qemu/hw/char/virtio-serial-bus.c
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   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 "qemu/osdep.h"
  22#include "qapi/error.h"
  23#include "qemu/iov.h"
  24#include "qemu/module.h"
  25#include "monitor/monitor.h"
  26#include "qemu/error-report.h"
  27#include "qemu/queue.h"
  28#include "hw/sysbus.h"
  29#include "trace.h"
  30#include "hw/virtio/virtio-serial.h"
  31#include "hw/virtio/virtio-access.h"
  32
  33static struct VirtIOSerialDevices {
  34    QLIST_HEAD(, VirtIOSerial) devices;
  35} vserdevices;
  36
  37static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
  38{
  39    VirtIOSerialPort *port;
  40
  41    if (id == VIRTIO_CONSOLE_BAD_ID) {
  42        return NULL;
  43    }
  44
  45    QTAILQ_FOREACH(port, &vser->ports, next) {
  46        if (port->id == id)
  47            return port;
  48    }
  49    return NULL;
  50}
  51
  52static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
  53{
  54    VirtIOSerialPort *port;
  55
  56    QTAILQ_FOREACH(port, &vser->ports, next) {
  57        if (port->ivq == vq || port->ovq == vq)
  58            return port;
  59    }
  60    return NULL;
  61}
  62
  63static VirtIOSerialPort *find_port_by_name(char *name)
  64{
  65    VirtIOSerial *vser;
  66
  67    QLIST_FOREACH(vser, &vserdevices.devices, next) {
  68        VirtIOSerialPort *port;
  69
  70        QTAILQ_FOREACH(port, &vser->ports, next) {
  71            if (port->name && !strcmp(port->name, name)) {
  72                return port;
  73            }
  74        }
  75    }
  76    return NULL;
  77}
  78
  79static VirtIOSerialPort *find_first_connected_console(VirtIOSerial *vser)
  80{
  81    VirtIOSerialPort *port;
  82
  83    QTAILQ_FOREACH(port, &vser->ports, next) {
  84        VirtIOSerialPortClass const *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
  85        if (vsc->is_console && port->host_connected) {
  86            return port;
  87        }
  88    }
  89    return NULL;
  90}
  91
  92static bool use_multiport(VirtIOSerial *vser)
  93{
  94    VirtIODevice *vdev = VIRTIO_DEVICE(vser);
  95    return virtio_vdev_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT);
  96}
  97
  98static size_t write_to_port(VirtIOSerialPort *port,
  99                            const uint8_t *buf, size_t size)
 100{
 101    VirtQueueElement *elem;
 102    VirtQueue *vq;
 103    size_t offset;
 104
 105    vq = port->ivq;
 106    if (!virtio_queue_ready(vq)) {
 107        return 0;
 108    }
 109
 110    offset = 0;
 111    while (offset < size) {
 112        size_t len;
 113
 114        elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 115        if (!elem) {
 116            break;
 117        }
 118
 119        len = iov_from_buf(elem->in_sg, elem->in_num, 0,
 120                           buf + offset, size - offset);
 121        offset += len;
 122
 123        virtqueue_push(vq, elem, len);
 124        g_free(elem);
 125    }
 126
 127    virtio_notify(VIRTIO_DEVICE(port->vser), vq);
 128    return offset;
 129}
 130
 131static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
 132{
 133    VirtQueueElement *elem;
 134
 135    if (!virtio_queue_ready(vq)) {
 136        return;
 137    }
 138    for (;;) {
 139        elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 140        if (!elem) {
 141            break;
 142        }
 143        virtqueue_push(vq, elem, 0);
 144        g_free(elem);
 145    }
 146    virtio_notify(vdev, vq);
 147}
 148
 149static void discard_throttle_data(VirtIOSerialPort *port)
 150{
 151    if (port->elem) {
 152        virtqueue_detach_element(port->ovq, port->elem, 0);
 153        g_free(port->elem);
 154        port->elem = NULL;
 155    }
 156}
 157
 158static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 159                                 VirtIODevice *vdev)
 160{
 161    VirtIOSerialPortClass *vsc;
 162
 163    assert(port);
 164    assert(virtio_queue_ready(vq));
 165
 166    vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 167
 168    while (!port->throttled) {
 169        unsigned int i;
 170
 171        /* Pop an elem only if we haven't left off a previous one mid-way */
 172        if (!port->elem) {
 173            port->elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 174            if (!port->elem) {
 175                break;
 176            }
 177            port->iov_idx = 0;
 178            port->iov_offset = 0;
 179        }
 180
 181        for (i = port->iov_idx; i < port->elem->out_num; i++) {
 182            size_t buf_size;
 183            ssize_t ret;
 184
 185            buf_size = port->elem->out_sg[i].iov_len - port->iov_offset;
 186            ret = vsc->have_data(port,
 187                                  port->elem->out_sg[i].iov_base
 188                                  + port->iov_offset,
 189                                  buf_size);
 190            if (!port->elem) { /* bail if we got disconnected */
 191                return;
 192            }
 193            if (port->throttled) {
 194                port->iov_idx = i;
 195                if (ret > 0) {
 196                    port->iov_offset += ret;
 197                }
 198                break;
 199            }
