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
  58 static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
  59 {
  60     VirtIOSerialPort *port;
  61
  62     if (id == VIRTIO_CONSOLE_BAD_ID) {
  63         return NULL;
  64     }
  65
  66     QTAILQ_FOREACH(port, &vser->ports, next) {
  67         if (port->id == id)
  68             return port;
  69     }
  70     return NULL;
  71 }
  72
  73 static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
  74 {
  75     VirtIOSerialPort *port;
  76
  77     QTAILQ_FOREACH(port, &vser->ports, next) {
  78         if (port->ivq == vq || port->ovq == vq)
  79             return port;
  80     }
  81     return NULL;
  82 }
  83
  84 static bool use_multiport(VirtIOSerial *vser)
  85 {
  86     return vser->vdev.guest_features & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
  87 }
  88
  89 static size_t write_to_port(VirtIOSerialPort *port,
  90                             const uint8_t *buf, size_t size)
  91 {
  92     VirtQueueElement elem;
  93     VirtQueue *vq;
  94     size_t offset;
  95
  96     vq = port->ivq;
  97     if (!virtio_queue_ready(vq)) {
  98         return 0;
  99     }
 100
 101     offset = 0;
 102     while (offset < size) {
 103         size_t len;
 104
 105         if (!virtqueue_pop(vq, &elem)) {
 106             break;
 107         }
 108
 109         len = iov_from_buf(elem.in_sg, elem.in_num, 0,
 110                            buf + offset, size - offset);
 111         offset += len;
 112
 113         virtqueue_push(vq, &elem, len);
 114     }
 115
 116     virtio_notify(&port->vser->vdev, vq);
 117     return offset;
 118 }
 119
 120 static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
 121 {
 122     VirtQueueElement elem;
 123
 124     if (!virtio_queue_ready(vq)) {
 125         return;
 126     }
 127     while (virtqueue_pop(vq, &elem)) {
 128         virtqueue_push(vq, &elem, 0);
 129     }
 130     virtio_notify(vdev, vq);
 131 }
 132
 133 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 134                                  VirtIODevice *vdev)
 135 {
 136     VirtIOSerialPortClass *vsc;
 137
 138     assert(port);
 139     assert(virtio_queue_ready(vq));
 140
 141     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 142
 143     while (!port->throttled) {
 144         unsigned int i;
 145
 146         /* Pop an elem only if we haven't left off a previous one mid-way */
 147         if (!port->elem.out_num) {
 148             if (!virtqueue_pop(vq, &port->elem)) {
 149                 break;
 150             }
 151             port->iov_idx = 0;
 152             port->iov_offset = 0;
 153         }
 154
 155         for (i = port->iov_idx; i < port->elem.out_num; i++) {
 156             size_t buf_size;
 157             ssize_t ret;
 158
 159             buf_size = port->elem.out_sg[i].iov_len - port->iov_offset;
 160             ret = vsc->have_data(port,
 161                                   port->elem.out_sg[i].iov_base
 162                                   + port->iov_offset,
 163                                   buf_size);
 164             if (ret < 0 && ret != -EAGAIN) {
 165                 /* We don't handle any other type of errors here */
 166                 abort();
 167             }
 168             if (ret == -EAGAIN || (ret >= 0 && ret < buf_size)) {
 169                 /*
 170                  * this is a temporary check until chardevs can signal to
 171                  * frontends that they are writable again. This prevents
 172                  * the console from going into throttled mode (forever)
 173                  * if virtio-console is connected to a pty without a
 174                  * listener. Otherwise the guest spins forever.
