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                 /*
 167                  * this is a temporary check until chardevs can signal to
 168                  * frontends that they are writable again. This prevents
 169                  * the console from going into throttled mode (forever)
 170                  * if virtio-console is connected to a pty without a
 171                  * listener. Otherwise the guest spins forever.
 172                  * We can revert this if
 173                  * 1: chardevs can notify frondends
 174                  * 2: the guest driver does not spin in these cases
 175                  */
 176                 if (!info->is_console) {
 177                     virtio_serial_throttle_port(port, true);
 178                 }
 179                 port->iov_idx = i;
 180                 if (ret > 0) {
 181                     port->iov_offset += ret;
 182                 }
 183                 break;
 184             }
 185             port->iov_offset = 0;
 186         }
 187         if (port->throttled) {
 188             break;
 189         }
 190         virtqueue_push(vq, &port->elem, 0);
 191         port->elem.out_num = 0;
 192     }
 193     virtio_notify(vdev, vq);
 194 }
 195
 196 static void flush_queued_data(VirtIOSerialPort *port)
 197 {
 198     assert(port);
 199
 200     if (!virtio_queue_ready(port->ovq)) {
 201         return;
 202     }
 203     do_flush_queued_data(port, port->ovq, &port->vser->vdev);
 204 }
 205
 206 static size_t send_control_msg(VirtIOSerialPort *port, void *buf, size_t len)
 207 {
 208     VirtQueueElement elem;
 209     VirtQueue *vq;
 210     struct virtio_console_control *cpkt;
 211
 212     vq = port->vser->c_ivq;
 213     if (!virtio_queue_ready(vq)) {
 214         return 0;
 215     }
 216     if (!virtqueue_pop(vq, &elem)) {
 217         return 0;
 218     }
 219
 220     cpkt = (struct virtio_console_control *)buf;
 221     stl_p(&cpkt->id, port->id);
 222     memcpy(elem.in_sg[0].iov_base, buf, len);
 223
 224     virtqueue_push(vq, &elem, len);
 225     virtio_notify(&port->vser->vdev, vq);
 226     return len;
 227 }
 228
 229 static size_t send_control_event(VirtIOSerialPort *port, uint16_t event,
 230                                  uint16_t value)
 231 {
 232     struct virtio_console_control cpkt;
 233
 234     stw_p(&cpkt.event, event);
 235     stw_p(&cpkt.value, value);
 236
 237     trace_virtio_serial_send_control_event(port->id, event, value);
 238     return send_control_msg(port, &cpkt, sizeof(cpkt));
 239 }
 240
 241 /* Functions for use inside qemu to open and read from/write to ports */
 242 int virtio_serial_open(VirtIOSerialPort *port)
 243 {
 244     /* Don't allow opening an already-open port */
 245     if (port->host_connected) {
 246         return 0;
 247     }
 248     /* Send port open notification to the guest */
 249     port->host_connected = true;
 250     send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
 251
 252     return 0;
 253 }
 254
 255 int virtio_serial_close(VirtIOSerialPort *port)
 256 {
 257     port->host_connected = false;
 258     /*
 259      * If there's any data the guest sent which the app didn't
 260      * consume, reset the throttling flag and discard the data.
 261      */
 262     port->throttled = false;
 263     discard_vq_data(port->ovq, &port->vser->vdev);
 264
 265     send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
 266
 267     return 0;
 268 }
 269
 270 /* Individual ports/apps call this function to write to the guest. */
 271 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 272                             size_t size)
 273 {
 274     if (!port || !port->host_connected || !port->guest_connected) {
 275         return 0;
 276     }
 277     return write_to_port(port, buf, size);
 278 }
 279
 280 /*
 281  * Readiness of the guest to accept data on a port.
