hw/char/virtio-serial-bus.c

   1 /*
   2  * A bus for connecting virtio serial and console ports
   3  *
   4  * Copyright (C) 2009, 2010 Red Hat, Inc.
   5  *
   6  * Author(s):
   7  *  Amit Shah <amit.shah@redhat.com>
   8  *
   9  * Some earlier parts are:
  10  *  Copyright IBM, Corp. 2008
  11  * authored by
  12  *  Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
  13  *
  14  * This work is licensed under the terms of the GNU GPL, version 2.  See
  15  * the COPYING file in the top-level directory.
  16  *
  17  * Contributions after 2012-01-13 are licensed under the terms of the
  18  * GNU GPL, version 2 or (at your option) any later version.
  19  */
  20
  21 #include "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
  32 static struct VirtIOSerialDevices {
  33     QLIST_HEAD(, VirtIOSerial) devices;
  34 } vserdevices;
  35
  36 static 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
  51 static 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
  62 static 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
  78 static 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
  91 static 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
  97 static 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
 130 static 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
 148 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 149                                  VirtIODevice *vdev)
 150 {
 151     VirtIOSerialPortClass *vsc;
 152
 153     assert(port);
 154     assert(virtio_queue_ready(vq));
 155
 156     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 157
 158     while (!port->throttled) {
 159         unsigned int i;
 160
 161         /* Pop an elem only if we haven't left off a previous one mid-way */
 162         if (!port->elem) {
 163             port->elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 164             if (!port->elem) {
 165                 break;
 166             }
 167             port->iov_idx = 0;
 168             port->iov_offset = 0;
 169         }
 170
 171         for (i = port->iov_idx; i < port->elem->out_num; i++) {
 172             size_t buf_size;
 173             ssize_t ret;
 174
 175             buf_size = port->elem->out_sg[i].iov_len - port->iov_offset;
 176             ret = vsc->have_data(port,
 177                                   port->elem->out_sg[i].iov_base
 178                                   + port->iov_offset,
 179                                   buf_size);
 180             if (port->throttled) {
 181                 port->iov_idx = i;
 182                 if (ret > 0) {
 183                     port->iov_offset += ret;
 184                 }
 185                 break;
 186             }
 187             port->iov_offset = 0;
 188         }
 189         if (port->throttled) {
 190             break;
 191         }
 192         virtqueue_push(vq, port->elem, 0);
 193         g_free(port->elem);
 194         port->elem = NULL;
 195     }
 196     virtio_notify(vdev, vq);
 197 }
 198
 199 static void flush_queued_data(VirtIOSerialPort *port)
 200 {
 201     assert(port);
 202
 203     if (!virtio_queue_ready(port->ovq)) {
 204         return;
 205     }
 206     do_flush_queued_data(port, port->ovq, VIRTIO_DEVICE(port->vser));
 207 }
 208
 209 static size_t send_control_msg(VirtIOSerial *vser, void *buf, size_t len)
 210 {
 211     VirtQueueElement *elem;
 212     VirtQueue *vq;
 213
 214     vq = vser->c_ivq;
 215     if (!virtio_queue_ready(vq)) {
 216         return 0;
 217     }
 218
 219     elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 220     if (!elem) {
 221         return 0;
 222     }
 223
 224     /* TODO: detect a buffer that's too short, set NEEDS_RESET */
 225     iov_from_buf(elem->in_sg, elem->in_num, 0, buf, len);
 226
 227     virtqueue_push(vq, elem, len);
 228     virtio_notify(VIRTIO_DEVICE(vser), vq);
 229     g_free(elem);
 230
 231     return len;
 232 }
 233
 234 static size_t send_control_event(VirtIOSerial *vser, uint32_t port_id,
 235                                  uint16_t event, uint16_t value)
 236 {
 237     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 238     struct virtio_console_control cpkt;
 239
 240     virtio_stl_p(vdev, &cpkt.id, port_id);
 241     virtio_stw_p(vdev, &cpkt.event, event);
 242     virtio_stw_p(vdev, &cpkt.value, value);
 243
 244     trace_virtio_serial_send_control_event(port_id, event, value);
 245     return send_control_msg(vser, &cpkt, sizeof(cpkt));
 246 }
 247
 248 /* Functions for use inside qemu to open and read from/write to ports */
 249 int virtio_serial_open(VirtIOSerialPort *port)
 250 {
 251     /* Don't allow opening an already-open port */
 252     if (port->host_connected) {
 253         return 0;
 254     }
 255     /* Send port open notification to the guest */
 256     port->host_connected = true;
 257     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 258
 259     return 0;
 260 }
 261
 262 int virtio_serial_close(VirtIOSerialPort *port)
 263 {
 264     port->host_connected = false;
 265     /*
 266      * If there's any data the guest sent which the app didn't
 267      * consume, reset the throttling flag and discard the data.