 175                  * We can revert this if
 176                  * 1: chardevs can notify frondends
 177                  * 2: the guest driver does not spin in these cases
 178                  */
 179                 if (!vsc->is_console) {
 180                     virtio_serial_throttle_port(port, true);
 181                 }
 182                 port->iov_idx = i;
 183                 if (ret > 0) {
 184                     port->iov_offset += ret;
 185                 }
 186                 break;
 187             }
 188             port->iov_offset = 0;
 189         }
 190         if (port->throttled) {
 191             break;
 192         }
 193         virtqueue_push(vq, &port->elem, 0);
 194         port->elem.out_num = 0;
 195     }
 196     virtio_notify(vdev, vq);
 197 }
 198
 199 static void flush_queued_data(VirtIOSerialPort *port)
 200 {
 201     assert(port);
 202
 203     if (!virtio_queue_ready(port->ovq)) {
 204         return;
 205     }
 206     do_flush_queued_data(port, port->ovq, &port->vser->vdev);
 207 }
 208
 209 static size_t send_control_msg(VirtIOSerialPort *port, void *buf, size_t len)
 210 {
 211     VirtQueueElement elem;
 212     VirtQueue *vq;
 213     struct virtio_console_control *cpkt;
 214
 215     vq = port->vser->c_ivq;
 216     if (!virtio_queue_ready(vq)) {
 217         return 0;
 218     }
 219     if (!virtqueue_pop(vq, &elem)) {
 220         return 0;
 221     }
 222
 223     cpkt = (struct virtio_console_control *)buf;
 224     stl_p(&cpkt->id, port->id);
 225     memcpy(elem.in_sg[0].iov_base, buf, len);
 226
 227     virtqueue_push(vq, &elem, len);
 228     virtio_notify(&port->vser->vdev, vq);
 229     return len;
 230 }
 231
 232 static size_t send_control_event(VirtIOSerialPort *port, uint16_t event,
 233                                  uint16_t value)
 234 {
 235     struct virtio_console_control cpkt;
 236
 237     stw_p(&cpkt.event, event);
 238     stw_p(&cpkt.value, value);
 239
 240     trace_virtio_serial_send_control_event(port->id, event, value);
 241     return send_control_msg(port, &cpkt, sizeof(cpkt));
 242 }
 243
 244 /* Functions for use inside qemu to open and read from/write to ports */
 245 int virtio_serial_open(VirtIOSerialPort *port)
 246 {
 247     /* Don't allow opening an already-open port */
 248     if (port->host_connected) {
 249         return 0;
 250     }
 251     /* Send port open notification to the guest */
 252     port->host_connected = true;
 253     send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
 254
 255     return 0;
 256 }
 257
 258 int virtio_serial_close(VirtIOSerialPort *port)
 259 {
 260     port->host_connected = false;
 261     /*
 262      * If there's any data the guest sent which the app didn't
 263      * consume, reset the throttling flag and discard the data.
 264      */
 265     port->throttled = false;
 266     discard_vq_data(port->ovq, &port->vser->vdev);
 267
 268     send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
 269
 270     return 0;
 271 }
 272
 273 /* Individual ports/apps call this function to write to the guest. */
 274 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 275                             size_t size)
 276 {
 277     if (!port || !port->host_connected || !port->guest_connected) {
 278         return 0;
 279     }
 280     return write_to_port(port, buf, size);
 281 }
 282
 283 /*
 284  * Readiness of the guest to accept data on a port.
 285  * Returns max. data the guest can receive
 286  */
 287 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 288 {
 289     VirtQueue *vq = port->ivq;
 290     unsigned int bytes;
 291
 292     if (!virtio_queue_ready(vq) ||
 293         !(port->vser->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 294         virtio_queue_empty(vq)) {
 295         return 0;
 296     }
 297     if (use_multiport(port->vser) && !port->guest_connected) {
 298         return 0;
 299     }
 300     virtqueue_get_avail_bytes(vq, &bytes, NULL);
 301     return bytes;
 302 }
 303
 304 static void flush_queued_data_bh(void *opaque)
 305 {
 306     VirtIOSerialPort *port = opaque;
 307
 308     flush_queued_data(port);
 309 }
 310
 311 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 312 {
 313     if (!port) {
 314         return;
 315     }
 316
 317     trace_virtio_serial_throttle_port(port->id, throttle);
 318     port->throttled = throttle;
 319     if (throttle) {
 320         return;
 321     }
 322     qemu_bh_schedule(port->bh);
 323 }
 324
 325 /* Guest wants to notify us of some event */
 326 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 327 {
 328     struct VirtIOSerialPort *port;
 329     VirtIOSerialPortClass *vsc;
 330     struct virtio_console_control cpkt, *gcpkt;
 331     uint8_t *buffer;
 332     size_t buffer_len;
 333
 334     gcpkt = buf;
 335
 336     if (len < sizeof(cpkt)) {
 337         /* The guest sent an invalid control packet */
 338         return;
 339     }
 340
 341     cpkt.event = lduw_p(&gcpkt->event);
 342     cpkt.value = lduw_p(&gcpkt->value);
 343
 344     trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 345
 346     if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 347         if (!cpkt.value) {
 348             error_report("virtio-serial-bus: Guest failure in adding device %s",
 349                          vser->bus.qbus.name);
 350             return;
 351         }
 352         /*
 353          * The device is up, we can now tell the device about all the
 354          * ports we have here.
