hw/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
  18 #include "iov.h"
  19 #include "monitor.h"
  20 #include "qemu-queue.h"
  21 #include "sysbus.h"
  22 #include "trace.h"
  23 #include "virtio-serial.h"
  24
  25 /* The virtio-serial bus on top of which the ports will ride as devices */
  26 struct VirtIOSerialBus {
  27     BusState qbus;
  28
  29     /* This is the parent device that provides the bus for ports. */
  30     VirtIOSerial *vser;
  31
  32     /* The maximum number of ports that can ride on top of this bus */
  33     uint32_t max_nr_ports;
  34 };
  35
  36 struct VirtIOSerial {
  37     VirtIODevice vdev;
  38
  39     VirtQueue *c_ivq, *c_ovq;
  40     /* Arrays of ivqs and ovqs: one per port */
  41     VirtQueue **ivqs, **ovqs;
  42
  43     VirtIOSerialBus bus;
  44
  45     DeviceState *qdev;
  46
  47     QTAILQ_HEAD(, VirtIOSerialPort) ports;
  48
  49     /* bitmap for identifying active ports */
  50     uint32_t *ports_map;
  51
  52     struct virtio_console_config config;
  53 };
  54
  55 static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
  56 {
  57     VirtIOSerialPort *port;
  58
  59     if (id == VIRTIO_CONSOLE_BAD_ID) {
  60         return NULL;
  61     }
  62
  63     QTAILQ_FOREACH(port, &vser->ports, next) {
  64         if (port->id == id)
  65             return port;
  66     }
  67     return NULL;
  68 }
  69
  70 static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
  71 {
  72     VirtIOSerialPort *port;
  73
  74     QTAILQ_FOREACH(port, &vser->ports, next) {
  75         if (port->ivq == vq || port->ovq == vq)
  76             return port;
  77     }
  78     return NULL;
  79 }
  80
  81 static bool use_multiport(VirtIOSerial *vser)
  82 {
  83     return vser->vdev.guest_features & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
  84 }
  85
  86 static size_t write_to_port(VirtIOSerialPort *port,
  87                             const uint8_t *buf, size_t size)
  88 {
  89     VirtQueueElement elem;
  90     VirtQueue *vq;
  91     size_t offset;
  92
  93     vq = port->ivq;
  94     if (!virtio_queue_ready(vq)) {
  95         return 0;
  96     }
  97
  98     offset = 0;
  99     while (offset < size) {
 100         size_t len;
 101
 102         if (!virtqueue_pop(vq, &elem)) {
 103             break;
 104         }
 105
 106         len = iov_from_buf(elem.in_sg, elem.in_num,
 107                            buf + offset, 0, size - offset);
 108         offset += len;
 109
 110         virtqueue_push(vq, &elem, len);
 111     }
 112
 113     virtio_notify(&port->vser->vdev, 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     while (virtqueue_pop(vq, &elem)) {
 125         virtqueue_push(vq, &elem, 0);
 126     }
 127     virtio_notify(vdev, vq);
 128 }
 129
 130 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 131                                  VirtIODevice *vdev)
 132 {
 133     VirtIOSerialPortInfo *info;
 134
 135     assert(port);
 136     assert(virtio_queue_ready(vq));
 137
 138     info = DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info);
 139
 140     while (!port->throttled) {
 141         unsigned int i;
 142
 143         /* Pop an elem only if we haven't left off a previous one mid-way */
 144         if (!port->elem.out_num) {
 145             if (!virtqueue_pop(vq, &port->elem)) {
 146                 break;
 147             }
 148             port->iov_idx = 0;
 149             port->iov_offset = 0;
 150         }
 151
 152         for (i = port->iov_idx; i < port->elem.out_num; i++) {
 153             size_t buf_size;
 154             ssize_t ret;
 155
 156             buf_size = port->elem.out_sg[i].iov_len - port->iov_offset;