 268      */
 269     port->throttled = false;
 270     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 271
 272     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 0);
 273
 274     return 0;
 275 }
 276
 277 /* Individual ports/apps call this function to write to the guest. */
 278 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 279                             size_t size)
 280 {
 281     if (!port || !port->host_connected || !port->guest_connected) {
 282         return 0;
 283     }
 284     return write_to_port(port, buf, size);
 285 }
 286
 287 /*
 288  * Readiness of the guest to accept data on a port.
 289  * Returns max. data the guest can receive
 290  */
 291 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 292 {
 293     VirtIODevice *vdev = VIRTIO_DEVICE(port->vser);
 294     VirtQueue *vq = port->ivq;
 295     unsigned int bytes;
 296
 297     if (!virtio_queue_ready(vq) ||
 298         !(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 299         virtio_queue_empty(vq)) {
 300         return 0;
 301     }
 302     if (use_multiport(port->vser) && !port->guest_connected) {
 303         return 0;
 304     }
 305     virtqueue_get_avail_bytes(vq, &bytes, NULL, 4096, 0);
 306     return bytes;
 307 }
 308
 309 static void flush_queued_data_bh(void *opaque)
 310 {
 311     VirtIOSerialPort *port = opaque;
 312
 313     flush_queued_data(port);
 314 }
 315
 316 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 317 {
 318     if (!port) {
 319         return;
 320     }
 321
 322     trace_virtio_serial_throttle_port(port->id, throttle);
 323     port->throttled = throttle;
 324     if (throttle) {
 325         return;
 326     }
 327     qemu_bh_schedule(port->bh);
 328 }
 329
 330 /* Guest wants to notify us of some event */
 331 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 332 {
 333     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 334     struct VirtIOSerialPort *port;
 335     VirtIOSerialPortClass *vsc;
 336     struct virtio_console_control cpkt, *gcpkt;
 337     uint8_t *buffer;
 338     size_t buffer_len;
 339
 340     gcpkt = buf;
 341
 342     if (len < sizeof(cpkt)) {
 343         /* The guest sent an invalid control packet */
 344         return;
 345     }
 346
 347     cpkt.event = virtio_lduw_p(vdev, &gcpkt->event);
 348     cpkt.value = virtio_lduw_p(vdev, &gcpkt->value);
 349
 350     trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 351
 352     if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 353         if (!cpkt.value) {
 354             error_report("virtio-serial-bus: Guest failure in adding device %s",
 355                          vser->bus.qbus.name);
 356             return;
 357         }
 358         /*
 359          * The device is up, we can now tell the device about all the
 360          * ports we have here.
 361          */
 362         QTAILQ_FOREACH(port, &vser->ports, next) {
 363             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_ADD, 1);
 364         }
 365         return;
 366     }
 367
 368     port = find_port_by_id(vser, virtio_ldl_p(vdev, &gcpkt->id));
 369     if (!port) {
 370         error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 371                      virtio_ldl_p(vdev, &gcpkt->id), vser->bus.qbus.name);
 372         return;
 373     }
 374
 375     trace_virtio_serial_handle_control_message_port(port->id);
 376
 377     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 378
 379     switch(cpkt.event) {
 380     case VIRTIO_CONSOLE_PORT_READY:
 381         if (!cpkt.value) {
 382             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 383                          port->id, vser->bus.qbus.name);
 384             break;
 385         }
 386         /*
 387          * Now that we know the guest asked for the port name, we're
 388          * sure the guest has initialised whatever state is necessary
 389          * for this port. Now's a good time to let the guest know if
 390          * this port is a console port so that the guest can hook it
 391          * up to hvc.