 200            port->iov_offset = 0;
 201        }
 202        if (port->throttled) {
 203            break;
 204        }
 205        virtqueue_push(vq, port->elem, 0);
 206        g_free(port->elem);
 207        port->elem = NULL;
 208    }
 209    virtio_notify(vdev, vq);
 210}
 211
 212static void flush_queued_data(VirtIOSerialPort *port)
 213{
 214    assert(port);
 215
 216    if (!virtio_queue_ready(port->ovq)) {
 217        return;
 218    }
 219    do_flush_queued_data(port, port->ovq, VIRTIO_DEVICE(port->vser));
 220}
 221
 222static size_t send_control_msg(VirtIOSerial *vser, void *buf, size_t len)
 223{
 224    VirtQueueElement *elem;
 225    VirtQueue *vq;
 226
 227    vq = vser->c_ivq;
 228    if (!virtio_queue_ready(vq)) {
 229        return 0;
 230    }
 231
 232    elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 233    if (!elem) {
 234        return 0;
 235    }
 236
 237    /* TODO: detect a buffer that's too short, set NEEDS_RESET */
 238    iov_from_buf(elem->in_sg, elem->in_num, 0, buf, len);
 239
 240    virtqueue_push(vq, elem, len);
 241    virtio_notify(VIRTIO_DEVICE(vser), vq);
 242    g_free(elem);
 243
 244    return len;
 245}
 246
 247static size_t send_control_event(VirtIOSerial *vser, uint32_t port_id,
 248                                 uint16_t event, uint16_t value)
 249{
 250    VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 251    struct virtio_console_control cpkt;
 252
 253    virtio_stl_p(vdev, &cpkt.id, port_id);
 254    virtio_stw_p(vdev, &cpkt.event, event);
 255    virtio_stw_p(vdev, &cpkt.value, value);
 256
 257    trace_virtio_serial_send_control_event(port_id, event, value);
 258    return send_control_msg(vser, &cpkt, sizeof(cpkt));
 259}
 260
 261/* Functions for use inside qemu to open and read from/write to ports */
 262int virtio_serial_open(VirtIOSerialPort *port)
 263{
 264    /* Don't allow opening an already-open port */
 265    if (port->host_connected) {
 266        return 0;
 267    }
 268    /* Send port open notification to the guest */
 269    port->host_connected = true;
 270    send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 271
 272    return 0;
 273}
 274
 275int virtio_serial_close(VirtIOSerialPort *port)
 276{
 277    port->host_connected = false;
 278    /*
 279     * If there's any data the guest sent which the app didn't
 280     * consume, reset the throttling flag and discard the data.
 281     */
 282    port->throttled = false;
 283    discard_throttle_data(port);
 284    discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 285
 286    send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 0);
 287
 288    return 0;
 289}
 290
 291/* Individual ports/apps call this function to write to the guest. */
 292ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 293                            size_t size)
 294{
 295    if (!port || !port->host_connected || !port->guest_connected) {
 296        return 0;
 297    }
 298    return write_to_port(port, buf, size);
 299}
 300
 301/*
 302 * Readiness of the guest to accept data on a port.
 303 * Returns max. data the guest can receive
 304 */
 305size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 306{
 307    VirtIODevice *vdev = VIRTIO_DEVICE(port->vser);
 308    VirtQueue *vq = port->ivq;
 309    unsigned int bytes;
 310
 311    if (!virtio_queue_ready(vq) ||
 312        !(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 313        virtio_queue_empty(vq)) {
 314        return 0;
 315    }
 316    if (use_multiport(port->vser) && !port->guest_connected) {
 317        return 0;
 318    }
 319    virtqueue_get_avail_bytes(vq, &bytes, NULL, 4096, 0);
 320    return bytes;
 321}
 322
 323static void flush_queued_data_bh(void *opaque)
 324{
 325    VirtIOSerialPort *port = opaque;
 326
 327    flush_queued_data(port);
 328}
 329
 330void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 331{
 332    if (!port) {
 333        return;
 334    }
 335
 336    trace_virtio_serial_throttle_port(port->id, throttle);
 337    port->throttled = throttle;
 338    if (throttle) {
 339        return;
 340    }
 341    qemu_bh_schedule(port->bh);
 342}
 343
 344/* Guest wants to notify us of some event */
 345static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 346{
 347    VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 348    struct VirtIOSerialPort *port;
 349    VirtIOSerialPortClass *vsc;
 350    struct virtio_console_control cpkt, *gcpkt;
 351    uint8_t *buffer;
 352    size_t buffer_len;
 353
 354    gcpkt = buf;
 355
 356    if (len < sizeof(cpkt)) {
 357        /* The guest sent an invalid control packet */
 358        return;
 359    }
 360
 361    cpkt.event = virtio_lduw_p(vdev, &gcpkt->event);
 362    cpkt.value = virtio_lduw_p(vdev, &gcpkt->value);
 363
 364    trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 365
 366    if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 367        if (!cpkt.value) {
 368            error_report("virtio-serial-bus: Guest failure in adding device %s",
 369                         vser->bus.qbus.name);
 370            return;
 371        }
 372        /*
 373         * The device is up, we can now tell the device about all the
 374         * ports we have here.
