hw/char/virtio-serial-bus.c

   1 /*
   2  * A bus for connecting virtio serial and console ports
   3  *
   4  * Copyright (C) 2009, 2010 Red Hat, Inc.
   5  *
   6  * Author(s):
   7  *  Amit Shah <amit.shah@redhat.com>
   8  *
   9  * Some earlier parts are:
  10  *  Copyright IBM, Corp. 2008
  11  * authored by
  12  *  Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
  13  *
  14  * This work is licensed under the terms of the GNU GPL, version 2.  See
  15  * the COPYING file in the top-level directory.
  16  *
  17  * Contributions after 2012-01-13 are licensed under the terms of the
  18  * GNU GPL, version 2 or (at your option) any later version.
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "qapi/error.h"
  23 #include "qemu/iov.h"
  24 #include "monitor/monitor.h"
  25 #include "qemu/error-report.h"
  26 #include "qemu/queue.h"
  27 #include "hw/sysbus.h"
  28 #include "trace.h"
  29 #include "hw/virtio/virtio-serial.h"
  30 #include "hw/virtio/virtio-access.h"
  31
  32 static struct VirtIOSerialDevices {
  33     QLIST_HEAD(, VirtIOSerial) devices;
  34 } vserdevices;
  35
  36 static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
  37 {
  38     VirtIOSerialPort *port;
  39
  40     if (id == VIRTIO_CONSOLE_BAD_ID) {
  41         return NULL;
  42     }
  43
  44     QTAILQ_FOREACH(port, &vser->ports, next) {
  45         if (port->id == id)
  46             return port;
  47     }
  48     return NULL;
  49 }
  50
  51 static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
  52 {
  53     VirtIOSerialPort *port;
  54
  55     QTAILQ_FOREACH(port, &vser->ports, next) {
  56         if (port->ivq == vq || port->ovq == vq)
  57             return port;
  58     }
  59     return NULL;
  60 }
  61
  62 static VirtIOSerialPort *find_port_by_name(char *name)
  63 {
  64     VirtIOSerial *vser;
  65
  66     QLIST_FOREACH(vser, &vserdevices.devices, next) {
  67         VirtIOSerialPort *port;
  68
  69         QTAILQ_FOREACH(port, &vser->ports, next) {
  70             if (port->name && !strcmp(port->name, name)) {
  71                 return port;
  72             }
  73         }
  74     }
  75     return NULL;
  76 }
  77
  78 static VirtIOSerialPort *find_first_connected_console(VirtIOSerial *vser)
  79 {
  80     VirtIOSerialPort *port;
  81
  82     QTAILQ_FOREACH(port, &vser->ports, next) {
  83         VirtIOSerialPortClass const *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
  84         if (vsc->is_console && port->host_connected) {
  85             return port;
  86         }
  87     }
  88     return NULL;
  89 }
  90
  91 static bool use_multiport(VirtIOSerial *vser)
  92 {
  93     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
  94     return virtio_vdev_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT);
  95 }
  96
  97 static size_t write_to_port(VirtIOSerialPort *port,
  98                             const uint8_t *buf, size_t size)
  99 {
 100     VirtQueueElement *elem;
 101     VirtQueue *vq;
 102     size_t offset;
 103
 104     vq = port->ivq;
 105     if (!virtio_queue_ready(vq)) {
 106         return 0;
 107     }
 108
 109     offset = 0;
 110     while (offset < size) {
 111         size_t len;
 112
 113         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 114         if (!elem) {
 115             break;
 116         }
 117
 118         len = iov_from_buf(elem->in_sg, elem->in_num, 0,
 119                            buf + offset, size - offset);
 120         offset += len;
 121
 122         virtqueue_push(vq, elem, len);
 123         g_free(elem);
 124     }
 125
 126     virtio_notify(VIRTIO_DEVICE(port->vser), vq);
 127     return offset;
 128 }
 129
 130 static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
 131 {
 132     VirtQueueElement *elem;
 133
 134     if (!virtio_queue_ready(vq)) {
 135         return;
 136     }
 137     for (;;) {
 138         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 139         if (!elem) {
 140             break;
 141         }
 142         virtqueue_push(vq, elem, 0);
 143         g_free(elem);
 144     }
 145     virtio_notify(vdev, vq);
 146 }
 147
 148 static void discard_throttle_data(VirtIOSerialPort *port)
 149 {
 150     if (port->elem) {
 151         virtqueue_detach_element(port->ovq, port->elem, 0);
 152         g_free(port->elem);
 153         port->elem = NULL;
 154     }
 155 }
 156
 157 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 158                                  VirtIODevice *vdev)
