hw/char/virtio-serial-bus.c

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