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/iov.h"
  22 #include "monitor/monitor.h"
  23 #include "qemu/queue.h"
  24 #include "hw/sysbus.h"
  25 #include "trace.h"
  26 #include "hw/virtio/virtio-serial.h"
  27 #include "hw/virtio/virtio-access.h"
  28
  29 struct VirtIOSerialDevices {
  30     QLIST_HEAD(, VirtIOSerial) devices;
  31 } vserdevices;
  32
  33 static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
  34 {
  35     VirtIOSerialPort *port;
  36
  37     if (id == VIRTIO_CONSOLE_BAD_ID) {
  38         return NULL;
  39     }
  40
  41     QTAILQ_FOREACH(port, &vser->ports, next) {
  42         if (port->id == id)
  43             return port;
  44     }
  45     return NULL;
  46 }
  47
  48 static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
  49 {
  50     VirtIOSerialPort *port;
  51
  52     QTAILQ_FOREACH(port, &vser->ports, next) {
  53         if (port->ivq == vq || port->ovq == vq)
  54             return port;
  55     }
  56     return NULL;
  57 }
  58
  59 static VirtIOSerialPort *find_port_by_name(char *name)
  60 {
  61     VirtIOSerial *vser;
  62
  63     QLIST_FOREACH(vser, &vserdevices.devices, next) {
  64         VirtIOSerialPort *port;
  65
  66         QTAILQ_FOREACH(port, &vser->ports, next) {
  67             if (!strcmp(port->name, name)) {
  68                 return port;
  69             }
  70         }
  71     }
  72     return NULL;
  73 }
  74
  75 static bool use_multiport(VirtIOSerial *vser)
  76 {
  77     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
  78     return vdev->guest_features & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
  79 }
  80
  81 static size_t write_to_port(VirtIOSerialPort *port,
  82                             const uint8_t *buf, size_t size)
  83 {
  84     VirtQueueElement elem;
  85     VirtQueue *vq;
  86     size_t offset;
  87
  88     vq = port->ivq;
  89     if (!virtio_queue_ready(vq)) {
  90         return 0;
  91     }
  92
  93     offset = 0;
  94     while (offset < size) {
  95         size_t len;
  96
  97         if (!virtqueue_pop(vq, &elem)) {
  98             break;
  99         }
 100
 101         len = iov_from_buf(elem.in_sg, elem.in_num, 0,
 102                            buf + offset, size - offset);
 103         offset += len;
 104
 105         virtqueue_push(vq, &elem, len);
 106     }
 107
 108     virtio_notify(VIRTIO_DEVICE(port->vser), vq);
 109     return offset;
 110 }
 111
 112 static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
 113 {
 114     VirtQueueElement elem;
 115
 116     if (!virtio_queue_ready(vq)) {
 117         return;
 118     }
 119     while (virtqueue_pop(vq, &elem)) {
 120         virtqueue_push(vq, &elem, 0);
 121     }
 122     virtio_notify(vdev, vq);
 123 }
 124
 125 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 126                                  VirtIODevice *vdev)
 127 {
 128     VirtIOSerialPortClass *vsc;
 129
 130     assert(port);
 131     assert(virtio_queue_ready(vq));
 132
 133     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 134
 135     while (!port->throttled) {
 136         unsigned int i;
 137
 138         /* Pop an elem only if we haven't left off a previous one mid-way */
 139         if (!port->elem.out_num) {
 140             if (!virtqueue_pop(vq, &port->elem)) {
 141                 break;
 142             }
 143             port->iov_idx = 0;
 144             port->iov_offset = 0;
 145         }
 146
 147         for (i = port->iov_idx; i < port->elem.out_num; i++) {
 148             size_t buf_size;
 149             ssize_t ret;
 150
 151             buf_size = port->elem.out_sg[i].iov_len - port->iov_offset;
 152             ret = vsc->have_data(port,
 153                                   port->elem.out_sg[i].iov_base
 154                                   + port->iov_offset,
 155                                   buf_size);
 156             if (port->throttled) {
 157                 port->iov_idx = i;
 158                 if (ret > 0) {
 159                     port->iov_offset += ret;
 160                 }
 161                 break;
 162             }
 163             port->iov_offset = 0;
 164         }
 165         if (port->throttled) {
 166             break;
 167         }
 168         virtqueue_push(vq, &port->elem, 0);
 169         port->elem.out_num = 0;
 170     }
 171     virtio_notify(vdev, vq);
 172 }
 173
 174 static void flush_queued_data(VirtIOSerialPort *port)
 175 {
 176     assert(port);
 177
 178     if (!virtio_queue_ready(port->ovq)) {
 179         return;
 180     }
 181     do_flush_queued_data(port, port->ovq, VIRTIO_DEVICE(port->vser));
