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 "qapi/error.h"
  23 #include "qemu/iov.h"
  24 #include "monitor/monitor.h"
  25 #include "qemu/error-report.h"
  26 #include "qemu/queue.h"
  27 #include "hw/sysbus.h"
  28 #include "trace.h"
  29 #include "hw/virtio/virtio-serial.h"
  30 #include "hw/virtio/virtio-access.h"
  31
  32 static struct VirtIOSerialDevices {
  33     QLIST_HEAD(, VirtIOSerial) devices;
  34 } vserdevices;
  35
  36 static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
  37 {
  38     VirtIOSerialPort *port;
  39
  40     if (id == VIRTIO_CONSOLE_BAD_ID) {
  41         return NULL;
  42     }
  43
  44     QTAILQ_FOREACH(port, &vser->ports, next) {
  45         if (port->id == id)
  46             return port;
  47     }
  48     return NULL;
  49 }
  50
  51 static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
  52 {
  53     VirtIOSerialPort *port;
  54
  55     QTAILQ_FOREACH(port, &vser->ports, next) {
  56         if (port->ivq == vq || port->ovq == vq)
  57             return port;
  58     }
  59     return NULL;
  60 }
  61
  62 static VirtIOSerialPort *find_port_by_name(char *name)
  63 {
  64     VirtIOSerial *vser;
  65
  66     QLIST_FOREACH(vser, &vserdevices.devices, next) {
  67         VirtIOSerialPort *port;
  68
  69         QTAILQ_FOREACH(port, &vser->ports, next) {
  70             if (port->name && !strcmp(port->name, name)) {
  71                 return port;
  72             }
  73         }
  74     }
  75     return NULL;
  76 }
  77
  78 static VirtIOSerialPort *find_first_connected_console(VirtIOSerial *vser)
  79 {
  80     VirtIOSerialPort *port;
  81
  82     QTAILQ_FOREACH(port, &vser->ports, next) {
  83         VirtIOSerialPortClass const *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
  84         if (vsc->is_console && port->host_connected) {
  85             return port;
  86         }
  87     }
  88     return NULL;
  89 }
  90
  91 static bool use_multiport(VirtIOSerial *vser)
  92 {
  93     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
  94     return virtio_vdev_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT);
  95 }
  96
  97 static size_t write_to_port(VirtIOSerialPort *port,
  98                             const uint8_t *buf, size_t size)
  99 {
 100     VirtQueueElement *elem;
 101     VirtQueue *vq;
 102     size_t offset;
 103
 104     vq = port->ivq;
 105     if (!virtio_queue_ready(vq)) {
 106         return 0;
 107     }
 108
 109     offset = 0;
 110     while (offset < size) {
 111         size_t len;
 112
 113         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 114         if (!elem) {
 115             break;
 116         }
 117
 118         len = iov_from_buf(elem->in_sg, elem->in_num, 0,
 119                            buf + offset, size - offset);
 120         offset += len;
 121
 122         virtqueue_push(vq, elem, len);
 123         g_free(elem);
 124     }
 125
 126     virtio_notify(VIRTIO_DEVICE(port->vser), vq);
 127     return offset;
 128 }
 129
 130 static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
 131 {
 132     VirtQueueElement *elem;
 133
 134     if (!virtio_queue_ready(vq)) {
 135         return;
 136     }
 137     for (;;) {
 138         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 139         if (!elem) {
 140             break;
 141         }
 142         virtqueue_push(vq, elem, 0);
 143         g_free(elem);
 144     }
 145     virtio_notify(vdev, vq);
 146 }
 147
 148 static void discard_throttle_data(VirtIOSerialPort *port)
 149 {
 150     if (port->elem) {
 151         virtqueue_detach_element(port->ovq, port->elem, 0);
 152         g_free(port->elem);
 153         port->elem = NULL;
 154     }
 155 }
 156
 157 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 158                                  VirtIODevice *vdev)
 159 {