 355          */
 356         QTAILQ_FOREACH(port, &vser->ports, next) {
 357             send_control_event(port, VIRTIO_CONSOLE_PORT_ADD, 1);
 358         }
 359         return;
 360     }
 361
 362     port = find_port_by_id(vser, ldl_p(&gcpkt->id));
 363     if (!port) {
 364         error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 365                      ldl_p(&gcpkt->id), vser->bus.qbus.name);
 366         return;
 367     }
 368
 369     trace_virtio_serial_handle_control_message_port(port->id);
 370
 371     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 372
 373     switch(cpkt.event) {
 374     case VIRTIO_CONSOLE_PORT_READY:
 375         if (!cpkt.value) {
 376             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 377                          port->id, vser->bus.qbus.name);
 378             break;
 379         }
 380         /*
 381          * Now that we know the guest asked for the port name, we're
 382          * sure the guest has initialised whatever state is necessary
 383          * for this port. Now's a good time to let the guest know if
 384          * this port is a console port so that the guest can hook it
 385          * up to hvc.
 386          */
 387         if (vsc->is_console) {
 388             send_control_event(port, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 389         }
 390
 391         if (port->name) {
 392             stw_p(&cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 393             stw_p(&cpkt.value, 1);
 394
 395             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 396             buffer = g_malloc(buffer_len);
 397
 398             memcpy(buffer, &cpkt, sizeof(cpkt));
 399             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 400             buffer[buffer_len - 1] = 0;
 401
 402             send_control_msg(port, buffer, buffer_len);
 403             g_free(buffer);
 404         }
 405
 406         if (port->host_connected) {
 407             send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
 408         }
 409
 410         /*
 411          * When the guest has asked us for this information it means
 412          * the guest is all setup and has its virtqueues
 413          * initialised. If some app is interested in knowing about
 414          * this event, let it know.
 415          */
 416         if (vsc->guest_ready) {
 417             vsc->guest_ready(port);
 418         }
 419         break;
 420
 421     case VIRTIO_CONSOLE_PORT_OPEN:
 422         port->guest_connected = cpkt.value;
 423         if (cpkt.value && vsc->guest_open) {
 424             /* Send the guest opened notification if an app is interested */
 425             vsc->guest_open(port);
 426         }
 427
 428         if (!cpkt.value && vsc->guest_close) {
 429             /* Send the guest closed notification if an app is interested */
 430             vsc->guest_close(port);
 431         }
 432         break;
 433     }
 434 }
 435
 436 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 437 {
 438 }
 439
 440 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 441 {
 442     VirtQueueElement elem;
 443     VirtIOSerial *vser;
 444     uint8_t *buf;
 445     size_t len;
 446
 447     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 448
 449     len = 0;
 450     buf = NULL;
 451     while (virtqueue_pop(vq, &elem)) {
 452         size_t cur_len;
 453
 454         cur_len = iov_size(elem.out_sg, elem.out_num);
 455         /*
 456          * Allocate a new buf only if we didn't have one previously or
 457          * if the size of the buf differs
 458          */
 459         if (cur_len > len) {
 460             g_free(buf);
 461
 462             buf = g_malloc(cur_len);
 463             len = cur_len;
 464         }
 465         iov_to_buf(elem.out_sg, elem.out_num, 0, buf, cur_len);
 466
 467         handle_control_message(vser, buf, cur_len);
 468         virtqueue_push(vq, &elem, 0);