 159 {
 160     VirtIOSerialPortClass *vsc;
 161
 162     assert(port);
 163     assert(virtio_queue_ready(vq));
 164
 165     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 166
 167     while (!port->throttled) {
 168         unsigned int i;
 169
 170         /* Pop an elem only if we haven't left off a previous one mid-way */
 171         if (!port->elem) {
 172             port->elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 173             if (!port->elem) {
 174                 break;
 175             }
 176             port->iov_idx = 0;
 177             port->iov_offset = 0;
 178         }
 179
 180         for (i = port->iov_idx; i < port->elem->out_num; i++) {
 181             size_t buf_size;
 182             ssize_t ret;
 183
 184             buf_size = port->elem->out_sg[i].iov_len - port->iov_offset;
 185             ret = vsc->have_data(port,
 186                                   port->elem->out_sg[i].iov_base
 187                                   + port->iov_offset,
 188                                   buf_size);
 189             if (port->throttled) {
 190                 port->iov_idx = i;
 191                 if (ret > 0) {
 192                     port->iov_offset += ret;
 193                 }
 194                 break;
 195             }
 196             port->iov_offset = 0;
 197         }
 198         if (port->throttled) {
 199             break;
 200         }
 201         virtqueue_push(vq, port->elem, 0);
 202         g_free(port->elem);
 203         port->elem = NULL;
 204     }
 205     virtio_notify(vdev, vq);
 206 }
 207
 208 static void flush_queued_data(VirtIOSerialPort *port)
 209 {
 210     assert(port);
 211
 212     if (!virtio_queue_ready(port->ovq)) {
 213         return;
 214     }
 215     do_flush_queued_data(port, port->ovq, VIRTIO_DEVICE(port->vser));
 216 }
 217
 218 static size_t send_control_msg(VirtIOSerial *vser, void *buf, size_t len)
 219 {
 220     VirtQueueElement *elem;
 221     VirtQueue *vq;
 222
 223     vq = vser->c_ivq;
 224     if (!virtio_queue_ready(vq)) {
 225         return 0;
 226     }
 227
 228     elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 229     if (!elem) {
 230         return 0;
 231     }
 232
 233     /* TODO: detect a buffer that's too short, set NEEDS_RESET */
 234     iov_from_buf(elem->in_sg, elem->in_num, 0, buf, len);
 235
 236     virtqueue_push(vq, elem, len);
 237     virtio_notify(VIRTIO_DEVICE(vser), vq);
 238     g_free(elem);
 239
 240     return len;
 241 }
 242
 243 static size_t send_control_event(VirtIOSerial *vser, uint32_t port_id,
 244                                  uint16_t event, uint16_t value)
 245 {
 246     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 247     struct virtio_console_control cpkt;
 248
 249     virtio_stl_p(vdev, &cpkt.id, port_id);
 250     virtio_stw_p(vdev, &cpkt.event, event);
 251     virtio_stw_p(vdev, &cpkt.value, value);
 252
 253     trace_virtio_serial_send_control_event(port_id, event, value);
 254     return send_control_msg(vser, &cpkt, sizeof(cpkt));
 255 }
 256
 257 /* Functions for use inside qemu to open and read from/write to ports */
 258 int virtio_serial_open(VirtIOSerialPort *port)
 259 {
 260     /* Don't allow opening an already-open port */
 261     if (port->host_connected) {
 262         return 0;
 263     }
 264     /* Send port open notification to the guest */
 265     port->host_connected = true;
 266     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 267
 268     return 0;
 269 }
 270
 271 int virtio_serial_close(VirtIOSerialPort *port)
 272 {
 273     port->host_connected = false;
 274     /*
 275      * If there's any data the guest sent which the app didn't
 276      * consume, reset the throttling flag and discard the data.
 277      */
 278     port->throttled = false;
 279     discard_throttle_data(port);
 280     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 281
 282     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 0);
 283
 284     return 0;
 285 }
 286
 287 /* Individual ports/apps call this function to write to the guest. */
 288 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 289                             size_t size)
 290 {
 291     if (!port || !port->host_connected || !port->guest_connected) {
 292         return 0;
 293     }
 294     return write_to_port(port, buf, size);
 295 }
 296
 297 /*
 298  * Readiness of the guest to accept data on a port.