 282  * Returns max. data the guest can receive
 283  */
 284 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 285 {
 286     VirtQueue *vq = port->ivq;
 287
 288     if (!virtio_queue_ready(vq) ||
 289         !(port->vser->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 290         virtio_queue_empty(vq)) {
 291         return 0;
 292     }
 293     if (use_multiport(port->vser) && !port->guest_connected) {
 294         return 0;
 295     }
 296
 297     if (virtqueue_avail_bytes(vq, 4096, 0)) {
 298         return 4096;
 299     }
 300     if (virtqueue_avail_bytes(vq, 1, 0)) {
 301         return 1;
 302     }
 303     return 0;
 304 }
 305
 306 static void flush_queued_data_bh(void *opaque)
 307 {
 308     VirtIOSerialPort *port = opaque;
 309
 310     flush_queued_data(port);
 311 }
 312
 313 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 314 {
 315     if (!port) {
 316         return;
 317     }
 318
 319     trace_virtio_serial_throttle_port(port->id, throttle);
 320     port->throttled = throttle;
 321     if (throttle) {
 322         return;
 323     }
 324     qemu_bh_schedule(port->bh);
 325 }
 326
 327 /* Guest wants to notify us of some event */
 328 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 329 {
 330     struct VirtIOSerialPort *port;
 331     struct VirtIOSerialPortInfo *info;
 332     struct virtio_console_control cpkt, *gcpkt;
 333     uint8_t *buffer;
 334     size_t buffer_len;
 335
 336     gcpkt = buf;
 337
 338     if (len < sizeof(cpkt)) {
 339         /* The guest sent an invalid control packet */
 340         return;
 341     }
 342
 343     cpkt.event = lduw_p(&gcpkt->event);
 344     cpkt.value = lduw_p(&gcpkt->value);
 345
 346     trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 347
 348     if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 349         if (!cpkt.value) {
 350             error_report("virtio-serial-bus: Guest failure in adding device %s",
 351                          vser->bus.qbus.name);
 352             return;
 353         }
 354         /*
 355          * The device is up, we can now tell the device about all the
 356          * ports we have here.
 357          */
 358         QTAILQ_FOREACH(port, &vser->ports, next) {
 359             send_control_event(port, VIRTIO_CONSOLE_PORT_ADD, 1);
 360         }
 361         return;
 362     }
 363
 364     port = find_port_by_id(vser, ldl_p(&gcpkt->id));
 365     if (!port) {
 366         error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 367                      ldl_p(&gcpkt->id), vser->bus.qbus.name);
 368         return;
 369     }
 370
 371     trace_virtio_serial_handle_control_message_port(port->id);
 372
 373     info = DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info);
 374
 375     switch(cpkt.event) {
 376     case VIRTIO_CONSOLE_PORT_READY:
 377         if (!cpkt.value) {
 378             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 379                          port->id, vser->bus.qbus.name);
 380             break;
 381         }
 382         /*
 383          * Now that we know the guest asked for the port name, we're
 384          * sure the guest has initialised whatever state is necessary
 385          * for this port. Now's a good time to let the guest know if
 386          * this port is a console port so that the guest can hook it
 387          * up to hvc.
 388          */
 389         if (info->is_console) {
 390             send_control_event(port, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 391         }
 392
 393         if (port->name) {
 394             stw_p(&cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 395             stw_p(&cpkt.value, 1);
 396
 397             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 398             buffer = g_malloc(buffer_len);
 399
 400             memcpy(buffer, &cpkt, sizeof(cpkt));
 401             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 402             buffer[buffer_len - 1] = 0;
 403
 404             send_control_msg(port, buffer, buffer_len);
 405             g_free(buffer);
 406         }
 407
 408         if (port->host_connected) {
 409             send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
 410         }
 411
 412         /*
 413          * When the guest has asked us for this information it means
 414          * the guest is all setup and has its virtqueues
 415          * initialised. If some app is interested in knowing about
 416          * this event, let it know.
