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/osdep.h"
  22 #include "qemu/iov.h"
  23 #include "monitor/monitor.h"
  24 #include "qemu/error-report.h"
  25 #include "qemu/queue.h"
  26 #include "hw/sysbus.h"
  27 #include "trace.h"
  28 #include "hw/virtio/virtio-serial.h"
  29 #include "hw/virtio/virtio-access.h"
  30
  31 static struct VirtIOSerialDevices {
  32     QLIST_HEAD(, VirtIOSerial) devices;
  33 } vserdevices;
  34
  35 static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
  36 {
  37     VirtIOSerialPort *port;
  38
  39     if (id == VIRTIO_CONSOLE_BAD_ID) {
  40         return NULL;
  41     }
  42
  43     QTAILQ_FOREACH(port, &vser->ports, next) {
  44         if (port->id == id)
  45             return port;
  46     }
  47     return NULL;
  48 }
  49
  50 static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
  51 {
  52     VirtIOSerialPort *port;
  53
  54     QTAILQ_FOREACH(port, &vser->ports, next) {
  55         if (port->ivq == vq || port->ovq == vq)
  56             return port;
  57     }
  58     return NULL;
  59 }
  60
  61 static VirtIOSerialPort *find_port_by_name(char *name)
  62 {
  63     VirtIOSerial *vser;
  64
  65     QLIST_FOREACH(vser, &vserdevices.devices, next) {
  66         VirtIOSerialPort *port;
  67
  68         QTAILQ_FOREACH(port, &vser->ports, next) {
  69             if (port->name && !strcmp(port->name, name)) {
  70                 return port;
  71             }
  72         }
  73     }
  74     return NULL;
  75 }
  76
  77 static bool use_multiport(VirtIOSerial *vser)
  78 {
  79     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
  80     return virtio_vdev_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT);
  81 }
  82
  83 static size_t write_to_port(VirtIOSerialPort *port,
  84                             const uint8_t *buf, size_t size)
  85 {
  86     VirtQueueElement *elem;
  87     VirtQueue *vq;
  88     size_t offset;
  89
  90     vq = port->ivq;
  91     if (!virtio_queue_ready(vq)) {
  92         return 0;
  93     }
  94
  95     offset = 0;
  96     while (offset < size) {
  97         size_t len;
  98
  99         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 100         if (!elem) {
 101             break;
 102         }
 103
 104         len = iov_from_buf(elem->in_sg, elem->in_num, 0,
 105                            buf + offset, size - offset);
 106         offset += len;
 107
 108         virtqueue_push(vq, elem, len);
 109         g_free(elem);
 110     }
 111
 112     virtio_notify(VIRTIO_DEVICE(port->vser), vq);
 113     return offset;
 114 }
 115
 116 static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
 117 {
 118     VirtQueueElement *elem;
 119
 120     if (!virtio_queue_ready(vq)) {
 121         return;
 122     }
 123     for (;;) {
 124         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 125         if (!elem) {
 126             break;
 127         }
 128         virtqueue_push(vq, elem, 0);
 129         g_free(elem);
 130     }
 131     virtio_notify(vdev, vq);
 132 }
 133
 134 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 135                                  VirtIODevice *vdev)
 136 {
 137     VirtIOSerialPortClass *vsc;
 138
 139     assert(port);
 140     assert(virtio_queue_ready(vq));
 141
 142     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 143
 144     while (!port->throttled) {
 145         unsigned int i;
 146
 147         /* Pop an elem only if we haven't left off a previous one mid-way */
 148         if (!port->elem) {
 149             port->elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 150             if (!port->elem) {
 151                 break;
 152             }
 153             port->iov_idx = 0;
 154             port->iov_offset = 0;
 155         }
 156
 157         for (i = port->iov_idx; i < port->elem->out_num; i++) {
 158             size_t buf_size;
 159             ssize_t ret;
 160
 161             buf_size = port->elem->out_sg[i].iov_len - port->iov_offset;
 162             ret = vsc->have_data(port,
 163                                   port->elem->out_sg[i].iov_base
 164                                   + port->iov_offset,
 165                                   buf_size);
 166             if (port->throttled) {
 167                 port->iov_idx = i;
 168                 if (ret > 0) {
 169                     port->iov_offset += ret;
 170                 }
 171                 break;
 172             }
 173             port->iov_offset = 0;
 174         }
 175         if (port->throttled) {
 176             break;
 177         }
 178         virtqueue_push(vq, port->elem, 0);
 179         g_free(port->elem);
 180         port->elem = NULL;
 181     }
 182     virtio_notify(vdev, vq);
 183 }
 184
 185 static void flush_queued_data(VirtIOSerialPort *port)
 186 {
 187     assert(port);
 188
 189     if (!virtio_queue_ready(port->ovq)) {