 299  * Returns max. data the guest can receive
 300  */
 301 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 302 {
 303     VirtIODevice *vdev = VIRTIO_DEVICE(port->vser);
 304     VirtQueue *vq = port->ivq;
 305     unsigned int bytes;
 306
 307     if (!virtio_queue_ready(vq) ||
 308         !(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 309         virtio_queue_empty(vq)) {
 310         return 0;
 311     }
 312     if (use_multiport(port->vser) && !port->guest_connected) {
 313         return 0;
 314     }
 315     virtqueue_get_avail_bytes(vq, &bytes, NULL, 4096, 0);
 316     return bytes;
 317 }
 318
 319 static void flush_queued_data_bh(void *opaque)
 320 {
 321     VirtIOSerialPort *port = opaque;
 322
 323     flush_queued_data(port);
 324 }
 325
 326 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 327 {
 328     if (!port) {
 329         return;
 330     }
 331
 332     trace_virtio_serial_throttle_port(port->id, throttle);
 333     port->throttled = throttle;
 334     if (throttle) {
 335         return;
 336     }
 337     qemu_bh_schedule(port->bh);
 338 }
 339
 340 /* Guest wants to notify us of some event */
 341 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 342 {
 343     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 344     struct VirtIOSerialPort *port;
 345     VirtIOSerialPortClass *vsc;
 346     struct virtio_console_control cpkt, *gcpkt;
 347     uint8_t *buffer;
 348     size_t buffer_len;
 349
 350     gcpkt = buf;
 351
 352     if (len < sizeof(cpkt)) {
 353         /* The guest sent an invalid control packet */
 354         return;
 355     }
 356
 357     cpkt.event = virtio_lduw_p(vdev, &gcpkt->event);
 358     cpkt.value = virtio_lduw_p(vdev, &gcpkt->value);
 359
 360     trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 361
 362     if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 363         if (!cpkt.value) {
 364             error_report("virtio-serial-bus: Guest failure in adding device %s",
 365                          vser->bus.qbus.name);
 366             return;
 367         }
 368         /*
 369          * The device is up, we can now tell the device about all the
 370          * ports we have here.
 371          */
 372         QTAILQ_FOREACH(port, &vser->ports, next) {
 373             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_ADD, 1);
 374         }
 375         return;
 376     }
 377
 378     port = find_port_by_id(vser, virtio_ldl_p(vdev, &gcpkt->id));
 379     if (!port) {
 380         error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 381                      virtio_ldl_p(vdev, &gcpkt->id), vser->bus.qbus.name);
 382         return;
 383     }
 384
 385     trace_virtio_serial_handle_control_message_port(port->id);
 386
 387     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 388
 389     switch(cpkt.event) {
 390     case VIRTIO_CONSOLE_PORT_READY:
 391         if (!cpkt.value) {
 392             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 393                          port->id, vser->bus.qbus.name);
 394             break;
 395         }
 396         /*
 397          * Now that we know the guest asked for the port name, we're
 398          * sure the guest has initialised whatever state is necessary
 399          * for this port. Now's a good time to let the guest know if
 400          * this port is a console port so that the guest can hook it
 401          * up to hvc.
 402          */
 403         if (vsc->is_console) {
 404             send_control_event(vser, port->id, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 405         }
 406
 407         if (port->name) {
 408             virtio_stl_p(vdev, &cpkt.id, port->id);
 409             virtio_stw_p(vdev, &cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 410             virtio_stw_p(vdev, &cpkt.value, 1);
 411
 412             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 413             buffer = g_malloc(buffer_len);
 414
 415             memcpy(buffer, &cpkt, sizeof(cpkt));
 416             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 417             buffer[buffer_len - 1] = 0;
 418
 419             send_control_msg(vser, buffer, buffer_len);
 420             g_free(buffer);
 421         }
 422
 423         if (port->host_connected) {
 424             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 425         }
 426
 427         /*
 428          * When the guest has asked us for this information it means
 429          * the guest is all setup and has its virtqueues
 430          * initialised. If some app is interested in knowing about
 431          * this event, let it know.
 432          */
 433         if (vsc->guest_ready) {
 434             vsc->guest_ready(port);
 435         }
 436         break;
 437
 438     case VIRTIO_CONSOLE_PORT_OPEN:
 439         port->guest_connected = cpkt.value;
 440         if (vsc->set_guest_connected) {
 441             /* Send the guest opened notification if an app is interested */
 442             vsc->set_guest_connected(port, cpkt.value);
 443         }
 444         break;
 445     }
 446 }
 447
 448 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 449 {
 450 }
 451
 452 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 453 {
 454     VirtQueueElement *elem;
 455     VirtIOSerial *vser;
 456     uint8_t *buf;
 457     size_t len;
 458
 459     vser = VIRTIO_SERIAL(vdev);
 460
 461     len = 0;
 462     buf = NULL;
 463     for (;;) {
 464         size_t cur_len;
 465
 466         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 467         if (!elem) {
 468             break;
 469         }
 470
 471         cur_len = iov_size(elem->out_sg, elem->out_num);
 472         /*
 473          * Allocate a new buf only if we didn't have one previously or
 474          * if the size of the buf differs
 475          */
 476         if (cur_len > len) {
 477             g_free(buf);
 478
 479             buf = g_malloc(cur_len);
 480             len = cur_len;
 481         }
 482         iov_to_buf(elem->out_sg, elem->out_num, 0, buf, cur_len);
 483
 484         handle_control_message(vser, buf, cur_len);
 485         virtqueue_push(vq, elem, 0);
 486         g_free(elem);
 487     }
 488     g_free(buf);
 489     virtio_notify(vdev, vq);
 490 }
 491
 492 /* Guest wrote something to some port. */
 493 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 494 {
 495     VirtIOSerial *vser;
 496     VirtIOSerialPort *port;
 497
 498     vser = VIRTIO_SERIAL(vdev);
 499     port = find_port_by_vq(vser, vq);
 500
 501     if (!port || !port->host_connected) {
 502         discard_vq_data(vq, vdev);
 503         return;
 504     }
 505
 506     if (!port->throttled) {
 507         do_flush_queued_data(port, vq, vdev);
 508         return;
 509     }
 510 }
 511
 512 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 513 {
 514     /*
 515      * Users of virtio-serial would like to know when guest becomes
 516      * writable again -- i.e. if a vq had stuff queued up and the
 517      * guest wasn't reading at all, the host would not be able to
 518      * write to the vq anymore.  Once the guest reads off something,
 519      * we can start queueing things up again.  However, this call is
 520      * made for each buffer addition by the guest -- even though free
 521      * buffers existed prior to the current buffer addition.  This is
 522      * done so as not to maintain previous state, which will need
 523      * additional live-migration-related changes.