 392          */
 393         if (vsc->is_console) {
 394             send_control_event(vser, port->id, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 395         }
 396
 397         if (port->name) {
 398             virtio_stl_p(vdev, &cpkt.id, port->id);
 399             virtio_stw_p(vdev, &cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 400             virtio_stw_p(vdev, &cpkt.value, 1);
 401
 402             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 403             buffer = g_malloc(buffer_len);
 404
 405             memcpy(buffer, &cpkt, sizeof(cpkt));
 406             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 407             buffer[buffer_len - 1] = 0;
 408
 409             send_control_msg(vser, buffer, buffer_len);
 410             g_free(buffer);
 411         }
 412
 413         if (port->host_connected) {
 414             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 415         }
 416
 417         /*
 418          * When the guest has asked us for this information it means
 419          * the guest is all setup and has its virtqueues
 420          * initialised. If some app is interested in knowing about
 421          * this event, let it know.
 422          */
 423         if (vsc->guest_ready) {
 424             vsc->guest_ready(port);
 425         }
 426         break;
 427
 428     case VIRTIO_CONSOLE_PORT_OPEN:
 429         port->guest_connected = cpkt.value;
 430         if (vsc->set_guest_connected) {
 431             /* Send the guest opened notification if an app is interested */
 432             vsc->set_guest_connected(port, cpkt.value);
 433         }
 434         break;
 435     }
 436 }
 437
 438 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 439 {
 440 }
 441
 442 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 443 {
 444     VirtQueueElement *elem;
 445     VirtIOSerial *vser;
 446     uint8_t *buf;
 447     size_t len;
 448
 449     vser = VIRTIO_SERIAL(vdev);
 450
 451     len = 0;
 452     buf = NULL;
 453     for (;;) {
 454         size_t cur_len;
 455
 456         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 457         if (!elem) {
 458             break;
 459         }
 460
 461         cur_len = iov_size(elem->out_sg, elem->out_num);
 462         /*
 463          * Allocate a new buf only if we didn't have one previously or
 464          * if the size of the buf differs
 465          */
 466         if (cur_len > len) {
 467             g_free(buf);
 468
 469             buf = g_malloc(cur_len);
 470             len = cur_len;
 471         }
 472         iov_to_buf(elem->out_sg, elem->out_num, 0, buf, cur_len);
 473
 474         handle_control_message(vser, buf, cur_len);
 475         virtqueue_push(vq, elem, 0);
 476         g_free(elem);
 477     }
 478     g_free(buf);
 479     virtio_notify(vdev, vq);
 480 }
 481
 482 /* Guest wrote something to some port. */
 483 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 484 {
 485     VirtIOSerial *vser;
 486     VirtIOSerialPort *port;
 487
 488     vser = VIRTIO_SERIAL(vdev);
 489     port = find_port_by_vq(vser, vq);
 490
 491     if (!port || !port->host_connected) {
 492         discard_vq_data(vq, vdev);
 493         return;
 494     }
 495
 496     if (!port->throttled) {
 497         do_flush_queued_data(port, vq, vdev);
 498         return;
 499     }
 500 }
 501
 502 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 503 {
 504     /*
 505      * Users of virtio-serial would like to know when guest becomes
 506      * writable again -- i.e. if a vq had stuff queued up and the
 507      * guest wasn't reading at all, the host would not be able to
 508      * write to the vq anymore.  Once the guest reads off something,
 509      * we can start queueing things up again.  However, this call is
 510      * made for each buffer addition by the guest -- even though free
 511      * buffers existed prior to the current buffer addition.  This is
 512      * done so as not to maintain previous state, which will need
 513      * additional live-migration-related changes.
 514      */
 515     VirtIOSerial *vser;
 516     VirtIOSerialPort *port;
 517     VirtIOSerialPortClass *vsc;
 518
 519     vser = VIRTIO_SERIAL(vdev);
 520     port = find_port_by_vq(vser, vq);
 521
 522     if (!port) {
 523         return;
 524     }
 525     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 526
 527     /*
 528      * If guest_connected is false, this call is being made by the
 529      * early-boot queueing up of descriptors, which is just noise for
 530      * the host apps -- don't disturb them in that case.
