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/main-loop.h"
  25#include "qemu/module.h"
  26#include "migration/qemu-file-types.h"
  27#include "monitor/monitor.h"
  28#include "qemu/error-report.h"
  29#include "qemu/queue.h"
  30#include "hw/qdev-properties.h"
  31#include "hw/sysbus.h"
  32#include "trace.h"
  33#include "hw/virtio/virtio-serial.h"
  34#include "hw/virtio/virtio-access.h"
  35
  36static struct VirtIOSerialDevices {
  37    QLIST_HEAD(, VirtIOSerial) devices;
  38} vserdevices;
  39
  40static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
  41{
  42    VirtIOSerialPort *port;
  43
  44    if (id == VIRTIO_CONSOLE_BAD_ID) {
  45        return NULL;
  46    }
  47
  48    QTAILQ_FOREACH(port, &vser->ports, next) {
  49        if (port->id == id)
  50            return port;
  51    }
  52    return NULL;
  53}
  54
  55static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
  56{
  57    VirtIOSerialPort *port;
  58
  59    QTAILQ_FOREACH(port, &vser->ports, next) {
  60        if (port->ivq == vq || port->ovq == vq)
  61            return port;
  62    }
  63    return NULL;
  64}
  65
  66static VirtIOSerialPort *find_port_by_name(char *name)
  67{
  68    VirtIOSerial *vser;
  69
  70    QLIST_FOREACH(vser, &vserdevices.devices, next) {
  71        VirtIOSerialPort *port;
  72
  73        QTAILQ_FOREACH(port, &vser->ports, next) {
  74            if (port->name && !strcmp(port->name, name)) {
  75                return port;
  76            }
  77        }
  78    }
  79    return NULL;
  80}
  81
  82static VirtIOSerialPort *find_first_connected_console(VirtIOSerial *vser)
  83{
  84    VirtIOSerialPort *port;
  85
  86    QTAILQ_FOREACH(port, &vser->ports, next) {
  87        VirtIOSerialPortClass const *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
  88        if (vsc->is_console && port->host_connected) {
  89            return port;
  90        }
  91    }
  92    return NULL;
  93}
  94
  95static bool use_multiport(VirtIOSerial *vser)
  96{
  97    VirtIODevice *vdev = VIRTIO_DEVICE(vser);
  98    return virtio_vdev_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT);
  99}
 100
 101static size_t write_to_port(VirtIOSerialPort *port,
 102                            const uint8_t *buf, size_t size)
 103{
 104    VirtQueueElement *elem;
 105    VirtQueue *vq;
 106    size_t offset;
 107
 108    vq = port->ivq;
 109    if (!virtio_queue_ready(vq)) {
 110        return 0;
 111    }
 112
 113    offset = 0;
 114    while (offset < size) {
 115        size_t len;
 116
 117        elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 118        if (!elem) {
 119            break;
 120        }
 121
 122        len = iov_from_buf(elem->in_sg, elem->in_num, 0,
 123                           buf + offset, size - offset);
 124        offset += len;
 125
 126        virtqueue_push(vq, elem, len);
 127        g_free(elem);
 128    }
 129
 130    virtio_notify(VIRTIO_DEVICE(port->vser), vq);
 131    return offset;
 132}
 133
 134static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
 135{
 136    VirtQueueElement *elem;
 137
 138    if (!virtio_queue_ready(vq)) {
 139        return;
 140    }
 141    for (;;) {
 142        elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 143        if (!elem) {
 144            break;
 145        }
 146        virtqueue_push(vq, elem, 0);
 147        g_free(elem);
 148    }
 149    virtio_notify(vdev, vq);
 150}
 151
 152static void discard_throttle_data(VirtIOSerialPort *port)
 153{
 154    if (port->elem) {
 155        virtqueue_detach_element(port->ovq, port->elem, 0);
 156        g_free(port->elem);
 157        port->elem = NULL;
 158    }
 159}
 160
 161static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 162                                 VirtIODevice *vdev)
 163{
 164    VirtIOSerialPortClass *vsc;
 165
 166    assert(port);
 167    assert(virtio_queue_ready(vq));
 168
 169    vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 170
 171    while (!port->throttled) {
 172        unsigned int i;
 173
 174        /* Pop an elem only if we haven't left off a previous one mid-way */
 175        if (!port->elem) {
 176            port->elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 177            if (!port->elem) {
 178                break;
 179            }
 180            port->iov_idx = 0;
 181            port->iov_offset = 0;
 182        }
 183
 184        for (i = port->iov_idx; i < port->elem->out_num; i++) {
 185            size_t buf_size;
 186            ssize_t ret;
 187
 188            buf_size = port->elem->out_sg[i].iov_len - port->iov_offset;
 189            ret = vsc->have_data(port,
 190                                  port->elem->out_sg[i].iov_base
 191                                  + port->iov_offset,
 192                                  buf_size);
 193            if (!port->elem) { /* bail if we got disconnected */
 194                return;
 195            }
 196            if (port->throttled) {
 197                port->iov_idx = i;
 198                if (ret > 0) {
 199                    port->iov_offset += ret;
 200                }
 201                break;
 202            }
 203            port->iov_offset = 0;