 375         */
 376        QTAILQ_FOREACH(port, &vser->ports, next) {
 377            send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_ADD, 1);
 378        }
 379        return;
 380    }
 381
 382    port = find_port_by_id(vser, virtio_ldl_p(vdev, &gcpkt->id));
 383    if (!port) {
 384        error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 385                     virtio_ldl_p(vdev, &gcpkt->id), vser->bus.qbus.name);
 386        return;
 387    }
 388
 389    trace_virtio_serial_handle_control_message_port(port->id);
 390
 391    vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 392
 393    switch(cpkt.event) {
 394    case VIRTIO_CONSOLE_PORT_READY:
 395        if (!cpkt.value) {
 396            error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 397                         port->id, vser->bus.qbus.name);
 398            break;
 399        }
 400        /*
 401         * Now that we know the guest asked for the port name, we're
 402         * sure the guest has initialised whatever state is necessary
 403         * for this port. Now's a good time to let the guest know if
 404         * this port is a console port so that the guest can hook it
 405         * up to hvc.
 406         */
 407        if (vsc->is_console) {
 408            send_control_event(vser, port->id, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 409        }
 410
 411        if (port->name) {
 412            virtio_stl_p(vdev, &cpkt.id, port->id);
 413            virtio_stw_p(vdev, &cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 414            virtio_stw_p(vdev, &cpkt.value, 1);
 415
 416            buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 417            buffer = g_malloc(buffer_len);
 418
 419            memcpy(buffer, &cpkt, sizeof(cpkt));
 420            memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 421            buffer[buffer_len - 1] = 0;
 422
 423            send_control_msg(vser, buffer, buffer_len);
 424            g_free(buffer);
 425        }
 426
 427        if (port->host_connected) {
 428            send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 429        }
 430
 431        /*
 432         * When the guest has asked us for this information it means
 433         * the guest is all setup and has its virtqueues
 434         * initialised. If some app is interested in knowing about
 435         * this event, let it know.
 436         */
 437        if (vsc->guest_ready) {
 438            vsc->guest_ready(port);
 439        }
 440        break;
 441
 442    case VIRTIO_CONSOLE_PORT_OPEN:
 443        port->guest_connected = cpkt.value;
 444        if (vsc->set_guest_connected) {
 445            /* Send the guest opened notification if an app is interested */
 446            vsc->set_guest_connected(port, cpkt.value);
 447        }
 448        break;
 449    }
 450}
 451
 452static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 453{
 454}
 455
 456static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 457{
 458    VirtQueueElement *elem;
 459    VirtIOSerial *vser;
 460    uint8_t *buf;
 461    size_t len;
 462
 463    vser = VIRTIO_SERIAL(vdev);
 464
 465    len = 0;
 466    buf = NULL;
 467    for (;;) {
 468        size_t cur_len;
 469
 470        elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 471        if (!elem) {
 472            break;
 473        }
 474
 475        cur_len = iov_size(elem->out_sg, elem->out_num);
 476        /*
 477         * Allocate a new buf only if we didn't have one previously or
 478         * if the size of the buf differs
 479         */
 480        if (cur_len > len) {
 481            g_free(buf);
 482
 483            buf = g_malloc(cur_len);
 484            len = cur_len;
 485        }
 486        iov_to_buf(elem->out_sg, elem->out_num, 0, buf, cur_len);
 487
 488        handle_control_message(vser, buf, cur_len);
 489        virtqueue_push(vq, elem, 0);
 490        g_free(elem);
 491    }
 492    g_free(buf);
 493    virtio_notify(vdev, vq);
 494}
 495
 496/* Guest wrote something to some port. */
 497static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 498{
 499    VirtIOSerial *vser;
 500    VirtIOSerialPort *port;
 501
 502    vser = VIRTIO_SERIAL(vdev);
 503    port = find_port_by_vq(vser, vq);
 504
 505    if (!port || !port->host_connected) {
 506        discard_vq_data(vq, vdev);
 507        return;
 508    }
 509
 510    if (!port->throttled) {
 511        do_flush_queued_data(port, vq, vdev);
 512        return;
 513    }
 514}
 515
 516static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 517{
 518    /*
 519     * Users of virtio-serial would like to know when guest becomes
 520     * writable again -- i.e. if a vq had stuff queued up and the
 521     * guest wasn't reading at all, the host would not be able to
 522     * write to the vq anymore.  Once the guest reads off something,
 523     * we can start queueing things up again.  However, this call is
 524     * made for each buffer addition by the guest -- even though free
 525     * buffers existed prior to the current buffer addition.  This is
 526     * done so as not to maintain previous state, which will need
 527     * additional live-migration-related changes.