 160     VirtIOSerialPortClass *vsc;
 161
 162     assert(port);
 163     assert(virtio_queue_ready(vq));
 164
 165     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 166
 167     while (!port->throttled) {
 168         unsigned int i;
 169
 170         /* Pop an elem only if we haven't left off a previous one mid-way */
 171         if (!port->elem) {
 172             port->elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 173             if (!port->elem) {
 174                 break;
 175             }
 176             port->iov_idx = 0;
 177             port->iov_offset = 0;
 178         }
 179
 180         for (i = port->iov_idx; i < port->elem->out_num; i++) {
 181             size_t buf_size;
 182             ssize_t ret;
 183
 184             buf_size = port->elem->out_sg[i].iov_len - port->iov_offset;
 185             ret = vsc->have_data(port,
 186                                   port->elem->out_sg[i].iov_base
 187                                   + port->iov_offset,
 188                                   buf_size);
 189             if (!port->elem) { /* bail if we got disconnected */
 190                 return;
 191             }
 192             if (port->throttled) {
 193                 port->iov_idx = i;
 194                 if (ret > 0) {
 195                     port->iov_offset += ret;
 196                 }
 197                 break;
 198             }
 199             port->iov_offset = 0;
 200         }
 201         if (port->throttled) {
 202             break;
 203         }
 204         virtqueue_push(vq, port->elem, 0);
 205         g_free(port->elem);
 206         port->elem = NULL;
 207     }
 208     virtio_notify(vdev, vq);
 209 }
 210
 211 static void flush_queued_data(VirtIOSerialPort *port)
 212 {
 213     assert(port);
 214
 215     if (!virtio_queue_ready(port->ovq)) {
 216         return;
 217     }
 218     do_flush_queued_data(port, port->ovq, VIRTIO_DEVICE(port->vser));
 219 }
 220
 221 static size_t send_control_msg(VirtIOSerial *vser, void *buf, size_t len)
 222 {
 223     VirtQueueElement *elem;
 224     VirtQueue *vq;
 225
 226     vq = vser->c_ivq;
 227     if (!virtio_queue_ready(vq)) {
 228         return 0;
 229     }
 230
 231     elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 232     if (!elem) {
 233         return 0;
 234     }
 235
 236     /* TODO: detect a buffer that's too short, set NEEDS_RESET */
 237     iov_from_buf(elem->in_sg, elem->in_num, 0, buf, len);
 238
 239     virtqueue_push(vq, elem, len);
 240     virtio_notify(VIRTIO_DEVICE(vser), vq);
 241     g_free(elem);
 242
 243     return len;
 244 }
 245
 246 static size_t send_control_event(VirtIOSerial *vser, uint32_t port_id,
 247                                  uint16_t event, uint16_t value)
 248 {
 249     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 250     struct virtio_console_control cpkt;
 251
 252     virtio_stl_p(vdev, &cpkt.id, port_id);
 253     virtio_stw_p(vdev, &cpkt.event, event);
 254     virtio_stw_p(vdev, &cpkt.value, value);
 255
 256     trace_virtio_serial_send_control_event(port_id, event, value);
 257     return send_control_msg(vser, &cpkt, sizeof(cpkt));
 258 }
 259
 260 /* Functions for use inside qemu to open and read from/write to ports */
 261 int virtio_serial_open(VirtIOSerialPort *port)
 262 {
 263     /* Don't allow opening an already-open port */
 264     if (port->host_connected) {
 265         return 0;
 266     }
 267     /* Send port open notification to the guest */
 268     port->host_connected = true;
 269     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 270
 271     return 0;
 272 }
 273
 274 int virtio_serial_close(VirtIOSerialPort *port)
 275 {
 276     port->host_connected = false;
 277     /*
 278      * If there's any data the guest sent which the app didn't
 279      * consume, reset the throttling flag and discard the data.