 190         return;
 191     }
 192     do_flush_queued_data(port, port->ovq, VIRTIO_DEVICE(port->vser));
 193 }
 194
 195 static size_t send_control_msg(VirtIOSerial *vser, void *buf, size_t len)
 196 {
 197     VirtQueueElement *elem;
 198     VirtQueue *vq;
 199
 200     vq = vser->c_ivq;
 201     if (!virtio_queue_ready(vq)) {
 202         return 0;
 203     }
 204
 205     elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 206     if (!elem) {
 207         return 0;
 208     }
 209
 210     /* TODO: detect a buffer that's too short, set NEEDS_RESET */
 211     iov_from_buf(elem->in_sg, elem->in_num, 0, buf, len);
 212
 213     virtqueue_push(vq, elem, len);
 214     virtio_notify(VIRTIO_DEVICE(vser), vq);
 215     g_free(elem);
 216
 217     return len;
 218 }
 219
 220 static size_t send_control_event(VirtIOSerial *vser, uint32_t port_id,
 221                                  uint16_t event, uint16_t value)
 222 {
 223     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 224     struct virtio_console_control cpkt;
 225
 226     virtio_stl_p(vdev, &cpkt.id, port_id);
 227     virtio_stw_p(vdev, &cpkt.event, event);
 228     virtio_stw_p(vdev, &cpkt.value, value);
 229
 230     trace_virtio_serial_send_control_event(port_id, event, value);
 231     return send_control_msg(vser, &cpkt, sizeof(cpkt));
 232 }
 233
 234 /* Functions for use inside qemu to open and read from/write to ports */
 235 int virtio_serial_open(VirtIOSerialPort *port)
 236 {
 237     /* Don't allow opening an already-open port */
 238     if (port->host_connected) {
 239         return 0;
 240     }
 241     /* Send port open notification to the guest */
 242     port->host_connected = true;
 243     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 244
 245     return 0;
 246 }
 247
 248 int virtio_serial_close(VirtIOSerialPort *port)
 249 {
 250     port->host_connected = false;
 251     /*
 252      * If there's any data the guest sent which the app didn't
 253      * consume, reset the throttling flag and discard the data.
 254      */
 255     port->throttled = false;
 256     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 257
 258     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 0);
 259
 260     return 0;
 261 }
 262
 263 /* Individual ports/apps call this function to write to the guest. */
 264 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 265                             size_t size)
 266 {
 267     if (!port || !port->host_connected || !port->guest_connected) {
 268         return 0;
 269     }
 270     return write_to_port(port, buf, size);
 271 }
 272
 273 /*
 274  * Readiness of the guest to accept data on a port.
 275  * Returns max. data the guest can receive
 276  */
 277 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 278 {
 279     VirtIODevice *vdev = VIRTIO_DEVICE(port->vser);
 280     VirtQueue *vq = port->ivq;
 281     unsigned int bytes;
 282
 283     if (!virtio_queue_ready(vq) ||
 284         !(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 285         virtio_queue_empty(vq)) {
 286         return 0;
 287     }
 288     if (use_multiport(port->vser) && !port->guest_connected) {
 289         return 0;
 290     }
 291     virtqueue_get_avail_bytes(vq, &bytes, NULL, 4096, 0);
 292     return bytes;
 293 }
 294
 295 static void flush_queued_data_bh(void *opaque)
 296 {
 297     VirtIOSerialPort *port = opaque;
 298
 299     flush_queued_data(port);
 300 }
 301
 302 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 303 {
 304     if (!port) {
 305         return;
 306     }
 307
 308     trace_virtio_serial_throttle_port(port->id, throttle);
 309     port->throttled = throttle;
 310     if (throttle) {
 311         return;
 312     }
 313     qemu_bh_schedule(port->bh);
 314 }
 315
 316 /* Guest wants to notify us of some event */
 317 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 318 {
 319     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 320     struct VirtIOSerialPort *port;
 321     VirtIOSerialPortClass *vsc;
 322     struct virtio_console_control cpkt, *gcpkt;
 323     uint8_t *buffer;
 324     size_t buffer_len;
 325
 326     gcpkt = buf;
 327
 328     if (len < sizeof(cpkt)) {
 329         /* The guest sent an invalid control packet */
 330         return;
 331     }
 332
 333     cpkt.event = virtio_lduw_p(vdev, &gcpkt->event);
 334     cpkt.value = virtio_lduw_p(vdev, &gcpkt->value);
 335
 336     trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 337
 338     if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 339         if (!cpkt.value) {
 340             error_report("virtio-serial-bus: Guest failure in adding device %s",
 341                          vser->bus.qbus.name);
 342             return;
 343         }
 344         /*
 345          * The device is up, we can now tell the device about all the
 346          * ports we have here.