 528     */
 529    VirtIOSerial *vser;
 530    VirtIOSerialPort *port;
 531    VirtIOSerialPortClass *vsc;
 532
 533    vser = VIRTIO_SERIAL(vdev);
 534    port = find_port_by_vq(vser, vq);
 535
 536    if (!port) {
 537        return;
 538    }
 539    vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 540
 541    /*
 542     * If guest_connected is false, this call is being made by the
 543     * early-boot queueing up of descriptors, which is just noise for
 544     * the host apps -- don't disturb them in that case.
 545     */
 546    if (port->guest_connected && port->host_connected && vsc->guest_writable) {
 547        vsc->guest_writable(port);
 548    }
 549}
 550
 551static uint64_t get_features(VirtIODevice *vdev, uint64_t features,
 552                             Error **errp)
 553{
 554    VirtIOSerial *vser;
 555
 556    vser = VIRTIO_SERIAL(vdev);
 557
 558    features |= vser->host_features;
 559    if (vser->bus.max_nr_ports > 1) {
 560        virtio_add_feature(&features, VIRTIO_CONSOLE_F_MULTIPORT);
 561    }
 562    return features;
 563}
 564
 565/* Guest requested config info */
 566static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 567{
 568    VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 569    struct virtio_console_config *config =
 570        (struct virtio_console_config *)config_data;
 571
 572    config->cols = 0;
 573    config->rows = 0;
 574    config->max_nr_ports = virtio_tswap32(vdev,
 575                                          vser->serial.max_virtserial_ports);
 576}
 577
 578/* Guest sent new config info */
 579static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
 580{
 581    VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 582    struct virtio_console_config *config =
 583        (struct virtio_console_config *)config_data;
 584    VirtIOSerialPort *port = find_first_connected_console(vser);
 585    VirtIOSerialPortClass *vsc;
 586    uint8_t emerg_wr_lo;
 587
 588    if (!virtio_has_feature(vser->host_features,
 589        VIRTIO_CONSOLE_F_EMERG_WRITE) || !config->emerg_wr) {
 590        return;
 591    }
 592
 593    emerg_wr_lo = le32_to_cpu(config->emerg_wr);
 594    /* Make sure we don't misdetect an emergency write when the guest
 595     * does a short config write after an emergency write. */
 596    config->emerg_wr = 0;
 597    if (!port) {
 598        return;
 599    }
 600    vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 601    (void)vsc->have_data(port, &emerg_wr_lo, 1);
 602}
 603
 604static void guest_reset(VirtIOSerial *vser)
 605{
 606    VirtIOSerialPort *port;
 607    VirtIOSerialPortClass *vsc;
 608
 609    QTAILQ_FOREACH(port, &vser->ports, next) {
 610        vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 611
 612        discard_throttle_data(port);
 613
 614        if (port->guest_connected) {
 615            port->guest_connected = false;
 616            if (vsc->set_guest_connected) {
 617                vsc->set_guest_connected(port, false);
 618            }
 619        }
 620    }
 621}
 622
 623static void set_status(VirtIODevice *vdev, uint8_t status)
 624{
 625    VirtIOSerial *vser;
 626    VirtIOSerialPort *port;
 627
 628    vser = VIRTIO_SERIAL(vdev);
 629    port = find_port_by_id(vser, 0);
 630
 631    if (port && !use_multiport(port->vser)
 632        && (status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 633        /*
 634         * Non-multiport guests won't be able to tell us guest
 635         * open/close status.  Such guests can only have a port at id
 636         * 0, so set guest_connected for such ports as soon as guest
 637         * is up.
 638         */
 639        port->guest_connected = true;
 640    }
 641    if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 642        guest_reset(vser);
 643    }
 644
 645    QTAILQ_FOREACH(port, &vser->ports, next) {
 646        VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 647        if (vsc->enable_backend) {
 648            vsc->enable_backend(port, vdev->vm_running);
 649        }
 650    }
 651}
 652
 653static void vser_reset(VirtIODevice *vdev)
 654{
 655    VirtIOSerial *vser;
 656
 657    vser = VIRTIO_SERIAL(vdev);
 658    guest_reset(vser);
 659}
 660
 661static void virtio_serial_save_device(VirtIODevice *vdev, QEMUFile *f)
 662{
 663    VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 664    VirtIOSerialPort *port;
 665    uint32_t nr_active_ports;
 666    unsigned int i, max_nr_ports;
 667    struct virtio_console_config config;
 668
 669    /* The config space (ignored on the far end in current versions) */
 670    get_config(vdev, (uint8_t *)&config);
 671    qemu_put_be16(f, config.cols);
 672    qemu_put_be16(f, config.rows);
 673    qemu_put_be32(f, config.max_nr_ports);
 674
 675    /* The ports map */
 676    max_nr_ports = s->serial.max_virtserial_ports;
 677    for (i = 0; i < DIV_ROUND_UP(max_nr_ports, 32); i++) {
 678        qemu_put_be32s(f, &s->ports_map[i]);
 679    }
 680
 681    /* Ports */
 682
 683    nr_active_ports = 0;
 684    QTAILQ_FOREACH(port, &s->ports, next) {
 685        nr_active_ports++;
 686    }
 687
 688    qemu_put_be32s(f, &nr_active_ports);
 689
 690    /*
 691     * Items in struct VirtIOSerialPort.