 417          */
 418         if (info->guest_ready) {
 419             info->guest_ready(port);
 420         }
 421         break;
 422
 423     case VIRTIO_CONSOLE_PORT_OPEN:
 424         port->guest_connected = cpkt.value;
 425         if (cpkt.value && info->guest_open) {
 426             /* Send the guest opened notification if an app is interested */
 427             info->guest_open(port);
 428         }
 429
 430         if (!cpkt.value && info->guest_close) {
 431             /* Send the guest closed notification if an app is interested */
 432             info->guest_close(port);
 433         }
 434         break;
 435     }
 436 }
 437
 438 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 439 {
 440 }
 441
 442 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 443 {
 444     VirtQueueElement elem;
 445     VirtIOSerial *vser;
 446     uint8_t *buf;
 447     size_t len;
 448
 449     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 450
 451     len = 0;
 452     buf = NULL;
 453     while (virtqueue_pop(vq, &elem)) {
 454         size_t cur_len, copied;
 455
 456         cur_len = iov_size(elem.out_sg, elem.out_num);
 457         /*
 458          * Allocate a new buf only if we didn't have one previously or
 459          * if the size of the buf differs
 460          */
 461         if (cur_len > len) {
 462             g_free(buf);
 463
 464             buf = g_malloc(cur_len);
 465             len = cur_len;
 466         }
 467         copied = iov_to_buf(elem.out_sg, elem.out_num, buf, 0, len);
 468
 469         handle_control_message(vser, buf, copied);
 470         virtqueue_push(vq, &elem, 0);
 471     }
 472     g_free(buf);
 473     virtio_notify(vdev, vq);
 474 }
 475
 476 /* Guest wrote something to some port. */
 477 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 478 {
 479     VirtIOSerial *vser;
 480     VirtIOSerialPort *port;
 481
 482     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 483     port = find_port_by_vq(vser, vq);
 484
 485     if (!port || !port->host_connected) {
 486         discard_vq_data(vq, vdev);
 487         return;
 488     }
 489
 490     if (!port->throttled) {
 491         do_flush_queued_data(port, vq, vdev);
 492         return;
 493     }
 494 }
 495
 496 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 497 {
 498 }
 499
 500 static uint32_t get_features(VirtIODevice *vdev, uint32_t features)
 501 {
 502     VirtIOSerial *vser;
 503
 504     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 505
 506     if (vser->bus.max_nr_ports > 1) {
 507         features |= (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 508     }
 509     return features;
 510 }
 511
 512 /* Guest requested config info */
 513 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 514 {
 515     VirtIOSerial *vser;
 516
 517     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 518     memcpy(config_data, &vser->config, sizeof(struct virtio_console_config));
 519 }
 520
 521 static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
 522 {
 523     struct virtio_console_config config;
 524
 525     memcpy(&config, config_data, sizeof(config));
 526 }
 527
 528 static void virtio_serial_save(QEMUFile *f, void *opaque)
 529 {
 530     VirtIOSerial *s = opaque;
 531     VirtIOSerialPort *port;
 532     uint32_t nr_active_ports;
 533     unsigned int i, max_nr_ports;
 534
 535     /* The virtio device */
 536     virtio_save(&s->vdev, f);
 537
 538     /* The config space */
 539     qemu_put_be16s(f, &s->config.cols);
 540     qemu_put_be16s(f, &s->config.rows);
 541
 542     qemu_put_be32s(f, &s->config.max_nr_ports);
 543
 544     /* The ports map */
 545     max_nr_ports = tswap32(s->config.max_nr_ports);
 546     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 547         qemu_put_be32s(f, &s->ports_map[i]);
 548     }
 549
 550     /* Ports */
 551
 552     nr_active_ports = 0;
 553     QTAILQ_FOREACH(port, &s->ports, next) {
 554         nr_active_ports++;
 555     }
 556
 557     qemu_put_be32s(f, &nr_active_ports);
 558
 559     /*
 560      * Items in struct VirtIOSerialPort.