 531      */
 532     if (port->guest_connected && port->host_connected && vsc->guest_writable) {
 533         vsc->guest_writable(port);
 534     }
 535 }
 536
 537 static uint64_t get_features(VirtIODevice *vdev, uint64_t features,
 538                              Error **errp)
 539 {
 540     VirtIOSerial *vser;
 541
 542     vser = VIRTIO_SERIAL(vdev);
 543
 544     if (vser->bus.max_nr_ports > 1) {
 545         virtio_add_feature(&features, VIRTIO_CONSOLE_F_MULTIPORT);
 546     }
 547     return features;
 548 }
 549
 550 /* Guest requested config info */
 551 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 552 {
 553     VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 554     struct virtio_console_config *config =
 555         (struct virtio_console_config *)config_data;
 556
 557     config->cols = 0;
 558     config->rows = 0;
 559     config->max_nr_ports = virtio_tswap32(vdev,
 560                                           vser->serial.max_virtserial_ports);
 561 }
 562
 563 /* Guest sent new config info */
 564 static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
 565 {
 566     VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 567     struct virtio_console_config *config =
 568         (struct virtio_console_config *)config_data;
 569     uint8_t emerg_wr_lo = le32_to_cpu(config->emerg_wr);
 570     VirtIOSerialPort *port = find_first_connected_console(vser);
 571     VirtIOSerialPortClass *vsc;
 572
 573     if (!config->emerg_wr) {
 574         return;
 575     }
 576     /* Make sure we don't misdetect an emergency write when the guest
 577      * does a short config write after an emergency write. */
 578     config->emerg_wr = 0;
 579     if (!port) {
 580         return;
 581     }
 582     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 583     (void)vsc->have_data(port, &emerg_wr_lo, 1);
 584 }
 585
 586 static void guest_reset(VirtIOSerial *vser)
 587 {
 588     VirtIOSerialPort *port;
 589     VirtIOSerialPortClass *vsc;
 590
 591     QTAILQ_FOREACH(port, &vser->ports, next) {
 592         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 593         if (port->guest_connected) {
 594             port->guest_connected = false;
 595             if (vsc->set_guest_connected) {
 596                 vsc->set_guest_connected(port, false);
 597             }
 598         }
 599     }
 600 }
 601
 602 static void set_status(VirtIODevice *vdev, uint8_t status)
 603 {
 604     VirtIOSerial *vser;
 605     VirtIOSerialPort *port;
 606
 607     vser = VIRTIO_SERIAL(vdev);
 608     port = find_port_by_id(vser, 0);
 609
 610     if (port && !use_multiport(port->vser)
 611         && (status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 612         /*
 613          * Non-multiport guests won't be able to tell us guest
 614          * open/close status.  Such guests can only have a port at id
 615          * 0, so set guest_connected for such ports as soon as guest
 616          * is up.
 617          */
 618         port->guest_connected = true;
 619     }
 620     if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 621         guest_reset(vser);
 622     }
 623 }
 624
 625 static void vser_reset(VirtIODevice *vdev)
 626 {
 627     VirtIOSerial *vser;
 628
 629     vser = VIRTIO_SERIAL(vdev);
 630     guest_reset(vser);
 631 }
 632
 633 static void virtio_serial_save_device(VirtIODevice *vdev, QEMUFile *f)
 634 {
 635     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 636     VirtIOSerialPort *port;
 637     uint32_t nr_active_ports;
 638     unsigned int i, max_nr_ports;
 639     struct virtio_console_config config;
 640
 641     /* The config space (ignored on the far end in current versions) */
 642     get_config(vdev, (uint8_t *)&config);
 643     qemu_put_be16s(f, &config.cols);
 644     qemu_put_be16s(f, &config.rows);
 645     qemu_put_be32s(f, &config.max_nr_ports);
 646
 647     /* The ports map */
 648     max_nr_ports = s->serial.max_virtserial_ports;
 649     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 650         qemu_put_be32s(f, &s->ports_map[i]);
 651     }
 652
 653     /* Ports */
 654
 655     nr_active_ports = 0;
 656     QTAILQ_FOREACH(port, &s->ports, next) {
 657         nr_active_ports++;
 658     }
 659
 660     qemu_put_be32s(f, &nr_active_ports);
 661
 662     /*
 663      * Items in struct VirtIOSerialPort.
