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