 182 }
 183
 184 static size_t send_control_msg(VirtIOSerial *vser, void *buf, size_t len)
 185 {
 186     VirtQueueElement elem;
 187     VirtQueue *vq;
 188
 189     vq = vser->c_ivq;
 190     if (!virtio_queue_ready(vq)) {
 191         return 0;
 192     }
 193     if (!virtqueue_pop(vq, &elem)) {
 194         return 0;
 195     }
 196
 197     memcpy(elem.in_sg[0].iov_base, buf, len);
 198
 199     virtqueue_push(vq, &elem, len);
 200     virtio_notify(VIRTIO_DEVICE(vser), vq);
 201     return len;
 202 }
 203
 204 static size_t send_control_event(VirtIOSerial *vser, uint32_t port_id,
 205                                  uint16_t event, uint16_t value)
 206 {
 207     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 208     struct virtio_console_control cpkt;
 209
 210     virtio_stl_p(vdev, &cpkt.id, port_id);
 211     virtio_stw_p(vdev, &cpkt.event, event);
 212     virtio_stw_p(vdev, &cpkt.value, value);
 213
 214     trace_virtio_serial_send_control_event(port_id, event, value);
 215     return send_control_msg(vser, &cpkt, sizeof(cpkt));
 216 }
 217
 218 /* Functions for use inside qemu to open and read from/write to ports */
 219 int virtio_serial_open(VirtIOSerialPort *port)
 220 {
 221     /* Don't allow opening an already-open port */
 222     if (port->host_connected) {
 223         return 0;
 224     }
 225     /* Send port open notification to the guest */
 226     port->host_connected = true;
 227     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 228
 229     return 0;
 230 }
 231
 232 int virtio_serial_close(VirtIOSerialPort *port)
 233 {
 234     port->host_connected = false;
 235     /*
 236      * If there's any data the guest sent which the app didn't
 237      * consume, reset the throttling flag and discard the data.
 238      */
 239     port->throttled = false;
 240     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 241
 242     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 0);
 243
 244     return 0;
 245 }
 246
 247 /* Individual ports/apps call this function to write to the guest. */
 248 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 249                             size_t size)
 250 {
 251     if (!port || !port->host_connected || !port->guest_connected) {
 252         return 0;
 253     }
 254     return write_to_port(port, buf, size);
 255 }
 256
 257 /*
 258  * Readiness of the guest to accept data on a port.
 259  * Returns max. data the guest can receive
 260  */
 261 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 262 {
 263     VirtIODevice *vdev = VIRTIO_DEVICE(port->vser);
 264     VirtQueue *vq = port->ivq;
 265     unsigned int bytes;
 266
 267     if (!virtio_queue_ready(vq) ||
 268         !(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 269         virtio_queue_empty(vq)) {
 270         return 0;
 271     }
 272     if (use_multiport(port->vser) && !port->guest_connected) {
 273         return 0;
 274     }
 275     virtqueue_get_avail_bytes(vq, &bytes, NULL, 4096, 0);
 276     return bytes;
 277 }
 278
 279 static void flush_queued_data_bh(void *opaque)
 280 {
 281     VirtIOSerialPort *port = opaque;
 282
 283     flush_queued_data(port);
 284 }
 285
 286 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 287 {
 288     if (!port) {
 289         return;
 290     }
 291
 292     trace_virtio_serial_throttle_port(port->id, throttle);
 293     port->throttled = throttle;
 294     if (throttle) {
 295         return;
 296     }
 297     qemu_bh_schedule(port->bh);
 298 }
 299
 300 /* Guest wants to notify us of some event */
 301 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 302 {
 303     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 304     struct VirtIOSerialPort *port;
 305     VirtIOSerialPortClass *vsc;
 306     struct virtio_console_control cpkt, *gcpkt;
 307     uint8_t *buffer;
 308     size_t buffer_len;
 309
 310     gcpkt = buf;
 311
 312     if (len < sizeof(cpkt)) {
 313         /* The guest sent an invalid control packet */
 314         return;
 315     }
 316
 317     cpkt.event = virtio_lduw_p(vdev, &gcpkt->event);
 318     cpkt.value = virtio_lduw_p(vdev, &gcpkt->value);
 319
 320     trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 321
 322     if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 323         if (!cpkt.value) {
 324             error_report("virtio-serial-bus: Guest failure in adding device %s",
 325                          vser->bus.qbus.name);
 326             return;
 327         }
 328         /*
 329          * The device is up, we can now tell the device about all the
 330          * ports we have here.