 524      */
 525     VirtIOSerial *vser;
 526     VirtIOSerialPort *port;
 527     VirtIOSerialPortClass *vsc;
 528
 529     vser = VIRTIO_SERIAL(vdev);
 530     port = find_port_by_vq(vser, vq);
 531
 532     if (!port) {
 533         return;
 534     }
 535     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 536
 537     /*
 538      * If guest_connected is false, this call is being made by the
 539      * early-boot queueing up of descriptors, which is just noise for
 540      * the host apps -- don't disturb them in that case.
 541      */
 542     if (port->guest_connected && port->host_connected && vsc->guest_writable) {
 543         vsc->guest_writable(port);
 544     }
 545 }
 546
 547 static uint64_t get_features(VirtIODevice *vdev, uint64_t features,
 548                              Error **errp)
 549 {
 550     VirtIOSerial *vser;
 551
 552     vser = VIRTIO_SERIAL(vdev);
 553
 554     features |= vser->host_features;
 555     if (vser->bus.max_nr_ports > 1) {
 556         virtio_add_feature(&features, VIRTIO_CONSOLE_F_MULTIPORT);
 557     }
 558     return features;
 559 }
 560
 561 /* Guest requested config info */
 562 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 563 {
 564     VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 565     struct virtio_console_config *config =
 566         (struct virtio_console_config *)config_data;
 567
 568     config->cols = 0;
 569     config->rows = 0;
 570     config->max_nr_ports = virtio_tswap32(vdev,
 571                                           vser->serial.max_virtserial_ports);
 572 }
 573
 574 /* Guest sent new config info */
 575 static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
 576 {
 577     VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 578     struct virtio_console_config *config =
 579         (struct virtio_console_config *)config_data;
 580     uint8_t emerg_wr_lo = le32_to_cpu(config->emerg_wr);
 581     VirtIOSerialPort *port = find_first_connected_console(vser);
 582     VirtIOSerialPortClass *vsc;
 583
 584     if (!config->emerg_wr) {
 585         return;
 586     }
 587     /* Make sure we don't misdetect an emergency write when the guest
 588      * does a short config write after an emergency write. */
 589     config->emerg_wr = 0;
 590     if (!port) {
 591         return;
 592     }
 593     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 594     (void)vsc->have_data(port, &emerg_wr_lo, 1);
 595 }
 596
 597 static void guest_reset(VirtIOSerial *vser)
 598 {
 599     VirtIOSerialPort *port;
 600     VirtIOSerialPortClass *vsc;
 601
 602     QTAILQ_FOREACH(port, &vser->ports, next) {
 603         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 604
 605         discard_throttle_data(port);
 606
 607         if (port->guest_connected) {
 608             port->guest_connected = false;
 609             if (vsc->set_guest_connected) {
 610                 vsc->set_guest_connected(port, false);
 611             }
 612         }
 613     }
 614 }
 615
 616 static void set_status(VirtIODevice *vdev, uint8_t status)
 617 {
 618     VirtIOSerial *vser;
 619     VirtIOSerialPort *port;
 620
 621     vser = VIRTIO_SERIAL(vdev);
 622     port = find_port_by_id(vser, 0);
 623
 624     if (port && !use_multiport(port->vser)
 625         && (status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 626         /*
 627          * Non-multiport guests won't be able to tell us guest
 628          * open/close status.  Such guests can only have a port at id
 629          * 0, so set guest_connected for such ports as soon as guest
 630          * is up.