 280      */
 281     port->throttled = false;
 282     discard_throttle_data(port);
 283     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 284
 285     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 0);
 286
 287     return 0;
 288 }
 289
 290 /* Individual ports/apps call this function to write to the guest. */
 291 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 292                             size_t size)
 293 {
 294     if (!port || !port->host_connected || !port->guest_connected) {
 295         return 0;
 296     }
 297     return write_to_port(port, buf, size);
 298 }
 299
 300 /*
 301  * Readiness of the guest to accept data on a port.
 302  * Returns max. data the guest can receive
 303  */
 304 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 305 {
 306     VirtIODevice *vdev = VIRTIO_DEVICE(port->vser);
 307     VirtQueue *vq = port->ivq;
 308     unsigned int bytes;
 309
 310     if (!virtio_queue_ready(vq) ||
 311         !(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 312         virtio_queue_empty(vq)) {
 313         return 0;
 314     }
 315     if (use_multiport(port->vser) && !port->guest_connected) {
 316         return 0;
 317     }
 318     virtqueue_get_avail_bytes(vq, &bytes, NULL, 4096, 0);
 319     return bytes;
 320 }
 321
 322 static void flush_queued_data_bh(void *opaque)
 323 {
 324     VirtIOSerialPort *port = opaque;
 325
 326     flush_queued_data(port);
 327 }
 328
 329 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 330 {
 331     if (!port) {
 332         return;
 333     }
 334
 335     trace_virtio_serial_throttle_port(port->id, throttle);
 336     port->throttled = throttle;
 337     if (throttle) {
 338         return;
 339     }
 340     qemu_bh_schedule(port->bh);
 341 }
 342
 343 /* Guest wants to notify us of some event */
 344 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 345 {
 346     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 347     struct VirtIOSerialPort *port;
 348     VirtIOSerialPortClass *vsc;
 349     struct virtio_console_control cpkt, *gcpkt;
 350     uint8_t *buffer;
 351     size_t buffer_len;
 352
 353     gcpkt = buf;
 354
 355     if (len < sizeof(cpkt)) {
 356         /* The guest sent an invalid control packet */
 357         return;
 358     }
 359
 360     cpkt.event = virtio_lduw_p(vdev, &gcpkt->event);
 361     cpkt.value = virtio_lduw_p(vdev, &gcpkt->value);
 362
 363     trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 364
 365     if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 366         if (!cpkt.value) {
 367             error_report("virtio-serial-bus: Guest failure in adding device %s",
 368                          vser->bus.qbus.name);
 369             return;
 370         }
 371         /*
 372          * The device is up, we can now tell the device about all the
 373          * ports we have here.
 374          */
 375         QTAILQ_FOREACH(port, &vser->ports, next) {
 376             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_ADD, 1);
 377         }
 378         return;
 379     }
 380
 381     port = find_port_by_id(vser, virtio_ldl_p(vdev, &gcpkt->id));
 382     if (!port) {
 383         error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 384                      virtio_ldl_p(vdev, &gcpkt->id), vser->bus.qbus.name);
 385         return;
 386     }
 387
 388     trace_virtio_serial_handle_control_message_port(port->id);
 389
 390     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 391
 392     switch(cpkt.event) {
 393     case VIRTIO_CONSOLE_PORT_READY:
 394         if (!cpkt.value) {
 395             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 396                          port->id, vser->bus.qbus.name);
 397             break;
 398         }
 399         /*
 400          * Now that we know the guest asked for the port name, we're
 401          * sure the guest has initialised whatever state is necessary
 402          * for this port. Now's a good time to let the guest know if
 403          * this port is a console port so that the guest can hook it
 404          * up to hvc.