 331          */
 332         QTAILQ_FOREACH(port, &vser->ports, next) {
 333             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_ADD, 1);
 334         }
 335         return;
 336     }
 337
 338     port = find_port_by_id(vser, virtio_ldl_p(vdev, &gcpkt->id));
 339     if (!port) {
 340         error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 341                      virtio_ldl_p(vdev, &gcpkt->id), vser->bus.qbus.name);
 342         return;
 343     }
 344
 345     trace_virtio_serial_handle_control_message_port(port->id);
 346
 347     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 348
 349     switch(cpkt.event) {
 350     case VIRTIO_CONSOLE_PORT_READY:
 351         if (!cpkt.value) {
 352             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 353                          port->id, vser->bus.qbus.name);
 354             break;
 355         }
 356         /*
 357          * Now that we know the guest asked for the port name, we're
 358          * sure the guest has initialised whatever state is necessary
 359          * for this port. Now's a good time to let the guest know if
 360          * this port is a console port so that the guest can hook it
 361          * up to hvc.
 362          */
 363         if (vsc->is_console) {
 364             send_control_event(vser, port->id, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 365         }
 366
 367         if (port->name) {
 368             virtio_stl_p(vdev, &cpkt.id, port->id);
 369             virtio_stw_p(vdev, &cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 370             virtio_stw_p(vdev, &cpkt.value, 1);
 371
 372             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 373             buffer = g_malloc(buffer_len);
 374
 375             memcpy(buffer, &cpkt, sizeof(cpkt));
 376             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 377             buffer[buffer_len - 1] = 0;
 378
 379             send_control_msg(vser, buffer, buffer_len);
 380             g_free(buffer);
 381         }
 382
 383         if (port->host_connected) {
 384             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 385         }
 386
 387         /*
 388          * When the guest has asked us for this information it means
 389          * the guest is all setup and has its virtqueues
 390          * initialised. If some app is interested in knowing about
 391          * this event, let it know.
 392          */
 393         if (vsc->guest_ready) {
 394             vsc->guest_ready(port);
 395         }
 396         break;
 397
 398     case VIRTIO_CONSOLE_PORT_OPEN:
 399         port->guest_connected = cpkt.value;
 400         if (vsc->set_guest_connected) {
 401             /* Send the guest opened notification if an app is interested */
 402             vsc->set_guest_connected(port, cpkt.value);
 403         }
 404         break;
 405     }
 406 }
 407
 408 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 409 {
 410 }
 411
 412 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 413 {
 414     VirtQueueElement elem;
 415     VirtIOSerial *vser;
 416     uint8_t *buf;
 417     size_t len;
 418
 419     vser = VIRTIO_SERIAL(vdev);
 420
 421     len = 0;
 422     buf = NULL;
 423     while (virtqueue_pop(vq, &elem)) {
 424         size_t cur_len;
 425
 426         cur_len = iov_size(elem.out_sg, elem.out_num);
 427         /*
 428          * Allocate a new buf only if we didn't have one previously or
 429          * if the size of the buf differs
 430          */
 431         if (cur_len > len) {
 432             g_free(buf);
 433
 434             buf = g_malloc(cur_len);
 435             len = cur_len;
 436         }
 437         iov_to_buf(elem.out_sg, elem.out_num, 0, buf, cur_len);
 438
 439         handle_control_message(vser, buf, cur_len);
 440         virtqueue_push(vq, &elem, 0);
 441     }
 442     g_free(buf);