 204        }
 205        if (port->throttled) {
 206            break;
 207        }
 208        virtqueue_push(vq, port->elem, 0);
 209        g_free(port->elem);
 210        port->elem = NULL;
 211    }
 212    virtio_notify(vdev, vq);
 213}
 214
 215static void flush_queued_data(VirtIOSerialPort *port)
 216{
 217    assert(port);
 218
 219    if (!virtio_queue_ready(port->ovq)) {
 220        return;
 221    }
 222    do_flush_queued_data(port, port->ovq, VIRTIO_DEVICE(port->vser));
 223}
 224
 225static size_t send_control_msg(VirtIOSerial *vser, void *buf, size_t len)
 226{
 227    VirtQueueElement *elem;
 228    VirtQueue *vq;
 229
 230    vq = vser->c_ivq;
 231    if (!virtio_queue_ready(vq)) {
 232        return 0;
 233    }
 234
 235    elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 236    if (!elem) {
 237        return 0;
 238    }
 239
 240    /* TODO: detect a buffer that's too short, set NEEDS_RESET */
 241    iov_from_buf(elem->in_sg, elem->in_num, 0, buf, len);
 242
 243    virtqueue_push(vq, elem, len);
 244    virtio_notify(VIRTIO_DEVICE(vser), vq);
 245    g_free(elem);
 246
 247    return len;
 248}
 249
 250static size_t send_control_event(VirtIOSerial *vser, uint32_t port_id,
 251                                 uint16_t event, uint16_t value)
 252{
 253    VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 254    struct virtio_console_control cpkt;
 255
 256    virtio_stl_p(vdev, &cpkt.id, port_id);
 257    virtio_stw_p(vdev, &cpkt.event, event);
 258    virtio_stw_p(vdev, &cpkt.value, value);
 259
 260    trace_virtio_serial_send_control_event(port_id, event, value);
 261    return send_control_msg(vser, &cpkt, sizeof(cpkt));
 262}
 263
 264/* Functions for use inside qemu to open and read from/write to ports */
 265int virtio_serial_open(VirtIOSerialPort *port)
 266{
 267    /* Don't allow opening an already-open port */
 268    if (port->host_connected) {
 269        return 0;
 270    }
 271    /* Send port open notification to the guest */
 272    port->host_connected = true;
 273    send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 274
 275    return 0;
 276}
 277
 278int virtio_serial_close(VirtIOSerialPort *port)
 279{
 280    port->host_connected = false;
 281    /*
 282     * If there's any data the guest sent which the app didn't
 283     * consume, reset the throttling flag and discard the data.
 284     */
 285    port->throttled = false;
 286    discard_throttle_data(port);
 287    discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 288
 289    send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 0);
 290
 291    return 0;
 292}
 293
 294/* Individual ports/apps call this function to write to the guest. */
 295ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 296                            size_t size)
 297{
 298    if (!port || !port->host_connected || !port->guest_connected) {
 299        return 0;
 300    }
 301    return write_to_port(port, buf, size);
 302}
 303
 304/*
 305 * Readiness of the guest to accept data on a port.
 306 * Returns max. data the guest can receive
 307 */
 308size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 309{
 310    VirtIODevice *vdev = VIRTIO_DEVICE(port->vser);
 311    VirtQueue *vq = port->ivq;
 312    unsigned int bytes;
 313
 314    if (!virtio_queue_ready(vq) ||
 315        !(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 316        virtio_queue_empty(vq)) {
 317        return 0;
 318    }
 319    if (use_multiport(port->vser) && !port->guest_connected) {
 320        return 0;
 321    }
 322    virtqueue_get_avail_bytes(vq, &bytes, NULL, 4096, 0);
 323    return bytes;
 324}
 325
 326static void flush_queued_data_bh(void *opaque)
 327{
 328    VirtIOSerialPort *port = opaque;
 329
 330    flush_queued_data(port);
 331}
 332
 333void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 334{
 335    if (!port) {
 336        return;
 337    }
 338
 339    trace_virtio_serial_throttle_port(port->id, throttle);
 340    port->throttled = throttle;
 341    if (throttle) {
 342        return;
 343    }
 344    qemu_bh_schedule(port->bh);
 345}
 346
 347/* Guest wants to notify us of some event */
 348static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 349{
 350    VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 351    struct VirtIOSerialPort *port;
 352    VirtIOSerialPortClass *vsc;
 353    struct virtio_console_control cpkt, *gcpkt;
 354    uint8_t *buffer;
 355    size_t buffer_len;
 356
 357    gcpkt = buf;
 358
 359    if (len < sizeof(cpkt)) {
 360        /* The guest sent an invalid control packet */
 361        return;
 362    }
 363
 364    cpkt.event = virtio_lduw_p(vdev, &gcpkt->event);
 365    cpkt.value = virtio_lduw_p(vdev, &gcpkt->value);
 366
 367    trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 368
 369    if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 370        if (!cpkt.value) {
 371            error_report("virtio-serial-bus: Guest failure in adding device %s",
 372                         vser->bus.qbus.name);
 373            return;
 374        }
 375        /*
 376         * The device is up, we can now tell the device about all the
 377         * ports we have here.