 347          */
 348         QTAILQ_FOREACH(port, &vser->ports, next) {
 349             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_ADD, 1);
 350         }
 351         return;
 352     }
 353
 354     port = find_port_by_id(vser, virtio_ldl_p(vdev, &gcpkt->id));
 355     if (!port) {
 356         error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 357                      virtio_ldl_p(vdev, &gcpkt->id), vser->bus.qbus.name);
 358         return;
 359     }
 360
 361     trace_virtio_serial_handle_control_message_port(port->id);
 362
 363     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 364
 365     switch(cpkt.event) {
 366     case VIRTIO_CONSOLE_PORT_READY:
 367         if (!cpkt.value) {
 368             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 369                          port->id, vser->bus.qbus.name);
 370             break;
 371         }
 372         /*
 373          * Now that we know the guest asked for the port name, we're
 374          * sure the guest has initialised whatever state is necessary
 375          * for this port. Now's a good time to let the guest know if
 376          * this port is a console port so that the guest can hook it
 377          * up to hvc.
 378          */
 379         if (vsc->is_console) {
 380             send_control_event(vser, port->id, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 381         }
 382
 383         if (port->name) {
 384             virtio_stl_p(vdev, &cpkt.id, port->id);
 385             virtio_stw_p(vdev, &cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 386             virtio_stw_p(vdev, &cpkt.value, 1);
 387
 388             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 389             buffer = g_malloc(buffer_len);
 390
 391             memcpy(buffer, &cpkt, sizeof(cpkt));
 392             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 393             buffer[buffer_len - 1] = 0;
 394
 395             send_control_msg(vser, buffer, buffer_len);
 396             g_free(buffer);
 397         }
 398
 399         if (port->host_connected) {
 400             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 401         }
 402
 403         /*
 404          * When the guest has asked us for this information it means
 405          * the guest is all setup and has its virtqueues
 406          * initialised. If some app is interested in knowing about
 407          * this event, let it know.
 408          */
 409         if (vsc->guest_ready) {
 410             vsc->guest_ready(port);
 411         }
 412         break;
 413
 414     case VIRTIO_CONSOLE_PORT_OPEN:
 415         port->guest_connected = cpkt.value;
 416         if (vsc->set_guest_connected) {
 417             /* Send the guest opened notification if an app is interested */
 418             vsc->set_guest_connected(port, cpkt.value);
 419         }
 420         break;
 421     }
 422 }
 423
 424 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 425 {
 426 }
 427
 428 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 429 {
 430     VirtQueueElement *elem;
 431     VirtIOSerial *vser;
 432     uint8_t *buf;
 433     size_t len;
 434
 435     vser = VIRTIO_SERIAL(vdev);
 436
 437     len = 0;
 438     buf = NULL;
 439     for (;;) {
 440         size_t cur_len;
 441
 442         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 443         if (!elem) {
 444             break;
 445         }
 446
 447         cur_len = iov_size(elem->out_sg, elem->out_num);
 448         /*
 449          * Allocate a new buf only if we didn't have one previously or
 450          * if the size of the buf differs
 451          */
 452         if (cur_len > len) {
 453             g_free(buf);
 454
 455             buf = g_malloc(cur_len);
 456             len = cur_len;
 457         }
 458         iov_to_buf(elem->out_sg, elem->out_num, 0, buf, cur_len);
 459
 460         handle_control_message(vser, buf, cur_len);
 461         virtqueue_push(vq, elem, 0);
 462         g_free(elem);
 463     }
 464     g_free(buf);
 465     virtio_notify(vdev, vq);
 466 }
 467
 468 /* Guest wrote something to some port. */
 469 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 470 {
 471     VirtIOSerial *vser;
 472     VirtIOSerialPort *port;
 473
 474     vser = VIRTIO_SERIAL(vdev);
 475     port = find_port_by_vq(vser, vq);
 476
 477     if (!port || !port->host_connected) {
 478         discard_vq_data(vq, vdev);
 479         return;
 480     }
 481
 482     if (!port->throttled) {
 483         do_flush_queued_data(port, vq, vdev);
 484         return;
 485     }
 486 }
 487
 488 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 489 {
 490     /*
 491      * Users of virtio-serial would like to know when guest becomes
 492      * writable again -- i.e. if a vq had stuff queued up and the
 493      * guest wasn't reading at all, the host would not be able to
 494      * write to the vq anymore.  Once the guest reads off something,
 495      * we can start queueing things up again.  However, this call is
 496      * made for each buffer addition by the guest -- even though free
 497      * buffers existed prior to the current buffer addition.  This is
 498      * done so as not to maintain previous state, which will need
 499      * additional live-migration-related changes.