 469     }
 470     g_free(buf);
 471     virtio_notify(vdev, vq);
 472 }
 473
 474 /* Guest wrote something to some port. */
 475 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 476 {
 477     VirtIOSerial *vser;
 478     VirtIOSerialPort *port;
 479
 480     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 481     port = find_port_by_vq(vser, vq);
 482
 483     if (!port || !port->host_connected) {
 484         discard_vq_data(vq, vdev);
 485         return;
 486     }
 487
 488     if (!port->throttled) {
 489         do_flush_queued_data(port, vq, vdev);
 490         return;
 491     }
 492 }
 493
 494 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 495 {
 496 }
 497
 498 static uint32_t get_features(VirtIODevice *vdev, uint32_t features)
 499 {
 500     VirtIOSerial *vser;
 501
 502     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 503
 504     if (vser->bus.max_nr_ports > 1) {
 505         features |= (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 506     }
 507     return features;
 508 }
 509
 510 /* Guest requested config info */
 511 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 512 {
 513     VirtIOSerial *vser;
 514
 515     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 516     memcpy(config_data, &vser->config, sizeof(struct virtio_console_config));
 517 }
 518
 519 static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
 520 {
 521     struct virtio_console_config config;
 522
 523     memcpy(&config, config_data, sizeof(config));
 524 }
 525
 526 static void guest_reset(VirtIOSerial *vser)
 527 {
 528     VirtIOSerialPort *port;
 529     VirtIOSerialPortClass *vsc;
 530
 531     QTAILQ_FOREACH(port, &vser->ports, next) {
 532         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 533         if (port->guest_connected) {
 534             port->guest_connected = false;
 535
 536             if (vsc->guest_close)
 537                 vsc->guest_close(port);
 538         }
 539     }
 540 }
 541
 542 static void set_status(VirtIODevice *vdev, uint8_t status)
 543 {
 544     VirtIOSerial *vser;
 545     VirtIOSerialPort *port;
 546
 547     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 548     port = find_port_by_id(vser, 0);
 549
 550     if (port && !use_multiport(port->vser)
 551         && (status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 552         /*
 553          * Non-multiport guests won't be able to tell us guest
 554          * open/close status.  Such guests can only have a port at id
 555          * 0, so set guest_connected for such ports as soon as guest
 556          * is up.
 557          */
 558         port->guest_connected = true;
 559     }
 560     if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 561         guest_reset(vser);
 562     }
 563 }
 564
 565 static void vser_reset(VirtIODevice *vdev)
 566 {
 567     VirtIOSerial *vser;
 568
 569     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 570     guest_reset(vser);
 571 }
 572
 573 static void virtio_serial_save(QEMUFile *f, void *opaque)
 574 {
 575     VirtIOSerial *s = opaque;
 576     VirtIOSerialPort *port;
 577     uint32_t nr_active_ports;
 578     unsigned int i, max_nr_ports;
 579
 580     /* The virtio device */
 581     virtio_save(&s->vdev, f);
 582
 583     /* The config space */
 584     qemu_put_be16s(f, &s->config.cols);
 585     qemu_put_be16s(f, &s->config.rows);
 586
 587     qemu_put_be32s(f, &s->config.max_nr_ports);
 588
 589     /* The ports map */
 590     max_nr_ports = tswap32(s->config.max_nr_ports);
 591     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 592         qemu_put_be32s(f, &s->ports_map[i]);
 593     }
 594
 595     /* Ports */
 596
 597     nr_active_ports = 0;
 598     QTAILQ_FOREACH(port, &s->ports, next) {
 599         nr_active_ports++;
 600     }
 601
 602     qemu_put_be32s(f, &nr_active_ports);
 603
 604     /*
 605      * Items in struct VirtIOSerialPort.