 157             ret = info->have_data(port,
 158                                   port->elem.out_sg[i].iov_base
 159                                   + port->iov_offset,
 160                                   buf_size);
 161             if (ret < 0 && ret != -EAGAIN) {
 162                 /* We don't handle any other type of errors here */
 163                 abort();
 164             }
 165             if (ret == -EAGAIN || (ret >= 0 && ret < buf_size)) {
 166                 virtio_serial_throttle_port(port, true);
 167                 port->iov_idx = i;
 168                 if (ret > 0) {
 169                     port->iov_offset += ret;
 170                 }
 171                 break;
 172             }
 173             port->iov_offset = 0;
 174         }
 175         if (port->throttled) {
 176             break;
 177         }
 178         virtqueue_push(vq, &port->elem, 0);
 179         port->elem.out_num = 0;
 180     }
 181     virtio_notify(vdev, vq);
 182 }
 183
 184 static void flush_queued_data(VirtIOSerialPort *port)
 185 {
 186     assert(port);
 187
 188     if (!virtio_queue_ready(port->ovq)) {
 189         return;
 190     }
 191     do_flush_queued_data(port, port->ovq, &port->vser->vdev);
 192 }
 193
 194 static size_t send_control_msg(VirtIOSerialPort *port, void *buf, size_t len)
 195 {
 196     VirtQueueElement elem;
 197     VirtQueue *vq;
 198     struct virtio_console_control *cpkt;
 199
 200     vq = port->vser->c_ivq;
 201     if (!virtio_queue_ready(vq)) {
 202         return 0;
 203     }
 204     if (!virtqueue_pop(vq, &elem)) {
 205         return 0;
 206     }
 207
 208     cpkt = (struct virtio_console_control *)buf;
 209     stl_p(&cpkt->id, port->id);
 210     memcpy(elem.in_sg[0].iov_base, buf, len);
 211
 212     virtqueue_push(vq, &elem, len);
 213     virtio_notify(&port->vser->vdev, vq);
 214     return len;
 215 }
 216
 217 static size_t send_control_event(VirtIOSerialPort *port, uint16_t event,
 218                                  uint16_t value)
 219 {
 220     struct virtio_console_control cpkt;
 221
 222     stw_p(&cpkt.event, event);
 223     stw_p(&cpkt.value, value);
 224
 225     trace_virtio_serial_send_control_event(port->id, event, value);
 226     return send_control_msg(port, &cpkt, sizeof(cpkt));
 227 }
 228
 229 /* Functions for use inside qemu to open and read from/write to ports */
 230 int virtio_serial_open(VirtIOSerialPort *port)
 231 {
 232     /* Don't allow opening an already-open port */
 233     if (port->host_connected) {
 234         return 0;
 235     }
 236     /* Send port open notification to the guest */
 237     port->host_connected = true;
 238     send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
 239
 240     return 0;
 241 }
 242
 243 int virtio_serial_close(VirtIOSerialPort *port)
 244 {
 245     port->host_connected = false;
 246     /*
 247      * If there's any data the guest sent which the app didn't
 248      * consume, reset the throttling flag and discard the data.
 249      */
 250     port->throttled = false;
 251     discard_vq_data(port->ovq, &port->vser->vdev);
 252
 253     send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
 254
 255     return 0;
 256 }
 257
 258 /* Individual ports/apps call this function to write to the guest. */
 259 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 260                             size_t size)
 261 {
 262     if (!port || !port->host_connected || !port->guest_connected) {
 263         return 0;
 264     }
 265     return write_to_port(port, buf, size);
 266 }
 267
 268 /*
 269  * Readiness of the guest to accept data on a port.