 500      */
 501     VirtIOSerial *vser;
 502     VirtIOSerialPort *port;
 503     VirtIOSerialPortClass *vsc;
 504
 505     vser = VIRTIO_SERIAL(vdev);
 506     port = find_port_by_vq(vser, vq);
 507
 508     if (!port) {
 509         return;
 510     }
 511     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 512
 513     /*
 514      * If guest_connected is false, this call is being made by the
 515      * early-boot queueing up of descriptors, which is just noise for
 516      * the host apps -- don't disturb them in that case.
 517      */
 518     if (port->guest_connected && port->host_connected && vsc->guest_writable) {
 519         vsc->guest_writable(port);
 520     }
 521 }
 522
 523 static uint64_t get_features(VirtIODevice *vdev, uint64_t features,
 524                              Error **errp)
 525 {
 526     VirtIOSerial *vser;
 527
 528     vser = VIRTIO_SERIAL(vdev);
 529
 530     if (vser->bus.max_nr_ports > 1) {
 531         virtio_add_feature(&features, VIRTIO_CONSOLE_F_MULTIPORT);
 532     }
 533     return features;
 534 }
 535
 536 /* Guest requested config info */
 537 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 538 {
 539     VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 540     struct virtio_console_config *config =
 541         (struct virtio_console_config *)config_data;
 542
 543     config->cols = 0;
 544     config->rows = 0;
 545     config->max_nr_ports = virtio_tswap32(vdev,
 546                                           vser->serial.max_virtserial_ports);
 547 }
 548
 549 static void guest_reset(VirtIOSerial *vser)
 550 {
 551     VirtIOSerialPort *port;
 552     VirtIOSerialPortClass *vsc;
 553
 554     QTAILQ_FOREACH(port, &vser->ports, next) {
 555         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 556         if (port->guest_connected) {
 557             port->guest_connected = false;
 558             if (vsc->set_guest_connected) {
 559                 vsc->set_guest_connected(port, false);
 560             }
 561         }
 562     }
 563 }
 564
 565 static void set_status(VirtIODevice *vdev, uint8_t status)
 566 {
 567     VirtIOSerial *vser;
 568     VirtIOSerialPort *port;
 569
 570     vser = VIRTIO_SERIAL(vdev);
 571     port = find_port_by_id(vser, 0);
 572
 573     if (port && !use_multiport(port->vser)
 574         && (status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 575         /*
 576          * Non-multiport guests won't be able to tell us guest
 577          * open/close status.  Such guests can only have a port at id
 578          * 0, so set guest_connected for such ports as soon as guest
 579          * is up.
 580          */
 581         port->guest_connected = true;
 582     }
 583     if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 584         guest_reset(vser);
 585     }
 586 }
 587
 588 static void vser_reset(VirtIODevice *vdev)
 589 {
 590     VirtIOSerial *vser;
 591
 592     vser = VIRTIO_SERIAL(vdev);
 593     guest_reset(vser);
 594 }
 595
 596 static void virtio_serial_save(QEMUFile *f, void *opaque)
 597 {
 598     /* The virtio device */
 599     virtio_save(VIRTIO_DEVICE(opaque), f);
 600 }
 601
 602 static void virtio_serial_save_device(VirtIODevice *vdev, QEMUFile *f)
 603 {
 604     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 605     VirtIOSerialPort *port;
 606     uint32_t nr_active_ports;
 607     unsigned int i, max_nr_ports;
 608     struct virtio_console_config config;
 609
 610     /* The config space (ignored on the far end in current versions) */
 611     get_config(vdev, (uint8_t *)&config);
 612     qemu_put_be16s(f, &config.cols);
 613     qemu_put_be16s(f, &config.rows);
 614     qemu_put_be32s(f, &config.max_nr_ports);
 615
 616     /* The ports map */
 617     max_nr_ports = s->serial.max_virtserial_ports;
 618     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 619         qemu_put_be32s(f, &s->ports_map[i]);
 620     }
 621
 622     /* Ports */
 623
 624     nr_active_ports = 0;
 625     QTAILQ_FOREACH(port, &s->ports, next) {
 626         nr_active_ports++;
 627     }
 628
 629     qemu_put_be32s(f, &nr_active_ports);
 630
 631     /*
 632      * Items in struct VirtIOSerialPort.
