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/queue.h"
  24 #include "hw/sysbus.h"
  25 #include "trace.h"
  26 #include "hw/virtio/virtio-serial.h"
  27 #include "hw/virtio/virtio-access.h"
  28
  29 static struct VirtIOSerialDevices {
  30     QLIST_HEAD(, VirtIOSerial) devices;
  31 } vserdevices;
  32
  33 static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
  34 {
  35     VirtIOSerialPort *port;
  36
  37     if (id == VIRTIO_CONSOLE_BAD_ID) {
  38         return NULL;
  39     }
  40
  41     QTAILQ_FOREACH(port, &vser->ports, next) {
  42         if (port->id == id)
  43             return port;
  44     }
  45     return NULL;
  46 }
  47
  48 static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
  49 {
  50     VirtIOSerialPort *port;
  51
  52     QTAILQ_FOREACH(port, &vser->ports, next) {
  53         if (port->ivq == vq || port->ovq == vq)
  54             return port;
  55     }
  56     return NULL;
  57 }
  58
  59 static VirtIOSerialPort *find_port_by_name(char *name)
  60 {
  61     VirtIOSerial *vser;
  62
  63     QLIST_FOREACH(vser, &vserdevices.devices, next) {
  64         VirtIOSerialPort *port;
  65
  66         QTAILQ_FOREACH(port, &vser->ports, next) {
  67             if (port->name && !strcmp(port->name, name)) {
  68                 return port;
  69             }
  70         }
  71     }
  72     return NULL;
  73 }
  74
  75 static bool use_multiport(VirtIOSerial *vser)
  76 {
  77     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
  78     return virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT);
  79 }
  80
  81 static size_t write_to_port(VirtIOSerialPort *port,
  82                             const uint8_t *buf, size_t size)
  83 {
  84     VirtQueueElement elem;
  85     VirtQueue *vq;
  86     size_t offset;
  87
  88     vq = port->ivq;
  89     if (!virtio_queue_ready(vq)) {
  90         return 0;
  91     }
  92
  93     offset = 0;
  94     while (offset < size) {
  95         size_t len;
  96
  97         if (!virtqueue_pop(vq, &elem)) {
  98             break;
  99         }
 100
 101         len = iov_from_buf(elem.in_sg, elem.in_num, 0,
 102                            buf + offset, size - offset);
 103         offset += len;
 104
 105         virtqueue_push(vq, &elem, len);
 106     }
 107
 108     virtio_notify(VIRTIO_DEVICE(port->vser), vq);
 109     return offset;
 110 }
 111
 112 static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
 113 {
 114     VirtQueueElement elem;
 115
 116     if (!virtio_queue_ready(vq)) {
 117         return;
 118     }
 119     while (virtqueue_pop(vq, &elem)) {
 120         virtqueue_push(vq, &elem, 0);
 121     }
 122     virtio_notify(vdev, vq);
 123 }
 124
 125 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 126                                  VirtIODevice *vdev)
 127 {
 128     VirtIOSerialPortClass *vsc;
 129
 130     assert(port);
 131     assert(virtio_queue_ready(vq));
 132
 133     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 134
 135     while (!port->throttled) {
 136         unsigned int i;
 137
 138         /* Pop an elem only if we haven't left off a previous one mid-way */
 139         if (!port->elem.out_num) {
 140             if (!virtqueue_pop(vq, &port->elem)) {
 141                 break;
 142             }
 143             port->iov_idx = 0;
 144             port->iov_offset = 0;
 145         }
 146
 147         for (i = port->iov_idx; i < port->elem.out_num; i++) {
 148             size_t buf_size;