 270  * Returns max. data the guest can receive
 271  */
 272 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 273 {
 274     VirtQueue *vq = port->ivq;
 275
 276     if (!virtio_queue_ready(vq) ||
 277         !(port->vser->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 278         virtio_queue_empty(vq)) {
 279         return 0;
 280     }
 281     if (use_multiport(port->vser) && !port->guest_connected) {
 282         return 0;
 283     }
 284
 285     if (virtqueue_avail_bytes(vq, 4096, 0)) {
 286         return 4096;
 287     }
 288     if (virtqueue_avail_bytes(vq, 1, 0)) {
 289         return 1;
 290     }
 291     return 0;
 292 }
 293
 294 static void flush_queued_data_bh(void *opaque)
 295 {
 296     VirtIOSerialPort *port = opaque;
 297
 298     flush_queued_data(port);
 299 }
 300
 301 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 302 {
 303     if (!port) {
 304         return;
 305     }
 306
 307     trace_virtio_serial_throttle_port(port->id, throttle);
 308     port->throttled = throttle;
 309     if (throttle) {
 310         return;
 311     }
 312     qemu_bh_schedule(port->bh);
 313 }
 314
 315 /* Guest wants to notify us of some event */
 316 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 317 {
 318     struct VirtIOSerialPort *port;
 319     struct VirtIOSerialPortInfo *info;
 320     struct virtio_console_control cpkt, *gcpkt;
 321     uint8_t *buffer;
 322     size_t buffer_len;
 323
 324     gcpkt = buf;
 325
 326     if (len < sizeof(cpkt)) {
 327         /* The guest sent an invalid control packet */
 328         return;
 329     }
 330
 331     cpkt.event = lduw_p(&gcpkt->event);
 332     cpkt.value = lduw_p(&gcpkt->value);
 333
 334     trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 335
 336     if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 337         if (!cpkt.value) {
 338             error_report("virtio-serial-bus: Guest failure in adding device %s",
 339                          vser->bus.qbus.name);
 340             return;
 341         }
 342         /*
 343          * The device is up, we can now tell the device about all the
 344          * ports we have here.
 345          */
 346         QTAILQ_FOREACH(port, &vser->ports, next) {
 347             send_control_event(port, VIRTIO_CONSOLE_PORT_ADD, 1);
 348         }
 349         return;
 350     }
 351
 352     port = find_port_by_id(vser, ldl_p(&gcpkt->id));
 353     if (!port) {
 354         error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 355                      ldl_p(&gcpkt->id), vser->bus.qbus.name);
 356         return;
 357     }
 358
 359     trace_virtio_serial_handle_control_message_port(port->id);
 360
 361     info = DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info);
 362
 363     switch(cpkt.event) {
 364     case VIRTIO_CONSOLE_PORT_READY:
 365         if (!cpkt.value) {
 366             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 367                          port->id, vser->bus.qbus.name);
 368             break;
 369         }
 370         /*
 371          * Now that we know the guest asked for the port name, we're
 372          * sure the guest has initialised whatever state is necessary
 373          * for this port. Now's a good time to let the guest know if
 374          * this port is a console port so that the guest can hook it
 375          * up to hvc.
 376          */
 377         if (info->is_console) {
 378             send_control_event(port, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 379         }
 380
 381         if (port->name) {
 382             stw_p(&cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 383             stw_p(&cpkt.value, 1);
 384
 385             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 386             buffer = qemu_malloc(buffer_len);
 387
 388             memcpy(buffer, &cpkt, sizeof(cpkt));
 389             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 390             buffer[buffer_len - 1] = 0;
 391
 392             send_control_msg(port, buffer, buffer_len);
 393             qemu_free(buffer);
 394         }
 395
 396         if (port->host_connected) {
 397             send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
 398         }
 399
 400         /*
 401          * When the guest has asked us for this information it means
 402          * the guest is all setup and has its virtqueues
 403          * initialised. If some app is interested in knowing about
 404          * this event, let it know.