 561      */
 562     QTAILQ_FOREACH(port, &s->ports, next) {
 563         uint32_t elem_popped;
 564
 565         qemu_put_be32s(f, &port->id);
 566         qemu_put_byte(f, port->guest_connected);
 567         qemu_put_byte(f, port->host_connected);
 568
 569         elem_popped = 0;
 570         if (port->elem.out_num) {
 571             elem_popped = 1;
 572         }
 573         qemu_put_be32s(f, &elem_popped);
 574         if (elem_popped) {
 575             qemu_put_be32s(f, &port->iov_idx);
 576             qemu_put_be64s(f, &port->iov_offset);
 577
 578             qemu_put_buffer(f, (unsigned char *)&port->elem,
 579                             sizeof(port->elem));
 580         }
 581     }
 582 }
 583
 584 static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
 585 {
 586     VirtIOSerial *s = opaque;
 587     VirtIOSerialPort *port;
 588     uint32_t max_nr_ports, nr_active_ports, ports_map;
 589     unsigned int i;
 590
 591     if (version_id > 3) {
 592         return -EINVAL;
 593     }
 594
 595     /* The virtio device */
 596     virtio_load(&s->vdev, f);
 597
 598     if (version_id < 2) {
 599         return 0;
 600     }
 601
 602     /* The config space */
 603     qemu_get_be16s(f, &s->config.cols);
 604     qemu_get_be16s(f, &s->config.rows);
 605
 606     qemu_get_be32s(f, &max_nr_ports);
 607     tswap32s(&max_nr_ports);
 608     if (max_nr_ports > tswap32(s->config.max_nr_ports)) {
 609         /* Source could have had more ports than us. Fail migration. */
 610         return -EINVAL;
 611     }
 612
 613     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 614         qemu_get_be32s(f, &ports_map);
 615
 616         if (ports_map != s->ports_map[i]) {
 617             /*
 618              * Ports active on source and destination don't
 619              * match. Fail migration.
 620              */
 621             return -EINVAL;
 622         }
 623     }
 624
 625     qemu_get_be32s(f, &nr_active_ports);
 626
 627     /* Items in struct VirtIOSerialPort */
 628     for (i = 0; i < nr_active_ports; i++) {
 629         uint32_t id;
 630         bool host_connected;
 631
 632         id = qemu_get_be32(f);
 633         port = find_port_by_id(s, id);
 634         if (!port) {
 635             return -EINVAL;
 636         }
 637
 638         port->guest_connected = qemu_get_byte(f);
 639         host_connected = qemu_get_byte(f);
 640         if (host_connected != port->host_connected) {
 641             /*
 642              * We have to let the guest know of the host connection
 643              * status change
 644              */
 645             send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN,
 646                                port->host_connected);
 647         }
 648
 649         if (version_id > 2) {
 650             uint32_t elem_popped;
 651
 652             qemu_get_be32s(f, &elem_popped);
 653             if (elem_popped) {
 654                 qemu_get_be32s(f, &port->iov_idx);
 655                 qemu_get_be64s(f, &port->iov_offset);
 656
 657                 qemu_get_buffer(f, (unsigned char *)&port->elem,
 658                                 sizeof(port->elem));
 659                 virtqueue_map_sg(port->elem.in_sg, port->elem.in_addr,
 660                                  port->elem.in_num, 1);
 661                 virtqueue_map_sg(port->elem.out_sg, port->elem.out_addr,
 662                                  port->elem.out_num, 1);
 663
 664                 /*
 665                  *  Port was throttled on source machine.  Let's
 666                  *  unthrottle it here so data starts flowing again.