 631          */
 632         port->guest_connected = true;
 633     }
 634     if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 635         guest_reset(vser);
 636     }
 637 }
 638
 639 static void vser_reset(VirtIODevice *vdev)
 640 {
 641     VirtIOSerial *vser;
 642
 643     vser = VIRTIO_SERIAL(vdev);
 644     guest_reset(vser);
 645 }
 646
 647 static void virtio_serial_save_device(VirtIODevice *vdev, QEMUFile *f)
 648 {
 649     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 650     VirtIOSerialPort *port;
 651     uint32_t nr_active_ports;
 652     unsigned int i, max_nr_ports;
 653     struct virtio_console_config config;
 654
 655     /* The config space (ignored on the far end in current versions) */
 656     get_config(vdev, (uint8_t *)&config);
 657     qemu_put_be16s(f, &config.cols);
 658     qemu_put_be16s(f, &config.rows);
 659     qemu_put_be32s(f, &config.max_nr_ports);
 660
 661     /* The ports map */
 662     max_nr_ports = s->serial.max_virtserial_ports;
 663     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 664         qemu_put_be32s(f, &s->ports_map[i]);
 665     }
 666
 667     /* Ports */
 668
 669     nr_active_ports = 0;
 670     QTAILQ_FOREACH(port, &s->ports, next) {
 671         nr_active_ports++;
 672     }
 673
 674     qemu_put_be32s(f, &nr_active_ports);
 675
 676     /*
 677      * Items in struct VirtIOSerialPort.
 678      */
 679     QTAILQ_FOREACH(port, &s->ports, next) {
 680         uint32_t elem_popped;
 681
 682         qemu_put_be32s(f, &port->id);
 683         qemu_put_byte(f, port->guest_connected);
 684         qemu_put_byte(f, port->host_connected);
 685
 686         elem_popped = 0;
 687         if (port->elem) {
 688             elem_popped = 1;
 689         }
 690         qemu_put_be32s(f, &elem_popped);
 691         if (elem_popped) {
 692             qemu_put_be32s(f, &port->iov_idx);
 693             qemu_put_be64s(f, &port->iov_offset);
 694             qemu_put_virtqueue_element(f, port->elem);
 695         }
 696     }
 697 }
 698
 699 static void virtio_serial_post_load_timer_cb(void *opaque)
 700 {
 701     uint32_t i;
 702     VirtIOSerial *s = VIRTIO_SERIAL(opaque);
 703     VirtIOSerialPort *port;
 704     uint8_t host_connected;
 705     VirtIOSerialPortClass *vsc;
 706
 707     if (!s->post_load) {
 708         return;
 709     }
 710     for (i = 0 ; i < s->post_load->nr_active_ports; ++i) {
 711         port = s->post_load->connected[i].port;
 712         host_connected = s->post_load->connected[i].host_connected;
 713         if (host_connected != port->host_connected) {
 714             /*
 715              * We have to let the guest know of the host connection
 716              * status change
 717              */
 718             send_control_event(s, port->id, VIRTIO_CONSOLE_PORT_OPEN,
 719                                port->host_connected);
 720         }
 721         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 722         if (vsc->set_guest_connected) {
 723             vsc->set_guest_connected(port, port->guest_connected);
 724         }
 725     }
 726     g_free(s->post_load->connected);
 727     timer_del(s->post_load->timer);
 728     timer_free(s->post_load->timer);
 729     g_free(s->post_load);
 730     s->post_load = NULL;
 731 }
 732
 733 static int fetch_active_ports_list(QEMUFile *f,
 734                                    VirtIOSerial *s, uint32_t nr_active_ports)
 735 {
 736     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 737     uint32_t i;
 738
 739     s->post_load = g_malloc0(sizeof(*s->post_load));
 740     s->post_load->nr_active_ports = nr_active_ports;
 741     s->post_load->connected =
 742         g_malloc0(sizeof(*s->post_load->connected) * nr_active_ports);
 743
 744     s->post_load->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
 745                                             virtio_serial_post_load_timer_cb,
 746                                             s);
 747
 748     /* Items in struct VirtIOSerialPort */
 749     for (i = 0; i < nr_active_ports; i++) {
 750         VirtIOSerialPort *port;
 751         uint32_t elem_popped;
 752         uint32_t id;
 753
 754         id = qemu_get_be32(f);
 755         port = find_port_by_id(s, id);
 756         if (!port) {
 757             return -EINVAL;
 758         }
 759
 760         port->guest_connected = qemu_get_byte(f);
 761         s->post_load->connected[i].port = port;
 762         s->post_load->connected[i].host_connected = qemu_get_byte(f);
 763
 764         qemu_get_be32s(f, &elem_popped);
 765         if (elem_popped) {
 766             qemu_get_be32s(f, &port->iov_idx);
 767             qemu_get_be64s(f, &port->iov_offset);
 768
 769             port->elem =
 770                 qemu_get_virtqueue_element(vdev, f, sizeof(VirtQueueElement));
 771
 772             /*
 773              *  Port was throttled on source machine.  Let's
 774              *  unthrottle it here so data starts flowing again.
