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  * 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 "iov.h"
  22 #include "monitor.h"
  23 #include "qemu-queue.h"
  24 #include "sysbus.h"
  25 #include "trace.h"
  26 #include "virtio-serial.h"
  27
  28 /* The virtio-serial bus on top of which the ports will ride as devices */
  29 struct VirtIOSerialBus {
  30     BusState qbus;
  31
  32     /* This is the parent device that provides the bus for ports. */
  33     VirtIOSerial *vser;
  34
  35     /* The maximum number of ports that can ride on top of this bus */
  36     uint32_t max_nr_ports;
  37 };
  38
  39 struct VirtIOSerial {
  40     VirtIODevice vdev;
  41
  42     VirtQueue *c_ivq, *c_ovq;
  43     /* Arrays of ivqs and ovqs: one per port */
  44     VirtQueue **ivqs, **ovqs;
  45
  46     VirtIOSerialBus bus;
  47
  48     DeviceState *qdev;
  49
  50     QTAILQ_HEAD(, VirtIOSerialPort) ports;
  51
  52     /* bitmap for identifying active ports */
  53     uint32_t *ports_map;
  54
  55     struct virtio_console_config config;
  56
  57     struct {
  58         QEMUTimer *timer;
  59         int nr_active_ports;
  60         struct {
  61             VirtIOSerialPort *port;
  62             uint8_t host_connected;
  63         } *connected;
  64     } post_load;
  65 };
  66
  67 static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
  68 {
  69     VirtIOSerialPort *port;
  70
  71     if (id == VIRTIO_CONSOLE_BAD_ID) {
  72         return NULL;
  73     }
  74
  75     QTAILQ_FOREACH(port, &vser->ports, next) {
  76         if (port->id == id)
  77             return port;
  78     }
  79     return NULL;
  80 }
  81
  82 static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
  83 {
  84     VirtIOSerialPort *port;
  85
  86     QTAILQ_FOREACH(port, &vser->ports, next) {
  87         if (port->ivq == vq || port->ovq == vq)
  88             return port;
  89     }
  90     return NULL;
  91 }
  92
  93 static bool use_multiport(VirtIOSerial *vser)
  94 {
  95     return vser->vdev.guest_features & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
  96 }
  97
  98 static size_t write_to_port(VirtIOSerialPort *port,
  99                             const uint8_t *buf, size_t size)
 100 {
 101     VirtQueueElement elem;
 102     VirtQueue *vq;
 103     size_t offset;
 104
 105     vq = port->ivq;
 106     if (!virtio_queue_ready(vq)) {
 107         return 0;
 108     }
 109
 110     offset = 0;
 111     while (offset < size) {
 112         size_t len;
 113
 114         if (!virtqueue_pop(vq, &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     }
 124
 125     virtio_notify(&port->vser->vdev, vq);
 126     return offset;
 127 }
 128
 129 static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
 130 {
 131     VirtQueueElement elem;
 132
 133     if (!virtio_queue_ready(vq)) {
 134         return;
 135     }
 136     while (virtqueue_pop(vq, &elem)) {
 137         virtqueue_push(vq, &elem, 0);
 138     }
 139     virtio_notify(vdev, vq);
 140 }
 141
 142 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 143                                  VirtIODevice *vdev)
 144 {
 145     VirtIOSerialPortClass *vsc;
 146
 147     assert(port);
 148     assert(virtio_queue_ready(vq));
 149
 150     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 151
 152     while (!port->throttled) {
 153         unsigned int i;
 154
 155         /* Pop an elem only if we haven't left off a previous one mid-way */
 156         if (!port->elem.out_num) {
 157             if (!virtqueue_pop(vq, &port->elem)) {
 158                 break;
 159             }
 160             port->iov_idx = 0;
 161             port->iov_offset = 0;
 162         }
 163
 164         for (i = port->iov_idx; i < port->elem.out_num; i++) {
 165             size_t buf_size;
 166             ssize_t ret;
 167
 168             buf_size = port->elem.out_sg[i].iov_len - port->iov_offset;
 169             ret = vsc->have_data(port,
 170                                   port->elem.out_sg[i].iov_base
 171                                   + port->iov_offset,
 172                                   buf_size);
 173             if (ret < 0 && ret != -EAGAIN) {
 174                 /* We don't handle any other type of errors here */
 175                 abort();
 176             }
 177             if (ret == -EAGAIN || (ret >= 0 && ret < buf_size)) {
 178                 /*
 179                  * this is a temporary check until chardevs can signal to
 180                  * frontends that they are writable again. This prevents
 181                  * the console from going into throttled mode (forever)
 182                  * if virtio-console is connected to a pty without a
 183                  * listener. Otherwise the guest spins forever.
