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 bool use_multiport(VirtIOSerial *vser)
  79 {
  80     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
  81     return virtio_vdev_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT);
  82 }
  83
  84 static size_t write_to_port(VirtIOSerialPort *port,
  85                             const uint8_t *buf, size_t size)
  86 {
  87     VirtQueueElement *elem;
  88     VirtQueue *vq;
  89     size_t offset;
  90
  91     vq = port->ivq;
  92     if (!virtio_queue_ready(vq)) {
  93         return 0;
  94     }
  95
  96     offset = 0;
  97     while (offset < size) {
  98         size_t len;
  99
 100         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 101         if (!elem) {
 102             break;
 103         }
 104
 105         len = iov_from_buf(elem->in_sg, elem->in_num, 0,
 106                            buf + offset, size - offset);
 107         offset += len;
 108
 109         virtqueue_push(vq, elem, len);
 110         g_free(elem);
 111     }
 112
 113     virtio_notify(VIRTIO_DEVICE(port->vser), vq);
 114     return offset;
 115 }
 116
 117 static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
 118 {
 119     VirtQueueElement *elem;
 120
 121     if (!virtio_queue_ready(vq)) {
 122         return;
 123     }
 124     for (;;) {
 125         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 126         if (!elem) {
 127             break;
 128         }
 129         virtqueue_push(vq, elem, 0);
 130         g_free(elem);
 131     }
 132     virtio_notify(vdev, vq);
 133 }
 134
 135 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 136                                  VirtIODevice *vdev)
 137 {
 138     VirtIOSerialPortClass *vsc;
 139
 140     assert(port);
 141     assert(virtio_queue_ready(vq));
 142
 143     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 144
 145     while (!port->throttled) {
 146         unsigned int i;
 147
 148         /* Pop an elem only if we haven't left off a previous one mid-way */
 149         if (!port->elem) {
 150             port->elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 151             if (!port->elem) {
 152                 break;
 153             }
 154             port->iov_idx = 0;
 155             port->iov_offset = 0;
 156         }
 157
 158         for (i = port->iov_idx; i < port->elem->out_num; i++) {
 159             size_t buf_size;
 160             ssize_t ret;
 161
 162             buf_size = port->elem->out_sg[i].iov_len - port->iov_offset;
 163             ret = vsc->have_data(port,
 164                                   port->elem->out_sg[i].iov_base
 165                                   + port->iov_offset,
 166                                   buf_size);
 167             if (port->throttled) {
 168                 port->iov_idx = i;
 169                 if (ret > 0) {
 170                     port->iov_offset += ret;
 171                 }
 172                 break;
 173             }
 174             port->iov_offset = 0;
 175         }
 176         if (port->throttled) {
 177             break;
 178         }
 179         virtqueue_push(vq, port->elem, 0);
 180         g_free(port->elem);
 181         port->elem = NULL;
 182     }
 183     virtio_notify(vdev, vq);
 184 }
 185
 186 static void flush_queued_data(VirtIOSerialPort *port)
 187 {
 188     assert(port);
 189
 190     if (!virtio_queue_ready(port->ovq)) {
 191         return;
 192     }
 193     do_flush_queued_data(port, port->ovq, VIRTIO_DEVICE(port->vser));
 194 }
 195
 196 static size_t send_control_msg(VirtIOSerial *vser, void *buf, size_t len)
 197 {
 198     VirtQueueElement *elem;
 199     VirtQueue *vq;
 200
 201     vq = vser->c_ivq;
 202     if (!virtio_queue_ready(vq)) {
 203         return 0;
 204     }
 205
 206     elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 207     if (!elem) {
 208         return 0;
 209     }
 210
 211     /* TODO: detect a buffer that's too short, set NEEDS_RESET */
 212     iov_from_buf(elem->in_sg, elem->in_num, 0, buf, len);
 213
 214     virtqueue_push(vq, elem, len);
 215     virtio_notify(VIRTIO_DEVICE(vser), vq);
 216     g_free(elem);
 217
 218     return len;
 219 }
 220
 221 static size_t send_control_event(VirtIOSerial *vser, uint32_t port_id,
 222                                  uint16_t event, uint16_t value)
 223 {
 224     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 225     struct virtio_console_control cpkt;
 226
 227     virtio_stl_p(vdev, &cpkt.id, port_id);
 228     virtio_stw_p(vdev, &cpkt.event, event);
 229     virtio_stw_p(vdev, &cpkt.value, value);
 230
 231     trace_virtio_serial_send_control_event(port_id, event, value);
 232     return send_control_msg(vser, &cpkt, sizeof(cpkt));
 233 }
 234
 235 /* Functions for use inside qemu to open and read from/write to ports */
 236 int virtio_serial_open(VirtIOSerialPort *port)
 237 {
 238     /* Don't allow opening an already-open port */
 239     if (port->host_connected) {
 240         return 0;
 241     }
 242     /* Send port open notification to the guest */
 243     port->host_connected = true;
 244     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 245
 246     return 0;
 247 }
 248
 249 int virtio_serial_close(VirtIOSerialPort *port)
 250 {
 251     port->host_connected = false;
 252     /*
 253      * If there's any data the guest sent which the app didn't
 254      * consume, reset the throttling flag and discard the data.