 692     */
 693    QTAILQ_FOREACH(port, &s->ports, next) {
 694        uint32_t elem_popped;
 695
 696        qemu_put_be32s(f, &port->id);
 697        qemu_put_byte(f, port->guest_connected);
 698        qemu_put_byte(f, port->host_connected);
 699
 700        elem_popped = 0;
 701        if (port->elem) {
 702            elem_popped = 1;
 703        }
 704        qemu_put_be32s(f, &elem_popped);
 705        if (elem_popped) {
 706            qemu_put_be32s(f, &port->iov_idx);
 707            qemu_put_be64s(f, &port->iov_offset);
 708            qemu_put_virtqueue_element(f, port->elem);
 709        }
 710    }
 711}
 712
 713static void virtio_serial_post_load_timer_cb(void *opaque)
 714{
 715    uint32_t i;
 716    VirtIOSerial *s = VIRTIO_SERIAL(opaque);
 717    VirtIOSerialPort *port;
 718    uint8_t host_connected;
 719    VirtIOSerialPortClass *vsc;
 720
 721    if (!s->post_load) {
 722        return;
 723    }
 724    for (i = 0 ; i < s->post_load->nr_active_ports; ++i) {
 725        port = s->post_load->connected[i].port;
 726        host_connected = s->post_load->connected[i].host_connected;
 727        if (host_connected != port->host_connected) {
 728            /*
 729             * We have to let the guest know of the host connection
 730             * status change
 731             */
 732            send_control_event(s, port->id, VIRTIO_CONSOLE_PORT_OPEN,
 733                               port->host_connected);
 734        }
 735        vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 736        if (vsc->set_guest_connected) {
 737            vsc->set_guest_connected(port, port->guest_connected);
 738        }
 739    }
 740    g_free(s->post_load->connected);
 741    timer_del(s->post_load->timer);
 742    timer_free(s->post_load->timer);
 743    g_free(s->post_load);
 744    s->post_load = NULL;
 745}
 746
 747static int fetch_active_ports_list(QEMUFile *f,
 748                                   VirtIOSerial *s, uint32_t nr_active_ports)
 749{
 750    VirtIODevice *vdev = VIRTIO_DEVICE(s);
 751    uint32_t i;
 752
 753    s->post_load = g_malloc0(sizeof(*s->post_load));
 754    s->post_load->nr_active_ports = nr_active_ports;
 755    s->post_load->connected =
 756        g_malloc0(sizeof(*s->post_load->connected) * nr_active_ports);
 757
 758    s->post_load->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
 759                                            virtio_serial_post_load_timer_cb,
 760                                            s);
 761
 762    /* Items in struct VirtIOSerialPort */
 763    for (i = 0; i < nr_active_ports; i++) {
 764        VirtIOSerialPort *port;
 765        uint32_t elem_popped;
 766        uint32_t id;
 767
 768        id = qemu_get_be32(f);
 769        port = find_port_by_id(s, id);
 770        if (!port) {
 771            return -EINVAL;
 772        }
 773
 774        port->guest_connected = qemu_get_byte(f);
 775        s->post_load->connected[i].port = port;
 776        s->post_load->connected[i].host_connected = qemu_get_byte(f);
 777
 778        qemu_get_be32s(f, &elem_popped);
 779        if (elem_popped) {
 780            qemu_get_be32s(f, &port->iov_idx);
 781            qemu_get_be64s(f, &port->iov_offset);
 782
 783            port->elem =
 784                qemu_get_virtqueue_element(vdev, f, sizeof(VirtQueueElement));
 785
 786            /*
 787             *  Port was throttled on source machine.  Let's
 788             *  unthrottle it here so data starts flowing again.