 149             ssize_t ret;
 150
 151             buf_size = port->elem.out_sg[i].iov_len - port->iov_offset;
 152             ret = vsc->have_data(port,
 153                                   port->elem.out_sg[i].iov_base
 154                                   + port->iov_offset,
 155                                   buf_size);
 156             if (port->throttled) {
 157                 port->iov_idx = i;
 158                 if (ret > 0) {
 159                     port->iov_offset += ret;
 160                 }
 161                 break;
 162             }
 163             port->iov_offset = 0;
 164         }
 165         if (port->throttled) {
 166             break;
 167         }
 168         virtqueue_push(vq, &port->elem, 0);
 169         port->elem.out_num = 0;
 170     }
 171     virtio_notify(vdev, vq);
 172 }
 173
 174 static void flush_queued_data(VirtIOSerialPort *port)
 175 {
 176     assert(port);
 177
 178     if (!virtio_queue_ready(port->ovq)) {
 179         return;
 180     }
 181     do_flush_queued_data(port, port->ovq, VIRTIO_DEVICE(port->vser));
 182 }
 183
 184 static size_t send_control_msg(VirtIOSerial *vser, void *buf, size_t len)
 185 {
 186     VirtQueueElement elem;
 187     VirtQueue *vq;
 188
 189     vq = vser->c_ivq;
 190     if (!virtio_queue_ready(vq)) {
 191         return 0;
 192     }
 193     if (!virtqueue_pop(vq, &elem)) {
 194         return 0;
 195     }
 196
 197     memcpy(elem.in_sg[0].iov_base, buf, len);
 198
 199     virtqueue_push(vq, &elem, len);
 200     virtio_notify(VIRTIO_DEVICE(vser), vq);
 201     return len;
 202 }
 203
 204 static size_t send_control_event(VirtIOSerial *vser, uint32_t port_id,
 205                                  uint16_t event, uint16_t value)
 206 {
 207     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 208     struct virtio_console_control cpkt;
 209
 210     virtio_stl_p(vdev, &cpkt.id, port_id);
 211     virtio_stw_p(vdev, &cpkt.event, event);
 212     virtio_stw_p(vdev, &cpkt.value, value);
 213
 214     trace_virtio_serial_send_control_event(port_id, event, value);
 215     return send_control_msg(vser, &cpkt, sizeof(cpkt));
 216 }
 217
 218 /* Functions for use inside qemu to open and read from/write to ports */
 219 int virtio_serial_open(VirtIOSerialPort *port)
 220 {
 221     /* Don't allow opening an already-open port */
 222     if (port->host_connected) {
 223         return 0;
 224     }
 225     /* Send port open notification to the guest */
 226     port->host_connected = true;
 227     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 228
 229     return 0;
 230 }
 231
 232 int virtio_serial_close(VirtIOSerialPort *port)
 233 {
 234     port->host_connected = false;
 235     /*
 236      * If there's any data the guest sent which the app didn't
 237      * consume, reset the throttling flag and discard the data.
 238      */
 239     port->throttled = false;
 240     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 241
 242     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 0);
 243
 244     return 0;
 245 }
 246
 247 /* Individual ports/apps call this function to write to the guest. */
 248 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 249                             size_t size)
 250 {
 251     if (!port || !port->host_connected || !port->guest_connected) {
 252         return 0;
 253     }
 254     return write_to_port(port, buf, size);
 255 }
 256
 257 /*
 258  * Readiness of the guest to accept data on a port.