 443     virtio_notify(vdev, vq);
 444 }
 445
 446 /* Guest wrote something to some port. */
 447 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 448 {
 449     VirtIOSerial *vser;
 450     VirtIOSerialPort *port;
 451
 452     vser = VIRTIO_SERIAL(vdev);
 453     port = find_port_by_vq(vser, vq);
 454
 455     if (!port || !port->host_connected) {
 456         discard_vq_data(vq, vdev);
 457         return;
 458     }
 459
 460     if (!port->throttled) {
 461         do_flush_queued_data(port, vq, vdev);
 462         return;
 463     }
 464 }
 465
 466 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 467 {
 468 }
 469
 470 static uint32_t get_features(VirtIODevice *vdev, uint32_t features)
 471 {
 472     VirtIOSerial *vser;
 473
 474     vser = VIRTIO_SERIAL(vdev);
 475
 476     if (vser->bus.max_nr_ports > 1) {
 477         features |= (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 478     }
 479     return features;
 480 }
 481
 482 /* Guest requested config info */
 483 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 484 {
 485     VirtIOSerial *vser;
 486
 487     vser = VIRTIO_SERIAL(vdev);
 488     memcpy(config_data, &vser->config, sizeof(struct virtio_console_config));
 489 }
 490
 491 static void guest_reset(VirtIOSerial *vser)
 492 {
 493     VirtIOSerialPort *port;
 494     VirtIOSerialPortClass *vsc;
 495
 496     QTAILQ_FOREACH(port, &vser->ports, next) {
 497         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 498         if (port->guest_connected) {
 499             port->guest_connected = false;
 500             if (vsc->set_guest_connected) {
 501                 vsc->set_guest_connected(port, false);
 502             }
 503         }
 504     }
 505 }
 506
 507 static void set_status(VirtIODevice *vdev, uint8_t status)
 508 {
 509     VirtIOSerial *vser;
 510     VirtIOSerialPort *port;
 511
 512     vser = VIRTIO_SERIAL(vdev);
 513     port = find_port_by_id(vser, 0);
 514
 515     if (port && !use_multiport(port->vser)
 516         && (status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 517         /*
 518          * Non-multiport guests won't be able to tell us guest
 519          * open/close status.  Such guests can only have a port at id
 520          * 0, so set guest_connected for such ports as soon as guest
 521          * is up.
 522          */
 523         port->guest_connected = true;
 524     }
 525     if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 526         guest_reset(vser);
 527     }
 528 }
 529
 530 static void vser_reset(VirtIODevice *vdev)
 531 {
 532     VirtIOSerial *vser;
 533
 534     vser = VIRTIO_SERIAL(vdev);
 535     guest_reset(vser);
 536
 537     /* In case we have switched endianness */
 538     vser->config.max_nr_ports =
 539         virtio_tswap32(vdev, vser->serial.max_virtserial_ports);
 540 }
 541
 542 static void virtio_serial_save(QEMUFile *f, void *opaque)
 543 {
 544     /* The virtio device */
 545     virtio_save(VIRTIO_DEVICE(opaque), f);
 546 }
 547
 548 static void virtio_serial_save_device(VirtIODevice *vdev, QEMUFile *f)
 549 {
 550     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 551     VirtIOSerialPort *port;
 552     uint32_t nr_active_ports;
 553     unsigned int i, max_nr_ports;
 554
 555     /* The config space */
 556     qemu_put_be16s(f, &s->config.cols);
 557     qemu_put_be16s(f, &s->config.rows);
 558
 559     qemu_put_be32s(f, &s->config.max_nr_ports);
 560
 561     /* The ports map */
 562     max_nr_ports = virtio_tswap32(vdev, s->config.max_nr_ports);
 563     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 564         qemu_put_be32s(f, &s->ports_map[i]);
 565     }
 566
 567     /* Ports */
 568
 569     nr_active_ports = 0;
 570     QTAILQ_FOREACH(port, &s->ports, next) {
 571         nr_active_ports++;
 572     }
 573
 574     qemu_put_be32s(f, &nr_active_ports);
 575
 576     /*
 577      * Items in struct VirtIOSerialPort.
