaque;
 590     VirtIOSerialPort *port;
 591     uint32_t max_nr_ports, nr_active_ports, ports_map;
 592     unsigned int i;
 593
 594     if (version_id > 3) {
 595         return -EINVAL;
 596     }
 597
 598     /* The virtio device */
 599     virtio_load(&s->vdev, f);
 600
 601     if (version_id < 2) {
 602         return 0;
 603     }
 604
 605     /* The config space */
 606     qemu_get_be16s(f, &s->config.cols);
 607     qemu_get_be16s(f, &s->config.rows);
 608
 609     qemu_get_be32s(f, &max_nr_ports);
 610     tswap32s(&max_nr_ports);
 611     if (max_nr_ports > tswap32(s->config.max_nr_ports)) {
 612         /* Source could have had more ports than us. Fail migration. */
 613         return -EINVAL;
 614     }
 615
 616     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 617         qemu_get_be32s(f, &ports_map);
 618
 619         if (ports_map != s->ports_map[i]) {
 620             /*
 621              * Ports active on source and destination don't
 622              * match. Fail migration.
 623              */
 624             return -EINVAL;
 625         }
 626     }
 627
 628     qemu_get_be32s(f, &nr_active_ports);
 629
 630     /* Items in struct VirtIOSerialPort */
 631     for (i = 0; i < nr_active_ports; i++) {
 632         uint32_t id;
 633         bool host_connected;
 634
 635         id = qemu_get_be32(f);
 636         port = find_port_by_id(s, id);
 637         if (!port) {
 638             return -EINVAL;
 639         }
 640
 641         port->guest_connected = qemu_get_byte(f);
 642         host_connected = qemu_get_byte(f);
 643         if (host_connected != port->host_connected) {
 644             /*
 645              * We have to let the guest know of the host connection
 646              * status change
 647              */
 648             send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN,
 649                                port->host_connected);
 650         }
 651
 652         if (version_id > 2) {
 653             uint32_t elem_popped;
 654
 655             qemu_get_be32s(f, &elem_popped);
 656             if (elem_popped) {
 657                 qemu_get_be32s(f, &port->iov_idx);
 658                 qemu_get_be64s(f, &port->iov_offset);
 659
 660                 qemu_get_buffer(f, (unsigned char *)&port->elem,
 661                                 sizeof(port->elem));
 662                 virtqueue_map_sg(port->elem.in_sg, port->elem.in_addr,
 663                                  port->elem.in_num, 1);
 664                 virtqueue_map_sg(port->elem.out_sg, port->elem.out_addr,
 665                                  port->elem.out_num, 1);
 666
 667                 /*
 668                  *  Port was throttled on source machine.  Let's
 669                  *  unthrottle it here so data starts flowing again.
 670                  */
 671                 virtio_serial_throttle_port(port, false);
 672             }
 673         }
 674     }
 675     return 0;
 676 }
 677
 678 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 679
 680 static struct BusInfo virtser_bus_info = {
 681     .name      = "virtio-serial-bus",
 682     .size      = sizeof(VirtIOSerialBus),
 683     .print_dev = virtser_bus_dev_print,
 684     .props      = (Property[]) {
 685         DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 686         DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 687         DEFINE_PROP_END_OF_LIST()
 688     }
 689 };
 690
 691 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 692 {
 693     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 694
 695     monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 696                    indent, "", port->id,
 697                    port->guest_connected ? "on" : "off",
 698                    port->host_connected ? "on" : "off",
 699                    port->throttled ? "on" : "off");
 700 }
 701
 702 /* This function is only used if a port id is not provided by the user */
 703 static uint32_t find_free_port_id(VirtIOSerial *vser)
 704 {
 705     unsigned int i, max_nr_ports;
 706
 707     max_nr_ports = tswap32(vser->config.max_nr_ports);
 708     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 709         uint32_t map, bit;
 710
 711         map = vser->ports_map[i];