 255      */
 256     port->throttled = false;
 257     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 258
 259     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 0);
 260
 261     return 0;
 262 }
 263
 264 /* Individual ports/apps call this function to write to the guest. */
 265 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 266                             size_t size)
 267 {
 268     if (!port || !port->host_connected || !port->guest_connected) {
 269         return 0;
 270     }
 271     return write_to_port(port, buf, size);
 272 }
 273
 274 /*
 275  * Readiness of the guest to accept data on a port.
 276  * Returns max. data the guest can receive
 277  */
 278 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 279 {
 280     VirtIODevice *vdev = VIRTIO_DEVICE(port->vser);
 281     VirtQueue *vq = port->ivq;
 282     unsigned int bytes;
 283
 284     if (!virtio_queue_ready(vq) ||
 285         !(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 286         virtio_queue_empty(vq)) {
 287         return 0;
 288     }
 289     if (use_multiport(port->vser) && !port->guest_connected) {
 290         return 0;
 291     }
 292     virtqueue_get_avail_bytes(vq, &bytes, NULL, 4096, 0);
 293     return bytes;
 294 }
 295
 296 static void flush_queued_data_bh(void *opaque)
 297 {
 298     VirtIOSerialPort *port = opaque;
 299
 300     flush_queued_data(port);
 301 }
 302
 303 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 304 {
 305     if (!port) {
 306         return;
 307     }
 308
 309     trace_virtio_serial_throttle_port(port->id, throttle);
 310     port->throttled = throttle;
 311     if (throttle) {
 312         return;
 313     }
 314     qemu_bh_schedule(port->bh);
 315 }
 316
 317 /* Guest wants to notify us of some event */
 318 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 319 {
 320     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 321     struct VirtIOSerialPort *port;
 322     VirtIOSerialPortClass *vsc;
 323     struct virtio_console_control cpkt, *gcpkt;
 324     uint8_t *buffer;
 325     size_t buffer_len;
 326
 327     gcpkt = buf;
 328
 329     if (len < sizeof(cpkt)) {
 330         /* The guest sent an invalid control packet */
 331         return;
 332     }
 333
 334     cpkt.event = virtio_lduw_p(vdev, &gcpkt->event);
 335     cpkt.value = virtio_lduw_p(vdev, &gcpkt->value);
 336
 337     trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 338
 339     if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 340         if (!cpkt.value) {
 341             error_report("virtio-serial-bus: Guest failure in adding device %s",
 342                          vser->bus.qbus.name);
 343             return;
 344         }
 345         /*
 346          * The device is up, we can now tell the device about all the
 347          * ports we have here.
 348          */
 349         QTAILQ_FOREACH(port, &vser->ports, next) {
 350             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_ADD, 1);
 351         }
 352         return;
 353     }
 354
 355     port = find_port_by_id(vser, virtio_ldl_p(vdev, &gcpkt->id));
 356     if (!port) {
 357         error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 358                      virtio_ldl_p(vdev, &gcpkt->id), vser->bus.qbus.name);
 359         return;
 360     }
 361
 362     trace_virtio_serial_handle_control_message_port(port->id);
 363
 364     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 365
 366     switch(cpkt.event) {
 367     case VIRTIO_CONSOLE_PORT_READY:
 368         if (!cpkt.value) {
 369             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 370                          port->id, vser->bus.qbus.name);
 371             break;
 372         }
 373         /*
 374          * Now that we know the guest asked for the port name, we're
 375          * sure the guest has initialised whatever state is necessary
 376          * for this port. Now's a good time to let the guest know if
 377          * this port is a console port so that the guest can hook it
 378          * up to hvc.