 378         */
 379        QTAILQ_FOREACH(port, &vser->ports, next) {
 380            send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_ADD, 1);
 381        }
 382        return;
 383    }
 384
 385    port = find_port_by_id(vser, virtio_ldl_p(vdev, &gcpkt->id));
 386    if (!port) {
 387        error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 388                     virtio_ldl_p(vdev, &gcpkt->id), vser->bus.qbus.name);
 389        return;
 390    }
 391
 392    trace_virtio_serial_handle_control_message_port(port->id);
 393
 394    vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 395
 396    switch(cpkt.event) {
 397    case VIRTIO_CONSOLE_PORT_READY:
 398        if (!cpkt.value) {
 399            error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 400                         port->id, vser->bus.qbus.name);
 401            break;
 402        }
 403        /*
 404         * Now that we know the guest asked for the port name, we're
 405         * sure the guest has initialised whatever state is necessary
 406         * for this port. Now's a good time to let the guest know if
 407         * this port is a console port so that the guest can hook it
 408         * up to hvc.
 409         */
 410        if (vsc->is_console) {
 411            send_control_event(vser, port->id, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 412        }
 413
 414        if (port->name) {
 415            virtio_stl_p(vdev, &cpkt.id, port->id);
 416            virtio_stw_p(vdev, &cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 417            virtio_stw_p(vdev, &cpkt.value, 1);
 418
 419            buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 420            buffer = g_malloc(buffer_len);
 421
 422            memcpy(buffer, &cpkt, sizeof(cpkt));
 423            memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 424            buffer[buffer_len - 1] = 0;
 425
 426            send_control_msg(vser, buffer, buffer_len);
 427            g_free(buffer);
 428        }
 429
 430        if (port->host_connected) {
 431            send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 432        }
 433
 434        /*
 435         * When the guest has asked us for this information it means
 436         * the guest is all setup and has its virtqueues
 437         * initialised. If some app is interested in knowing about
 438         * this event, let it know.
 439         */
 440        if (vsc->guest_ready) {
 441            vsc->guest_ready(port);
 442        }
 443        break;
 444
 445    case VIRTIO_CONSOLE_PORT_OPEN:
 446        port->guest_connected = cpkt.value;
 447        if (vsc->set_guest_connected) {
 448            /* Send the guest opened notification if an app is interested */
 449            vsc->set_guest_connected(port, cpkt.value);
 450        }
 451        break;
 452    }
 453}
 454
 455static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 456{
 457}
 458
 459static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 460{
 461    VirtQueueElement *elem;
 462    VirtIOSerial *vser;
 463    uint8_t *buf;
 464    size_t len;
 465
 466    vser = VIRTIO_SERIAL(vdev);
 467
 468    len = 0;
 469    buf = NULL;
 470    for (;;) {
 471        size_t cur_len;
 472
 473        elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 474        if (!elem) {
 475            break;
 476        }
 477
 478        cur_len = iov_size(elem->out_sg, elem->out_num);
 479        /*
 480         * Allocate a new buf only if we didn't have one previously or
 481         * if the size of the buf differs
 482         */
 483        if (cur_len > len) {
 484            g_free(buf);
 485
 486            buf = g_malloc(cur_len);
 487            len = cur_len;
 488        }
 489        iov_to_buf(elem->out_sg, elem->out_num, 0, buf, cur_len);
 490
 491        handle_control_message(vser, buf, cur_len);
 492        virtqueue_push(vq, elem, 0);
 493        g_free(elem);
 494    }
 495    g_free(buf);
 496    virtio_notify(vdev, vq);
 497}
 498
 499/* Guest wrote something to some port. */
 500static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 501{
 502    VirtIOSerial *vser;
 503    VirtIOSerialPort *port;
 504
 505    vser = VIRTIO_SERIAL(vdev);
 506    port = find_port_by_vq(vser, vq);
 507
 508    if (!port || !port->host_connected) {
 509        discard_vq_data(vq, vdev);
 510        return;
 511    }
 512
 513    if (!port->throttled) {
 514        do_flush_queued_data(port, vq, vdev);
 515        return;
 516    }
 517}
 518
 519static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 520{
 521    /*
 522     * Users of virtio-serial would like to know when guest becomes
 523     * writable again -- i.e. if a vq had stuff queued up and the
 524     * guest wasn't reading at all, the host would not be able to
 525     * write to the vq anymore.  Once the guest reads off something,
 526     * we can start queueing things up again.  However, this call is
 527     * made for each buffer addition by the guest -- even though free
 528     * buffers existed prior to the current buffer addition.  This is
 529     * done so as not to maintain previous state, which will need
 530     * additional live-migration-related changes.