 664      */
 665     QTAILQ_FOREACH(port, &s->ports, next) {
 666         uint32_t elem_popped;
 667
 668         qemu_put_be32s(f, &port->id);
 669         qemu_put_byte(f, port->guest_connected);
 670         qemu_put_byte(f, port->host_connected);
 671
 672         elem_popped = 0;
 673         if (port->elem) {
 674             elem_popped = 1;
 675         }
 676         qemu_put_be32s(f, &elem_popped);
 677         if (elem_popped) {
 678             qemu_put_be32s(f, &port->iov_idx);
 679             qemu_put_be64s(f, &port->iov_offset);
 680             qemu_put_virtqueue_element(f, port->elem);
 681         }
 682     }
 683 }
 684
 685 static void virtio_serial_post_load_timer_cb(void *opaque)
 686 {
 687     uint32_t i;
 688     VirtIOSerial *s = VIRTIO_SERIAL(opaque);
 689     VirtIOSerialPort *port;
 690     uint8_t host_connected;
 691     VirtIOSerialPortClass *vsc;
 692
 693     if (!s->post_load) {
 694         return;
 695     }
 696     for (i = 0 ; i < s->post_load->nr_active_ports; ++i) {
 697         port = s->post_load->connected[i].port;
 698         host_connected = s->post_load->connected[i].host_connected;
 699         if (host_connected != port->host_connected) {
 700             /*
 701              * We have to let the guest know of the host connection
 702              * status change
 703              */
 704             send_control_event(s, port->id, VIRTIO_CONSOLE_PORT_OPEN,
 705                                port->host_connected);
 706         }
 707         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 708         if (vsc->set_guest_connected) {
 709             vsc->set_guest_connected(port, port->guest_connected);
 710         }
 711     }
 712     g_free(s->post_load->connected);
 713     timer_free(s->post_load->timer);
 714     g_free(s->post_load);
 715     s->post_load = NULL;
 716 }
 717
 718 static int fetch_active_ports_list(QEMUFile *f,
 719                                    VirtIOSerial *s, uint32_t nr_active_ports)
 720 {
 721     uint32_t i;
 722
 723     s->post_load = g_malloc0(sizeof(*s->post_load));
 724     s->post_load->nr_active_ports = nr_active_ports;
 725     s->post_load->connected =
 726         g_malloc0(sizeof(*s->post_load->connected) * nr_active_ports);
 727
 728     s->post_load->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
 729                                             virtio_serial_post_load_timer_cb,
 730                                             s);
 731
 732     /* Items in struct VirtIOSerialPort */
 733     for (i = 0; i < nr_active_ports; i++) {
 734         VirtIOSerialPort *port;
 735         uint32_t elem_popped;
 736         uint32_t id;
 737
 738         id = qemu_get_be32(f);
 739         port = find_port_by_id(s, id);
 740         if (!port) {
 741             return -EINVAL;
 742         }
 743
 744         port->guest_connected = qemu_get_byte(f);
 745         s->post_load->connected[i].port = port;
 746         s->post_load->connected[i].host_connected = qemu_get_byte(f);
 747
 748         qemu_get_be32s(f, &elem_popped);
 749         if (elem_popped) {
 750             qemu_get_be32s(f, &port->iov_idx);
 751             qemu_get_be64s(f, &port->iov_offset);
 752
 753             port->elem =
 754                 qemu_get_virtqueue_element(f, sizeof(VirtQueueElement));
 755
 756             /*
 757              *  Port was throttled on source machine.  Let's
 758              *  unthrottle it here so data starts flowing again.
 759              */
 760             virtio_serial_throttle_port(port, false);
 761         }
 762     }
 763     timer_mod(s->post_load->timer, 1);
 764     return 0;
 765 }
 766
 767 static int virtio_serial_load(QEMUFile *f, void *opaque, size_t size)
 768 {
 769     /* The virtio device */
 770     return virtio_load(VIRTIO_DEVICE(opaque), f, 3);
 771 }
 772
 773 static int virtio_serial_load_device(VirtIODevice *vdev, QEMUFile *f,
 774                                      int version_id)
 775 {
 776     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 777     uint32_t max_nr_ports, nr_active_ports, ports_map;
 778     unsigned int i;
 779     int ret;
 780     uint32_t tmp;
 781
 782     /* Unused */
 783     qemu_get_be16s(f, (uint16_t *) &tmp);
 784     qemu_get_be16s(f, (uint16_t *) &tmp);
 785     qemu_get_be32s(f, &tmp);
 786
 787     max_nr_ports = s->serial.max_virtserial_ports;
 788     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 789         qemu_get_be32s(f, &ports_map);
 790
 791         if (ports_map != s->ports_map[i]) {
 792             /*
 793              * Ports active on source and destination don't
 794              * match. Fail migration.