 379          */
 380         if (vsc->is_console) {
 381             send_control_event(vser, port->id, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 382         }
 383
 384         if (port->name) {
 385             virtio_stl_p(vdev, &cpkt.id, port->id);
 386             virtio_stw_p(vdev, &cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 387             virtio_stw_p(vdev, &cpkt.value, 1);
 388
 389             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 390             buffer = g_malloc(buffer_len);
 391
 392             memcpy(buffer, &cpkt, sizeof(cpkt));
 393             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 394             buffer[buffer_len - 1] = 0;
 395
 396             send_control_msg(vser, buffer, buffer_len);
 397             g_free(buffer);
 398         }
 399
 400         if (port->host_connected) {
 401             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 402         }
 403
 404         /*
 405          * When the guest has asked us for this information it means
 406          * the guest is all setup and has its virtqueues
 407          * initialised. If some app is interested in knowing about
 408          * this event, let it know.
 409          */
 410         if (vsc->guest_ready) {
 411             vsc->guest_ready(port);
 412         }
 413         break;
 414
 415     case VIRTIO_CONSOLE_PORT_OPEN:
 416         port->guest_connected = cpkt.value;
 417         if (vsc->set_guest_connected) {
 418             /* Send the guest opened notification if an app is interested */
 419             vsc->set_guest_connected(port, cpkt.value);
 420         }
 421         break;
 422     }
 423 }
 424
 425 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 426 {
 427 }
 428
 429 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 430 {
 431     VirtQueueElement *elem;
 432     VirtIOSerial *vser;
 433     uint8_t *buf;
 434     size_t len;
 435
 436     vser = VIRTIO_SERIAL(vdev);
 437
 438     len = 0;
 439     buf = NULL;
 440     for (;;) {
 441         size_t cur_len;
 442
 443         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 444         if (!elem) {
 445             break;
 446         }
 447
 448         cur_len = iov_size(elem->out_sg, elem->out_num);
 449         /*
 450          * Allocate a new buf only if we didn't have one previously or
 451          * if the size of the buf differs
 452          */
 453         if (cur_len > len) {
 454             g_free(buf);
 455
 456             buf = g_malloc(cur_len);
 457             len = cur_len;
 458         }
 459         iov_to_buf(elem->out_sg, elem->out_num, 0, buf, cur_len);
 460
 461         handle_control_message(vser, buf, cur_len);
 462         virtqueue_push(vq, elem, 0);
 463         g_free(elem);
 464     }
 465     g_free(buf);
 466     virtio_notify(vdev, vq);
 467 }
 468
 469 /* Guest wrote something to some port. */
 470 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 471 {
 472     VirtIOSerial *vser;
 473     VirtIOSerialPort *port;
 474
 475     vser = VIRTIO_SERIAL(vdev);
 476     port = find_port_by_vq(vser, vq);
 477
 478     if (!port || !port->host_connected) {
 479         discard_vq_data(vq, vdev);
 480         return;
 481     }
 482
 483     if (!port->throttled) {
 484         do_flush_queued_data(port, vq, vdev);
 485         return;
 486     }
 487 }
 488
 489 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 490 {
 491     /*
 492      * Users of virtio-serial would like to know when guest becomes
 493      * writable again -- i.e. if a vq had stuff queued up and the
 494      * guest wasn't reading at all, the host would not be able to
 495      * write to the vq anymore.  Once the guest reads off something,
 496      * we can start queueing things up again.  However, this call is
 497      * made for each buffer addition by the guest -- even though free
 498      * buffers existed prior to the current buffer addition.  This is
 499      * done so as not to maintain previous state, which will need
 500      * additional live-migration-related changes.
 501      */
 502     VirtIOSerial *vser;
 503     VirtIOSerialPort *port;
 504     VirtIOSerialPortClass *vsc;
 505
 506     vser = VIRTIO_SERIAL(vdev);
 507     port = find_port_by_vq(vser, vq);
 508
 509     if (!port) {
 510         return;
 511     }
 512     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 513
 514     /*
 515      * If guest_connected is false, this call is being made by the
 516      * early-boot queueing up of descriptors, which is just noise for
 517      * the host apps -- don't disturb them in that case.