 775              */
 776             virtio_serial_throttle_port(port, false);
 777         }
 778     }
 779     timer_mod(s->post_load->timer, 1);
 780     return 0;
 781 }
 782
 783 static int virtio_serial_load_device(VirtIODevice *vdev, QEMUFile *f,
 784                                      int version_id)
 785 {
 786     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 787     uint32_t max_nr_ports, nr_active_ports, ports_map;
 788     unsigned int i;
 789     int ret;
 790     uint32_t tmp;
 791
 792     /* Unused */
 793     qemu_get_be16s(f, (uint16_t *) &tmp);
 794     qemu_get_be16s(f, (uint16_t *) &tmp);
 795     qemu_get_be32s(f, &tmp);
 796
 797     max_nr_ports = s->serial.max_virtserial_ports;
 798     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 799         qemu_get_be32s(f, &ports_map);
 800
 801         if (ports_map != s->ports_map[i]) {
 802             /*
 803              * Ports active on source and destination don't
 804              * match. Fail migration.
 805              */
 806             return -EINVAL;
 807         }
 808     }
 809
 810     qemu_get_be32s(f, &nr_active_ports);
 811
 812     if (nr_active_ports) {
 813         ret = fetch_active_ports_list(f, s, nr_active_ports);
 814         if (ret) {
 815             return ret;
 816         }
 817     }
 818     return 0;
 819 }
 820
 821 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 822
 823 static Property virtser_props[] = {
 824     DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 825     DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 826     DEFINE_PROP_END_OF_LIST()
 827 };
 828
 829 #define TYPE_VIRTIO_SERIAL_BUS "virtio-serial-bus"
 830 #define VIRTIO_SERIAL_BUS(obj) \
 831       OBJECT_CHECK(VirtIOSerialBus, (obj), TYPE_VIRTIO_SERIAL_BUS)
 832
 833 static void virtser_bus_class_init(ObjectClass *klass, void *data)
 834 {
 835     BusClass *k = BUS_CLASS(klass);
 836     k->print_dev = virtser_bus_dev_print;
 837 }
 838
 839 static const TypeInfo virtser_bus_info = {
 840     .name = TYPE_VIRTIO_SERIAL_BUS,
 841     .parent = TYPE_BUS,
 842     .instance_size = sizeof(VirtIOSerialBus),
 843     .class_init = virtser_bus_class_init,
 844 };
 845
 846 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 847 {
 848     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(qdev);
 849
 850     monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 851                    indent, "", port->id,
 852                    port->guest_connected ? "on" : "off",
 853                    port->host_connected ? "on" : "off",
 854                    port->throttled ? "on" : "off");
 855 }
 856
 857 /* This function is only used if a port id is not provided by the user */
 858 static uint32_t find_free_port_id(VirtIOSerial *vser)
 859 {
 860     unsigned int i, max_nr_ports;
 861
 862     max_nr_ports = vser->serial.max_virtserial_ports;
 863     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 864         uint32_t map, zeroes;
 865
 866         map = vser->ports_map[i];
 867         zeroes = ctz32(~map);
 868         if (zeroes != 32) {
 869             return zeroes + i * 32;
 870         }
 871     }
 872     return VIRTIO_CONSOLE_BAD_ID;
 873 }
 874
 875 static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 876 {
 877     unsigned int i;
 878
 879     i = port_id / 32;
 880     vser->ports_map[i] |= 1U << (port_id % 32);
 881 }
 882
 883 static void add_port(VirtIOSerial *vser, uint32_t port_id)
 884 {
 885     mark_port_added(vser, port_id);
 886     send_control_event(vser, port_id, VIRTIO_CONSOLE_PORT_ADD, 1);
 887 }
 888
 889 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 890 {
 891     VirtIOSerialPort *port;
 892
 893     /*
 894      * Don't mark port 0 removed -- we explicitly reserve it for
 895      * backward compat with older guests, ensure a virtconsole device
 896      * unplug retains the reservation.
 897      */
 898     if (port_id) {
 899         unsigned int i;
 900
 901         i = port_id / 32;
 902         vser->ports_map[i] &= ~(1U << (port_id % 32));
 903     }
 904
 905     port = find_port_by_id(vser, port_id);
 906     /*
 907      * This function is only called from qdev's unplug callback; if we
 908      * get a NULL port here, we're in trouble.
 909      */
 910     assert(port);
 911
 912     /* Flush out any unconsumed buffers first */
 913     discard_throttle_data(port);
 914     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 915
 916     send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 917 }
 918
 919 static void virtser_port_device_realize(DeviceState *dev, Error **errp)
 920 {
 921     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 922     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 923     VirtIOSerialBus *bus = VIRTIO_SERIAL_BUS(qdev_get_parent_bus(dev));
 924     int max_nr_ports;
 925     bool plugging_port0;
 926     Error *err = NULL;
 927
 928     port->vser = bus->vser;
 929     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 930
 931     assert(vsc->have_data);
 932
 933     /*
 934      * Is the first console port we're seeing? If so, put it up at
 935      * location 0. This is done for backward compatibility (old
 936      * kernel, new qemu).