 184                  * We can revert this if
 185                  * 1: chardevs can notify frondends
 186                  * 2: the guest driver does not spin in these cases
 187                  */
 188                 if (!vsc->is_console) {
 189                     virtio_serial_throttle_port(port, true);
 190                 }
 191                 port->iov_idx = i;
 192                 if (ret > 0) {
 193                     port->iov_offset += ret;
 194                 }
 195                 break;
 196             }
 197             port->iov_offset = 0;
 198         }
 199         if (port->throttled) {
 200             break;
 201         }
 202         virtqueue_push(vq, &port->elem, 0);
 203         port->elem.out_num = 0;
 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, &port->vser->vdev);
 216 }
 217
 218 static size_t send_control_msg(VirtIOSerialPort *port, void *buf, size_t len)
 219 {
 220     VirtQueueElement elem;
 221     VirtQueue *vq;
 222     struct virtio_console_control *cpkt;
 223
 224     vq = port->vser->c_ivq;
 225     if (!virtio_queue_ready(vq)) {
 226         return 0;
 227     }
 228     if (!virtqueue_pop(vq, &elem)) {
 229         return 0;
 230     }
 231
 232     cpkt = (struct virtio_console_control *)buf;
 233     stl_p(&cpkt->id, port->id);
 234     memcpy(elem.in_sg[0].iov_base, buf, len);
 235
 236     virtqueue_push(vq, &elem, len);
 237     virtio_notify(&port->vser->vdev, vq);
 238     return len;
 239 }
 240
 241 static size_t send_control_event(VirtIOSerialPort *port, uint16_t event,
 242                                  uint16_t value)
 243 {
 244     struct virtio_console_control cpkt;
 245
 246     stw_p(&cpkt.event, event);
 247     stw_p(&cpkt.value, value);
 248
 249     trace_virtio_serial_send_control_event(port->id, event, value);
 250     return send_control_msg(port, &cpkt, sizeof(cpkt));
 251 }
 252
 253 /* Functions for use inside qemu to open and read from/write to ports */
 254 int virtio_serial_open(VirtIOSerialPort *port)
 255 {
 256     /* Don't allow opening an already-open port */
 257     if (port->host_connected) {
 258         return 0;
 259     }
 260     /* Send port open notification to the guest */
 261     port->host_connected = true;
 262     send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
 263
 264     return 0;
 265 }
 266
 267 int virtio_serial_close(VirtIOSerialPort *port)
 268 {
 269     port->host_connected = false;
 270     /*
 271      * If there's any data the guest sent which the app didn't
 272      * consume, reset the throttling flag and discard the data.
 273      */
 274     port->throttled = false;
 275     discard_vq_data(port->ovq, &port->vser->vdev);
 276
 277     send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
 278
 279     return 0;
 280 }
 281
 282 /* Individual ports/apps call this function to write to the guest. */
 283 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 284                             size_t size)
 285 {
 286     if (!port || !port->host_connected || !port->guest_connected) {
 287         return 0;
 288     }
 289     return write_to_port(port, buf, size);
 290 }
 291
 292 /*
 293  * Readiness of the guest to accept data on a port.