 518      */
 519     if (port->guest_connected && port->host_connected && vsc->guest_writable) {
 520         vsc->guest_writable(port);
 521     }
 522 }
 523
 524 static uint64_t get_features(VirtIODevice *vdev, uint64_t features,
 525                              Error **errp)
 526 {
 527     VirtIOSerial *vser;
 528
 529     vser = VIRTIO_SERIAL(vdev);
 530
 531     if (vser->bus.max_nr_ports > 1) {
 532         virtio_add_feature(&features, VIRTIO_CONSOLE_F_MULTIPORT);
 533     }
 534     return features;
 535 }
 536
 537 /* Guest requested config info */
 538 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 539 {
 540     VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 541     struct virtio_console_config *config =
 542         (struct virtio_console_config *)config_data;
 543
 544     config->cols = 0;
 545     config->rows = 0;
 546     config->max_nr_ports = virtio_tswap32(vdev,
 547                                           vser->serial.max_virtserial_ports);
 548 }
 549
 550 static void guest_reset(VirtIOSerial *vser)
 551 {
 552     VirtIOSerialPort *port;
 553     VirtIOSerialPortClass *vsc;
 554
 555     QTAILQ_FOREACH(port, &vser->ports, next) {
 556         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 557         if (port->guest_connected) {
 558             port->guest_connected = false;
 559             if (vsc->set_guest_connected) {
 560                 vsc->set_guest_connected(port, false);
 561             }
 562         }
 563     }
 564 }
 565
 566 static void set_status(VirtIODevice *vdev, uint8_t status)
 567 {
 568     VirtIOSerial *vser;
 569     VirtIOSerialPort *port;
 570
 571     vser = VIRTIO_SERIAL(vdev);
 572     port = find_port_by_id(vser, 0);
 573
 574     if (port && !use_multiport(port->vser)
 575         && (status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 576         /*
 577          * Non-multiport guests won't be able to tell us guest
 578          * open/close status.  Such guests can only have a port at id
 579          * 0, so set guest_connected for such ports as soon as guest
 580          * is up.
 581          */
 582         port->guest_connected = true;
 583     }
 584     if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 585         guest_reset(vser);
 586     }
 587 }
 588
 589 static void vser_reset(VirtIODevice *vdev)
 590 {
 591     VirtIOSerial *vser;
 592
 593     vser = VIRTIO_SERIAL(vdev);
 594     guest_reset(vser);
 595 }
 596
 597 static void virtio_serial_save(QEMUFile *f, void *opaque)
 598 {
 599     /* The virtio device */
 600     virtio_save(VIRTIO_DEVICE(opaque), f);
 601 }
 602
 603 static void virtio_serial_save_device(VirtIODevice *vdev, QEMUFile *f)
 604 {
 605     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 606     VirtIOSerialPort *port;
 607     uint32_t nr_active_ports;
 608     unsigned int i, max_nr_ports;
 609     struct virtio_console_config config;
 610
 611     /* The config space (ignored on the far end in current versions) */
 612     get_config(vdev, (uint8_t *)&config);
 613     qemu_put_be16s(f, &config.cols);
 614     qemu_put_be16s(f, &config.rows);
 615     qemu_put_be32s(f, &config.max_nr_ports);
 616
 617     /* The ports map */
 618     max_nr_ports = s->serial.max_virtserial_ports;
 619     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 620         qemu_put_be32s(f, &s->ports_map[i]);
 621     }
 622
 623     /* Ports */
 624
 625     nr_active_ports = 0;
 626     QTAILQ_FOREACH(port, &s->ports, next) {
 627         nr_active_ports++;
 628     }
 629
 630     qemu_put_be32s(f, &nr_active_ports);
 631
 632     /*
 633      * Items in struct VirtIOSerialPort.