 633      */
 634     QTAILQ_FOREACH(port, &s->ports, next) {
 635         uint32_t elem_popped;
 636
 637         qemu_put_be32s(f, &port->id);
 638         qemu_put_byte(f, port->guest_connected);
 639         qemu_put_byte(f, port->host_connected);
 640
 641         elem_popped = 0;
 642         if (port->elem) {
 643             elem_popped = 1;
 644         }
 645         qemu_put_be32s(f, &elem_popped);
 646         if (elem_popped) {
 647             qemu_put_be32s(f, &port->iov_idx);
 648             qemu_put_be64s(f, &port->iov_offset);
 649             qemu_put_virtqueue_element(f, port->elem);
 650         }
 651     }
 652 }
 653
 654 static void virtio_serial_post_load_timer_cb(void *opaque)
 655 {
 656     uint32_t i;
 657     VirtIOSerial *s = VIRTIO_SERIAL(opaque);
 658     VirtIOSerialPort *port;
 659     uint8_t host_connected;
 660     VirtIOSerialPortClass *vsc;
 661
 662     if (!s->post_load) {
 663         return;
 664     }
 665     for (i = 0 ; i < s->post_load->nr_active_ports; ++i) {
 666         port = s->post_load->connected[i].port;
 667         host_connected = s->post_load->connected[i].host_connected;
 668         if (host_connected != port->host_connected) {
 669             /*
 670              * We have to let the guest know of the host connection
 671              * status change
 672              */
 673             send_control_event(s, port->id, VIRTIO_CONSOLE_PORT_OPEN,
 674                                port->host_connected);
 675         }
 676         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 677         if (vsc->set_guest_connected) {
 678             vsc->set_guest_connected(port, port->guest_connected);
 679         }
 680     }
 681     g_free(s->post_load->connected);
 682     timer_free(s->post_load->timer);
 683     g_free(s->post_load);
 684     s->post_load = NULL;
 685 }
 686
 687 static int fetch_active_ports_list(QEMUFile *f, int version_id,
 688                                    VirtIOSerial *s, uint32_t nr_active_ports)
 689 {
 690     uint32_t i;
 691
 692     s->post_load = g_malloc0(sizeof(*s->post_load));
 693     s->post_load->nr_active_ports = nr_active_ports;
 694     s->post_load->connected =
 695         g_malloc0(sizeof(*s->post_load->connected) * nr_active_ports);
 696
 697     s->post_load->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
 698                                             virtio_serial_post_load_timer_cb,
 699                                             s);
 700
 701     /* Items in struct VirtIOSerialPort */
 702     for (i = 0; i < nr_active_ports; i++) {
 703         VirtIOSerialPort *port;
 704         uint32_t id;
 705
 706         id = qemu_get_be32(f);
 707         port = find_port_by_id(s, id);
 708         if (!port) {
 709             return -EINVAL;
 710         }
 711
 712         port->guest_connected = qemu_get_byte(f);
 713         s->post_load->connected[i].port = port;
 714         s->post_load->connected[i].host_connected = qemu_get_byte(f);
 715
 716         if (version_id > 2) {
 717             uint32_t elem_popped;
 718
 719             qemu_get_be32s(f, &elem_popped);
 720             if (elem_popped) {
 721                 qemu_get_be32s(f, &port->iov_idx);
 722                 qemu_get_be64s(f, &port->iov_offset);
 723
 724                 port->elem =
 725                     qemu_get_virtqueue_element(f, sizeof(VirtQueueElement));
 726
 727                 /*
 728                  *  Port was throttled on source machine.  Let's
 729                  *  unthrottle it here so data starts flowing again.
 730                  */
 731                 virtio_serial_throttle_port(port, false);
 732             }
 733         }
 734     }
 735     timer_mod(s->post_load->timer, 1);
 736     return 0;
 737 }
 738
 739 static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
 740 {
 741     if (version_id > 3) {
 742         return -EINVAL;
 743     }
 744
 745     /* The virtio device */
 746     return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
 747 }
 748
 749 static int virtio_serial_load_device(VirtIODevice *vdev, QEMUFile *f,
 750                                      int version_id)
 751 {
 752     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 753     uint32_t max_nr_ports, nr_active_ports, ports_map;
 754     unsigned int i;
 755     int ret;
 756     uint32_t tmp;
 757
 758     if (version_id < 2) {
 759         return 0;
 760     }
 761
 762     /* Unused */
 763     qemu_get_be16s(f, (uint16_t *) &tmp);
 764     qemu_get_be16s(f, (uint16_t *) &tmp);
 765     qemu_get_be32s(f, &tmp);
 766
 767     max_nr_ports = s->serial.max_virtserial_ports;
 768     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 769         qemu_get_be32s(f, &ports_map);
 770
 771         if (ports_map != s->ports_map[i]) {
 772             /*
 773              * Ports active on source and destination don't
 774              * match. Fail migration.