 259  * Returns max. data the guest can receive
 260  */
 261 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 262 {
 263     VirtIODevice *vdev = VIRTIO_DEVICE(port->vser);
 264     VirtQueue *vq = port->ivq;
 265     unsigned int bytes;
 266
 267     if (!virtio_queue_ready(vq) ||
 268         !(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 269         virtio_queue_empty(vq)) {
 270         return 0;
 271     }
 272     if (use_multiport(port->vser) && !port->guest_connected) {
 273         return 0;
 274     }
 275     virtqueue_get_avail_bytes(vq, &bytes, NULL, 4096, 0);
 276     return bytes;
 277 }
 278
 279 static void flush_queued_data_bh(void *opaque)
 280 {
 281     VirtIOSerialPort *port = opaque;
 282
 283     flush_queued_data(port);
 284 }
 285
 286 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 287 {
 288     if (!port) {
 289         return;
 290     }
 291
 292     trace_virtio_serial_throttle_port(port->id, throttle);
 293     port->throttled = throttle;
 294     if (throttle) {
 295         return;
 296     }
 297     qemu_bh_schedule(port->bh);
 298 }
 299
 300 /* Guest wants to notify us of some event */
 301 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 302 {
 303     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 304     struct VirtIOSerialPort *port;
 305     VirtIOSerialPortClass *vsc;
 306     struct virtio_console_control cpkt, *gcpkt;
 307     uint8_t *buffer;
 308     size_t buffer_len;
 309
 310     gcpkt = buf;
 311
 312     if (len < sizeof(cpkt)) {
 313         /* The guest sent an invalid control packet */
 314         return;
 315     }
 316
 317     cpkt.event = virtio_lduw_p(vdev, &gcpkt->event);
 318     cpkt.value = virtio_lduw_p(vdev, &gcpkt->value);
 319
 320     trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 321
 322     if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 323         if (!cpkt.value) {
 324             error_report("virtio-serial-bus: Guest failure in adding device %s",
 325                          vser->bus.qbus.name);
 326             return;
 327         }
 328         /*
 329          * The device is up, we can now tell the device about all the
 330          * ports we have here.
 331          */
 332         QTAILQ_FOREACH(port, &vser->ports, next) {
 333             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_ADD, 1);
 334         }
 335         return;
 336     }
 337
 338     port = find_port_by_id(vser, virtio_ldl_p(vdev, &gcpkt->id));
 339     if (!port) {
 340         error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 341                      virtio_ldl_p(vdev, &gcpkt->id), vser->bus.qbus.name);
 342         return;
 343     }
 344
 345     trace_virtio_serial_handle_control_message_port(port->id);
 346
 347     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 348
 349     switch(cpkt.event) {
 350     case VIRTIO_CONSOLE_PORT_READY:
 351         if (!cpkt.value) {
 352             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 353                          port->id, vser->bus.qbus.name);
 354             break;
 355         }
 356         /*
 357          * Now that we know the guest asked for the port name, we're
 358          * sure the guest has initialised whatever state is necessary
 359          * for this port. Now's a good time to let the guest know if
 360          * this port is a console port so that the guest can hook it
 361          * up to hvc.
 362          */
 363         if (vsc->is_console) {
 364             send_control_event(vser, port->id, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 365         }
 366
 367         if (port->name) {
 368             virtio_stl_p(vdev, &cpkt.id, port->id);
 369             virtio_stw_p(vdev, &cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 370             virtio_stw_p(vdev, &cpkt.value, 1);
 371
 372             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 373             buffer = g_malloc(buffer_len);
 374
 375             memcpy(buffer, &cpkt, sizeof(cpkt));
 376             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 377             buffer[buffer_len - 1] = 0;
 378
 379             send_control_msg(vser, buffer, buffer_len);
 380             g_free(buffer);
 381         }
 382
 383         if (port->host_connected) {
 384             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 385         }
 386
 387         /*
 388          * When the guest has asked us for this information it means
 389          * the guest is all setup and has its virtqueues
 390          * initialised. If some app is interested in knowing about
 391          * this event, let it know.