 634      */
 635     QTAILQ_FOREACH(port, &s->ports, next) {
 636         uint32_t elem_popped;
 637
 638         qemu_put_be32s(f, &port->id);
 639         qemu_put_byte(f, port->guest_connected);
 640         qemu_put_byte(f, port->host_connected);
 641
 642         elem_popped = 0;
 643         if (port->elem) {
 644             elem_popped = 1;
 645         }
 646         qemu_put_be32s(f, &elem_popped);
 647         if (elem_popped) {
 648             qemu_put_be32s(f, &port->iov_idx);
 649             qemu_put_be64s(f, &port->iov_offset);
 650             qemu_put_virtqueue_element(f, port->elem);
 651         }
 652     }
 653 }
 654
 655 static void virtio_serial_post_load_timer_cb(void *opaque)
 656 {
 657     uint32_t i;
 658     VirtIOSerial *s = VIRTIO_SERIAL(opaque);
 659     VirtIOSerialPort *port;
 660     uint8_t host_connected;
 661     VirtIOSerialPortClass *vsc;
 662
 663     if (!s->post_load) {
 664         return;
 665     }
 666     for (i = 0 ; i < s->post_load->nr_active_ports; ++i) {
 667         port = s->post_load->connected[i].port;
 668         host_connected = s->post_load->connected[i].host_connected;
 669         if (host_connected != port->host_connected) {
 670             /*
 671              * We have to let the guest know of the host connection
 672              * status change
 673              */
 674             send_control_event(s, port->id, VIRTIO_CONSOLE_PORT_OPEN,
 675                                port->host_connected);
 676         }
 677         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 678         if (vsc->set_guest_connected) {
 679             vsc->set_guest_connected(port, port->guest_connected);
 680         }
 681     }
 682     g_free(s->post_load->connected);
 683     timer_free(s->post_load->timer);
 684     g_free(s->post_load);
 685     s->post_load = NULL;
 686 }
 687
 688 static int fetch_active_ports_list(QEMUFile *f, int version_id,
 689                                    VirtIOSerial *s, uint32_t nr_active_ports)
 690 {
 691     uint32_t i;
 692
 693     s->post_load = g_malloc0(sizeof(*s->post_load));
 694     s->post_load->nr_active_ports = nr_active_ports;
 695     s->post_load->connected =
 696         g_malloc0(sizeof(*s->post_load->connected) * nr_active_ports);
 697
 698     s->post_load->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
 699                                             virtio_serial_post_load_timer_cb,
 700                                             s);
 701
 702     /* Items in struct VirtIOSerialPort */
 703     for (i = 0; i < nr_active_ports; i++) {
 704         VirtIOSerialPort *port;
 705         uint32_t id;
 706
 707         id = qemu_get_be32(f);
 708         port = find_port_by_id(s, id);
 709         if (!port) {
 710             return -EINVAL;
 711         }
 712
 713         port->guest_connected = qemu_get_byte(f);
 714         s->post_load->connected[i].port = port;
 715         s->post_load->connected[i].host_connected = qemu_get_byte(f);
 716
 717         if (version_id > 2) {
 718             uint32_t elem_popped;
 719
 720             qemu_get_be32s(f, &elem_popped);
 721             if (elem_popped) {
 722                 qemu_get_be32s(f, &port->iov_idx);
 723                 qemu_get_be64s(f, &port->iov_offset);
 724
 725                 port->elem =
 726                     qemu_get_virtqueue_element(f, sizeof(VirtQueueElement));
 727
 728                 /*
 729                  *  Port was throttled on source machine.  Let's
 730                  *  unthrottle it here so data starts flowing again.
 731                  */
 732                 virtio_serial_throttle_port(port, false);
 733             }
 734         }
 735     }
 736     timer_mod(s->post_load->timer, 1);
 737     return 0;
 738 }
 739
 740 static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
 741 {
 742     if (version_id > 3) {
 743         return -EINVAL;
 744     }
 745
 746     /* The virtio device */
 747     return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
 748 }
 749
 750 static int virtio_serial_load_device(VirtIODevice *vdev, QEMUFile *f,
 751                                      int version_id)
 752 {
 753     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 754     uint32_t max_nr_ports, nr_active_ports, ports_map;
 755     unsigned int i;
 756     int ret;
 757     uint32_t tmp;
 758
 759     if (version_id < 2) {
 760         return 0;
 761     }
 762
 763     /* Unused */
 764     qemu_get_be16s(f, (uint16_t *) &tmp);
 765     qemu_get_be16s(f, (uint16_t *) &tmp);
 766     qemu_get_be32s(f, &tmp);
 767
 768     max_nr_ports = s->serial.max_virtserial_ports;
 769     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 770         qemu_get_be32s(f, &ports_map);
 771
 772         if (ports_map != s->ports_map[i]) {
 773             /*
 774              * Ports active on source and destination don't
 775              * match. Fail migration.