 405          */
 406         if (info->guest_ready) {
 407             info->guest_ready(port);
 408         }
 409         break;
 410
 411     case VIRTIO_CONSOLE_PORT_OPEN:
 412         port->guest_connected = cpkt.value;
 413         if (cpkt.value && info->guest_open) {
 414             /* Send the guest opened notification if an app is interested */
 415             info->guest_open(port);
 416         }
 417
 418         if (!cpkt.value && info->guest_close) {
 419             /* Send the guest closed notification if an app is interested */
 420             info->guest_close(port);
 421         }
 422         break;
 423     }
 424 }
 425
 426 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 427 {
 428 }
 429
 430 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 431 {
 432     VirtQueueElement elem;
 433     VirtIOSerial *vser;
 434     uint8_t *buf;
 435     size_t len;
 436
 437     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 438
 439     len = 0;
 440     buf = NULL;
 441     while (virtqueue_pop(vq, &elem)) {
 442         size_t cur_len, copied;
 443
 444         cur_len = iov_size(elem.out_sg, elem.out_num);
 445         /*
 446          * Allocate a new buf only if we didn't have one previously or
 447          * if the size of the buf differs
 448          */
 449         if (cur_len > len) {
 450             qemu_free(buf);
 451
 452             buf = qemu_malloc(cur_len);
 453             len = cur_len;
 454         }
 455         copied = iov_to_buf(elem.out_sg, elem.out_num, buf, 0, len);
 456
 457         handle_control_message(vser, buf, copied);
 458         virtqueue_push(vq, &elem, 0);
 459     }
 460     qemu_free(buf);
 461     virtio_notify(vdev, vq);
 462 }
 463
 464 /* Guest wrote something to some port. */
 465 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 466 {
 467     VirtIOSerial *vser;
 468     VirtIOSerialPort *port;
 469     VirtIOSerialPortInfo *info;
 470
 471     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 472     port = find_port_by_vq(vser, vq);
 473     info = port ? DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info) : NULL;
 474
 475     if (!port || !port->host_connected || !info->have_data) {
 476         discard_vq_data(vq, vdev);
 477         return;
 478     }
 479
 480     if (!port->throttled) {
 481         do_flush_queued_data(port, vq, vdev);
 482         return;
 483     }
 484 }
 485
 486 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 487 {
 488 }
 489
 490 static uint32_t get_features(VirtIODevice *vdev, uint32_t features)
 491 {
 492     VirtIOSerial *vser;
 493
 494     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 495
 496     if (vser->bus.max_nr_ports > 1) {
 497         features |= (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 498     }
 499     return features;
 500 }
 501
 502 /* Guest requested config info */
 503 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 504 {
 505     VirtIOSerial *vser;
 506
 507     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 508     memcpy(config_data, &vser->config, sizeof(struct virtio_console_config));
 509 }
 510
 511 static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
 512 {
 513     struct virtio_console_config config;
 514
 515     memcpy(&config, config_data, sizeof(config));
 516 }
 517
 518 static void virtio_serial_save(QEMUFile *f, void *opaque)
 519 {
 520     VirtIOSerial *s = opaque;
 521     VirtIOSerialPort *port;
 522     uint32_t nr_active_ports;
 523     unsigned int i, max_nr_ports;
 524
 525     /* The virtio device */
 526     virtio_save(&s->vdev, f);
 527
 528     /* The config space */
 529     qemu_put_be16s(f, &s->config.cols);
 530     qemu_put_be16s(f, &s->config.rows);
 531
 532     qemu_put_be32s(f, &s->config.max_nr_ports);
 533
 534     /* The ports map */
 535     max_nr_ports = tswap32(s->config.max_nr_ports);
 536     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 537         qemu_put_be32s(f, &s->ports_map[i]);
 538     }
 539
 540     /* Ports */
 541
 542     nr_active_ports = 0;
 543     QTAILQ_FOREACH(port, &s->ports, next) {
 544         nr_active_ports++;
 545     }
 546
 547     qemu_put_be32s(f, &nr_active_ports);
 548
 549     /*
 550      * Items in struct VirtIOSerialPort.