 578      */
 579     QTAILQ_FOREACH(port, &s->ports, next) {
 580         uint32_t elem_popped;
 581
 582         qemu_put_be32s(f, &port->id);
 583         qemu_put_byte(f, port->guest_connected);
 584         qemu_put_byte(f, port->host_connected);
 585
 586         elem_popped = 0;
 587         if (port->elem.out_num) {
 588             elem_popped = 1;
 589         }
 590         qemu_put_be32s(f, &elem_popped);
 591         if (elem_popped) {
 592             qemu_put_be32s(f, &port->iov_idx);
 593             qemu_put_be64s(f, &port->iov_offset);
 594
 595             qemu_put_buffer(f, (unsigned char *)&port->elem,
 596                             sizeof(port->elem));
 597         }
 598     }
 599 }
 600
 601 static void virtio_serial_post_load_timer_cb(void *opaque)
 602 {
 603     uint32_t i;
 604     VirtIOSerial *s = VIRTIO_SERIAL(opaque);
 605     VirtIOSerialPort *port;
 606     uint8_t host_connected;
 607     VirtIOSerialPortClass *vsc;
 608
 609     if (!s->post_load) {
 610         return;
 611     }
 612     for (i = 0 ; i < s->post_load->nr_active_ports; ++i) {
 613         port = s->post_load->connected[i].port;
 614         host_connected = s->post_load->connected[i].host_connected;
 615         if (host_connected != port->host_connected) {
 616             /*
 617              * We have to let the guest know of the host connection
 618              * status change
 619              */
 620             send_control_event(s, port->id, VIRTIO_CONSOLE_PORT_OPEN,
 621                                port->host_connected);
 622         }
 623         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 624         if (vsc->set_guest_connected) {
 625             vsc->set_guest_connected(port, port->guest_connected);
 626         }
 627     }
 628     g_free(s->post_load->connected);
 629     timer_free(s->post_load->timer);
 630     g_free(s->post_load);
 631     s->post_load = NULL;
 632 }
 633
 634 static int fetch_active_ports_list(QEMUFile *f, int version_id,
 635                                    VirtIOSerial *s, uint32_t nr_active_ports)
 636 {
 637     uint32_t i;
 638
 639     s->post_load = g_malloc0(sizeof(*s->post_load));
 640     s->post_load->nr_active_ports = nr_active_ports;
 641     s->post_load->connected =
 642         g_malloc0(sizeof(*s->post_load->connected) * nr_active_ports);
 643
 644     s->post_load->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
 645                                             virtio_serial_post_load_timer_cb,
 646                                             s);
 647
 648     /* Items in struct VirtIOSerialPort */
 649     for (i = 0; i < nr_active_ports; i++) {
 650         VirtIOSerialPort *port;
 651         uint32_t id;
 652
 653         id = qemu_get_be32(f);
 654         port = find_port_by_id(s, id);
 655         if (!port) {
 656             return -EINVAL;
 657         }
 658
 659         port->guest_connected = qemu_get_byte(f);
 660         s->post_load->connected[i].port = port;
 661         s->post_load->connected[i].host_connected = qemu_get_byte(f);
 662
 663         if (version_id > 2) {
 664             uint32_t elem_popped;
 665
 666             qemu_get_be32s(f, &elem_popped);
 667             if (elem_popped) {
 668                 qemu_get_be32s(f, &port->iov_idx);
 669                 qemu_get_be64s(f, &port->iov_offset);
 670
 671                 qemu_get_buffer(f, (unsigned char *)&port->elem,
 672                                 sizeof(port->elem));
 673                 virtqueue_map_sg(port->elem.in_sg, port->elem.in_addr,
 674                                  port->elem.in_num, 1);
 675                 virtqueue_map_sg(port->elem.out_sg, port->elem.out_addr,
 676                                  port->elem.out_num, 1);
 677
 678                 /*
 679                  *  Port was throttled on source machine.  Let's
 680                  *  unthrottle it here so data starts flowing again.
 681                  */
 682                 virtio_serial_throttle_port(port, false);
 683             }
 684         }
 685     }
 686     timer_mod(s->post_load->timer, 1);
 687     return 0;
 688 }
 689
 690 static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
 691 {
 692     if (version_id > 3) {
 693         return -EINVAL;
 694     }
 695
 696     /* The virtio device */
 697     return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
 698 }
 699
 700 static int virtio_serial_load_device(VirtIODevice *vdev, QEMUFile *f,
 701                                      int version_id)
 702 {
 703     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 704     uint32_t max_nr_ports, nr_active_ports, ports_map;
 705     unsigned int i;
 706     int ret;
 707     uint32_t tmp;
 708
 709     if (version_id < 2) {
 710         return 0;
 711     }
 712
 713     /* Unused */
 714     qemu_get_be16s(f, (uint16_t *) &tmp);
 715     qemu_get_be16s(f, (uint16_t *) &tmp);
 716     qemu_get_be32s(f, &tmp);
 717
 718     /* Note: this is the only location where we use tswap32() instead of
 719      * virtio_tswap32() because:
 720      * - virtio_tswap32() only makes sense when the device is fully restored
 721      * - the target endianness that was used to populate s->config is
 722      *   necessarly the default one
 723      */
 724     max_nr_ports = tswap32(s->config.max_nr_ports);
 725     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 726         qemu_get_be32s(f, &ports_map);
 727
 728         if (ports_map != s->ports_map[i]) {
 729             /*
 730              * Ports active on source and destination don't
 731              * match. Fail migration.