 776              */
 777             return -EINVAL;
 778         }
 779     }
 780
 781     qemu_get_be32s(f, &nr_active_ports);
 782
 783     if (nr_active_ports) {
 784         ret = fetch_active_ports_list(f, version_id, s, nr_active_ports);
 785         if (ret) {
 786             return ret;
 787         }
 788     }
 789     return 0;
 790 }
 791
 792 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 793
 794 static Property virtser_props[] = {
 795     DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 796     DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 797     DEFINE_PROP_END_OF_LIST()
 798 };
 799
 800 #define TYPE_VIRTIO_SERIAL_BUS "virtio-serial-bus"
 801 #define VIRTIO_SERIAL_BUS(obj) \
 802       OBJECT_CHECK(VirtIOSerialBus, (obj), TYPE_VIRTIO_SERIAL_BUS)
 803
 804 static void virtser_bus_class_init(ObjectClass *klass, void *data)
 805 {
 806     BusClass *k = BUS_CLASS(klass);
 807     k->print_dev = virtser_bus_dev_print;
 808 }
 809
 810 static const TypeInfo virtser_bus_info = {
 811     .name = TYPE_VIRTIO_SERIAL_BUS,
 812     .parent = TYPE_BUS,
 813     .instance_size = sizeof(VirtIOSerialBus),
 814     .class_init = virtser_bus_class_init,
 815 };
 816
 817 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 818 {
 819     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(qdev);
 820
 821     monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 822                    indent, "", port->id,
 823                    port->guest_connected ? "on" : "off",
 824                    port->host_connected ? "on" : "off",
 825                    port->throttled ? "on" : "off");
 826 }
 827
 828 /* This function is only used if a port id is not provided by the user */
 829 static uint32_t find_free_port_id(VirtIOSerial *vser)
 830 {
 831     unsigned int i, max_nr_ports;
 832
 833     max_nr_ports = vser->serial.max_virtserial_ports;
 834     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 835         uint32_t map, zeroes;
 836
 837         map = vser->ports_map[i];
 838         zeroes = ctz32(~map);
 839         if (zeroes != 32) {
 840             return zeroes + i * 32;
 841         }
 842     }
 843     return VIRTIO_CONSOLE_BAD_ID;
 844 }
 845
 846 static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 847 {
 848     unsigned int i;
 849
 850     i = port_id / 32;
 851     vser->ports_map[i] |= 1U << (port_id % 32);
 852 }
 853
 854 static void add_port(VirtIOSerial *vser, uint32_t port_id)
 855 {
 856     mark_port_added(vser, port_id);
 857     send_control_event(vser, port_id, VIRTIO_CONSOLE_PORT_ADD, 1);
 858 }
 859
 860 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 861 {
 862     VirtIOSerialPort *port;
 863
 864     /*
 865      * Don't mark port 0 removed -- we explicitly reserve it for
 866      * backward compat with older guests, ensure a virtconsole device
 867      * unplug retains the reservation.
 868      */
 869     if (port_id) {
 870         unsigned int i;
 871
 872         i = port_id / 32;
 873         vser->ports_map[i] &= ~(1U << (port_id % 32));
 874     }
 875
 876     port = find_port_by_id(vser, port_id);
 877     /*
 878      * This function is only called from qdev's unplug callback; if we
 879      * get a NULL port here, we're in trouble.
 880      */
 881     assert(port);
 882
 883     /* Flush out any unconsumed buffers first */
 884     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 885
 886     send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 887 }
 888
 889 static void virtser_port_device_realize(DeviceState *dev, Error **errp)
 890 {
 891     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 892     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 893     VirtIOSerialBus *bus = VIRTIO_SERIAL_BUS(qdev_get_parent_bus(dev));
 894     int max_nr_ports;
 895     bool plugging_port0;
 896     Error *err = NULL;
 897
 898     port->vser = bus->vser;
 899     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 900
 901     assert(vsc->have_data);
 902
 903     /*
 904      * Is the first console port we're seeing? If so, put it up at
 905      * location 0. This is done for backward compatibility (old
 906      * kernel, new qemu).