 392          */
 393         if (vsc->guest_ready) {
 394             vsc->guest_ready(port);
 395         }
 396         break;
 397
 398     case VIRTIO_CONSOLE_PORT_OPEN:
 399         port->guest_connected = cpkt.value;
 400         if (vsc->set_guest_connected) {
 401             /* Send the guest opened notification if an app is interested */
 402             vsc->set_guest_connected(port, cpkt.value);
 403         }
 404         break;
 405     }
 406 }
 407
 408 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 409 {
 410 }
 411
 412 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 413 {
 414     VirtQueueElement elem;
 415     VirtIOSerial *vser;
 416     uint8_t *buf;
 417     size_t len;
 418
 419     vser = VIRTIO_SERIAL(vdev);
 420
 421     len = 0;
 422     buf = NULL;
 423     while (virtqueue_pop(vq, &elem)) {
 424         size_t cur_len;
 425
 426         cur_len = iov_size(elem.out_sg, elem.out_num);
 427         /*
 428          * Allocate a new buf only if we didn't have one previously or
 429          * if the size of the buf differs
 430          */
 431         if (cur_len > len) {
 432             g_free(buf);
 433
 434             buf = g_malloc(cur_len);
 435             len = cur_len;
 436         }
 437         iov_to_buf(elem.out_sg, elem.out_num, 0, buf, cur_len);
 438
 439         handle_control_message(vser, buf, cur_len);
 440         virtqueue_push(vq, &elem, 0);
 441     }
 442     g_free(buf);
 443     virtio_notify(vdev, vq);
 444 }
 445
 446 /* Guest wrote something to some port. */
 447 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 448 {
 449     VirtIOSerial *vser;
 450     VirtIOSerialPort *port;
 451
 452     vser = VIRTIO_SERIAL(vdev);
 453     port = find_port_by_vq(vser, vq);
 454
 455     if (!port || !port->host_connected) {
 456         discard_vq_data(vq, vdev);
 457         return;
 458     }
 459
 460     if (!port->throttled) {
 461         do_flush_queued_data(port, vq, vdev);
 462         return;
 463     }
 464 }
 465
 466 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 467 {
 468     /*
 469      * Users of virtio-serial would like to know when guest becomes
 470      * writable again -- i.e. if a vq had stuff queued up and the
 471      * guest wasn't reading at all, the host would not be able to
 472      * write to the vq anymore.  Once the guest reads off something,
 473      * we can start queueing things up again.  However, this call is
 474      * made for each buffer addition by the guest -- even though free
 475      * buffers existed prior to the current buffer addition.  This is
 476      * done so as not to maintain previous state, which will need
 477      * additional live-migration-related changes.
 478      */
 479     VirtIOSerial *vser;
 480     VirtIOSerialPort *port;
 481     VirtIOSerialPortClass *vsc;
 482
 483     vser = VIRTIO_SERIAL(vdev);
 484     port = find_port_by_vq(vser, vq);
 485
 486     if (!port) {
 487         return;
 488     }
 489     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 490
 491     /*
 492      * If guest_connected is false, this call is being made by the
 493      * early-boot queueing up of descriptors, which is just noise for
 494      * the host apps -- don't disturb them in that case.
 495      */
 496     if (port->guest_connected && port->host_connected && vsc->guest_writable) {
 497         vsc->guest_writable(port);
 498     }
 499 }
 500
 501 static uint32_t get_features(VirtIODevice *vdev, uint32_t features)
 502 {
 503     VirtIOSerial *vser;
 504
 505     vser = VIRTIO_SERIAL(vdev);
 506
 507     if (vser->bus.max_nr_ports > 1) {
 508         virtio_add_feature(&features, VIRTIO_CONSOLE_F_MULTIPORT);
 509     }
 510     return features;
 511 }
 512
 513 /* Guest requested config info */
 514 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 515 {
 516     VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 517     struct virtio_console_config *config =
 518         (struct virtio_console_config *)config_data;
 519
 520     config->cols = 0;
 521     config->rows = 0;
 522     config->max_nr_ports = virtio_tswap32(vdev,
 523                                           vser->serial.max_virtserial_ports);
 524 }
 525
 526 static void guest_reset(VirtIOSerial *vser)
 527 {
 528     VirtIOSerialPort *port;
 529     VirtIOSerialPortClass *vsc;
 530
 531     QTAILQ_FOREACH(port, &vser->ports, next) {
 532         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 533         if (port->guest_connected) {
 534             port->guest_connected = false;
 535             if (vsc->set_guest_connected) {
 536                 vsc->set_guest_connected(port, false);
 537             }
 538         }
 539     }
 540 }
 541
 542 static void set_status(VirtIODevice *vdev, uint8_t status)
 543 {
 544     VirtIOSerial *vser;
 545     VirtIOSerialPort *port;
 546
 547     vser = VIRTIO_SERIAL(vdev);
 548     port = find_port_by_id(vser, 0);
 549
 550     if (port && !use_multiport(port->vser)
 551         && (status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 552         /*
 553          * Non-multiport guests won't be able to tell us guest
 554          * open/close status.  Such guests can only have a port at id
 555          * 0, so set guest_connected for such ports as soon as guest
 556          * is up.