 775              */
 776             return -EINVAL;
 777         }
 778     }
 779
 780     qemu_get_be32s(f, &nr_active_ports);
 781
 782     if (nr_active_ports) {
 783         ret = fetch_active_ports_list(f, version_id, s, nr_active_ports);
 784         if (ret) {
 785             return ret;
 786         }
 787     }
 788     return 0;
 789 }
 790
 791 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 792
 793 static Property virtser_props[] = {
 794     DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 795     DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 796     DEFINE_PROP_END_OF_LIST()
 797 };
 798
 799 #define TYPE_VIRTIO_SERIAL_BUS "virtio-serial-bus"
 800 #define VIRTIO_SERIAL_BUS(obj) \
 801       OBJECT_CHECK(VirtIOSerialBus, (obj), TYPE_VIRTIO_SERIAL_BUS)
 802
 803 static void virtser_bus_class_init(ObjectClass *klass, void *data)
 804 {
 805     BusClass *k = BUS_CLASS(klass);
 806     k->print_dev = virtser_bus_dev_print;
 807 }
 808
 809 static const TypeInfo virtser_bus_info = {
 810     .name = TYPE_VIRTIO_SERIAL_BUS,
 811     .parent = TYPE_BUS,
 812     .instance_size = sizeof(VirtIOSerialBus),
 813     .class_init = virtser_bus_class_init,
 814 };
 815
 816 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 817 {
 818     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(qdev);
 819
 820     monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 821                    indent, "", port->id,
 822                    port->guest_connected ? "on" : "off",
 823                    port->host_connected ? "on" : "off",
 824                    port->throttled ? "on" : "off");
 825 }
 826
 827 /* This function is only used if a port id is not provided by the user */
 828 static uint32_t find_free_port_id(VirtIOSerial *vser)
 829 {
 830     unsigned int i, max_nr_ports;
 831
 832     max_nr_ports = vser->serial.max_virtserial_ports;
 833     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 834         uint32_t map, zeroes;
 835
 836         map = vser->ports_map[i];
 837         zeroes = ctz32(~map);
 838         if (zeroes != 32) {
 839             return zeroes + i * 32;
 840         }
 841     }
 842     return VIRTIO_CONSOLE_BAD_ID;
 843 }
 844
 845 static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 846 {
 847     unsigned int i;
 848
 849     i = port_id / 32;
 850     vser->ports_map[i] |= 1U << (port_id % 32);
 851 }
 852
 853 static void add_port(VirtIOSerial *vser, uint32_t port_id)
 854 {
 855     mark_port_added(vser, port_id);
 856     send_control_event(vser, port_id, VIRTIO_CONSOLE_PORT_ADD, 1);
 857 }
 858
 859 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 860 {
 861     VirtIOSerialPort *port;
 862
 863     /*
 864      * Don't mark port 0 removed -- we explicitly reserve it for
 865      * backward compat with older guests, ensure a virtconsole device
 866      * unplug retains the reservation.
 867      */
 868     if (port_id) {
 869         unsigned int i;
 870
 871         i = port_id / 32;
 872         vser->ports_map[i] &= ~(1U << (port_id % 32));
 873     }
 874
 875     port = find_port_by_id(vser, port_id);
 876     /*
 877      * This function is only called from qdev's unplug callback; if we
 878      * get a NULL port here, we're in trouble.
 879      */
 880     assert(port);
 881
 882     /* Flush out any unconsumed buffers first */
 883     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 884
 885     send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 886 }
 887
 888 static void virtser_port_device_realize(DeviceState *dev, Error **errp)
 889 {
 890     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 891     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 892     VirtIOSerialBus *bus = VIRTIO_SERIAL_BUS(qdev_get_parent_bus(dev));
 893     int max_nr_ports;
 894     bool plugging_port0;
 895     Error *err = NULL;
 896
 897     port->vser = bus->vser;
 898     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 899
 900     assert(vsc->have_data);
 901
 902     /*
 903      * Is the first console port we're seeing? If so, put it up at
 904      * location 0. This is done for backward compatibility (old
 905      * kernel, new qemu).