 606      */
 607     QTAILQ_FOREACH(port, &s->ports, next) {
 608         uint32_t elem_popped;
 609
 610         qemu_put_be32s(f, &port->id);
 611         qemu_put_byte(f, port->guest_connected);
 612         qemu_put_byte(f, port->host_connected);
 613
 614         elem_popped = 0;
 615         if (port->elem.out_num) {
 616             elem_popped = 1;
 617         }
 618         qemu_put_be32s(f, &elem_popped);
 619         if (elem_popped) {
 620             qemu_put_be32s(f, &port->iov_idx);
 621             qemu_put_be64s(f, &port->iov_offset);
 622
 623             qemu_put_buffer(f, (unsigned char *)&port->elem,
 624                             sizeof(port->elem));
 625         }
 626     }
 627 }
 628
 629 static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
 630 {
 631     VirtIOSerial *s = opaque;
 632     VirtIOSerialPort *port;
 633     uint32_t max_nr_ports, nr_active_ports, ports_map;
 634     unsigned int i;
 635     int ret;
 636
 637     if (version_id > 3) {
 638         return -EINVAL;
 639     }
 640
 641     /* The virtio device */
 642     ret = virtio_load(&s->vdev, f);
 643     if (ret) {
 644         return ret;
 645     }
 646
 647     if (version_id < 2) {
 648         return 0;
 649     }
 650
 651     /* The config space */
 652     qemu_get_be16s(f, &s->config.cols);
 653     qemu_get_be16s(f, &s->config.rows);
 654
 655     qemu_get_be32s(f, &max_nr_ports);
 656     tswap32s(&max_nr_ports);
 657     if (max_nr_ports > tswap32(s->config.max_nr_ports)) {
 658         /* Source could have had more ports than us. Fail migration. */
 659         return -EINVAL;
 660     }
 661
 662     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 663         qemu_get_be32s(f, &ports_map);
 664
 665         if (ports_map != s->ports_map[i]) {
 666             /*
 667              * Ports active on source and destination don't
 668              * match. Fail migration.
 669              */
 670             return -EINVAL;
 671         }
 672     }
 673
 674     qemu_get_be32s(f, &nr_active_ports);
 675
 676     /* Items in struct VirtIOSerialPort */
 677     for (i = 0; i < nr_active_ports; i++) {
 678         uint32_t id;
 679         bool host_connected;
 680
 681         id = qemu_get_be32(f);
 682         port = find_port_by_id(s, id);
 683         if (!port) {
 684             return -EINVAL;
 685         }
 686
 687         port->guest_connected = qemu_get_byte(f);
 688         host_connected = qemu_get_byte(f);
 689         if (host_connected != port->host_connected) {
 690             /*
 691              * We have to let the guest know of the host connection
 692              * status change
 693              */
 694             send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN,
 695                                port->host_connected);
 696         }
 697
 698         if (version_id > 2) {
 699             uint32_t elem_popped;
 700
 701             qemu_get_be32s(f, &elem_popped);
 702             if (elem_popped) {
 703                 qemu_get_be32s(f, &port->iov_idx);
 704                 qemu_get_be64s(f, &port->iov_offset);
 705
 706                 qemu_get_buffer(f, (unsigned char *)&port->elem,
 707                                 sizeof(port->elem));
 708                 virtqueue_map_sg(port->elem.in_sg, port->elem.in_addr,
 709                                  port->elem.in_num, 1);
 710                 virtqueue_map_sg(port->elem.out_sg, port->elem.out_addr,
 711                                  port->elem.out_num, 1);
 712
 713                 /*
 714                  *  Port was throttled on source machine.  Let's
 715                  *  unthrottle it here so data starts flowing again.
 716                  */
 717                 virtio_serial_throttle_port(port, false);
 718             }
 719         }
 720     }
 721     return 0;
 722 }
 723
 724 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 725
 726 static Property virtser_props[] = {
 727     DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 728     DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 729     DEFINE_PROP_END_OF_LIST()
 730 };
 731
 732 #define TYPE_VIRTIO_SERIAL_BUS "virtio-serial-bus"
 733 #define VIRTIO_SERIAL_BUS(obj) \
 734       OBJECT_CHECK(VirtIOSerialBus, (obj), TYPE_VIRTIO_SERIAL_BUS)
 735
 736 static void virtser_bus_class_init(ObjectClass *klass, void *data)
 737 {
 738     BusClass *k = BUS_CLASS(klass);
 739     k->print_dev = virtser_bus_dev_print;
 740 }
 741
 742 static const TypeInfo virtser_bus_info = {
 743     .name = TYPE_VIRTIO_SERIAL_BUS,
 744     .parent = TYPE_BUS,
 745     .instance_size = sizeof(VirtIOSerialBus),