 557          */
 558         port->guest_connected = true;
 559     }
 560     if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 561         guest_reset(vser);
 562     }
 563 }
 564
 565 static void vser_reset(VirtIODevice *vdev)
 566 {
 567     VirtIOSerial *vser;
 568
 569     vser = VIRTIO_SERIAL(vdev);
 570     guest_reset(vser);
 571 }
 572
 573 static void virtio_serial_save(QEMUFile *f, void *opaque)
 574 {
 575     /* The virtio device */
 576     virtio_save(VIRTIO_DEVICE(opaque), f);
 577 }
 578
 579 static void virtio_serial_save_device(VirtIODevice *vdev, QEMUFile *f)
 580 {
 581     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 582     VirtIOSerialPort *port;
 583     uint32_t nr_active_ports;
 584     unsigned int i, max_nr_ports;
 585     struct virtio_console_config config;
 586
 587     /* The config space (ignored on the far end in current versions) */
 588     get_config(vdev, (uint8_t *)&config);
 589     qemu_put_be16s(f, &config.cols);
 590     qemu_put_be16s(f, &config.rows);
 591     qemu_put_be32s(f, &config.max_nr_ports);
 592
 593     /* The ports map */
 594     max_nr_ports = s->serial.max_virtserial_ports;
 595     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 596         qemu_put_be32s(f, &s->ports_map[i]);
 597     }
 598
 599     /* Ports */
 600
 601     nr_active_ports = 0;
 602     QTAILQ_FOREACH(port, &s->ports, next) {
 603         nr_active_ports++;
 604     }
 605
 606     qemu_put_be32s(f, &nr_active_ports);
 607
 608     /*
 609      * Items in struct VirtIOSerialPort.
 610      */
 611     QTAILQ_FOREACH(port, &s->ports, next) {
 612         uint32_t elem_popped;
 613
 614         qemu_put_be32s(f, &port->id);
 615         qemu_put_byte(f, port->guest_connected);
 616         qemu_put_byte(f, port->host_connected);
 617
 618         elem_popped = 0;
 619         if (port->elem.out_num) {
 620             elem_popped = 1;
 621         }
 622         qemu_put_be32s(f, &elem_popped);
 623         if (elem_popped) {
 624             qemu_put_be32s(f, &port->iov_idx);
 625             qemu_put_be64s(f, &port->iov_offset);
 626
 627             qemu_put_buffer(f, (unsigned char *)&port->elem,
 628                             sizeof(port->elem));
 629         }
 630     }
 631 }
 632
 633 static void virtio_serial_post_load_timer_cb(void *opaque)
 634 {
 635     uint32_t i;
 636     VirtIOSerial *s = VIRTIO_SERIAL(opaque);
 637     VirtIOSerialPort *port;
 638     uint8_t host_connected;
 639     VirtIOSerialPortClass *vsc;
 640
 641     if (!s->post_load) {
 642         return;
 643     }
 644     for (i = 0 ; i < s->post_load->nr_active_ports; ++i) {
 645         port = s->post_load->connected[i].port;
 646         host_connected = s->post_load->connected[i].host_connected;
 647         if (host_connected != port->host_connected) {
 648             /*
 649              * We have to let the guest know of the host connection
 650              * status change
 651              */
 652             send_control_event(s, port->id, VIRTIO_CONSOLE_PORT_OPEN,
 653                                port->host_connected);
 654         }
 655         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 656         if (vsc->set_guest_connected) {
 657             vsc->set_guest_connected(port, port->guest_connected);
 658         }
 659     }
 660     g_free(s->post_load->connected);
 661     timer_free(s->post_load->timer);
 662     g_free(s->post_load);
 663     s->post_load = NULL;
 664 }
 665
 666 static int fetch_active_ports_list(QEMUFile *f, int version_id,