 294  * Returns max. data the guest can receive
 295  */
 296 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 297 {
 298     VirtQueue *vq = port->ivq;
 299     unsigned int bytes;
 300
 301     if (!virtio_queue_ready(vq) ||
 302         !(port->vser->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 303         virtio_queue_empty(vq)) {
 304         return 0;
 305     }
 306     if (use_multiport(port->vser) && !port->guest_connected) {
 307         return 0;
 308     }
 309     virtqueue_get_avail_bytes(vq, &bytes, NULL);
 310     return bytes;
 311 }
 312
 313 static void flush_queued_data_bh(void *opaque)
 314 {
 315     VirtIOSerialPort *port = opaque;
 316
 317     flush_queued_data(port);
 318 }
 319
 320 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 321 {
 322     if (!port) {
 323         return;
 324     }
 325
 326     trace_virtio_serial_throttle_port(port->id, throttle);
 327     port->throttled = throttle;
 328     if (throttle) {
 329         return;
 330     }
 331     qemu_bh_schedule(port->bh);
 332 }
 333
 334 /* Guest wants to notify us of some event */
 335 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 336 {
 337     struct VirtIOSerialPort *port;
 338     VirtIOSerialPortClass *vsc;
 339     struct virtio_console_control cpkt, *gcpkt;
 340     uint8_t *buffer;
 341     size_t buffer_len;
 342
 343     gcpkt = buf;
 344
 345     if (len < sizeof(cpkt)) {
 346         /* The guest sent an invalid control packet */
 347         return;
 348     }
 349
 350     cpkt.event = lduw_p(&gcpkt->event);
 351     cpkt.value = lduw_p(&gcpkt->value);
 352
 353     trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 354
 355     if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 356         if (!cpkt.value) {
 357             error_report("virtio-serial-bus: Guest failure in adding device %s",
 358                          vser->bus.qbus.name);
 359             return;
 360         }
 361         /*
 362          * The device is up, we can now tell the device about all the
 363          * ports we have here.
 364          */
 365         QTAILQ_FOREACH(port, &vser->ports, next) {
 366             send_control_event(port, VIRTIO_CONSOLE_PORT_ADD, 1);
 367         }
 368         return;
 369     }
 370
 371     port = find_port_by_id(vser, ldl_p(&gcpkt->id));
 372     if (!port) {
 373         error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 374                      ldl_p(&gcpkt->id), vser->bus.qbus.name);
 375         return;
 376     }
 377
 378     trace_virtio_serial_handle_control_message_port(port->id);
 379
 380     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 381
 382     switch(cpkt.event) {
 383     case VIRTIO_CONSOLE_PORT_READY:
 384         if (!cpkt.value) {
 385             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 386                          port->id, vser->bus.qbus.name);
 387             break;
 388         }
 389         /*
 390          * Now that we know the guest asked for the port name, we're
 391          * sure the guest has initialised whatever state is necessary
 392          * for this port. Now's a good time to let the guest know if
 393          * this port is a console port so that the guest can hook it
 394          * up to hvc.
 395          */
 396         if (vsc->is_console) {
 397             send_control_event(port, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 398         }
 399
 400         if (port->name) {
 401             stw_p(&cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 402             stw_p(&cpkt.value, 1);
 403
 404             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 405             buffer = g_malloc(buffer_len);
 406
 407             memcpy(buffer, &cpkt, sizeof(cpkt));
 408             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 409             buffer[buffer_len - 1] = 0;
 410
 411             send_control_msg(port, buffer, buffer_len);
 412             g_free(buffer);
 413         }
 414
 415         if (port->host_connected) {
 416             send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
 417         }
 418
 419         /*
 420          * When the guest has asked us for this information it means
 421          * the guest is all setup and has its virtqueues
 422          * initialised. If some app is interested in knowing about
 423          * this event, let it know.