 795              */
 796             return -EINVAL;
 797         }
 798     }
 799
 800     qemu_get_be32s(f, &nr_active_ports);
 801
 802     if (nr_active_ports) {
 803         ret = fetch_active_ports_list(f, s, nr_active_ports);
 804         if (ret) {
 805             return ret;
 806         }
 807     }
 808     return 0;
 809 }
 810
 811 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 812
 813 static Property virtser_props[] = {
 814     DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 815     DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 816     DEFINE_PROP_END_OF_LIST()
 817 };
 818
 819 #define TYPE_VIRTIO_SERIAL_BUS "virtio-serial-bus"
 820 #define VIRTIO_SERIAL_BUS(obj) \
 821       OBJECT_CHECK(VirtIOSerialBus, (obj), TYPE_VIRTIO_SERIAL_BUS)
 822
 823 static void virtser_bus_class_init(ObjectClass *klass, void *data)
 824 {
 825     BusClass *k = BUS_CLASS(klass);
 826     k->print_dev = virtser_bus_dev_print;
 827 }
 828
 829 static const TypeInfo virtser_bus_info = {
 830     .name = TYPE_VIRTIO_SERIAL_BUS,
 831     .parent = TYPE_BUS,
 832     .instance_size = sizeof(VirtIOSerialBus),
 833     .class_init = virtser_bus_class_init,
 834 };
 835
 836 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 837 {
 838     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(qdev);
 839
 840     monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 841                    indent, "", port->id,
 842                    port->guest_connected ? "on" : "off",
 843                    port->host_connected ? "on" : "off",
 844                    port->throttled ? "on" : "off");
 845 }
 846
 847 /* This function is only used if a port id is not provided by the user */
 848 static uint32_t find_free_port_id(VirtIOSerial *vser)
 849 {
 850     unsigned int i, max_nr_ports;
 851
 852     max_nr_ports = vser->serial.max_virtserial_ports;
 853     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 854         uint32_t map, zeroes;
 855
 856         map = vser->ports_map[i];
 857         zeroes = ctz32(~map);
 858         if (zeroes != 32) {
 859             return zeroes + i * 32;
 860         }
 861     }
 862     return VIRTIO_CONSOLE_BAD_ID;
 863 }
 864
 865 static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 866 {
 867     unsigned int i;
 868
 869     i = port_id / 32;
 870     vser->ports_map[i] |= 1U << (port_id % 32);
 871 }
 872
 873 static void add_port(VirtIOSerial *vser, uint32_t port_id)
 874 {
 875     mark_port_added(vser, port_id);
 876     send_control_event(vser, port_id, VIRTIO_CONSOLE_PORT_ADD, 1);
 877 }
 878
 879 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 880 {
 881     VirtIOSerialPort *port;
 882
 883     /*
 884      * Don't mark port 0 removed -- we explicitly reserve it for
 885      * backward compat with older guests, ensure a virtconsole device
 886      * unplug retains the reservation.
 887      */
 888     if (port_id) {
 889         unsigned int i;
 890
 891         i = port_id / 32;
 892         vser->ports_map[i] &= ~(1U << (port_id % 32));
 893     }
 894
 895     port = find_port_by_id(vser, port_id);
 896     /*
 897      * This function is only called from qdev's unplug callback; if we
 898      * get a NULL port here, we're in trouble.
 899      */
 900     assert(port);
 901
 902     /* Flush out any unconsumed buffers first */
 903     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 904
 905     send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 906 }
 907
 908 static void virtser_port_device_realize(DeviceState *dev, Error **errp)
 909 {
 910     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 911     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 912     VirtIOSerialBus *bus = VIRTIO_SERIAL_BUS(qdev_get_parent_bus(dev));
 913     int max_nr_ports;
 914     bool plugging_port0;
 915     Error *err = NULL;
 916
 917     port->vser = bus->vser;
 918     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 919
 920     assert(vsc->have_data);
 921
 922     /*
 923      * Is the first console port we're seeing? If so, put it up at
 924      * location 0. This is done for backward compatibility (old
 925      * kernel, new qemu).