 906      */
 907     plugging_port0 = vsc->is_console && !find_port_by_id(port->vser, 0);
 908
 909     if (find_port_by_id(port->vser, port->id)) {
 910         error_setg(errp, "virtio-serial-bus: A port already exists at id %u",
 911                    port->id);
 912         return;
 913     }
 914
 915     if (port->name != NULL && find_port_by_name(port->name)) {
 916         error_setg(errp, "virtio-serial-bus: A port already exists by name %s",
 917                    port->name);
 918         return;
 919     }
 920
 921     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 922         if (plugging_port0) {
 923             port->id = 0;
 924         } else {
 925             port->id = find_free_port_id(port->vser);
 926             if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 927                 error_setg(errp, "virtio-serial-bus: Maximum port limit for "
 928                                  "this device reached");
 929                 return;
 930             }
 931         }
 932     }
 933
 934     max_nr_ports = port->vser->serial.max_virtserial_ports;
 935     if (port->id >= max_nr_ports) {
 936         error_setg(errp, "virtio-serial-bus: Out-of-range port id specified, "
 937                          "max. allowed: %u", max_nr_ports - 1);
 938         return;
 939     }
 940
 941     vsc->realize(dev, &err);
 942     if (err != NULL) {
 943         error_propagate(errp, err);
 944         return;
 945     }
 946
 947     port->elem = NULL;
 948 }
 949
 950 static void virtser_port_device_plug(HotplugHandler *hotplug_dev,
 951                                      DeviceState *dev, Error **errp)
 952 {
 953     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 954
 955     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
 956     port->ivq = port->vser->ivqs[port->id];
 957     port->ovq = port->vser->ovqs[port->id];
 958
 959     add_port(port->vser, port->id);
 960
 961     /* Send an update to the guest about this new port added */
 962     virtio_notify_config(VIRTIO_DEVICE(hotplug_dev));
 963 }
 964
 965 static void virtser_port_device_unrealize(DeviceState *dev, Error **errp)
 966 {
 967     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 968     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(dev);
 969     VirtIOSerial *vser = port->vser;
 970
 971     qemu_bh_delete(port->bh);
 972     remove_port(port->vser, port->id);
 973
 974     QTAILQ_REMOVE(&vser->ports, port, next);
 975
 976     if (vsc->unrealize) {
 977         vsc->unrealize(dev, errp);
 978     }
 979 }
 980
 981 static void virtio_serial_device_realize(DeviceState *dev, Error **errp)
 982 {
 983     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 984     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
 985     uint32_t i, max_supported_ports;
 986
 987     if (!vser->serial.max_virtserial_ports) {
 988         error_setg(errp, "Maximum number of serial ports not specified");
 989         return;
 990     }
 991
 992     /* Each port takes 2 queues, and one pair is for the control queue */
 993     max_supported_ports = VIRTIO_QUEUE_MAX / 2 - 1;
 994
 995     if (vser->serial.max_virtserial_ports > max_supported_ports) {
 996         error_setg(errp, "maximum ports supported: %u", max_supported_ports);
 997         return;
 998     }
 999
1000     /* We don't support emergency write, skip it for now. */
1001     /* TODO: cleaner fix, depending on host features. */
1002     virtio_init(vdev, "virtio-serial", VIRTIO_ID_CONSOLE,
1003                 offsetof(struct virtio_console_config, emerg_wr));
1004
1005     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
1006     qbus_create_inplace(&vser->bus, sizeof(vser->bus), TYPE_VIRTIO_SERIAL_BUS,
1007                         dev, vdev->bus_name);
1008     qbus_set_hotplug_handler(BUS(&vser->bus), DEVICE(vser), errp);
1009     vser->bus.vser = vser;
1010     QTAILQ_INIT(&vser->ports);
1011
1012     vser->bus.max_nr_ports = vser->serial.max_virtserial_ports;
1013     vser->ivqs = g_malloc(vser->serial.max_virtserial_ports
1014                           * sizeof(VirtQueue *));
1015     vser->ovqs = g_malloc(vser->serial.max_virtserial_ports
1016                           * sizeof(VirtQueue *));
1017
1018     /* Add a queue for host to guest transfers for port 0 (backward compat) */
1019     vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
1020     /* Add a queue for guest to host transfers for port 0 (backward compat) */
1021     vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
1022
1023     /* TODO: host to guest notifications can get dropped