 424          */
 425         if (vsc->guest_ready) {
 426             vsc->guest_ready(port);
 427         }
 428         break;
 429
 430     case VIRTIO_CONSOLE_PORT_OPEN:
 431         port->guest_connected = cpkt.value;
 432         if (cpkt.value && vsc->guest_open) {
 433             /* Send the guest opened notification if an app is interested */
 434             vsc->guest_open(port);
 435         }
 436
 437         if (!cpkt.value && vsc->guest_close) {
 438             /* Send the guest closed notification if an app is interested */
 439             vsc->guest_close(port);
 440         }
 441         break;
 442     }
 443 }
 444
 445 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 446 {
 447 }
 448
 449 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 450 {
 451     VirtQueueElement elem;
 452     VirtIOSerial *vser;
 453     uint8_t *buf;
 454     size_t len;
 455
 456     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 457
 458     len = 0;
 459     buf = NULL;
 460     while (virtqueue_pop(vq, &elem)) {
 461         size_t cur_len;
 462
 463         cur_len = iov_size(elem.out_sg, elem.out_num);
 464         /*
 465          * Allocate a new buf only if we didn't have one previously or
 466          * if the size of the buf differs
 467          */
 468         if (cur_len > len) {
 469             g_free(buf);
 470
 471             buf = g_malloc(cur_len);
 472             len = cur_len;
 473         }
 474         iov_to_buf(elem.out_sg, elem.out_num, 0, buf, cur_len);
 475
 476         handle_control_message(vser, buf, cur_len);
 477         virtqueue_push(vq, &elem, 0);
 478     }
 479     g_free(buf);
 480     virtio_notify(vdev, vq);
 481 }
 482
 483 /* Guest wrote something to some port. */
 484 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 485 {
 486     VirtIOSerial *vser;
 487     VirtIOSerialPort *port;
 488
 489     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 490     port = find_port_by_vq(vser, vq);
 491
 492     if (!port || !port->host_connected) {
 493         discard_vq_data(vq, vdev);
 494         return;
 495     }
 496
 497     if (!port->throttled) {
 498         do_flush_queued_data(port, vq, vdev);
 499         return;
 500     }
 501 }
 502
 503 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 504 {
 505 }
 506
 507 static uint32_t get_features(VirtIODevice *vdev, uint32_t features)
 508 {
 509     VirtIOSerial *vser;
 510
 511     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 512
 513     if (vser->bus.max_nr_ports > 1) {
 514         features |= (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 515     }
 516     return features;
 517 }
 518
 519 /* Guest requested config info */
 520 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 521 {
 522     VirtIOSerial *vser;
 523
 524     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 525     memcpy(config_data, &vser->config, sizeof(struct virtio_console_config));
 526 }
 527
 528 static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
 529 {
 530     struct virtio_console_config config;
 531
 532     memcpy(&config, config_data, sizeof(config));
 533 }
 534
 535 static void guest_reset(VirtIOSerial *vser)
 536 {
 537     VirtIOSerialPort *port;
 538     VirtIOSerialPortClass *vsc;
 539
 540     QTAILQ_FOREACH(port, &vser->ports, next) {
 541         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 542         if (port->guest_connected) {
 543             port->guest_connected = false;
 544
 545             if (vsc->guest_close)
 546                 vsc->guest_close(port);
 547         }
 548     }
 549 }
 550
 551 static void set_status(VirtIODevice *vdev, uint8_t status)
 552 {
 553     VirtIOSerial *vser;
 554     VirtIOSerialPort *port;
 555
 556     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 557     port = find_port_by_id(vser, 0);
 558
 559     if (port && !use_multiport(port->vser)
 560         && (status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 561         /*
 562          * Non-multiport guests won't be able to tell us guest
 563          * open/close status.  Such guests can only have a port at id
 564          * 0, so set guest_connected for such ports as soon as guest
 565          * is up.