 926      */
 927     plugging_port0 = vsc->is_console && !find_port_by_id(port->vser, 0);
 928
 929     if (find_port_by_id(port->vser, port->id)) {
 930         error_setg(errp, "virtio-serial-bus: A port already exists at id %u",
 931                    port->id);
 932         return;
 933     }
 934
 935     if (port->name != NULL && find_port_by_name(port->name)) {
 936         error_setg(errp, "virtio-serial-bus: A port already exists by name %s",
 937                    port->name);
 938         return;
 939     }
 940
 941     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 942         if (plugging_port0) {
 943             port->id = 0;
 944         } else {
 945             port->id = find_free_port_id(port->vser);
 946             if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 947                 error_setg(errp, "virtio-serial-bus: Maximum port limit for "
 948                                  "this device reached");
 949                 return;
 950             }
 951         }
 952     }
 953
 954     max_nr_ports = port->vser->serial.max_virtserial_ports;
 955     if (port->id >= max_nr_ports) {
 956         error_setg(errp, "virtio-serial-bus: Out-of-range port id specified, "
 957                          "max. allowed: %u", max_nr_ports - 1);
 958         return;
 959     }
 960
 961     vsc->realize(dev, &err);
 962     if (err != NULL) {
 963         error_propagate(errp, err);
 964         return;
 965     }
 966
 967     port->elem = NULL;
 968 }
 969
 970 static void virtser_port_device_plug(HotplugHandler *hotplug_dev,
 971                                      DeviceState *dev, Error **errp)
 972 {
 973     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 974
 975     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
 976     port->ivq = port->vser->ivqs[port->id];
 977     port->ovq = port->vser->ovqs[port->id];
 978
 979     add_port(port->vser, port->id);
 980
 981     /* Send an update to the guest about this new port added */
 982     virtio_notify_config(VIRTIO_DEVICE(hotplug_dev));
 983 }
 984
 985 static void virtser_port_device_unrealize(DeviceState *dev, Error **errp)
 986 {
 987     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 988     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(dev);
 989     VirtIOSerial *vser = port->vser;
 990
 991     qemu_bh_delete(port->bh);
 992     remove_port(port->vser, port->id);
 993
 994     QTAILQ_REMOVE(&vser->ports, port, next);
 995
 996     if (vsc->unrealize) {
 997         vsc->unrealize(dev, errp);
 998     }
 999 }
1000
1001 static void virtio_serial_device_realize(DeviceState *dev, Error **errp)
1002 {
1003     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1004     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1005     uint32_t i, max_supported_ports;
1006
1007     if (!vser->serial.max_virtserial_ports) {
1008         error_setg(errp, "Maximum number of serial ports not specified");
1009         return;
1010     }
1011
1012     /* Each port takes 2 queues, and one pair is for the control queue */
1013     max_supported_ports = VIRTIO_QUEUE_MAX / 2 - 1;
1014
1015     if (vser->serial.max_virtserial_ports > max_supported_ports) {
1016         error_setg(errp, "maximum ports supported: %u", max_supported_ports);
1017         return;
1018     }
1019
1020     /* We don't support emergency write, skip it for now. */
1021     /* TODO: cleaner fix, depending on host features. */
1022     virtio_init(vdev, "virtio-serial", VIRTIO_ID_CONSOLE,
1023                 offsetof(struct virtio_console_config, emerg_wr));
1024
1025     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
1026     qbus_create_inplace(&vser->bus, sizeof(vser->bus), TYPE_VIRTIO_SERIAL_BUS,
1027                         dev, vdev->bus_name);
1028     qbus_set_hotplug_handler(BUS(&vser->bus), DEVICE(vser), errp);
1029     vser->bus.vser = vser;
1030     QTAILQ_INIT(&vser->ports);
1031
1032     vser->bus.max_nr_ports = vser->serial.max_virtserial_ports;
1033     vser->ivqs = g_malloc(vser->serial.max_virtserial_ports
1034                           * sizeof(VirtQueue *));
1035     vser->ovqs = g_malloc(vser->serial.max_virtserial_ports
1036                           * sizeof(VirtQueue *));
1037
1038     /* Add a queue for host to guest transfers for port 0 (backward compat) */
1039     vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
1040     /* Add a queue for guest to host transfers for port 0 (backward compat) */
1041     vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
1042