 789             */
 790            virtio_serial_throttle_port(port, false);
 791        }
 792    }
 793    timer_mod(s->post_load->timer, 1);
 794    return 0;
 795}
 796
 797static int virtio_serial_load_device(VirtIODevice *vdev, QEMUFile *f,
 798                                     int version_id)
 799{
 800    VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 801    uint32_t max_nr_ports, nr_active_ports, ports_map;
 802    unsigned int i;
 803    int ret;
 804    uint32_t tmp;
 805
 806    /* Unused */
 807    qemu_get_be16s(f, (uint16_t *) &tmp);
 808    qemu_get_be16s(f, (uint16_t *) &tmp);
 809    qemu_get_be32s(f, &tmp);
 810
 811    max_nr_ports = s->serial.max_virtserial_ports;
 812    for (i = 0; i < DIV_ROUND_UP(max_nr_ports, 32); i++) {
 813        qemu_get_be32s(f, &ports_map);
 814
 815        if (ports_map != s->ports_map[i]) {
 816            /*
 817             * Ports active on source and destination don't
 818             * match. Fail migration.
 819             */
 820            return -EINVAL;
 821        }
 822    }
 823
 824    qemu_get_be32s(f, &nr_active_ports);
 825
 826    if (nr_active_ports) {
 827        ret = fetch_active_ports_list(f, s, nr_active_ports);
 828        if (ret) {
 829            return ret;
 830        }
 831    }
 832    return 0;
 833}
 834
 835static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 836
 837static Property virtser_props[] = {
 838    DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 839    DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 840    DEFINE_PROP_END_OF_LIST()
 841};
 842
 843#define TYPE_VIRTIO_SERIAL_BUS "virtio-serial-bus"
 844#define VIRTIO_SERIAL_BUS(obj) \
 845      OBJECT_CHECK(VirtIOSerialBus, (obj), TYPE_VIRTIO_SERIAL_BUS)
 846
 847static void virtser_bus_class_init(ObjectClass *klass, void *data)
 848{
 849    BusClass *k = BUS_CLASS(klass);
 850    k->print_dev = virtser_bus_dev_print;
 851}
 852
 853static const TypeInfo virtser_bus_info = {
 854    .name = TYPE_VIRTIO_SERIAL_BUS,
 855    .parent = TYPE_BUS,
 856    .instance_size = sizeof(VirtIOSerialBus),
 857    .class_init = virtser_bus_class_init,
 858};
 859
 860static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 861{
 862    VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(qdev);
 863
 864    monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 865                   indent, "", port->id,
 866                   port->guest_connected ? "on" : "off",
 867                   port->host_connected ? "on" : "off",
 868                   port->throttled ? "on" : "off");
 869}
 870
 871/* This function is only used if a port id is not provided by the user */
 872static uint32_t find_free_port_id(VirtIOSerial *vser)
 873{
 874    unsigned int i, max_nr_ports;
 875
 876    max_nr_ports = vser->serial.max_virtserial_ports;
 877    for (i = 0; i < DIV_ROUND_UP(max_nr_ports, 32); i++) {
 878        uint32_t map, zeroes;
 879
 880        map = vser->ports_map[i];
 881        zeroes = ctz32(~map);
 882        if (zeroes != 32) {
 883            return zeroes + i * 32;
 884        }
 885    }
 886    return VIRTIO_CONSOLE_BAD_ID;
 887}
 888
 889static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 890{
 891    unsigned int i;
 892
 893    i = port_id / 32;
 894    vser->ports_map[i] |= 1U << (port_id % 32);
 895}
 896
 897static void add_port(VirtIOSerial *vser, uint32_t port_id)
 898{
 899    mark_port_added(vser, port_id);
 900    send_control_event(vser, port_id, VIRTIO_CONSOLE_PORT_ADD, 1);
 901}
 902
 903static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 904{
 905    VirtIOSerialPort *port;
 906
 907    /*
 908     * Don't mark port 0 removed -- we explicitly reserve it for
 909     * backward compat with older guests, ensure a virtconsole device
 910     * unplug retains the reservation.
 911     */
 912    if (port_id) {
 913        unsigned int i;
 914
 915        i = port_id / 32;
 916        vser->ports_map[i] &= ~(1U << (port_id % 32));
 917    }
 918
 919    port = find_port_by_id(vser, port_id);
 920    /*
 921     * This function is only called from qdev's unplug callback; if we
 922     * get a NULL port here, we're in trouble.
 923     */
 924    assert(port);
 925
 926    /* Flush out any unconsumed buffers first */
 927    discard_throttle_data(port);
 928    discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 929
 930    send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 931}
 932
 933static void virtser_port_device_realize(DeviceState *dev, Error **errp)
 934{
 935    VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 936    VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 937    VirtIOSerialBus *bus = VIRTIO_SERIAL_BUS(qdev_get_parent_bus(dev));
 938    int max_nr_ports;
 939    bool plugging_port0;
 940    Error *err = NULL;
 941
 942    port->vser = bus->vser;
 943    port->bh = qemu_bh_new(flush_queued_data_bh, port);
 944
 945    assert(vsc->have_data);
 946
 947    /*
 948     * Is the first console port we're seeing? If so, put it up at
 949     * location 0. This is done for backward compatibility (old
 950     * kernel, new qemu).