 551      */
 552     QTAILQ_FOREACH(port, &s->ports, next) {
 553         uint32_t elem_popped;
 554
 555         qemu_put_be32s(f, &port->id);
 556         qemu_put_byte(f, port->guest_connected);
 557         qemu_put_byte(f, port->host_connected);
 558
 559         elem_popped = 0;
 560         if (port->elem.out_num) {
 561             elem_popped = 1;
 562         }
 563         qemu_put_be32s(f, &elem_popped);
 564         if (elem_popped) {
 565             qemu_put_be32s(f, &port->iov_idx);
 566             qemu_put_be64s(f, &port->iov_offset);
 567
 568             qemu_put_buffer(f, (unsigned char *)&port->elem,
 569                             sizeof(port->elem));
 570         }
 571     }
 572 }
 573
 574 static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
 575 {
 576     VirtIOSerial *s = opaque;
 577     VirtIOSerialPort *port;
 578     uint32_t max_nr_ports, nr_active_ports, ports_map;
 579     unsigned int i;
 580
 581     if (version_id > 3) {
 582         return -EINVAL;
 583     }
 584
 585     /* The virtio device */
 586     virtio_load(&s->vdev, f);
 587
 588     if (version_id < 2) {
 589         return 0;
 590     }
 591
 592     /* The config space */
 593     qemu_get_be16s(f, &s->config.cols);
 594     qemu_get_be16s(f, &s->config.rows);
 595
 596     qemu_get_be32s(f, &max_nr_ports);
 597     tswap32s(&max_nr_ports);
 598     if (max_nr_ports > tswap32(s->config.max_nr_ports)) {
 599         /* Source could have had more ports than us. Fail migration. */
 600         return -EINVAL;
 601     }
 602
 603     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 604         qemu_get_be32s(f, &ports_map);
 605
 606         if (ports_map != s->ports_map[i]) {
 607             /*
 608              * Ports active on source and destination don't
 609              * match. Fail migration.
 610              */
 611             return -EINVAL;
 612         }
 613     }
 614
 615     qemu_get_be32s(f, &nr_active_ports);
 616
 617     /* Items in struct VirtIOSerialPort */
 618     for (i = 0; i < nr_active_ports; i++) {
 619         uint32_t id;
 620         bool host_connected;
 621
 622         id = qemu_get_be32(f);
 623         port = find_port_by_id(s, id);
 624         if (!port) {
 625             return -EINVAL;
 626         }
 627
 628         port->guest_connected = qemu_get_byte(f);
 629         host_connected = qemu_get_byte(f);
 630         if (host_connected != port->host_connected) {
 631             /*
 632              * We have to let the guest know of the host connection
 633              * status change
 634              */
 635             send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN,
 636                                port->host_connected);
 637         }
 638
 639         if (version_id > 2) {
 640             uint32_t elem_popped;
 641
 642             qemu_get_be32s(f, &elem_popped);
 643             if (elem_popped) {
 644                 qemu_get_be32s(f, &port->iov_idx);
 645                 qemu_get_be64s(f, &port->iov_offset);
 646
 647                 qemu_get_buffer(f, (unsigned char *)&port->elem,
 648                                 sizeof(port->elem));
 649                 virtqueue_map_sg(port->elem.in_sg, port->elem.in_addr,
 650                                  port->elem.in_num, 1);
 651                 virtqueue_map_sg(port->elem.out_sg, port->elem.out_addr,
 652                                  port->elem.out_num, 1);
 653
 654                 /*
 655                  *  Port was throttled on source machine.  Let's
 656                  *  unthrottle it here so data starts flowing again.