 907      */
 908     plugging_port0 = vsc->is_console && !find_port_by_id(port->vser, 0);
 909
 910     if (find_port_by_id(port->vser, port->id)) {
 911         error_setg(errp, "virtio-serial-bus: A port already exists at id %u",
 912                    port->id);
 913         return;
 914     }
 915
 916     if (port->name != NULL && find_port_by_name(port->name)) {
 917         error_setg(errp, "virtio-serial-bus: A port already exists by name %s",
 918                    port->name);
 919         return;
 920     }
 921
 922     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 923         if (plugging_port0) {
 924             port->id = 0;
 925         } else {
 926             port->id = find_free_port_id(port->vser);
 927             if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 928                 error_setg(errp, "virtio-serial-bus: Maximum port limit for "
 929                                  "this device reached");
 930                 return;
 931             }
 932         }
 933     }
 934
 935     max_nr_ports = port->vser->serial.max_virtserial_ports;
 936     if (port->id >= max_nr_ports) {
 937         error_setg(errp, "virtio-serial-bus: Out-of-range port id specified, "
 938                          "max. allowed: %u", max_nr_ports - 1);
 939         return;
 940     }
 941
 942     vsc->realize(dev, &err);
 943     if (err != NULL) {
 944         error_propagate(errp, err);
 945         return;
 946     }
 947
 948     port->elem = NULL;
 949 }
 950
 951 static void virtser_port_device_plug(HotplugHandler *hotplug_dev,
 952                                      DeviceState *dev, Error **errp)
 953 {
 954     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 955
 956     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
 957     port->ivq = port->vser->ivqs[port->id];
 958     port->ovq = port->vser->ovqs[port->id];
 959
 960     add_port(port->vser, port->id);
 961
 962     /* Send an update to the guest about this new port added */
 963     virtio_notify_config(VIRTIO_DEVICE(hotplug_dev));
 964 }
 965
 966 static void virtser_port_device_unrealize(DeviceState *dev, Error **errp)
 967 {
 968     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 969     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(dev);
 970     VirtIOSerial *vser = port->vser;
 971
 972     qemu_bh_delete(port->bh);
 973     remove_port(port->vser, port->id);
 974
 975     QTAILQ_REMOVE(&vser->ports, port, next);
 976
 977     if (vsc->unrealize) {
 978         vsc->unrealize(dev, errp);
 979     }
 980 }
 981
 982 static void virtio_serial_device_realize(DeviceState *dev, Error **errp)
 983 {
 984     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 985     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
 986     uint32_t i, max_supported_ports;
 987
 988     if (!vser->serial.max_virtserial_ports) {
 989         error_setg(errp, "Maximum number of serial ports not specified");
 990         return;
 991     }
 992
 993     /* Each port takes 2 queues, and one pair is for the control queue */
 994     max_supported_ports = VIRTIO_QUEUE_MAX / 2 - 1;
 995
 996     if (vser->serial.max_virtserial_ports > max_supported_ports) {
 997         error_setg(errp, "maximum ports supported: %u", max_supported_ports);
 998         return;
 999     }
1000
1001     /* We don't support emergency write, skip it for now. */
1002     /* TODO: cleaner fix, depending on host features. */
1003     virtio_init(vdev, "virtio-serial", VIRTIO_ID_CONSOLE,
1004                 offsetof(struct virtio_console_config, emerg_wr));
1005
1006     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
1007     qbus_create_inplace(&vser->bus, sizeof(vser->bus), TYPE_VIRTIO_SERIAL_BUS,
1008                         dev, vdev->bus_name);
1009     qbus_set_hotplug_handler(BUS(&vser->bus), DEVICE(vser), errp);
1010     vser->bus.vser = vser;
1011     QTAILQ_INIT(&vser->ports);
1012
1013     vser->bus.max_nr_ports = vser->serial.max_virtserial_ports;
1014     vser->ivqs = g_malloc(vser->serial.max_virtserial_ports
1015                           * sizeof(VirtQueue *));
1016     vser->ovqs = g_malloc(vser->serial.max_virtserial_ports
1017                           * sizeof(VirtQueue *));
1018
1019     /* Add a queue for host to guest transfers for port 0 (backward compat) */
1020     vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
1021     /* Add a queue for guest to host transfers for port 0 (backward compat) */
1022     vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
1023
1024     /* TODO: host to guest notifications can get dropped