 566          */
 567         port->guest_connected = true;
 568     }
 569     if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 570         guest_reset(vser);
 571     }
 572 }
 573
 574 static void vser_reset(VirtIODevice *vdev)
 575 {
 576     VirtIOSerial *vser;
 577
 578     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 579     guest_reset(vser);
 580 }
 581
 582 static void virtio_serial_save(QEMUFile *f, void *opaque)
 583 {
 584     VirtIOSerial *s = opaque;
 585     VirtIOSerialPort *port;
 586     uint32_t nr_active_ports;
 587     unsigned int i, max_nr_ports;
 588
 589     /* The virtio device */
 590     virtio_save(&s->vdev, f);
 591
 592     /* The config space */
 593     qemu_put_be16s(f, &s->config.cols);
 594     qemu_put_be16s(f, &s->config.rows);
 595
 596     qemu_put_be32s(f, &s->config.max_nr_ports);
 597
 598     /* The ports map */
 599     max_nr_ports = tswap32(s->config.max_nr_ports);
 600     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 601         qemu_put_be32s(f, &s->ports_map[i]);
 602     }
 603
 604     /* Ports */
 605
 606     nr_active_ports = 0;
 607     QTAILQ_FOREACH(port, &s->ports, next) {
 608         nr_active_ports++;
 609     }
 610
 611     qemu_put_be32s(f, &nr_active_ports);
 612
 613     /*
 614      * Items in struct VirtIOSerialPort.
 615      */
 616     QTAILQ_FOREACH(port, &s->ports, next) {
 617         uint32_t elem_popped;
 618
 619         qemu_put_be32s(f, &port->id);
 620         qemu_put_byte(f, port->guest_connected);
 621         qemu_put_byte(f, port->host_connected);
 622
 623         elem_popped = 0;
 624         if (port->elem.out_num) {
 625             elem_popped = 1;
 626         }
 627         qemu_put_be32s(f, &elem_popped);
 628         if (elem_popped) {
 629             qemu_put_be32s(f, &port->iov_idx);
 630             qemu_put_be64s(f, &port->iov_offset);
 631
 632             qemu_put_buffer(f, (unsigned char *)&port->elem,
 633                             sizeof(port->elem));
 634         }
 635     }
 636 }
 637
 638 static void virtio_serial_post_load_timer_cb(void *opaque)
 639 {
 640     int i;
 641     VirtIOSerial *s = opaque;
 642     VirtIOSerialPort *port;
 643     uint8_t host_connected;
 644
 645     for (i = 0 ; i < s->post_load.nr_active_ports; ++i) {
 646         port = s->post_load.connected[i].port;
 647         host_connected = s->post_load.connected[i].host_connected;
 648         if (host_connected != port->host_connected) {
 649             /*
 650              * We have to let the guest know of the host connection
 651              * status change
 652              */
 653             send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN,
 654                                port->host_connected);
 655         }
 656     }
 657     g_free(s->post_load.connected);
 658     s->post_load.connected = NULL;
 659 }
 660
 661 static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
 662 {
 663     VirtIOSerial *s = opaque;
 664     VirtIOSerialPort *port;
 665     uint32_t max_nr_ports, nr_active_ports, ports_map;
 666     unsigned int i;
 667     int ret;
 668
 669     if (version_id > 3) {
 670         return -EINVAL;
 671     }
 672
 673     /* The virtio device */
 674     ret = virtio_load(&s->vdev, f);
 675     if (ret) {
 676         return ret;
 677     }
 678
 679     if (version_id < 2) {
 680         return 0;
 681     }
 682
 683     /* The config space */
 684     qemu_get_be16s(f, &s->config.cols);
 685     qemu_get_be16s(f, &s->config.rows);
 686
 687     qemu_get_be32s(f, &max_nr_ports);
 688     tswap32s(&max_nr_ports);
 689     if (max_nr_ports > tswap32(s->config.max_nr_ports)) {
 690         /* Source could have had more ports than us. Fail migration. */
 691         return -EINVAL;
 692     }
 693
 694     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 695         qemu_get_be32s(f, &ports_map);
 696
 697         if (ports_map != s->ports_map[i]) {
 698             /*
 699              * Ports active on source and destination don't
 700              * match. Fail migration.