 531     */
 532    VirtIOSerial *vser;
 533    VirtIOSerialPort *port;
 534    VirtIOSerialPortClass *vsc;
 535
 536    vser = VIRTIO_SERIAL(vdev);
 537    port = find_port_by_vq(vser, vq);
 538
 539    if (!port) {
 540        return;
 541    }
 542    vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 543
 544    /*
 545     * If guest_connected is false, this call is being made by the
 546     * early-boot queueing up of descriptors, which is just noise for
 547     * the host apps -- don't disturb them in that case.
 548     */
 549    if (port->guest_connected && port->host_connected && vsc->guest_writable) {
 550        vsc->guest_writable(port);
 551    }
 552}
 553
 554static uint64_t get_features(VirtIODevice *vdev, uint64_t features,
 555                             Error **errp)
 556{
 557    VirtIOSerial *vser;
 558
 559    vser = VIRTIO_SERIAL(vdev);
 560
 561    features |= vser->host_features;
 562    if (vser->bus.max_nr_ports > 1) {
 563        virtio_add_feature(&features, VIRTIO_CONSOLE_F_MULTIPORT);
 564    }
 565    return features;
 566}
 567
 568/* Guest requested config info */
 569static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 570{
 571    VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 572    struct virtio_console_config *config =
 573        (struct virtio_console_config *)config_data;
 574
 575    config->cols = 0;
 576    config->rows = 0;
 577    config->max_nr_ports = virtio_tswap32(vdev,
 578                                          vser->serial.max_virtserial_ports);
 579}
 580
 581/* Guest sent new config info */
 582static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
 583{
 584    VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 585    struct virtio_console_config *config =
 586        (struct virtio_console_config *)config_data;
 587    VirtIOSerialPort *port = find_first_connected_console(vser);
 588    VirtIOSerialPortClass *vsc;
 589    uint8_t emerg_wr_lo;
 590
 591    if (!virtio_has_feature(vser->host_features,
 592        VIRTIO_CONSOLE_F_EMERG_WRITE) || !config->emerg_wr) {
 593        return;
 594    }
 595
 596    emerg_wr_lo = le32_to_cpu(config->emerg_wr);
 597    /* Make sure we don't misdetect an emergency write when the guest
 598     * does a short config write after an emergency write. */
 599    config->emerg_wr = 0;
 600    if (!port) {
 601        return;
 602    }
 603    vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 604    (void)vsc->have_data(port, &emerg_wr_lo, 1);
 605}
 606
 607static void guest_reset(VirtIOSerial *vser)
 608{
 609    VirtIOSerialPort *port;
 610    VirtIOSerialPortClass *vsc;
 611
 612    QTAILQ_FOREACH(port, &vser->ports, next) {
 613        vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 614
 615        discard_throttle_data(port);
 616
 617        if (port->guest_connected) {
 618            port->guest_connected = false;
 619            if (vsc->set_guest_connected) {
 620                vsc->set_guest_connected(port, false);
 621            }
 622        }
 623    }
 624}
 625
 626static void set_status(VirtIODevice *vdev, uint8_t status)
 627{
 628    VirtIOSerial *vser;
 629    VirtIOSerialPort *port;
 630
 631    vser = VIRTIO_SERIAL(vdev);
 632    port = find_port_by_id(vser, 0);
 633
 634    if (port && !use_multiport(port->vser)
 635        && (status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 636        /*
 637         * Non-multiport guests won't be able to tell us guest
 638         * open/close status.  Such guests can only have a port at id
 639         * 0, so set guest_connected for such ports as soon as guest
 640         * is up.
 641         */
 642        port->guest_connected = true;
 643    }
 644    if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 645        guest_reset(vser);
 646    }
 647
 648    QTAILQ_FOREACH(port, &vser->ports, next) {
 649        VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 650        if (vsc->enable_backend) {
 651            vsc->enable_backend(port, vdev->vm_running);
 652        }
 653    }
 654}
 655
 656static void vser_reset(VirtIODevice *vdev)
 657{
 658    VirtIOSerial *vser;
 659
 660    vser = VIRTIO_SERIAL(vdev);
 661    guest_reset(vser);
 662}
 663
 664static void virtio_serial_save_device(VirtIODevice *vdev, QEMUFile *f)
 665{
 666    VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 667    VirtIOSerialPort *port;
 668    uint32_t nr_active_ports;
 669    unsigned int i, max_nr_ports;
 670    struct virtio_console_config config;
 671
 672    /* The config space (ignored on the far end in current versions) */
 673    get_config(vdev, (uint8_t *)&config);
 674    qemu_put_be16(f, config.cols);
 675    qemu_put_be16(f, config.rows);
 676    qemu_put_be32(f, config.max_nr_ports);
 677
 678    /* The ports map */
 679    max_nr_ports = s->serial.max_virtserial_ports;
 680    for (i = 0; i < DIV_ROUND_UP(max_nr_ports, 32); i++) {
 681        qemu_put_be32s(f, &s->ports_map[i]);
 682    }
 683
 684    /* Ports */
 685
 686    nr_active_ports = 0;
 687    QTAILQ_FOREACH(port, &s->ports, next) {
 688        nr_active_ports++;
 689    }
 690
 691    qemu_put_be32s(f, &nr_active_ports);
 692
 693    /*
 694     * Items in struct VirtIOSerialPort.