 657                  */
 658                 virtio_serial_throttle_port(port, false);
 659             }
 660         }
 661     }
 662     return 0;
 663 }
 664
 665 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 666
 667 static struct BusInfo virtser_bus_info = {
 668     .name      = "virtio-serial-bus",
 669     .size      = sizeof(VirtIOSerialBus),
 670     .print_dev = virtser_bus_dev_print,
 671     .props      = (Property[]) {
 672         DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 673         DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 674         DEFINE_PROP_END_OF_LIST()
 675     }
 676 };
 677
 678 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 679 {
 680     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 681
 682     monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 683                    indent, "", port->id,
 684                    port->guest_connected ? "on" : "off",
 685                    port->host_connected ? "on" : "off",
 686                    port->throttled ? "on" : "off");
 687 }
 688
 689 /* This function is only used if a port id is not provided by the user */
 690 static uint32_t find_free_port_id(VirtIOSerial *vser)
 691 {
 692     unsigned int i, max_nr_ports;
 693
 694     max_nr_ports = tswap32(vser->config.max_nr_ports);
 695     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 696         uint32_t map, bit;
 697
 698         map = vser->ports_map[i];
 699         bit = ffs(~map);
 700         if (bit) {
 701             return (bit - 1) + i * 32;
 702         }
 703     }
 704     return VIRTIO_CONSOLE_BAD_ID;
 705 }
 706
 707 static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 708 {
 709     unsigned int i;
 710
 711     i = port_id / 32;
 712     vser->ports_map[i] |= 1U << (port_id % 32);
 713 }
 714
 715 static void add_port(VirtIOSerial *vser, uint32_t port_id)
 716 {
 717     mark_port_added(vser, port_id);
 718
 719     send_control_event(find_port_by_id(vser, port_id),
 720                        VIRTIO_CONSOLE_PORT_ADD, 1);
 721 }
 722
 723 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 724 {
 725     VirtIOSerialPort *port;
 726     unsigned int i;
 727
 728     i = port_id / 32;
 729     vser->ports_map[i] &= ~(1U << (port_id % 32));
 730
 731     port = find_port_by_id(vser, port_id);
 732     /* Flush out any unconsumed buffers first */
 733     discard_vq_data(port->ovq, &port->vser->vdev);
 734
 735     send_control_event(port, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 736 }
 737
 738 static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
 739 {
 740     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 741     VirtIOSerialPortInfo *info = DO_UPCAST(VirtIOSerialPortInfo, qdev, base);
 742     VirtIOSerialBus *bus = DO_UPCAST(VirtIOSerialBus, qbus, qdev->parent_bus);
 743     int ret, max_nr_ports;
 744     bool plugging_port0;
 745
 746     port->vser = bus->vser;
 747     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 748
 749     /*
 750      * Is the first console port we're seeing? If so, put it up at
 751      * location 0. This is done for backward compatibility (old
 752      * kernel, new qemu).
 753      */
 754     plugging_port0 = info->is_console && !find_port_by_id(port->vser, 0);
 755
 756     if (find_port_by_id(port->vser, port->id)) {
 757         error_report("virtio-serial-bus: A port already exists at id %u",
 758                      port->id);
 759         return -1;
 760     }
 761
 762     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 763         if (plugging_port0) {
 764             port->id = 0;
 765         } else {
 766             port->id = find_free_port_id(port->vser);
 767             if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 768                 error_report("virtio-serial-bus: Maximum port limit for this device reached");
 769                 return -1;
 770             }
 771         }
 772     }
 773
 774     max_nr_ports = tswap32(port->vser->config.max_nr_ports);
 775     if (port->id >= max_nr_ports) {
 776         error_report("virtio-serial-bus: Out-of-range port id specified, max. allowed: %u",
 777                      max_nr_ports - 1);
 778         return -1;
 779     }
 780
 781     ret = info->init(port);
 782     if (ret) {
 783         return ret;
 784     }
 785
 786     if (!use_multiport(port->vser)) {
 787         /*
 788          * Allow writes to guest in this case; we have no way of
 789          * knowing if a guest port is connected.
