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