 937      */
 938     plugging_port0 = vsc->is_console && !find_port_by_id(port->vser, 0);
 939
 940     if (find_port_by_id(port->vser, port->id)) {
 941         error_setg(errp, "virtio-serial-bus: A port already exists at id %u",
 942                    port->id);
 943         return;
 944     }
 945
 946     if (port->name != NULL && find_port_by_name(port->name)) {
 947         error_setg(errp, "virtio-serial-bus: A port already exists by name %s",
 948                    port->name);
 949         return;
 950     }
 951
 952     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 953         if (plugging_port0) {
 954             port->id = 0;
 955         } else {
 956             port->id = find_free_port_id(port->vser);
 957             if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 958                 error_setg(errp, "virtio-serial-bus: Maximum port limit for "
 959                                  "this device reached");
 960                 return;
 961             }
 962         }
 963     }
 964
 965     max_nr_ports = port->vser->serial.max_virtserial_ports;
 966     if (port->id >= max_nr_ports) {
 967         error_setg(errp, "virtio-serial-bus: Out-of-range port id specified, "
 968                          "max. allowed: %u", max_nr_ports - 1);
 969         return;
 970     }
 971
 972     vsc->realize(dev, &err);
 973     if (err != NULL) {
 974         error_propagate(errp, err);
 975         return;
 976     }
 977
 978     port->elem = NULL;
 979 }
 980
 981 static void virtser_port_device_plug(HotplugHandler *hotplug_dev,
 982                                      DeviceState *dev, Error **errp)
 983 {
 984     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 985
 986     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
 987     port->ivq = port->vser->ivqs[port->id];
 988     port->ovq = port->vser->ovqs[port->id];
 989
 990     add_port(port->vser, port->id);
 991
 992     /* Send an update to the guest about this new port added */
 993     virtio_notify_config(VIRTIO_DEVICE(hotplug_dev));
 994 }
 995
 996 static void virtser_port_device_unrealize(DeviceState *dev, Error **errp)
 997 {
 998     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 999     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(dev);
1000     VirtIOSerial *vser = port->vser;
1001
1002     qemu_bh_delete(port->bh);
1003     remove_port(port->vser, port->id);
1004
1005     QTAILQ_REMOVE(&vser->ports, port, next);
1006
1007     if (vsc->unrealize) {
1008         vsc->unrealize(dev, errp);
1009     }
1010 }
1011
1012 static void virtio_serial_device_realize(DeviceState *dev, Error **errp)
1013 {
1014     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1015     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1016     uint32_t i, max_supported_ports;
1017     size_t config_size = sizeof(struct virtio_console_config);
1018
1019     if (!vser->serial.max_virtserial_ports) {
1020         error_setg(errp, "Maximum number of serial ports not specified");
1021         return;
1022     }
1023
1024     /* Each port takes 2 queues, and one pair is for the control queue */
1025     max_supported_ports = VIRTIO_QUEUE_MAX / 2 - 1;
1026
1027     if (vser->serial.max_virtserial_ports > max_supported_ports) {
1028         error_setg(errp, "maximum ports supported: %u", max_supported_ports);
1029         return;
1030     }
1031
1032     if (!virtio_has_feature(vser->host_features,
1033                             VIRTIO_CONSOLE_F_EMERG_WRITE)) {
1034         config_size = offsetof(struct virtio_console_config, emerg_wr);
1035     }
1036     virtio_init(vdev, "virtio-serial", VIRTIO_ID_CONSOLE,
1037                 config_size);
1038
1039     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
1040     qbus_create_inplace(&vser->bus, sizeof(vser->bus), TYPE_VIRTIO_SERIAL_BUS,
1041                         dev, vdev->bus_name);
1042     qbus_set_hotplug_handler(BUS(&vser->bus), DEVICE(vser), errp);
1043     vser->bus.vser = vser;
1044     QTAILQ_INIT(&vser->ports);
1045
1046     vser->bus.max_nr_ports = vser->serial.max_virtserial_ports;
1047     vser->ivqs = g_malloc(vser->serial.max_virtserial_ports
1048                           * sizeof(VirtQueue *));
1049     vser->ovqs = g_malloc(vser->serial.max_virtserial_ports
1050                           * sizeof(VirtQueue *));
1051
1052     /* Add a queue for host to guest transfers for port 0 (backward compat) */
1053     vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
1054     /* Add a queue for guest to host transfers for port 0 (backward compat) */
1055     vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
1056
1057     /* TODO: host to guest notifications can get dropped
1058      * if the queue fills up. Implement queueing in host,
1059      * this might also make it possible to reduce the control