 951     */
 952    plugging_port0 = vsc->is_console && !find_port_by_id(port->vser, 0);
 953
 954    if (find_port_by_id(port->vser, port->id)) {
 955        error_setg(errp, "virtio-serial-bus: A port already exists at id %u",
 956                   port->id);
 957        return;
 958    }
 959
 960    if (port->name != NULL && find_port_by_name(port->name)) {
 961        error_setg(errp, "virtio-serial-bus: A port already exists by name %s",
 962                   port->name);
 963        return;
 964    }
 965
 966    if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 967        if (plugging_port0) {
 968            port->id = 0;
 969        } else {
 970            port->id = find_free_port_id(port->vser);
 971            if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 972                error_setg(errp, "virtio-serial-bus: Maximum port limit for "
 973                                 "this device reached");
 974                return;
 975            }
 976        }
 977    }
 978
 979    max_nr_ports = port->vser->serial.max_virtserial_ports;
 980    if (port->id >= max_nr_ports) {
 981        error_setg(errp, "virtio-serial-bus: Out-of-range port id specified, "
 982                         "max. allowed: %u", max_nr_ports - 1);
 983        return;
 984    }
 985
 986    vsc->realize(dev, &err);
 987    if (err != NULL) {
 988        error_propagate(errp, err);
 989        return;
 990    }
 991
 992    port->elem = NULL;
 993}
 994
 995static void virtser_port_device_plug(HotplugHandler *hotplug_dev,
 996                                     DeviceState *dev, Error **errp)
 997{
 998    VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 999
1000    QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
1001    port->ivq = port->vser->ivqs[port->id];
1002    port->ovq = port->vser->ovqs[port->id];
1003
1004    add_port(port->vser, port->id);
1005
1006    /* Send an update to the guest about this new port added */
1007    virtio_notify_config(VIRTIO_DEVICE(hotplug_dev));
1008}
1009
1010static void virtser_port_device_unrealize(DeviceState *dev, Error **errp)
1011{
1012    VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
1013    VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(dev);
1014    VirtIOSerial *vser = port->vser;
1015
1016    qemu_bh_delete(port->bh);
1017    remove_port(port->vser, port->id);
1018
1019    QTAILQ_REMOVE(&vser->ports, port, next);
1020
1021    if (vsc->unrealize) {
1022        vsc->unrealize(dev, errp);
1023    }
1024}
1025
1026static void virtio_serial_device_realize(DeviceState *dev, Error **errp)
1027{
1028    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1029    VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1030    uint32_t i, max_supported_ports;
1031    size_t config_size = sizeof(struct virtio_console_config);
1032
1033    if (!vser->serial.max_virtserial_ports) {
1034        error_setg(errp, "Maximum number of serial ports not specified");
1035        return;
1036    }
1037
1038    /* Each port takes 2 queues, and one pair is for the control queue */
1039    max_supported_ports = VIRTIO_QUEUE_MAX / 2 - 1;
1040
1041    if (vser->serial.max_virtserial_ports > max_supported_ports) {
1042        error_setg(errp, "maximum ports supported: %u", max_supported_ports);
1043        return;
1044    }
1045
1046    if (!virtio_has_feature(vser->host_features,
1047                            VIRTIO_CONSOLE_F_EMERG_WRITE)) {
1048        config_size = offsetof(struct virtio_console_config, emerg_wr);
1049    }
1050    virtio_init(vdev, "virtio-serial", VIRTIO_ID_CONSOLE,
1051                config_size);
1052
1053    /* Spawn a new virtio-serial bus on which the ports will ride as devices */
1054    qbus_create_inplace(&vser->bus, sizeof(vser->bus), TYPE_VIRTIO_SERIAL_BUS,
1055                        dev, vdev->bus_name);
1056    qbus_set_hotplug_handler(BUS(&vser->bus), OBJECT(vser), errp);
1057    vser->bus.vser = vser;
1058    QTAILQ_INIT(&vser->ports);
1059
1060    vser->bus.max_nr_ports = vser->serial.max_virtserial_ports;
1061    vser->ivqs = g_malloc(vser->serial.max_virtserial_ports
1062                          * sizeof(VirtQueue *));
1063    vser->ovqs = g_malloc(vser->serial.max_virtserial_ports
1064                          * sizeof(VirtQueue *));
1065
1066    /* Add a queue for host to guest transfers for port 0 (backward compat) */
1067    vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
1068    /* Add a queue for guest to host transfers for port 0 (backward compat) */
1069    vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
1070
1071    /* TODO: host to guest notifications can get dropped
1072     * if the queue fills up. Implement queueing in host,
1073     * this might also make it possible to reduce the control