 667                                    VirtIOSerial *s, uint32_t nr_active_ports)
 668 {
 669     uint32_t i;
 670
 671     s->post_load = g_malloc0(sizeof(*s->post_load));
 672     s->post_load->nr_active_ports = nr_active_ports;
 673     s->post_load->connected =
 674         g_malloc0(sizeof(*s->post_load->connected) * nr_active_ports);
 675
 676     s->post_load->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
 677                                             virtio_serial_post_load_timer_cb,
 678                                             s);
 679
 680     /* Items in struct VirtIOSerialPort */
 681     for (i = 0; i < nr_active_ports; i++) {
 682         VirtIOSerialPort *port;
 683         uint32_t id;
 684
 685         id = qemu_get_be32(f);
 686         port = find_port_by_id(s, id);
 687         if (!port) {
 688             return -EINVAL;
 689         }
 690
 691         port->guest_connected = qemu_get_byte(f);
 692         s->post_load->connected[i].port = port;
 693         s->post_load->connected[i].host_connected = qemu_get_byte(f);
 694
 695         if (version_id > 2) {
 696             uint32_t elem_popped;
 697
 698             qemu_get_be32s(f, &elem_popped);
 699             if (elem_popped) {
 700                 qemu_get_be32s(f, &port->iov_idx);
 701                 qemu_get_be64s(f, &port->iov_offset);
 702
 703                 qemu_get_buffer(f, (unsigned char *)&port->elem,
 704                                 sizeof(port->elem));
 705                 virtqueue_map_sg(port->elem.in_sg, port->elem.in_addr,
 706                                  port->elem.in_num, 1);
 707                 virtqueue_map_sg(port->elem.out_sg, port->elem.out_addr,
 708                                  port->elem.out_num, 1);
 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 = DO_UPCAST(VirtIOSerialPort, dev, 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_VIRTIO_SERIAL_PROPERTIES(VirtIOSerial, serial),
1087     DEFINE_PROP_END_OF_LIST(),
1088 };
1089
1090 static void virtio_serial_class_init(ObjectClass *klass, void *data)
1091 {
1092     DeviceClass *dc = DEVICE_CLASS(klass);
1093     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1094     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
1095
1096     QLIST_INIT(&vserdevices.devices);
1097
1098     dc->props = virtio_serial_properties;
1099     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
1100     vdc->realize = virtio_serial_device_realize;
1101     vdc->unrealize = virtio_serial_device_unrealize;
1102     vdc->get_features = get_features;
1103     vdc->get_config = get_config;
1104     vdc->set_status = set_status;
1105     vdc->reset = vser_reset;
1106     vdc->save = virtio_serial_save_device;
1107     vdc->load = virtio_serial_load_device;
1108     hc->plug = virtser_port_device_plug;
1109     hc->unplug = qdev_simple_device_unplug_cb;
1110 }
1111
1112 static const TypeInfo virtio_device_info = {
1113     .name = TYPE_VIRTIO_SERIAL,
1114     .parent = TYPE_VIRTIO_DEVICE,
1115     .instance_size = sizeof(VirtIOSerial),
1116     .class_init = virtio_serial_class_init,
1117     .interfaces = (InterfaceInfo[]) {
1118         { TYPE_HOTPLUG_HANDLER },
1119         { }
1120     }
1121 };
1122
1123 static void virtio_serial_register_types(void)
1124 {
1125     type_register_static(&virtser_bus_info);
1126     type_register_static(&virtio_serial_port_type_info);
1127     type_register_static(&virtio_device_info);
1128 }
1129
1130 type_init(virtio_serial_register_types)