1060      * queue size: as guest preposts buffers there,
1061      * this will save 4Kbyte of guest memory per entry. */
1062
1063     /* control queue: host to guest */
1064     vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
1065     /* control queue: guest to host */
1066     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
1067
1068     for (i = 1; i < vser->bus.max_nr_ports; i++) {
1069         /* Add a per-port queue for host to guest transfers */
1070         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
1071         /* Add a per-per queue for guest to host transfers */
1072         vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
1073     }
1074
1075     vser->ports_map = g_malloc0(((vser->serial.max_virtserial_ports + 31) / 32)
1076         * sizeof(vser->ports_map[0]));
1077     /*
1078      * Reserve location 0 for a console port for backward compat
1079      * (old kernel, new qemu)
1080      */
1081     mark_port_added(vser, 0);
1082
1083     vser->post_load = NULL;
1084
1085     QLIST_INSERT_HEAD(&vserdevices.devices, vser, next);
1086 }
1087
1088 static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
1089 {
1090     DeviceClass *k = DEVICE_CLASS(klass);
1091
1092     set_bit(DEVICE_CATEGORY_INPUT, k->categories);
1093     k->bus_type = TYPE_VIRTIO_SERIAL_BUS;
1094     k->realize = virtser_port_device_realize;
1095     k->unrealize = virtser_port_device_unrealize;
1096     k->props = virtser_props;
1097 }
1098
1099 static const TypeInfo virtio_serial_port_type_info = {
1100     .name = TYPE_VIRTIO_SERIAL_PORT,
1101     .parent = TYPE_DEVICE,
1102     .instance_size = sizeof(VirtIOSerialPort),
1103     .abstract = true,
1104     .class_size = sizeof(VirtIOSerialPortClass),
1105     .class_init = virtio_serial_port_class_init,
1106 };
1107
1108 static void virtio_serial_device_unrealize(DeviceState *dev, Error **errp)
1109 {
1110     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1111     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1112
1113     QLIST_REMOVE(vser, next);
1114
1115     g_free(vser->ivqs);
1116     g_free(vser->ovqs);
1117     g_free(vser->ports_map);
1118     if (vser->post_load) {
1119         g_free(vser->post_load->connected);
1120         timer_del(vser->post_load->timer);
1121         timer_free(vser->post_load->timer);
1122         g_free(vser->post_load);
1123     }
1124
1125     qbus_set_hotplug_handler(BUS(&vser->bus), NULL, errp);
1126
1127     virtio_cleanup(vdev);
1128 }
1129
1130 /* Note: 'console' is used for backwards compatibility */
1131 static const VMStateDescription vmstate_virtio_console = {
1132     .name = "virtio-console",
1133     .minimum_version_id = 3,
1134     .version_id = 3,
1135     .fields = (VMStateField[]) {
1136         VMSTATE_VIRTIO_DEVICE,
1137         VMSTATE_END_OF_LIST()
1138     },
1139 };
1140
1141 static Property virtio_serial_properties[] = {
1142     DEFINE_PROP_UINT32("max_ports", VirtIOSerial, serial.max_virtserial_ports,
1143                                                   31),
1144     DEFINE_PROP_BIT64("emergency-write", VirtIOSerial, host_features,
1145                       VIRTIO_CONSOLE_F_EMERG_WRITE, true),
1146     DEFINE_PROP_END_OF_LIST(),
1147 };
1148
1149 static void virtio_serial_class_init(ObjectClass *klass, void *data)
1150 {
1151     DeviceClass *dc = DEVICE_CLASS(klass);
1152     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1153     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
1154
1155     QLIST_INIT(&vserdevices.devices);
1156
1157     dc->props = virtio_serial_properties;
1158     dc->vmsd = &vmstate_virtio_console;
1159     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
1160     vdc->realize = virtio_serial_device_realize;
1161     vdc->unrealize = virtio_serial_device_unrealize;
1162     vdc->get_features = get_features;
1163     vdc->get_config = get_config;
1164     vdc->set_config = set_config;
1165     vdc->set_status = set_status;
1166     vdc->reset = vser_reset;
1167     vdc->save = virtio_serial_save_device;
1168     vdc->load = virtio_serial_load_device;
1169     hc->plug = virtser_port_device_plug;
1170     hc->unplug = qdev_simple_device_unplug_cb;
1171 }
1172
1173 static const TypeInfo virtio_device_info = {
1174     .name = TYPE_VIRTIO_SERIAL,
1175     .parent = TYPE_VIRTIO_DEVICE,
1176     .instance_size = sizeof(VirtIOSerial),
1177     .class_init = virtio_serial_class_init,
1178     .interfaces = (InterfaceInfo[]) {
1179         { TYPE_HOTPLUG_HANDLER },
1180         { }
1181     }
1182 };
1183
1184 static void virtio_serial_register_types(void)
1185 {
1186     type_register_static(&virtser_bus_info);
1187     type_register_static(&virtio_serial_port_type_info);
1188     type_register_static(&virtio_device_info);
1189 }
1190
1191 type_init(virtio_serial_register_types)