 701              */
 702             return -EINVAL;
 703         }
 704     }
 705
 706     qemu_get_be32s(f, &nr_active_ports);
 707
 708     s->post_load.nr_active_ports = nr_active_ports;
 709     s->post_load.connected =
 710         g_malloc0(sizeof(*s->post_load.connected) * nr_active_ports);
 711
 712     /* Items in struct VirtIOSerialPort */
 713     for (i = 0; i < nr_active_ports; i++) {
 714         uint32_t id;
 715
 716         id = qemu_get_be32(f);
 717         port = find_port_by_id(s, id);
 718         if (!port) {
 719             return -EINVAL;
 720         }
 721
 722         port->guest_connected = qemu_get_byte(f);
 723         s->post_load.connected[i].port = port;
 724         s->post_load.connected[i].host_connected = qemu_get_byte(f);
 725
 726         if (version_id > 2) {
 727             uint32_t elem_popped;
 728
 729             qemu_get_be32s(f, &elem_popped);
 730             if (elem_popped) {
 731                 qemu_get_be32s(f, &port->iov_idx);
 732                 qemu_get_be64s(f, &port->iov_offset);
 733
 734                 qemu_get_buffer(f, (unsigned char *)&port->elem,
 735                                 sizeof(port->elem));
 736                 virtqueue_map_sg(port->elem.in_sg, port->elem.in_addr,
 737                                  port->elem.in_num, 1);
 738                 virtqueue_map_sg(port->elem.out_sg, port->elem.out_addr,
 739                                  port->elem.out_num, 1);
 740
 741                 /*
 742                  *  Port was throttled on source machine.  Let's
 743                  *  unthrottle it here so data starts flowing again.
 744                  */
 745                 virtio_serial_throttle_port(port, false);
 746             }
 747         }
 748     }
 749     qemu_mod_timer(s->post_load.timer, 1);
 750     return 0;
 751 }
 752
 753 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 754
 755 static Property virtser_props[] = {
 756     DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 757     DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 758     DEFINE_PROP_END_OF_LIST()
 759 };
 760
 761 #define TYPE_VIRTIO_SERIAL_BUS "virtio-serial-bus"
 762 #define VIRTIO_SERIAL_BUS(obj) \
 763       OBJECT_CHECK(VirtIOSerialBus, (obj), TYPE_VIRTIO_SERIAL_BUS)
 764
 765 static void virtser_bus_class_init(ObjectClass *klass, void *data)
 766 {
 767     BusClass *k = BUS_CLASS(klass);
 768     k->print_dev = virtser_bus_dev_print;
 769 }
 770
 771 static const TypeInfo virtser_bus_info = {
 772     .name = TYPE_VIRTIO_SERIAL_BUS,
 773     .parent = TYPE_BUS,
 774     .instance_size = sizeof(VirtIOSerialBus),
 775     .class_init = virtser_bus_class_init,
 776 };
 777
 778 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 779 {
 780     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 781
 782     monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 783                    indent, "", port->id,
 784                    port->guest_connected ? "on" : "off",
 785                    port->host_connected ? "on" : "off",
 786                    port->throttled ? "on" : "off");
 787 }
 788
 789 /* This function is only used if a port id is not provided by the user */
 790 static uint32_t find_free_port_id(VirtIOSerial *vser)
 791 {
 792     unsigned int i, max_nr_ports;
 793
 794     max_nr_ports = tswap32(vser->config.max_nr_ports);
 795     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 796         uint32_t map, bit;
 797
 798         map = vser->ports_map[i];
 799         bit = ffs(~map);
 800         if (bit) {
 801             return (bit - 1) + i * 32;
 802         }
 803     }
 804     return VIRTIO_CONSOLE_BAD_ID;
 805 }
 806
 807 static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 808 {
 809     unsigned int i;
 810
 811     i = port_id / 32;
 812     vser->ports_map[i] |= 1U << (port_id % 32);
 813 }
 814
 815 static void add_port(VirtIOSerial *vser, uint32_t port_id)
 816 {
 817     mark_port_added(vser, port_id);
 818
 819     send_control_event(find_port_by_id(vser, port_id),
 820                        VIRTIO_CONSOLE_PORT_ADD, 1);
 821 }
 822
 823 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 824 {
 825     VirtIOSerialPort *port;
 826     unsigned int i;
 827
 828     i = port_id / 32;
 829     vser->ports_map[i] &= ~(1U << (port_id % 32));
 830
 831     port = find_port_by_id(vser, port_id);
 832     /* Flush out any unconsumed buffers first */
 833     discard_vq_data(port->ovq, &port->vser->vdev);
 834
 835     send_control_event(port, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 836 }
 837
 838 static int virtser_port_qdev_init(DeviceState *qdev)
 839 {
 840     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 841     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 842     VirtIOSerialBus *bus = DO_UPCAST(VirtIOSerialBus, qbus, qdev->parent_bus);
 843     int ret, max_nr_ports;
 844     bool plugging_port0;
 845
 846     port->vser = bus->vser;
 847     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 848
 849     assert(vsc->have_data);
 850
 851     /*
 852      * Is the first console port we're seeing? If so, put it up at
 853      * location 0. This is done for backward compatibility (old
 854      * kernel, new qemu).