1074     * queue size: as guest preposts buffers there,
1075     * this will save 4Kbyte of guest memory per entry. */
1076
1077    /* control queue: host to guest */
1078    vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
1079    /* control queue: guest to host */
1080    vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
1081
1082    for (i = 1; i < vser->bus.max_nr_ports; i++) {
1083        /* Add a per-port queue for host to guest transfers */
1084        vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
1085        /* Add a per-per queue for guest to host transfers */
1086        vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
1087    }
1088
1089    vser->ports_map = g_malloc0((DIV_ROUND_UP(vser->serial.max_virtserial_ports, 32))
1090        * sizeof(vser->ports_map[0]));
1091    /*
1092     * Reserve location 0 for a console port for backward compat
1093     * (old kernel, new qemu)
1094     */
1095    mark_port_added(vser, 0);
1096
1097    vser->post_load = NULL;
1098
1099    QLIST_INSERT_HEAD(&vserdevices.devices, vser, next);
1100}
1101
1102static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
1103{
1104    DeviceClass *k = DEVICE_CLASS(klass);
1105
1106    set_bit(DEVICE_CATEGORY_INPUT, k->categories);
1107    k->bus_type = TYPE_VIRTIO_SERIAL_BUS;
1108    k->realize = virtser_port_device_realize;
1109    k->unrealize = virtser_port_device_unrealize;
1110    k->props = virtser_props;
1111}
1112
1113static const TypeInfo virtio_serial_port_type_info = {
1114    .name = TYPE_VIRTIO_SERIAL_PORT,
1115    .parent = TYPE_DEVICE,
1116    .instance_size = sizeof(VirtIOSerialPort),
1117    .abstract = true,
1118    .class_size = sizeof(VirtIOSerialPortClass),
1119    .class_init = virtio_serial_port_class_init,
1120};
1121
1122static void virtio_serial_device_unrealize(DeviceState *dev, Error **errp)
1123{
1124    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1125    VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1126
1127    QLIST_REMOVE(vser, next);
1128
1129    g_free(vser->ivqs);
1130    g_free(vser->ovqs);
1131    g_free(vser->ports_map);
1132    if (vser->post_load) {
1133        g_free(vser->post_load->connected);
1134        timer_del(vser->post_load->timer);
1135        timer_free(vser->post_load->timer);
1136        g_free(vser->post_load);
1137    }
1138
1139    qbus_set_hotplug_handler(BUS(&vser->bus), NULL, errp);
1140
1141    virtio_cleanup(vdev);
1142}
1143
1144/* Note: 'console' is used for backwards compatibility */
1145static const VMStateDescription vmstate_virtio_console = {
1146    .name = "virtio-console",
1147    .minimum_version_id = 3,
1148    .version_id = 3,
1149    .fields = (VMStateField[]) {
1150        VMSTATE_VIRTIO_DEVICE,
1151        VMSTATE_END_OF_LIST()
1152    },
1153};
1154
1155static Property virtio_serial_properties[] = {
1156    DEFINE_PROP_UINT32("max_ports", VirtIOSerial, serial.max_virtserial_ports,
1157                                                  31),
1158    DEFINE_PROP_BIT64("emergency-write", VirtIOSerial, host_features,
1159                      VIRTIO_CONSOLE_F_EMERG_WRITE, true),
1160    DEFINE_PROP_END_OF_LIST(),
1161};
1162
1163static void virtio_serial_class_init(ObjectClass *klass, void *data)
1164{
1165    DeviceClass *dc = DEVICE_CLASS(klass);
1166    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1167    HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
1168
1169    QLIST_INIT(&vserdevices.devices);
1170
1171    dc->props = virtio_serial_properties;
1172    dc->vmsd = &vmstate_virtio_console;
1173    set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
1174    vdc->realize = virtio_serial_device_realize;
1175    vdc->unrealize = virtio_serial_device_unrealize;
1176    vdc->get_features = get_features;
1177    vdc->get_config = get_config;
1178    vdc->set_config = set_config;
1179    vdc->set_status = set_status;
1180    vdc->reset = vser_reset;
1181    vdc->save = virtio_serial_save_device;
1182    vdc->load = virtio_serial_load_device;
1183    hc->plug = virtser_port_device_plug;
1184    hc->unplug = qdev_simple_device_unplug_cb;
1185}
1186
1187static const TypeInfo virtio_device_info = {
1188    .name = TYPE_VIRTIO_SERIAL,
1189    .parent = TYPE_VIRTIO_DEVICE,
1190    .instance_size = sizeof(VirtIOSerial),
1191    .class_init = virtio_serial_class_init,
1192    .interfaces = (InterfaceInfo[]) {
1193        { TYPE_HOTPLUG_HANDLER },
1194        { }
1195    }
1196};
1197
1198static void virtio_serial_register_types(void)
1199{
1200    type_register_static(&virtser_bus_info);
1201    type_register_static(&virtio_serial_port_type_info);
1202    type_register_static(&virtio_device_info);
1203}
1204
1205type_init(virtio_serial_register_types)
1206