 667                  */
 668                 virtio_serial_throttle_port(port, false);
 669             }
 670         }
 671     }
 672     return 0;
 673 }
 674
 675 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 676
 677 static struct BusInfo virtser_bus_info = {
 678     .name      = "virtio-serial-bus",
 679     .size      = sizeof(VirtIOSerialBus),
 680     .print_dev = virtser_bus_dev_print,
 681     .props      = (Property[]) {
 682         DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 683         DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 684         DEFINE_PROP_END_OF_LIST()
 685     }
 686 };
 687
 688 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 689 {
 690     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 691
 692     monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 693                    indent, "", port->id,
 694                    port->guest_connected ? "on" : "off",
 695                    port->host_connected ? "on" : "off",
 696                    port->throttled ? "on" : "off");
 697 }
 698
 699 /* This function is only used if a port id is not provided by the user */
 700 static uint32_t find_free_port_id(VirtIOSerial *vser)
 701 {
 702     unsigned int i, max_nr_ports;
 703
 704     max_nr_ports = tswap32(vser->config.max_nr_ports);
 705     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 706         uint32_t map, bit;
 707
 708         map = vser->ports_map[i];
 709         bit = ffs(~map);
 710         if (bit) {
 711             return (bit - 1) + i * 32;
 712         }
 713     }
 714     return VIRTIO_CONSOLE_BAD_ID;
 715 }
 716
 717 static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 718 {
 719     unsigned int i;
 720
 721     i = port_id / 32;
 722     vser->ports_map[i] |= 1U << (port_id % 32);
 723 }
 724
 725 static void add_port(VirtIOSerial *vser, uint32_t port_id)
 726 {
 727     mark_port_added(vser, port_id);
 728
 729     send_control_event(find_port_by_id(vser, port_id),
 730                        VIRTIO_CONSOLE_PORT_ADD, 1);
 731 }
 732
 733 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 734 {
 735     VirtIOSerialPort *port;
 736     unsigned int i;
 737
 738     i = port_id / 32;
 739     vser->ports_map[i] &= ~(1U << (port_id % 32));
 740
 741     port = find_port_by_id(vser, port_id);
 742     /* Flush out any unconsumed buffers first */
 743     discard_vq_data(port->ovq, &port->vser->vdev);
 744
 745     send_control_event(port, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 746 }
 747
 748 static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
 749 {
 750     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 751     VirtIOSerialPortInfo *info = DO_UPCAST(VirtIOSerialPortInfo, qdev, base);
 752     VirtIOSerialBus *bus = DO_UPCAST(VirtIOSerialBus, qbus, qdev->parent_bus);
 753     int ret, max_nr_ports;
 754     bool plugging_port0;
 755
 756     port->vser = bus->vser;
 757     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 758
 759     assert(info->have_data);
 760
 761     /*
 762      * Is the first console port we're seeing? If so, put it up at
 763      * location 0. This is done for backward compatibility (old
 764      * kernel, new qemu).
 765      */
 766     plugging_port0 = info->is_console && !find_port_by_id(port->vser, 0);
 767
 768     if (find_port_by_id(port->vser, port->id)) {
 769         error_report("virtio-serial-bus: A port already exists at id %u",
 770                      port->id);
 771         return -1;
 772     }
 773
 774     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 775         if (plugging_port0) {
 776             port->id = 0;
 777         } else {
 778             port->id = find_free_port_id(port->vser);
 779             if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 780                 error_report("virtio-serial-bus: Maximum port limit for this device reached");
 781                 return -1;
 782             }
 783         }
 784     }
 785
 786     max_nr_ports = tswap32(port->vser->config.max_nr_ports);
 787     if (port->id >= max_nr_ports) {
 788         error_report("virtio-serial-bus: Out-of-range port id specified, max. allowed: %u",
 789                      max_nr_ports - 1);
 790         return -1;
 791     }
 792
 793     ret = info->init(port);
 794     if (ret) {
 795         return ret;
 796     }
 797
 798     if (!use_multiport(port->vser)) {
 799         /*
 800          * Allow writes to guest in this case; we have no way of
 801          * knowing if a guest port is connected.