 732              */
 733             return -EINVAL;
 734         }
 735     }
 736
 737     qemu_get_be32s(f, &nr_active_ports);
 738
 739     if (nr_active_ports) {
 740         ret = fetch_active_ports_list(f, version_id, s, nr_active_ports);
 741         if (ret) {
 742             return ret;
 743         }
 744     }
 745     return 0;
 746 }
 747
 748 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 749
 750 static Property virtser_props[] = {
 751     DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 752     DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 753     DEFINE_PROP_END_OF_LIST()
 754 };
 755
 756 #define TYPE_VIRTIO_SERIAL_BUS "virtio-serial-bus"
 757 #define VIRTIO_SERIAL_BUS(obj) \
 758       OBJECT_CHECK(VirtIOSerialBus, (obj), TYPE_VIRTIO_SERIAL_BUS)
 759
 760 static void virtser_bus_class_init(ObjectClass *klass, void *data)
 761 {
 762     BusClass *k = BUS_CLASS(klass);
 763     k->print_dev = virtser_bus_dev_print;
 764 }
 765
 766 static const TypeInfo virtser_bus_info = {
 767     .name = TYPE_VIRTIO_SERIAL_BUS,
 768     .parent = TYPE_BUS,
 769     .instance_size = sizeof(VirtIOSerialBus),
 770     .class_init = virtser_bus_class_init,
 771 };
 772
 773 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 774 {
 775     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 776
 777     monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 778                    indent, "", port->id,
 779                    port->guest_connected ? "on" : "off",
 780                    port->host_connected ? "on" : "off",
 781                    port->throttled ? "on" : "off");
 782 }
 783
 784 /* This function is only used if a port id is not provided by the user */
 785 static uint32_t find_free_port_id(VirtIOSerial *vser)
 786 {
 787     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 788     unsigned int i, max_nr_ports;
 789
 790     max_nr_ports = virtio_tswap32(vdev, vser->config.max_nr_ports);
 791     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 792         uint32_t map, bit;
 793
 794         map = vser->ports_map[i];
 795         bit = ffs(~map);
 796         if (bit) {
 797             return (bit - 1) + i * 32;
 798         }
 799     }
 800     return VIRTIO_CONSOLE_BAD_ID;
 801 }
 802
 803 static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 804 {
 805     unsigned int i;
 806
 807     i = port_id / 32;
 808     vser->ports_map[i] |= 1U << (port_id % 32);
 809 }
 810
 811 static void add_port(VirtIOSerial *vser, uint32_t port_id)
 812 {
 813     mark_port_added(vser, port_id);
 814     send_control_event(vser, port_id, VIRTIO_CONSOLE_PORT_ADD, 1);
 815 }
 816
 817 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 818 {
 819     VirtIOSerialPort *port;
 820
 821     /*
 822      * Don't mark port 0 removed -- we explicitly reserve it for
 823      * backward compat with older guests, ensure a virtconsole device
 824      * unplug retains the reservation.
 825      */
 826     if (port_id) {
 827         unsigned int i;
 828
 829         i = port_id / 32;
 830         vser->ports_map[i] &= ~(1U << (port_id % 32));
 831     }
 832
 833     port = find_port_by_id(vser, port_id);
 834     /*
 835      * This function is only called from qdev's unplug callback; if we
 836      * get a NULL port here, we're in trouble.
 837      */
 838     assert(port);
 839
 840     /* Flush out any unconsumed buffers first */
 841     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 842
 843     send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 844 }
 845
 846 static void virtser_port_device_realize(DeviceState *dev, Error **errp)
 847 {
 848     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 849     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 850     VirtIOSerialBus *bus = VIRTIO_SERIAL_BUS(qdev_get_parent_bus(dev));
 851     VirtIODevice *vdev = VIRTIO_DEVICE(bus->vser);
 852     int max_nr_ports;
 853     bool plugging_port0;
 854     Error *err = NULL;
 855
 856     port->vser = bus->vser;
 857     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 858
 859     assert(vsc->have_data);
 860
 861     /*
 862      * Is the first console port we're seeing? If so, put it up at
 863      * location 0. This is done for backward compatibility (old
 864      * kernel, new qemu).