1025      * if the queue fills up. Implement queueing in host,
1026      * this might also make it possible to reduce the control
1027      * queue size: as guest preposts buffers there,
1028      * this will save 4Kbyte of guest memory per entry. */
1029
1030     /* control queue: host to guest */
1031     vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
1032     /* control queue: guest to host */
1033     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
1034
1035     for (i = 1; i < vser->bus.max_nr_ports; i++) {
1036         /* Add a per-port queue for host to guest transfers */
1037         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
1038         /* Add a per-per queue for guest to host transfers */
1039         vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
1040     }
1041
1042     vser->ports_map = g_malloc0(((vser->serial.max_virtserial_ports + 31) / 32)
1043         * sizeof(vser->ports_map[0]));
1044     /*
1045      * Reserve location 0 for a console port for backward compat
1046      * (old kernel, new qemu)
1047      */
1048     mark_port_added(vser, 0);
1049
1050     vser->post_load = NULL;
1051
1052     /*
1053      * Register for the savevm section with the virtio-console name
1054      * to preserve backward compat
1055      */
1056     register_savevm(dev, "virtio-console", -1, 3, virtio_serial_save,
1057                     virtio_serial_load, vser);
1058
1059     QLIST_INSERT_HEAD(&vserdevices.devices, vser, next);
1060 }
1061
1062 static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
1063 {
1064     DeviceClass *k = DEVICE_CLASS(klass);
1065
1066     set_bit(DEVICE_CATEGORY_INPUT, k->categories);
1067     k->bus_type = TYPE_VIRTIO_SERIAL_BUS;
1068     k->realize = virtser_port_device_realize;
1069     k->unrealize = virtser_port_device_unrealize;
1070     k->props = virtser_props;
1071 }
1072
1073 static const TypeInfo virtio_serial_port_type_info = {
1074     .name = TYPE_VIRTIO_SERIAL_PORT,
1075     .parent = TYPE_DEVICE,
1076     .instance_size = sizeof(VirtIOSerialPort),
1077     .abstract = true,
1078     .class_size = sizeof(VirtIOSerialPortClass),
1079     .class_init = virtio_serial_port_class_init,
1080 };
1081
1082 static void virtio_serial_device_unrealize(DeviceState *dev, Error **errp)
1083 {
1084     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1085     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1086
1087     QLIST_REMOVE(vser, next);
1088
1089     unregister_savevm(dev, "virtio-console", vser);
1090
1091     g_free(vser->ivqs);
1092     g_free(vser->ovqs);
1093     g_free(vser->ports_map);
1094     if (vser->post_load) {
1095         g_free(vser->post_load->connected);
1096         timer_del(vser->post_load->timer);
1097         timer_free(vser->post_load->timer);
1098         g_free(vser->post_load);
1099     }
1100     virtio_cleanup(vdev);
1101 }
1102
1103 static Property virtio_serial_properties[] = {
1104     DEFINE_PROP_UINT32("max_ports", VirtIOSerial, serial.max_virtserial_ports,
1105                                                   31),
1106     DEFINE_PROP_END_OF_LIST(),
1107 };
1108
1109 static void virtio_serial_class_init(ObjectClass *klass, void *data)
1110 {
1111     DeviceClass *dc = DEVICE_CLASS(klass);
1112     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1113     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
1114
1115     QLIST_INIT(&vserdevices.devices);
1116
1117     dc->props = virtio_serial_properties;
1118     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
1119     vdc->realize = virtio_serial_device_realize;
1120     vdc->unrealize = virtio_serial_device_unrealize;
1121     vdc->get_features = get_features;
1122     vdc->get_config = get_config;
1123     vdc->set_status = set_status;
1124     vdc->reset = vser_reset;
1125     vdc->save = virtio_serial_save_device;
1126     vdc->load = virtio_serial_load_device;
1127     hc->plug = virtser_port_device_plug;
1128     hc->unplug = qdev_simple_device_unplug_cb;
1129 }
1130
1131 static const TypeInfo virtio_device_info = {
1132     .name = TYPE_VIRTIO_SERIAL,
1133     .parent = TYPE_VIRTIO_DEVICE,
1134     .instance_size = sizeof(VirtIOSerial),
1135     .class_init = virtio_serial_class_init,
1136     .interfaces = (InterfaceInfo[]) {
1137         { TYPE_HOTPLUG_HANDLER },
1138         { }
1139     }
1140 };
1141
1142 static void virtio_serial_register_types(void)
1143 {
1144     type_register_static(&virtser_bus_info);
1145     type_register_static(&virtio_serial_port_type_info);
1146     type_register_static(&virtio_device_info);
1147 }
1148
1149 type_init(virtio_serial_register_types)