 746     .class_init = virtser_bus_class_init,
 747 };
 748
 749 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 750 {
 751     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 752
 753     monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 754                    indent, "", port->id,
 755                    port->guest_connected ? "on" : "off",
 756                    port->host_connected ? "on" : "off",
 757                    port->throttled ? "on" : "off");
 758 }
 759
 760 /* This function is only used if a port id is not provided by the user */
 761 static uint32_t find_free_port_id(VirtIOSerial *vser)
 762 {
 763     unsigned int i, max_nr_ports;
 764
 765     max_nr_ports = tswap32(vser->config.max_nr_ports);
 766     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 767         uint32_t map, bit;
 768
 769         map = vser->ports_map[i];
 770         bit = ffs(~map);
 771         if (bit) {
 772             return (bit - 1) + i * 32;
 773         }
 774     }
 775     return VIRTIO_CONSOLE_BAD_ID;
 776 }
 777
 778 static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 779 {
 780     unsigned int i;
 781
 782     i = port_id / 32;
 783     vser->ports_map[i] |= 1U << (port_id % 32);
 784 }
 785
 786 static void add_port(VirtIOSerial *vser, uint32_t port_id)
 787 {
 788     mark_port_added(vser, port_id);
 789
 790     send_control_event(find_port_by_id(vser, port_id),
 791                        VIRTIO_CONSOLE_PORT_ADD, 1);
 792 }
 793
 794 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 795 {
 796     VirtIOSerialPort *port;
 797     unsigned int i;
 798
 799     i = port_id / 32;
 800     vser->ports_map[i] &= ~(1U << (port_id % 32));
 801
 802     port = find_port_by_id(vser, port_id);
 803     /* Flush out any unconsumed buffers first */
 804     discard_vq_data(port->ovq, &port->vser->vdev);
 805
 806     send_control_event(port, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 807 }
 808
 809 static int virtser_port_qdev_init(DeviceState *qdev)
 810 {
 811     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 812     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 813     VirtIOSerialBus *bus = DO_UPCAST(VirtIOSerialBus, qbus, qdev->parent_bus);
 814     int ret, max_nr_ports;
 815     bool plugging_port0;
 816
 817     port->vser = bus->vser;
 818     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 819
 820     assert(vsc->have_data);
 821
 822     /*
 823      * Is the first console port we're seeing? If so, put it up at
 824      * location 0. This is done for backward compatibility (old
 825      * kernel, new qemu).
 826      */
 827     plugging_port0 = vsc->is_console && !find_port_by_id(port->vser, 0);
 828
 829     if (find_port_by_id(port->vser, port->id)) {
 830         error_report("virtio-serial-bus: A port already exists at id %u",
 831                      port->id);
 832         return -1;
 833     }
 834
 835     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 836         if (plugging_port0) {
 837             port->id = 0;
 838         } else {
 839             port->id = find_free_port_id(port->vser);
 840             if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 841                 error_report("virtio-serial-bus: Maximum port limit for this device reached");
 842                 return -1;
 843             }
 844         }
 845     }
 846
 847     max_nr_ports = tswap32(port->vser->config.max_nr_ports);
 848     if (port->id >= max_nr_ports) {
 849         error_report("virtio-serial-bus: Out-of-range port id specified, max. allowed: %u",
 850                      max_nr_ports - 1);
 851         return -1;
 852     }
 853
 854     ret = vsc->init(port);
 855     if (ret) {
 856         return ret;
 857     }
 858
 859     port->elem.out_num = 0;
 860
 861     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
 862     port->ivq = port->vser->ivqs[port->id];
 863     port->ovq = port->vser->ovqs[port->id];
 864
 865     add_port(port->vser, port->id);
 866
 867     /* Send an update to the guest about this new port added */
 868     virtio_notify_config(&port->vser->vdev);
 869
 870     return ret;
 871 }
 872
 873 static int virtser_port_qdev_exit(DeviceState *qdev)
 874 {
 875     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 876     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 877     VirtIOSerial *vser = port->vser;
 878
 879     qemu_bh_delete(port->bh);
 880     remove_port(port->vser, port->id);
 881
 882     QTAILQ_REMOVE(&vser->ports, port, next);
 883
 884     if (vsc->exit) {
 885         vsc->exit(port);
 886     }
 887     return 0;
 888 }
 889