 695     */
 696    QTAILQ_FOREACH(port, &s->ports, next) {
 697        uint32_t elem_popped;
 698
 699        qemu_put_be32s(f, &port->id);
 700        qemu_put_byte(f, port->guest_connected);
 701        qemu_put_byte(f, port->host_connected);
 702
 703        elem_popped = 0;
 704        if (port->elem) {
 705            elem_popped = 1;
 706        }
 707        qemu_put_be32s(f, &elem_popped);
 708        if (elem_popped) {
 709            qemu_put_be32s(f, &port->iov_idx);
 710            qemu_put_be64s(f, &port->iov_offset);
 711            qemu_put_virtqueue_element(vdev, f, port->elem);
 712        }
 713    }
 714}
 715
 716static void virtio_serial_post_load_timer_cb(void *opaque)
 717{
 718    uint32_t i;
 719    VirtIOSerial *s = VIRTIO_SERIAL(opaque);
 720    VirtIOSerialPort *port;
 721    uint8_t host_connected;
 722    VirtIOSerialPortClass *vsc;
 723
 724    if (!s->post_load) {
 725        return;
 726    }
 727    for (i = 0 ; i < s->post_load->nr_active_ports; ++i) {
 728        port = s->post_load->connected[i].port;
 729        host_connected = s->post_load->connected[i].host_connected;
 730        if (host_connected != port->host_connected) {
 731            /*
 732             * We have to let the guest know of the host connection
 733             * status change
 734             */
 735            send_control_event(s, port->id, VIRTIO_CONSOLE_PORT_OPEN,
 736                               port->host_connected);
 737        }
 738        vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 739        if (vsc->set_guest_connected) {
 740            vsc->set_guest_connected(port, port->guest_connected);
 741        }
 742    }
 743    g_free(s->post_load->connected);
 744    timer_del(s->post_load->timer);
 745    timer_free(s->post_load->timer);
 746    g_free(s->post_load);
 747    s->post_load = NULL;
 748}
 749
 750static int fetch_active_ports_list(QEMUFile *f,
 751                                   VirtIOSerial *s, uint32_t nr_active_ports)
 752{
 753    VirtIODevice *vdev = VIRTIO_DEVICE(s);
 754    uint32_t i;
 755
 756    s->post_load = g_malloc0(sizeof(*s->post_load));
 757    s->post_load->nr_active_ports = nr_active_ports;
 758    s->post_load->connected =
 759        g_malloc0(sizeof(*s->post_load->connected) * nr_active_ports);
 760
 761    s->post_load->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
 762                                            virtio_serial_post_load_timer_cb,
 763                                            s);
 764
 765    /* Items in struct VirtIOSerialPort */
 766    for (i = 0; i < nr_active_ports; i++) {
 767        VirtIOSerialPort *port;
 768        uint32_t elem_popped;
 769        uint32_t id;
 770
 771        id = qemu_get_be32(f);
 772        port = find_port_by_id(s, id);
 773        if (!port) {
 774            return -EINVAL;
 775        }
 776
 777        port->guest_connected = qemu_get_byte(f);
 778        s->post_load->connected[i].port = port;
 779        s->post_load->connected[i].host_connected = qemu_get_byte(f);
 780
 781        qemu_get_be32s(f, &elem_popped);
 782        if (elem_popped) {
 783            qemu_get_be32s(f, &port->iov_idx);
 784            qemu_get_be64s(f, &port->iov_offset);
 785
 786            port->elem =
 787                qemu_get_virtqueue_element(vdev, f, sizeof(VirtQueueElement));
 788
 789            /*
 790             *  Port was throttled on source machine.  Let's
 791             *  unthrottle it here so data starts flowing again.
 792             */
 793            virtio_serial_throttle_port(port, false);
 794        }
 795    }
 796    timer_mod(s->post_load->timer, 1);
 797    return 0;
 798}
 799
 800static int virtio_serial_load_device(VirtIODevice *vdev, QEMUFile *f,
 801                                     int version_id)
 802{
 803    VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 804    uint32_t max_nr_ports, nr_active_ports, ports_map;
 805    unsigned int i;
 806    int ret;
 807    uint32_t tmp;
 808
 809    /* Unused */
 810    qemu_get_be16s(f, (uint16_t *) &tmp);
 811    qemu_get_be16s(f, (uint16_t *) &tmp);
 812    qemu_get_be32s(f, &tmp);
 813
 814    max_nr_ports = s->serial.max_virtserial_ports;
 815    for (i = 0; i < DIV_ROUND_UP(max_nr_ports, 32); i++) {
 816        qemu_get_be32s(f, &ports_map);
 817
 818        if (ports_map != s->ports_map[i]) {
 819            /*
 820             * Ports active on source and destination don't
 821             * match. Fail migration.