 790          */
 791         port->guest_connected = true;
 792     }
 793
 794     port->elem.out_num = 0;
 795
 796     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
 797     port->ivq = port->vser->ivqs[port->id];
 798     port->ovq = port->vser->ovqs[port->id];
 799
 800     add_port(port->vser, port->id);
 801
 802     /* Send an update to the guest about this new port added */
 803     virtio_notify_config(&port->vser->vdev);
 804
 805     return ret;
 806 }
 807
 808 static int virtser_port_qdev_exit(DeviceState *qdev)
 809 {
 810     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 811     VirtIOSerialPortInfo *info = DO_UPCAST(VirtIOSerialPortInfo, qdev,
 812                                            port->dev.info);
 813     VirtIOSerial *vser = port->vser;
 814
 815     qemu_bh_delete(port->bh);
 816     remove_port(port->vser, port->id);
 817
 818     QTAILQ_REMOVE(&vser->ports, port, next);
 819
 820     if (info->exit) {
 821         info->exit(port);
 822     }
 823     return 0;
 824 }
 825
 826 void virtio_serial_port_qdev_register(VirtIOSerialPortInfo *info)
 827 {
 828     info->qdev.init = virtser_port_qdev_init;
 829     info->qdev.bus_info = &virtser_bus_info;
 830     info->qdev.exit = virtser_port_qdev_exit;
 831     info->qdev.unplug = qdev_simple_unplug_cb;
 832     qdev_register(&info->qdev);
 833 }
 834
 835 VirtIODevice *virtio_serial_init(DeviceState *dev, virtio_serial_conf *conf)
 836 {
 837     VirtIOSerial *vser;
 838     VirtIODevice *vdev;
 839     uint32_t i, max_supported_ports;
 840
 841     if (!conf->max_virtserial_ports)
 842         return NULL;
 843
 844     /* Each port takes 2 queues, and one pair is for the control queue */
 845     max_supported_ports = VIRTIO_PCI_QUEUE_MAX / 2 - 1;
 846
 847     if (conf->max_virtserial_ports > max_supported_ports) {
 848         error_report("maximum ports supported: %u", max_supported_ports);
 849         return NULL;
 850     }
 851
 852     vdev = virtio_common_init("virtio-serial", VIRTIO_ID_CONSOLE,
 853                               sizeof(struct virtio_console_config),
 854                               sizeof(VirtIOSerial));
 855
 856     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 857
 858     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
 859     qbus_create_inplace(&vser->bus.qbus, &virtser_bus_info, dev, NULL);
 860     vser->bus.qbus.allow_hotplug = 1;
 861     vser->bus.vser = vser;
 862     QTAILQ_INIT(&vser->ports);
 863
 864     vser->bus.max_nr_ports = conf->max_virtserial_ports;
 865     vser->ivqs = qemu_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 866     vser->ovqs = qemu_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 867
 868     /* Add a queue for host to guest transfers for port 0 (backward compat) */
 869     vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
 870     /* Add a queue for guest to host transfers for port 0 (backward compat) */
 871     vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
 872
 873     /* TODO: host to guest notifications can get dropped
 874      * if the queue fills up. Implement queueing in host,
 875      * this might also make it possible to reduce the control
 876      * queue size: as guest preposts buffers there,
 877      * this will save 4Kbyte of guest memory per entry. */
 878
 879     /* control queue: host to guest */
 880     vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
 881     /* control queue: guest to host */
 882     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
 883
 884     for (i = 1; i < vser->bus.max_nr_ports; i++) {
 885         /* Add a per-port queue for host to guest transfers */
 886         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
 887         /* Add a per-per queue for guest to host transfers */
 888         vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
 889     }
 890
 891     vser->config.max_nr_ports = tswap32(conf->max_virtserial_ports);
 892     vser->ports_map = qemu_mallocz(((conf->max_virtserial_ports + 31) / 32)
 893         * sizeof(vser->ports_map[0]));
 894     /*
 895      * Reserve location 0 for a console port for backward compat
 896      * (old kernel, new qemu)
 897      */
 898     mark_port_added(vser, 0);
 899
 900     vser->vdev.get_features = get_features;
 901     vser->vdev.get_config = get_config;
 902     vser->vdev.set_config = set_config;
 903
 904     vser->qdev = dev;
 905
 906     /*
 907      * Register for the savevm section with the virtio-console name
 908      * to preserve backward compat
 909      */
 910     register_savevm(dev, "virtio-console", -1, 3, virtio_serial_save,
 911                     virtio_serial_load, vser);
 912
 913     return vdev;
 914 }
 915
 916 void virtio_serial_exit(VirtIODevice *vdev)
 917 {
 918     VirtIOSerial *vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 919
 920     unregister_savevm(vser->qdev, "virtio-console", vser);
 921
 922     qemu_free(vser->ivqs);
 923     qemu_free(vser->ovqs);
 924     qemu_free(vser->ports_map);
 925
 926     virtio_cleanup(vdev);
 927 }