 890 VirtIODevice *virtio_serial_init(DeviceState *dev, virtio_serial_conf *conf)
 891 {
 892     VirtIOSerial *vser;
 893     VirtIODevice *vdev;
 894     uint32_t i, max_supported_ports;
 895
 896     if (!conf->max_virtserial_ports)
 897         return NULL;
 898
 899     /* Each port takes 2 queues, and one pair is for the control queue */
 900     max_supported_ports = VIRTIO_PCI_QUEUE_MAX / 2 - 1;
 901
 902     if (conf->max_virtserial_ports > max_supported_ports) {
 903         error_report("maximum ports supported: %u", max_supported_ports);
 904         return NULL;
 905     }
 906
 907     vdev = virtio_common_init("virtio-serial", VIRTIO_ID_CONSOLE,
 908                               sizeof(struct virtio_console_config),
 909                               sizeof(VirtIOSerial));
 910
 911     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 912
 913     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
 914     qbus_create_inplace(&vser->bus.qbus, TYPE_VIRTIO_SERIAL_BUS, dev, NULL);
 915     vser->bus.qbus.allow_hotplug = 1;
 916     vser->bus.vser = vser;
 917     QTAILQ_INIT(&vser->ports);
 918
 919     vser->bus.max_nr_ports = conf->max_virtserial_ports;
 920     vser->ivqs = g_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 921     vser->ovqs = g_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 922
 923     /* Add a queue for host to guest transfers for port 0 (backward compat) */
 924     vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
 925     /* Add a queue for guest to host transfers for port 0 (backward compat) */
 926     vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
 927
 928     /* TODO: host to guest notifications can get dropped
 929      * if the queue fills up. Implement queueing in host,
 930      * this might also make it possible to reduce the control
 931      * queue size: as guest preposts buffers there,
 932      * this will save 4Kbyte of guest memory per entry. */
 933
 934     /* control queue: host to guest */
 935     vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
 936     /* control queue: guest to host */
 937     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
 938
 939     for (i = 1; i < vser->bus.max_nr_ports; i++) {
 940         /* Add a per-port queue for host to guest transfers */
 941         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
 942         /* Add a per-per queue for guest to host transfers */
 943         vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
 944     }
 945
 946     vser->config.max_nr_ports = tswap32(conf->max_virtserial_ports);
 947     vser->ports_map = g_malloc0(((conf->max_virtserial_ports + 31) / 32)
 948         * sizeof(vser->ports_map[0]));
 949     /*
 950      * Reserve location 0 for a console port for backward compat
 951      * (old kernel, new qemu)
 952      */
 953     mark_port_added(vser, 0);
 954
 955     vser->vdev.get_features = get_features;
 956     vser->vdev.get_config = get_config;
 957     vser->vdev.set_config = set_config;
 958     vser->vdev.set_status = set_status;
 959     vser->vdev.reset = vser_reset;
 960
 961     vser->qdev = dev;
 962
 963     /*
 964      * Register for the savevm section with the virtio-console name
 965      * to preserve backward compat
 966      */
 967     register_savevm(dev, "virtio-console", -1, 3, virtio_serial_save,
 968                     virtio_serial_load, vser);
 969
 970     return vdev;
 971 }
 972
 973 void virtio_serial_exit(VirtIODevice *vdev)
 974 {
 975     VirtIOSerial *vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 976
 977     unregister_savevm(vser->qdev, "virtio-console", vser);
 978
 979     g_free(vser->ivqs);
 980     g_free(vser->ovqs);
 981     g_free(vser->ports_map);
 982
 983     virtio_cleanup(vdev);
 984 }
 985
 986 static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
 987 {
 988     DeviceClass *k = DEVICE_CLASS(klass);
 989     k->init = virtser_port_qdev_init;
 990     k->bus_type = TYPE_VIRTIO_SERIAL_BUS;
 991     k->exit = virtser_port_qdev_exit;
 992     k->unplug = qdev_simple_unplug_cb;
 993     k->props = virtser_props;
 994 }
 995
 996 static TypeInfo virtio_serial_port_type_info = {
 997     .name = TYPE_VIRTIO_SERIAL_PORT,
 998     .parent = TYPE_DEVICE,
 999     .instance_size = sizeof(VirtIOSerialPort),
1000     .abstract = true,
1001     .class_size = sizeof(VirtIOSerialPortClass),
1002     .class_init = virtio_serial_port_class_init,
1003 };
1004
1005 static void virtio_serial_register_types(void)
1006 {
1007     type_register_static(&virtser_bus_info);
1008     type_register_static(&virtio_serial_port_type_info);
1009 }
1010
1011 type_init(virtio_serial_register_types)