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