 822             */
 823            return -EINVAL;
 824        }
 825    }
 826
 827    qemu_get_be32s(f, &nr_active_ports);
 828
 829    if (nr_active_ports) {
 830        ret = fetch_active_ports_list(f, s, nr_active_ports);
 831        if (ret) {
 832            return ret;
 833        }
 834    }
 835    return 0;
 836}
 837
 838static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 839
 840static Property virtser_props[] = {
 841    DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 842    DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 843    DEFINE_PROP_END_OF_LIST()
 844};
 845
 846#define TYPE_VIRTIO_SERIAL_BUS "virtio-serial-bus"
 847#define VIRTIO_SERIAL_BUS(obj) \
 848      OBJECT_CHECK(VirtIOSerialBus, (obj), TYPE_VIRTIO_SERIAL_BUS)
 849
 850static void virtser_bus_class_init(ObjectClass *klass, void *data)
 851{
 852    BusClass *k = BUS_CLASS(klass);
 853    k->print_dev = virtser_bus_dev_print;
 854}
 855
 856static const TypeInfo virtser_bus_info = {
 857    .name = TYPE_VIRTIO_SERIAL_BUS,
 858    .parent = TYPE_BUS,
 859    .instance_size = sizeof(VirtIOSerialBus),
 860    .class_init = virtser_bus_class_init,
 861};
 862
 863static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 864{
 865    VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(qdev);
 866
 867    monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 868                   indent, "", port->id,
 869                   port->guest_connected ? "on" : "off",
 870                   port->host_connected ? "on" : "off",
 871                   port->throttled ? "on" : "off");
 872}
 873
 874/* This function is only used if a port id is not provided by the user */
 875static uint32_t find_free_port_id(VirtIOSerial *vser)
 876{
 877    unsigned int i, max_nr_ports;
 878
 879    max_nr_ports = vser->serial.max_virtserial_ports;
 880    for (i = 0; i < DIV_ROUND_UP(max_nr_ports, 32); i++) {
 881        uint32_t map, zeroes;
 882
 883        map = vser->ports_map[i];
 884        zeroes = ctz32(~map);
 885        if (zeroes != 32) {
 886            return zeroes + i * 32;
 887        }
 888    }
 889    return VIRTIO_CONSOLE_BAD_ID;
 890}
 891
 892static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 893{
 894    unsigned int i;
 895
 896    i = port_id / 32;
 897    vser->ports_map[i] |= 1U << (port_id % 32);
 898}
 899
 900static void add_port(VirtIOSerial *vser, uint32_t port_id)
 901{
 902    mark_port_added(vser, port_id);
 903    send_control_event(vser, port_id, VIRTIO_CONSOLE_PORT_ADD, 1);
 904}
 905
 906static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 907{
 908    VirtIOSerialPort *port;
 909
 910    /*
 911     * Don't mark port 0 removed -- we explicitly reserve it for
 912     * backward compat with older guests, ensure a virtconsole device
 913     * unplug retains the reservation.
 914     */
 915    if (port_id) {
 916        unsigned int i;
 917
 918        i = port_id / 32;
 919        vser->ports_map[i] &= ~(1U << (port_id % 32));
 920    }
 921
 922    port = find_port_by_id(vser, port_id);
 923    /*
 924     * This function is only called from qdev's unplug callback; if we
 925     * get a NULL port here, we're in trouble.
 926     */
 927    assert(port);
 928
 929    /* Flush out any unconsumed buffers first */
 930    discard_throttle_data(port);
 931    discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 932
 933    send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 934}
 935
 936static void virtser_port_device_realize(DeviceState *dev, Error **errp)
 937{
 938    VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 939    VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 940    VirtIOSerialBus *bus = VIRTIO_SERIAL_BUS(qdev_get_parent_bus(dev));
 941    int max_nr_ports;
 942    bool plugging_port0;
 943    Error *err = NULL;
 944
 945    port->vser = bus->vser;
 946
 947    assert(vsc->have_data);
 948
 949    /*
 950     * Is the first console port we're seeing? If so, put it up at
 951     * location 0. This is done for backward compatibility (old
 952     * kernel, new qemu).