1024      * if the queue fills up. Implement queueing in host,
1025      * this might also make it possible to reduce the control
1026      * queue size: as guest preposts buffers there,
1027      * this will save 4Kbyte of guest memory per entry. */
1028
1029     /* control queue: host to guest */
1030     vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
1031     /* control queue: guest to host */
1032     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
1033
1034     for (i = 1; i < vser->bus.max_nr_ports; i++) {
1035         /* Add a per-port queue for host to guest transfers */
1036         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
1037         /* Add a per-per queue for guest to host transfers */
1038         vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
1039     }
1040
1041     vser->ports_map = g_malloc0(((vser->serial.max_virtserial_ports + 31) / 32)
1042         * sizeof(vser->ports_map[0]));
1043     /*
1044      * Reserve location 0 for a console port for backward compat
1045      * (old kernel, new qemu)
1046      */
1047     mark_port_added(vser, 0);
1048
1049     vser->post_load = NULL;
1050
1051     /*
1052      * Register for the savevm section with the virtio-console name
1053      * to preserve backward compat
1054      */
1055     register_savevm(dev, "virtio-console", -1, 3, virtio_serial_save,
1056                     virtio_serial_load, vser);
1057
1058     QLIST_INSERT_HEAD(&vserdevices.devices, vser, next);
1059 }
1060
1061 static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
1062 {
1063     DeviceClass *k = DEVICE_CLASS(klass);
1064
1065     set_bit(DEVICE_CATEGORY_INPUT, k->categories);
1066     k->bus_type = TYPE_VIRTIO_SERIAL_BUS;
1067     k->realize = virtser_port_device_realize;
1068     k->unrealize = virtser_port_device_unrealize;
1069     k->props = virtser_props;
1070 }
1071
1072 static const TypeInfo virtio_serial_port_type_info = {
1073     .name = TYPE_VIRTIO_SERIAL_PORT,
1074     .parent = TYPE_DEVICE,
1075     .instance_size = sizeof(VirtIOSerialPort),
1076     .abstract = true,
1077     .class_size = sizeof(VirtIOSerialPortClass),
1078     .class_init = virtio_serial_port_class_init,
1079 };
1080
1081 static void virtio_serial_device_unrealize(DeviceState *dev, Error **errp)
1082 {
1083     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1084     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1085
1086     QLIST_REMOVE(vser, next);
1087
1088     unregister_savevm(dev, "virtio-console", vser);
1089
1090     g_free(vser->ivqs);
1091     g_free(vser->ovqs);
1092     g_free(vser->ports_map);
1093     if (vser->post_load) {
1094         g_free(vser->post_load->connected);
1095         timer_del(vser->post_load->timer);
1096         timer_free(vser->post_load->timer);
1097         g_free(vser->post_load);
1098     }
1099     virtio_cleanup(vdev);
1100 }
1101
1102 static Property virtio_serial_properties[] = {
1103     DEFINE_PROP_UINT32("max_ports", VirtIOSerial, serial.max_virtserial_ports,
1104                                                   31),
1105     DEFINE_PROP_END_OF_LIST(),
1106 };
1107
1108 static void virtio_serial_class_init(ObjectClass *klass, void *data)
1109 {
1110     DeviceClass *dc = DEVICE_CLASS(klass);
1111     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1112     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
1113
1114     QLIST_INIT(&vserdevices.devices);
1115
1116     dc->props = virtio_serial_properties;
1117     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
1118     vdc->realize = virtio_serial_device_realize;
1119     vdc->unrealize = virtio_serial_device_unrealize;
1120     vdc->get_features = get_features;
1121     vdc->get_config = get_config;
1122     vdc->set_status = set_status;
1123     vdc->reset = vser_reset;
1124     vdc->save = virtio_serial_save_device;
1125     vdc->load = virtio_serial_load_device;
1126     hc->plug = virtser_port_device_plug;
1127     hc->unplug = qdev_simple_device_unplug_cb;
1128 }
1129
1130 static const TypeInfo virtio_device_info = {
1131     .name = TYPE_VIRTIO_SERIAL,
1132     .parent = TYPE_VIRTIO_DEVICE,
1133     .instance_size = sizeof(VirtIOSerial),
1134     .class_init = virtio_serial_class_init,
1135     .interfaces = (InterfaceInfo[]) {
1136         { TYPE_HOTPLUG_HANDLER },
1137         { }
1138     }
1139 };
1140
1141 static void virtio_serial_register_types(void)
1142 {
1143     type_register_static(&virtser_bus_info);
1144     type_register_static(&virtio_serial_port_type_info);
1145     type_register_static(&virtio_device_info);
1146 }
1147
1148 type_init(virtio_serial_register_types)