 712         bit = ffs(~map);
 713         if (bit) {
 714             return (bit - 1) + i * 32;
 715         }
 716     }
 717     return VIRTIO_CONSOLE_BAD_ID;
 718 }
 719
 720 static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 721 {
 722     unsigned int i;
 723
 724     i = port_id / 32;
 725     vser->ports_map[i] |= 1U << (port_id % 32);
 726 }
 727
 728 static void add_port(VirtIOSerial *vser, uint32_t port_id)
 729 {
 730     mark_port_added(vser, port_id);
 731
 732     send_control_event(find_port_by_id(vser, port_id),
 733                        VIRTIO_CONSOLE_PORT_ADD, 1);
 734 }
 735
 736 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 737 {
 738     VirtIOSerialPort *port;
 739     unsigned int i;
 740
 741     i = port_id / 32;
 742     vser->ports_map[i] &= ~(1U << (port_id % 32));
 743
 744     port = find_port_by_id(vser, port_id);
 745     /* Flush out any unconsumed buffers first */
 746     discard_vq_data(port->ovq, &port->vser->vdev);
 747
 748     send_control_event(port, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 749 }
 750
 751 static int virtser_port_qdev_init(DeviceState *qdev)
 752 {
 753     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 754     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 755     VirtIOSerialBus *bus = DO_UPCAST(VirtIOSerialBus, qbus, qdev->parent_bus);
 756     int ret, max_nr_ports;
 757     bool plugging_port0;
 758
 759     port->vser = bus->vser;
 760     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 761
 762     assert(vsc->have_data);
 763
 764     /*
 765      * Is the first console port we're seeing? If so, put it up at
 766      * location 0. This is done for backward compatibility (old
 767      * kernel, new qemu).
 768      */
 769     plugging_port0 = vsc->is_console && !find_port_by_id(port->vser, 0);
 770
 771     if (find_port_by_id(port->vser, port->id)) {
 772         error_report("virtio-serial-bus: A port already exists at id %u",
 773                      port->id);
 774         return -1;
 775     }
 776
 777     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 778         if (plugging_port0) {
 779             port->id = 0;
 780         } else {
 781             port->id = find_free_port_id(port->vser);
 782             if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 783                 error_report("virtio-serial-bus: Maximum port limit for this device reached");
 784                 return -1;
 785             }
 786         }
 787     }
 788
 789     max_nr_ports = tswap32(port->vser->config.max_nr_ports);
 790     if (port->id >= max_nr_ports) {
 791         error_report("virtio-serial-bus: Out-of-range port id specified, max. allowed: %u",
 792                      max_nr_ports - 1);
 793         return -1;
 794     }
 795
 796     ret = vsc->init(port);
 797     if (ret) {
 798         return ret;
 799     }
 800
 801     if (!use_multiport(port->vser)) {
 802         /*
 803          * Allow writes to guest in this case; we have no way of
 804          * knowing if a guest port is connected.
 805          */
 806         port->guest_connected = true;
 807     }
 808
 809     port->elem.out_num = 0;
 810
 811     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
 812     port->ivq = port->vser->ivqs[port->id];
 813     port->ovq = port->vser->ovqs[port->id];
 814
 815     add_port(port->vser, port->id);
 816
 817     /* Send an update to the guest about this new port added */
 818     virtio_notify_config(&port->vser->vdev);
 819
 820     return ret;
 821 }
 822
 823 static int virtser_port_qdev_exit(DeviceState *qdev)
 824 {
 825     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 826     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 827     VirtIOSerial *vser = port->vser;
 828
 829     qemu_bh_delete(port->bh);
 830     remove_port(port->vser, port->id);
 831
 832     QTAILQ_REMOVE(&vser->ports, port, next);
 833
 834     if (vsc->exit) {
 835         vsc->exit(port);
 836     }
 837     return 0;
 838 }
 839
 840 VirtIODevice *virtio_serial_init(DeviceState *dev, virtio_serial_conf *conf)
 841 {
 842     VirtIOSerial *vser;
 843     VirtIODevice *vdev;
 844     uint32_t i, max_supported_ports;
 845
 846     if (!conf->max_virtserial_ports)
 847         return NULL;