 802          */
 803         port->guest_connected = true;
 804     }
 805
 806     port->elem.out_num = 0;
 807
 808     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
 809     port->ivq = port->vser->ivqs[port->id];
 810     port->ovq = port->vser->ovqs[port->id];
 811
 812     add_port(port->vser, port->id);
 813
 814     /* Send an update to the guest about this new port added */
 815     virtio_notify_config(&port->vser->vdev);
 816
 817     return ret;
 818 }
 819
 820 static int virtser_port_qdev_exit(DeviceState *qdev)
 821 {
 822     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 823     VirtIOSerialPortInfo *info = DO_UPCAST(VirtIOSerialPortInfo, qdev,
 824                                            port->dev.info);
 825     VirtIOSerial *vser = port->vser;
 826
 827     qemu_bh_delete(port->bh);
 828     remove_port(port->vser, port->id);
 829
 830     QTAILQ_REMOVE(&vser->ports, port, next);
 831
 832     if (info->exit) {
 833         info->exit(port);
 834     }
 835     return 0;
 836 }
 837
 838 void virtio_serial_port_qdev_register(VirtIOSerialPortInfo *info)
 839 {
 840     info->qdev.init = virtser_port_qdev_init;
 841     info->qdev.bus_info = &virtser_bus_info;
 842     info->qdev.exit = virtser_port_qdev_exit;
 843     info->qdev.unplug = qdev_simple_unplug_cb;
 844     qdev_register(&info->qdev);
 845 }
 846
 847 VirtIODevice *virtio_serial_init(DeviceState *dev, virtio_serial_conf *conf)
 848 {
 849     VirtIOSerial *vser;
 850     VirtIODevice *vdev;
 851     uint32_t i, max_supported_ports;
 852
 853     if (!conf->max_virtserial_ports)
 854         return NULL;
 855
 856     /* Each port takes 2 queues, and one pair is for the control queue */
 857     max_supported_ports = VIRTIO_PCI_QUEUE_MAX / 2 - 1;
 858
 859     if (conf->max_virtserial_ports > max_supported_ports) {
 860         error_report("maximum ports supported: %u", max_supported_ports);
 861         return NULL;
 862     }
 863
 864     vdev = virtio_common_init("virtio-serial", VIRTIO_ID_CONSOLE,
 865                               sizeof(struct virtio_console_config),
 866                               sizeof(VirtIOSerial));
 867
 868     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 869
 870     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
 871     qbus_create_inplace(&vser->bus.qbus, &virtser_bus_info, dev, NULL);
 872     vser->bus.qbus.allow_hotplug = 1;
 873     vser->bus.vser = vser;
 874     QTAILQ_INIT(&vser->ports);
 875
 876     vser->bus.max_nr_ports = conf->max_virtserial_ports;
 877     vser->ivqs = g_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 878     vser->ovqs = g_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 879
 880     /* Add a queue for host to guest transfers for port 0 (backward compat) */
 881     vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
 882     /* Add a queue for guest to host transfers for port 0 (backward compat) */
 883     vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
 884
 885     /* TODO: host to guest notifications can get dropped
 886      * if the queue fills up. Implement queueing in host,
 887      * this might also make it possible to reduce the control
 888      * queue size: as guest preposts buffers there,
 889      * this will save 4Kbyte of guest memory per entry. */
 890
 891     /* control queue: host to guest */
 892     vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
 893     /* control queue: guest to host */
 894     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
 895
 896     for (i = 1; i < vser->bus.max_nr_ports; i++) {
 897         /* Add a per-port queue for host to guest transfers */
 898         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
 899         /* Add a per-per queue for guest to host transfers */
 900         vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
 901     }
 902
 903     vser->config.max_nr_ports = tswap32(conf->max_virtserial_ports);
 904     vser->ports_map = g_malloc0(((conf->max_virtserial_ports + 31) / 32)
 905         * sizeof(vser->ports_map[0]));
 906     /*
 907      * Reserve location 0 for a console port for backward compat
 908      * (old kernel, new qemu)
 909      */
 910     mark_port_added(vser, 0);
 911
 912     vser->vdev.get_features = get_features;
 913     vser->vdev.get_config = get_config;
 914     vser->vdev.set_config = set_config;
 915
 916     vser->qdev = dev;
 917
 918     /*
 919      * Register for the savevm section with the virtio-console name
 920      * to preserve backward compat
 921      */
 922     register_savevm(dev, "virtio-console", -1, 3, virtio_serial_save,
 923                     virtio_serial_load, vser);
 924
 925     return vdev;
 926 }
 927
 928 void virtio_serial_exit(VirtIODevice *vdev)
 929 {
 930     VirtIOSerial *vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 931
 932     unregister_savevm(vser->qdev, "virtio-console", vser);
 933
 934     g_free(vser->ivqs);
 935     g_free(vser->ovqs);
 936     g_free(vser->ports_map);
 937
 938     virtio_cleanup(vdev);
 939 }