 865      */
 866     plugging_port0 = vsc->is_console && !find_port_by_id(port->vser, 0);
 867
 868     if (find_port_by_id(port->vser, port->id)) {
 869         error_setg(errp, "virtio-serial-bus: A port already exists at id %u",
 870                    port->id);
 871         return;
 872     }
 873
 874     if (port->name != NULL && find_port_by_name(port->name)) {
 875         error_setg(errp, "virtio-serial-bus: A port already exists by name %s",
 876                    port->name);
 877         return;
 878     }
 879
 880     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 881         if (plugging_port0) {
 882             port->id = 0;
 883         } else {
 884             port->id = find_free_port_id(port->vser);
 885             if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 886                 error_setg(errp, "virtio-serial-bus: Maximum port limit for "
 887                                  "this device reached");
 888                 return;
 889             }
 890         }
 891     }
 892
 893     max_nr_ports = virtio_tswap32(vdev, port->vser->config.max_nr_ports);
 894     if (port->id >= max_nr_ports) {
 895         error_setg(errp, "virtio-serial-bus: Out-of-range port id specified, "
 896                          "max. allowed: %u", max_nr_ports - 1);
 897         return;
 898     }
 899
 900     vsc->realize(dev, &err);
 901     if (err != NULL) {
 902         error_propagate(errp, err);
 903         return;
 904     }
 905
 906     port->elem.out_num = 0;
 907 }
 908
 909 static void virtser_port_device_plug(HotplugHandler *hotplug_dev,
 910                                      DeviceState *dev, Error **errp)
 911 {
 912     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 913
 914     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
 915     port->ivq = port->vser->ivqs[port->id];
 916     port->ovq = port->vser->ovqs[port->id];
 917
 918     add_port(port->vser, port->id);
 919
 920     /* Send an update to the guest about this new port added */
 921     virtio_notify_config(VIRTIO_DEVICE(hotplug_dev));
 922 }
 923
 924 static void virtser_port_device_unrealize(DeviceState *dev, Error **errp)
 925 {
 926     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 927     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(dev);
 928     VirtIOSerial *vser = port->vser;
 929
 930     qemu_bh_delete(port->bh);
 931     remove_port(port->vser, port->id);
 932
 933     QTAILQ_REMOVE(&vser->ports, port, next);
 934
 935     if (vsc->unrealize) {
 936         vsc->unrealize(dev, errp);
 937     }
 938 }
 939
 940 static void virtio_serial_device_realize(DeviceState *dev, Error **errp)
 941 {
 942     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 943     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
 944     uint32_t i, max_supported_ports;
 945
 946     if (!vser->serial.max_virtserial_ports) {
 947         error_setg(errp, "Maximum number of serial ports not specified");
 948         return;
 949     }
 950
 951     /* Each port takes 2 queues, and one pair is for the control queue */
 952     max_supported_ports = VIRTIO_PCI_QUEUE_MAX / 2 - 1;
 953
 954     if (vser->serial.max_virtserial_ports > max_supported_ports) {
 955         error_setg(errp, "maximum ports supported: %u", max_supported_ports);
 956         return;
 957     }
 958
 959     virtio_init(vdev, "virtio-serial", VIRTIO_ID_CONSOLE,
 960                 sizeof(struct virtio_console_config));
 961
 962     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
 963     qbus_create_inplace(&vser->bus, sizeof(vser->bus), TYPE_VIRTIO_SERIAL_BUS,
 964                         dev, vdev->bus_name);
 965     qbus_set_hotplug_handler(BUS(&vser->bus), DEVICE(vser), errp);
 966     vser->bus.vser = vser;
 967     QTAILQ_INIT(&vser->ports);
 968
 969     vser->bus.max_nr_ports = vser->serial.max_virtserial_ports;
 970     vser->ivqs = g_malloc(vser->serial.max_virtserial_ports
 971                           * sizeof(VirtQueue *));
 972     vser->ovqs = g_malloc(vser->serial.max_virtserial_ports
 973                           * sizeof(VirtQueue *));
 974
 975     /* Add a queue for host to guest transfers for port 0 (backward compat) */
 976     vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
 977     /* Add a queue for guest to host transfers for port 0 (backward compat) */
 978     vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
 979
 980     /* TODO: host to guest notifications can get dropped
 981      * if the queue fills up. Implement queueing in host,