 848
 849     /* Each port takes 2 queues, and one pair is for the control queue */
 850     max_supported_ports = VIRTIO_PCI_QUEUE_MAX / 2 - 1;
 851
 852     if (conf->max_virtserial_ports > max_supported_ports) {
 853         error_report("maximum ports supported: %u", max_supported_ports);
 854         return NULL;
 855     }
 856
 857     vdev = virtio_common_init("virtio-serial", VIRTIO_ID_CONSOLE,
 858                               sizeof(struct virtio_console_config),
 859                               sizeof(VirtIOSerial));
 860
 861     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 862
 863     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
 864     qbus_create_inplace(&vser->bus.qbus, &virtser_bus_info, dev, NULL);
 865     vser->bus.qbus.allow_hotplug = 1;
 866     vser->bus.vser = vser;
 867     QTAILQ_INIT(&vser->ports);
 868
 869     vser->bus.max_nr_ports = conf->max_virtserial_ports;
 870     vser->ivqs = g_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 871     vser->ovqs = g_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 872
 873     /* Add a queue for host to guest transfers for port 0 (backward compat) */
 874     vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
 875     /* Add a queue for guest to host transfers for port 0 (backward compat) */
 876     vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
 877
 878     /* TODO: host to guest notifications can get dropped
 879      * if the queue fills up. Implement queueing in host,
 880      * this might also make it possible to reduce the control
 881      * queue size: as guest preposts buffers there,
 882      * this will save 4Kbyte of guest memory per entry. */
 883
 884     /* control queue: host to guest */
 885     vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
 886     /* control queue: guest to host */
 887     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
 888
 889     for (i = 1; i < vser->bus.max_nr_ports; i++) {
 890         /* Add a per-port queue for host to guest transfers */
 891         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
 892         /* Add a per-per queue for guest to host transfers */
 893         vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
 894     }
 895
 896     vser->config.max_nr_ports = tswap32(conf->max_virtserial_ports);
 897     vser->ports_map = g_malloc0(((conf->max_virtserial_ports + 31) / 32)
 898         * sizeof(vser->ports_map[0]));
 899     /*
 900      * Reserve location 0 for a console port for backward compat
 901      * (old kernel, new qemu)
 902      */
 903     mark_port_added(vser, 0);
 904
 905     vser->vdev.get_features = get_features;
 906     vser->vdev.get_config = get_config;
 907     vser->vdev.set_config = set_config;
 908
 909     vser->qdev = dev;
 910
 911     /*
 912      * Register for the savevm section with the virtio-console name
 913      * to preserve backward compat
 914      */
 915     register_savevm(dev, "virtio-console", -1, 3, virtio_serial_save,
 916                     virtio_serial_load, vser);
 917
 918     return vdev;
 919 }
 920
 921 void virtio_serial_exit(VirtIODevice *vdev)
 922 {
 923     VirtIOSerial *vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 924
 925     unregister_savevm(vser->qdev, "virtio-console", vser);
 926
 927     g_free(vser->ivqs);
 928     g_free(vser->ovqs);
 929     g_free(vser->ports_map);
 930
 931     virtio_cleanup(vdev);
 932 }
 933
 934 static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
 935 {
 936     DeviceClass *k = DEVICE_CLASS(klass);
 937     k->init = virtser_port_qdev_init;
 938     k->bus_info = &virtser_bus_info;
 939     k->exit = virtser_port_qdev_exit;
 940     k->unplug = qdev_simple_unplug_cb;
 941 }
 942
 943 static TypeInfo virtio_serial_port_type_info = {
 944     .name = TYPE_VIRTIO_SERIAL_PORT,
 945     .parent = TYPE_DEVICE,
 946     .instance_size = sizeof(VirtIOSerialPort),
 947     .abstract = true,
 948     .class_size = sizeof(VirtIOSerialPortClass),
 949     .class_init = virtio_serial_port_class_init,
 950 };
 951
 952 static void virtio_serial_register_devices(void)
 953 {
 954     type_register_static(&virtio_serial_port_type_info);
 955 }
 956
 957 device_init(virtio_serial_register_devices);