1043     /* TODO: host to guest notifications can get dropped
1044      * if the queue fills up. Implement queueing in host,
1045      * this might also make it possible to reduce the control
1046      * queue size: as guest preposts buffers there,
1047      * this will save 4Kbyte of guest memory per entry. */
1048
1049     /* control queue: host to guest */
1050     vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
1051     /* control queue: guest to host */
1052     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
1053
1054     for (i = 1; i < vser->bus.max_nr_ports; i++) {
1055         /* Add a per-port queue for host to guest transfers */
1056         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
1057         /* Add a per-per queue for guest to host transfers */
1058         vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
1059     }
1060
1061     vser->ports_map = g_malloc0(((vser->serial.max_virtserial_ports + 31) / 32)
1062         * sizeof(vser->ports_map[0]));
1063     /*
1064      * Reserve location 0 for a console port for backward compat
1065      * (old kernel, new qemu)
1066      */
1067     mark_port_added(vser, 0);
1068
1069     vser->post_load = NULL;
1070
1071     QLIST_INSERT_HEAD(&vserdevices.devices, vser, next);
1072 }
1073
1074 static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
1075 {
1076     DeviceClass *k = DEVICE_CLASS(klass);
1077
1078     set_bit(DEVICE_CATEGORY_INPUT, k->categories);
1079     k->bus_type = TYPE_VIRTIO_SERIAL_BUS;
1080     k->realize = virtser_port_device_realize;
1081     k->unrealize = virtser_port_device_unrealize;
1082     k->props = virtser_props;
1083 }
1084
1085 static const TypeInfo virtio_serial_port_type_info = {
1086     .name = TYPE_VIRTIO_SERIAL_PORT,
1087     .parent = TYPE_DEVICE,
1088     .instance_size = sizeof(VirtIOSerialPort),
1089     .abstract = true,
1090     .class_size = sizeof(VirtIOSerialPortClass),
1091     .class_init = virtio_serial_port_class_init,
1092 };
1093
1094 static void virtio_serial_device_unrealize(DeviceState *dev, Error **errp)
1095 {
1096     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1097     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1098
1099     QLIST_REMOVE(vser, next);
1100
1101     g_free(vser->ivqs);
1102     g_free(vser->ovqs);
1103     g_free(vser->ports_map);
1104     if (vser->post_load) {
1105         g_free(vser->post_load->connected);
1106         timer_del(vser->post_load->timer);
1107         timer_free(vser->post_load->timer);
1108         g_free(vser->post_load);
1109     }
1110     virtio_cleanup(vdev);
1111 }
1112
1113 /* Note: 'console' is used for backwards compatibility */
1114 VMSTATE_VIRTIO_DEVICE(console, 3, virtio_serial_load, virtio_vmstate_save);
1115
1116 static Property virtio_serial_properties[] = {
1117     DEFINE_PROP_UINT32("max_ports", VirtIOSerial, serial.max_virtserial_ports,
1118                                                   31),
1119     DEFINE_PROP_END_OF_LIST(),
1120 };
1121
1122 static void virtio_serial_class_init(ObjectClass *klass, void *data)
1123 {
1124     DeviceClass *dc = DEVICE_CLASS(klass);
1125     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1126     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
1127
1128     QLIST_INIT(&vserdevices.devices);
1129
1130     dc->props = virtio_serial_properties;
1131     dc->vmsd = &vmstate_virtio_console;
1132     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
1133     vdc->realize = virtio_serial_device_realize;
1134     vdc->unrealize = virtio_serial_device_unrealize;
1135     vdc->get_features = get_features;
1136     vdc->get_config = get_config;
1137     vdc->set_config = set_config;
1138     vdc->set_status = set_status;
1139     vdc->reset = vser_reset;
1140     vdc->save = virtio_serial_save_device;
1141     vdc->load = virtio_serial_load_device;
1142     hc->plug = virtser_port_device_plug;
1143     hc->unplug = qdev_simple_device_unplug_cb;
1144 }
1145
1146 static const TypeInfo virtio_device_info = {
1147     .name = TYPE_VIRTIO_SERIAL,
1148     .parent = TYPE_VIRTIO_DEVICE,
1149     .instance_size = sizeof(VirtIOSerial),
1150     .class_init = virtio_serial_class_init,
1151     .interfaces = (InterfaceInfo[]) {
1152         { TYPE_HOTPLUG_HANDLER },
1153         { }
1154     }
1155 };
1156
1157 static void virtio_serial_register_types(void)
1158 {
1159     type_register_static(&virtser_bus_info);
1160     type_register_static(&virtio_serial_port_type_info);
1161     type_register_static(&virtio_device_info);
1162 }
1163
1164 type_init(virtio_serial_register_types)