 982      * this might also make it possible to reduce the control
 983      * queue size: as guest preposts buffers there,
 984      * this will save 4Kbyte of guest memory per entry. */
 985
 986     /* control queue: host to guest */
 987     vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
 988     /* control queue: guest to host */
 989     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
 990
 991     for (i = 1; i < vser->bus.max_nr_ports; i++) {
 992         /* Add a per-port queue for host to guest transfers */
 993         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
 994         /* Add a per-per queue for guest to host transfers */
 995         vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
 996     }
 997
 998     vser->config.max_nr_ports =
 999         virtio_tswap32(vdev, vser->serial.max_virtserial_ports);
1000     vser->ports_map = g_malloc0(((vser->serial.max_virtserial_ports + 31) / 32)
1001         * sizeof(vser->ports_map[0]));
1002     /*
1003      * Reserve location 0 for a console port for backward compat
1004      * (old kernel, new qemu)
1005      */
1006     mark_port_added(vser, 0);
1007
1008     vser->post_load = NULL;
1009
1010     /*
1011      * Register for the savevm section with the virtio-console name
1012      * to preserve backward compat
1013      */
1014     register_savevm(dev, "virtio-console", -1, 3, virtio_serial_save,
1015                     virtio_serial_load, vser);
1016
1017     QLIST_INSERT_HEAD(&vserdevices.devices, vser, next);
1018 }
1019
1020 static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
1021 {
1022     DeviceClass *k = DEVICE_CLASS(klass);
1023
1024     set_bit(DEVICE_CATEGORY_INPUT, k->categories);
1025     k->bus_type = TYPE_VIRTIO_SERIAL_BUS;
1026     k->realize = virtser_port_device_realize;
1027     k->unrealize = virtser_port_device_unrealize;
1028     k->props = virtser_props;
1029 }
1030
1031 static const TypeInfo virtio_serial_port_type_info = {
1032     .name = TYPE_VIRTIO_SERIAL_PORT,
1033     .parent = TYPE_DEVICE,
1034     .instance_size = sizeof(VirtIOSerialPort),
1035     .abstract = true,
1036     .class_size = sizeof(VirtIOSerialPortClass),
1037     .class_init = virtio_serial_port_class_init,
1038 };
1039
1040 static void virtio_serial_device_unrealize(DeviceState *dev, Error **errp)
1041 {
1042     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1043     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1044
1045     QLIST_REMOVE(vser, next);
1046
1047     unregister_savevm(dev, "virtio-console", vser);
1048
1049     g_free(vser->ivqs);
1050     g_free(vser->ovqs);
1051     g_free(vser->ports_map);
1052     if (vser->post_load) {
1053         g_free(vser->post_load->connected);
1054         timer_del(vser->post_load->timer);
1055         timer_free(vser->post_load->timer);
1056         g_free(vser->post_load);
1057     }
1058     virtio_cleanup(vdev);
1059 }
1060
1061 static Property virtio_serial_properties[] = {
1062     DEFINE_VIRTIO_SERIAL_PROPERTIES(VirtIOSerial, serial),
1063     DEFINE_PROP_END_OF_LIST(),
1064 };
1065
1066 static void virtio_serial_class_init(ObjectClass *klass, void *data)
1067 {
1068     DeviceClass *dc = DEVICE_CLASS(klass);
1069     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1070     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
1071
1072     QLIST_INIT(&vserdevices.devices);
1073
1074     dc->props = virtio_serial_properties;
1075     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
1076     vdc->realize = virtio_serial_device_realize;
1077     vdc->unrealize = virtio_serial_device_unrealize;
1078     vdc->get_features = get_features;
1079     vdc->get_config = get_config;
1080     vdc->set_status = set_status;
1081     vdc->reset = vser_reset;
1082     vdc->save = virtio_serial_save_device;
1083     vdc->load = virtio_serial_load_device;
1084     hc->plug = virtser_port_device_plug;
1085     hc->unplug = qdev_simple_device_unplug_cb;
1086 }
1087
1088 static const TypeInfo virtio_device_info = {
1089     .name = TYPE_VIRTIO_SERIAL,
1090     .parent = TYPE_VIRTIO_DEVICE,
1091     .instance_size = sizeof(VirtIOSerial),
1092     .class_init = virtio_serial_class_init,
1093     .interfaces = (InterfaceInfo[]) {
1094         { TYPE_HOTPLUG_HANDLER },
1095         { }
1096     }
1097 };
1098
1099 static void virtio_serial_register_types(void)
1100 {
1101     type_register_static(&virtser_bus_info);
1102     type_register_static(&virtio_serial_port_type_info);
1103     type_register_static(&virtio_device_info);
1104 }
1105
1106 type_init(virtio_serial_register_types)