 953     */
 954    plugging_port0 = vsc->is_console && !find_port_by_id(port->vser, 0);
 955
 956    if (find_port_by_id(port->vser, port->id)) {
 957        error_setg(errp, "virtio-serial-bus: A port already exists at id %u",
 958                   port->id);
 959        return;
 960    }
 961
 962    if (port->name != NULL && find_port_by_name(port->name)) {
 963        error_setg(errp, "virtio-serial-bus: A port already exists by name %s",
 964                   port->name);
 965        return;
 966    }
 967
 968    if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 969        if (plugging_port0) {
 970            port->id = 0;
 971        } else {
 972            port->id = find_free_port_id(port->vser);
 973            if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 974                error_setg(errp, "virtio-serial-bus: Maximum port limit for "
 975                                 "this device reached");
 976                return;
 977            }
 978        }
 979    }
 980
 981    max_nr_ports = port->vser->serial.max_virtserial_ports;
 982    if (port->id >= max_nr_ports) {
 983        error_setg(errp, "virtio-serial-bus: Out-of-range port id specified, "
 984                         "max. allowed: %u", max_nr_ports - 1);
 985        return;
 986    }
 987
 988    vsc->realize(dev, &err);
 989    if (err != NULL) {
 990        error_propagate(errp, err);
 991        return;
 992    }
 993
 994    port->bh = qemu_bh_new(flush_queued_data_bh, port);
 995    port->elem = NULL;
 996}
 997
 998static void virtser_port_device_plug(HotplugHandler *hotplug_dev,
 999                                     DeviceState *dev, Error **errp)
1000{
1001    VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
1002
1003    QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
1004    port->ivq = port->vser->ivqs[port->id];
1005    port->ovq = port->vser->ovqs[port->id];
1006
1007    add_port(port->vser, port->id);
1008
1009    /* Send an update to the guest about this new port added */
1010    virtio_notify_config(VIRTIO_DEVICE(hotplug_dev));
1011}
1012
1013static void virtser_port_device_unrealize(DeviceState *dev, Error **errp)
1014{
1015    VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
1016    VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(dev);
1017    VirtIOSerial *vser = port->vser;
1018
1019    qemu_bh_delete(port->bh);
1020    remove_port(port->vser, port->id);
1021
1022    QTAILQ_REMOVE(&vser->ports, port, next);
1023
1024    if (vsc->unrealize) {
1025        vsc->unrealize(dev, errp);
1026    }
1027}
1028
1029static void virtio_serial_device_realize(DeviceState *dev, Error **errp)
1030{
1031    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1032    VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1033    uint32_t i, max_supported_ports;
1034    size_t config_size = sizeof(struct virtio_console_config);
1035
1036    if (!vser->serial.max_virtserial_ports) {
1037        error_setg(errp, "Maximum number of serial ports not specified");
1038        return;
1039    }
1040
1041    /* Each port takes 2 queues, and one pair is for the control queue */
1042    max_supported_ports = VIRTIO_QUEUE_MAX / 2 - 1;
1043
1044    if (vser->serial.max_virtserial_ports > max_supported_ports) {
1045        error_setg(errp, "maximum ports supported: %u", max_supported_ports);
1046        return;
1047    }
1048
1049    if (!virtio_has_feature(vser->host_features,
1050                            VIRTIO_CONSOLE_F_EMERG_WRITE)) {
1051        config_size = offsetof(struct virtio_console_config, emerg_wr);
1052    }
1053    virtio_init(vdev, "virtio-serial", VIRTIO_ID_CONSOLE,
1054                config_size);
1055
1056    /* Spawn a new virtio-serial bus on which the ports will ride as devices */
1057    qbus_create_inplace(&vser->bus, sizeof(vser->bus), TYPE_VIRTIO_SERIAL_BUS,
1058                        dev, vdev->bus_name);
1059    qbus_set_hotplug_handler(BUS(&vser->bus), OBJECT(vser), errp);
1060    vser->bus.vser = vser;
1061    QTAILQ_INIT(&vser->ports);
1062
1063    vser->bus.max_nr_ports = vser->serial.max_virtserial_ports;
1064    vser->ivqs = g_malloc(vser->serial.max_virtserial_ports
1065                          * sizeof(VirtQueue *));
1066    vser->ovqs = g_malloc(vser->serial.max_virtserial_ports
1067                          * sizeof(VirtQueue *));
1068
1069    /* Add a queue for host to guest transfers for port 0 (backward compat) */
1070    vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
1071    /* Add a queue for guest to host transfers for port 0 (backward compat) */
1072    vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
1073
1074    /* TODO: host to guest notifications can get dropped
1075     * if the queue fills up. Implement queueing in host,
1076     * this might also make it possible to reduce the control
1077     * queue size: as guest preposts buffers there,
1078     * this will save 4Kbyte of guest memory per entry. */