 855      */
 856     plugging_port0 = vsc->is_console && !find_port_by_id(port->vser, 0);
 857
 858     if (find_port_by_id(port->vser, port->id)) {
 859         error_report("virtio-serial-bus: A port already exists at id %u",
 860                      port->id);
 861         return -1;
 862     }
 863
 864     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 865         if (plugging_port0) {
 866             port->id = 0;
 867         } else {
 868             port->id = find_free_port_id(port->vser);
 869             if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 870                 error_report("virtio-serial-bus: Maximum port limit for this device reached");
 871                 return -1;
 872             }
 873         }
 874     }
 875
 876     max_nr_ports = tswap32(port->vser->config.max_nr_ports);
 877     if (port->id >= max_nr_ports) {
 878         error_report("virtio-serial-bus: Out-of-range port id specified, max. allowed: %u",
 879                      max_nr_ports - 1);
 880         return -1;
 881     }
 882
 883     ret = vsc->init(port);
 884     if (ret) {
 885         return ret;
 886     }
 887
 888     port->elem.out_num = 0;
 889
 890     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
 891     port->ivq = port->vser->ivqs[port->id];
 892     port->ovq = port->vser->ovqs[port->id];
 893
 894     add_port(port->vser, port->id);
 895
 896     /* Send an update to the guest about this new port added */
 897     virtio_notify_config(&port->vser->vdev);
 898
 899     return ret;
 900 }
 901
 902 static int virtser_port_qdev_exit(DeviceState *qdev)
 903 {
 904     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 905     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 906     VirtIOSerial *vser = port->vser;
 907
 908     qemu_bh_delete(port->bh);
 909     remove_port(port->vser, port->id);
 910
 911     QTAILQ_REMOVE(&vser->ports, port, next);
 912
 913     if (vsc->exit) {
 914         vsc->exit(port);
 915     }
 916     return 0;
 917 }
 918
 919 VirtIODevice *virtio_serial_init(DeviceState *dev, virtio_serial_conf *conf)
 920 {
 921     VirtIOSerial *vser;
 922     VirtIODevice *vdev;
 923     uint32_t i, max_supported_ports;
 924
 925     if (!conf->max_virtserial_ports)
 926         return NULL;
 927
 928     /* Each port takes 2 queues, and one pair is for the control queue */
 929     max_supported_ports = VIRTIO_PCI_QUEUE_MAX / 2 - 1;
 930
 931     if (conf->max_virtserial_ports > max_supported_ports) {
 932         error_report("maximum ports supported: %u", max_supported_ports);
 933         return NULL;
 934     }
 935
 936     vdev = virtio_common_init("virtio-serial", VIRTIO_ID_CONSOLE,
 937                               sizeof(struct virtio_console_config),
 938                               sizeof(VirtIOSerial));
 939
 940     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 941
 942     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
 943     qbus_create_inplace(&vser->bus.qbus, TYPE_VIRTIO_SERIAL_BUS, dev, NULL);
 944     vser->bus.qbus.allow_hotplug = 1;
 945     vser->bus.vser = vser;
 946     QTAILQ_INIT(&vser->ports);
 947
 948     vser->bus.max_nr_ports = conf->max_virtserial_ports;
 949     vser->ivqs = g_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 950     vser->ovqs = g_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 951
 952     /* Add a queue for host to guest transfers for port 0 (backward compat) */
