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