1079
1080    /* control queue: host to guest */
1081    vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
1082    /* control queue: guest to host */
1083    vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
1084
1085    for (i = 1; i < vser->bus.max_nr_ports; i++) {
1086        /* Add a per-port queue for host to guest transfers */
1087        vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
1088        /* Add a per-per queue for guest to host transfers */
1089        vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
1090    }
1091
1092    vser->ports_map = g_malloc0((DIV_ROUND_UP(vser->serial.max_virtserial_ports, 32))
1093        * sizeof(vser->ports_map[0]));
1094    /*
1095     * Reserve location 0 for a console port for backward compat
1096     * (old kernel, new qemu)
1097     */
1098    mark_port_added(vser, 0);
1099
1100    vser->post_load = NULL;
1101
1102    QLIST_INSERT_HEAD(&vserdevices.devices, vser, next);
1103}
1104
1105static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
1106{
1107    DeviceClass *k = DEVICE_CLASS(klass);
1108
1109    set_bit(DEVICE_CATEGORY_INPUT, k->categories);
1110    k->bus_type = TYPE_VIRTIO_SERIAL_BUS;
1111    k->realize = virtser_port_device_realize;
1112    k->unrealize = virtser_port_device_unrealize;
1113    device_class_set_props(k, virtser_props);
1114}
1115
1116static const TypeInfo virtio_serial_port_type_info = {
1117    .name = TYPE_VIRTIO_SERIAL_PORT,
1118    .parent = TYPE_DEVICE,
1119    .instance_size = sizeof(VirtIOSerialPort),
1120    .abstract = true,
1121    .class_size = sizeof(VirtIOSerialPortClass),
1122    .class_init = virtio_serial_port_class_init,
1123};
1124
1125static void virtio_serial_device_unrealize(DeviceState *dev, Error **errp)
1126{
1127    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1128    VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1129    int i;
1130
1131    QLIST_REMOVE(vser, next);
1132
1133    virtio_delete_queue(vser->c_ivq);
1134    virtio_delete_queue(vser->c_ovq);
1135    for (i = 0; i < vser->bus.max_nr_ports; i++) {
1136        virtio_delete_queue(vser->ivqs[i]);
1137        virtio_delete_queue(vser->ovqs[i]);
1138    }
1139
1140    g_free(vser->ivqs);
1141    g_free(vser->ovqs);
1142    g_free(vser->ports_map);
1143    if (vser->post_load) {
1144        g_free(vser->post_load->connected);
1145        timer_del(vser->post_load->timer);
1146        timer_free(vser->post_load->timer);
1147        g_free(vser->post_load);
1148    }
1149
1150    qbus_set_hotplug_handler(BUS(&vser->bus), NULL, errp);
1151
1152    virtio_cleanup(vdev);
1153}
1154
1155/* Note: 'console' is used for backwards compatibility */
1156static const VMStateDescription vmstate_virtio_console = {
1157    .name = "virtio-console",
1158    .minimum_version_id = 3,
1159    .version_id = 3,
1160    .fields = (VMStateField[]) {
1161        VMSTATE_VIRTIO_DEVICE,
1162        VMSTATE_END_OF_LIST()
1163    },
1164};
1165
1166static Property virtio_serial_properties[] = {
1167    DEFINE_PROP_UINT32("max_ports", VirtIOSerial, serial.max_virtserial_ports,
1168                                                  31),
1169    DEFINE_PROP_BIT64("emergency-write", VirtIOSerial, host_features,
1170                      VIRTIO_CONSOLE_F_EMERG_WRITE, true),
1171    DEFINE_PROP_END_OF_LIST(),
1172};
1173
1174static void virtio_serial_class_init(ObjectClass *klass, void *data)
1175{
1176    DeviceClass *dc = DEVICE_CLASS(klass);
1177    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1178    HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
1179
1180    QLIST_INIT(&vserdevices.devices);
1181
1182    device_class_set_props(dc, virtio_serial_properties);
1183    dc->vmsd = &vmstate_virtio_console;
1184    set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
1185    vdc->realize = virtio_serial_device_realize;
1186    vdc->unrealize = virtio_serial_device_unrealize;
1187    vdc->get_features = get_features;
1188    vdc->get_config = get_config;
1189    vdc->set_config = set_config;
1190    vdc->set_status = set_status;
1191    vdc->reset = vser_reset;
1192    vdc->save = virtio_serial_save_device;
1193    vdc->load = virtio_serial_load_device;
1194    hc->plug = virtser_port_device_plug;
1195    hc->unplug = qdev_simple_device_unplug_cb;
1196}
1197
1198static const TypeInfo virtio_device_info = {
1199    .name = TYPE_VIRTIO_SERIAL,
1200    .parent = TYPE_VIRTIO_DEVICE,
1201    .instance_size = sizeof(VirtIOSerial),
1202    .class_init = virtio_serial_class_init,
1203    .interfaces = (InterfaceInfo[]) {
1204        { TYPE_HOTPLUG_HANDLER },
1205        { }
1206    }
1207};
1208
1209static void virtio_serial_register_types(void)
1210{
1211    type_register_static(&virtser_bus_info);
1212    type_register_static(&virtio_serial_port_type_info);
1213    type_register_static(&virtio_device_info);
1214}
1215
1216type_init(virtio_serial_register_types)
1217