 953     vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
 954     /* Add a queue for guest to host transfers for port 0 (backward compat) */
 955     vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
 956
 957     /* TODO: host to guest notifications can get dropped
 958      * if the queue fills up. Implement queueing in host,
 959      * this might also make it possible to reduce the control
 960      * queue size: as guest preposts buffers there,
 961      * this will save 4Kbyte of guest memory per entry. */
 962
 963     /* control queue: host to guest */
 964     vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
 965     /* control queue: guest to host */
 966     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
 967
 968     for (i = 1; i < vser->bus.max_nr_ports; i++) {
 969         /* Add a per-port queue for host to guest transfers */
 970         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
 971         /* Add a per-per queue for guest to host transfers */
 972         vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
 973     }
 974
 975     vser->config.max_nr_ports = tswap32(conf->max_virtserial_ports);
 976     vser->ports_map = g_malloc0(((conf->max_virtserial_ports + 31) / 32)
 977         * sizeof(vser->ports_map[0]));
 978     /*
 979      * Reserve location 0 for a console port for backward compat
 980      * (old kernel, new qemu)
 981      */
 982     mark_port_added(vser, 0);
 983
 984     vser->vdev.get_features = get_features;
 985     vser->vdev.get_config = get_config;
 986     vser->vdev.set_config = set_config;
 987     vser->vdev.set_status = set_status;
 988     vser->vdev.reset = vser_reset;
 989
 990     vser->qdev = dev;
 991
 992     /*
 993      * Register for the savevm section with the virtio-console name
 994      * to preserve backward compat
 995      */
 996     register_savevm(dev, "virtio-console", -1, 3, virtio_serial_save,
 997                     virtio_serial_load, vser);
 998
 999     vser->post_load.timer = qemu_new_timer_ns(vm_clock,
1000             virtio_serial_post_load_timer_cb, vser);
1001
1002     return vdev;
1003 }
1004
1005 void virtio_serial_exit(VirtIODevice *vdev)
1006 {
1007     VirtIOSerial *vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
1008
1009     unregister_savevm(vser->qdev, "virtio-console", vser);
1010
1011     g_free(vser->ivqs);
1012     g_free(vser->ovqs);
1013     g_free(vser->ports_map);
1014     g_free(vser->post_load.connected);
1015     qemu_free_timer(vser->post_load.timer);
1016
1017     virtio_cleanup(vdev);
1018 }
1019
1020 static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
1021 {
1022     DeviceClass *k = DEVICE_CLASS(klass);
1023     k->init = virtser_port_qdev_init;
1024     k->bus_type = TYPE_VIRTIO_SERIAL_BUS;
1025     k->exit = virtser_port_qdev_exit;
1026     k->unplug = qdev_simple_unplug_cb;
1027     k->props = virtser_props;
1028 }
1029
1030 static TypeInfo virtio_serial_port_type_info = {
1031     .name = TYPE_VIRTIO_SERIAL_PORT,
1032     .parent = TYPE_DEVICE,
1033     .instance_size = sizeof(VirtIOSerialPort),
1034     .abstract = true,
1035     .class_size = sizeof(VirtIOSerialPortClass),
1036     .class_init = virtio_serial_port_class_init,
1037 };
1038
1039 static void virtio_serial_register_types(void)
1040 {
1041     type_register_static(&virtser_bus_info);
1042     type_register_static(&virtio_serial_port_type_info);
1043 }
1044
1045 type_init(virtio_serial_register_types)