 405          */
 406         if (vsc->is_console) {
 407             send_control_event(vser, port->id, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 408         }
 409
 410         if (port->name) {
 411             virtio_stl_p(vdev, &cpkt.id, port->id);
 412             virtio_stw_p(vdev, &cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 413             virtio_stw_p(vdev, &cpkt.value, 1);
 414
 415             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 416             buffer = g_malloc(buffer_len);
 417
 418             memcpy(buffer, &cpkt, sizeof(cpkt));
 419             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 420             buffer[buffer_len - 1] = 0;
 421
 422             send_control_msg(vser, buffer, buffer_len);
 423             g_free(buffer);
 424         }
 425
 426         if (port->host_connected) {
 427             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 428         }
 429
 430         /*
 431          * When the guest has asked us for this information it means
 432          * the guest is all setup and has its virtqueues
 433          * initialised. If some app is interested in knowing about
 434          * this event, let it know.
 435          */
 436         if (vsc->guest_ready) {
 437             vsc->guest_ready(port);
 438         }
 439         break;
 440
 441     case VIRTIO_CONSOLE_PORT_OPEN:
 442         port->guest_connected = cpkt.value;
 443         if (vsc->set_guest_connected) {
 444             /* Send the guest opened notification if an app is interested */
 445             vsc->set_guest_connected(port, cpkt.value);
 446         }
 447         break;
 448     }
 449 }
 450
 451 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 452 {
 453 }
 454
 455 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 456 {
 457     VirtQueueElement *elem;
 458     VirtIOSerial *vser;
 459     uint8_t *buf;
 460     size_t len;
 461
 462     vser = VIRTIO_SERIAL(vdev);
 463
 464     len = 0;
 465     buf = NULL;
 466     for (;;) {
 467         size_t cur_len;
 468
 469         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 470         if (!elem) {
 471             break;
 472         }
 473
 474         cur_len = iov_size(elem->out_sg, elem->out_num);
 475         /*
 476          * Allocate a new buf only if we didn't have one previously or
 477          * if the size of the buf differs
 478          */
 479         if (cur_len > len) {
 480             g_free(buf);
 481
 482             buf = g_malloc(cur_len);
 483             len = cur_len;
 484         }
 485         iov_to_buf(elem->out_sg, elem->out_num, 0, buf, cur_len);
 486
 487         handle_control_message(vser, buf, cur_len);
 488         virtqueue_push(vq, elem, 0);
 489         g_free(elem);
 490     }
 491     g_free(buf);
 492     virtio_notify(vdev, vq);
 493 }
 494
 495 /* Guest wrote something to some port. */
 496 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 497 {
 498     VirtIOSerial *vser;
 499     VirtIOSerialPort *port;
 500
 501     vser = VIRTIO_SERIAL(vdev);
 502     port = find_port_by_vq(vser, vq);
 503
 504     if (!port || !port->host_connected) {
 505         discard_vq_data(vq, vdev);
 506         return;
 507     }
 508
 509     if (!port->throttled) {
 510         do_flush_queued_data(port, vq, vdev);
 511         return;
 512     }
 513 }
 514
 515 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 516 {
 517     /*
 518      * Users of virtio-serial would like to know when guest becomes
 519      * writable again -- i.e. if a vq had stuff queued up and the
 520      * guest wasn't reading at all, the host would not be able to
 521      * write to the vq anymore.  Once the guest reads off something,
 522      * we can start queueing things up again.  However, this call is
 523      * made for each buffer addition by the guest -- even though free
 524      * buffers existed prior to the current buffer addition.  This is
 525      * done so as not to maintain previous state, which will need
 526      * additional live-migration-related changes.
 527      */
 528     VirtIOSerial *vser;
 529     VirtIOSerialPort *port;
 530     VirtIOSerialPortClass *vsc;
 531
 532     vser = VIRTIO_SERIAL(vdev);
 533     port = find_port_by_vq(vser, vq);
 534
 535     if (!port) {
 536         return;
 537     }
 538     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 539
 540     /*
 541      * If guest_connected is false, this call is being made by the
 542      * early-boot queueing up of descriptors, which is just noise for
 543      * the host apps -- don't disturb them in that case.
 544      */
 545     if (port->guest_connected && port->host_connected && vsc->guest_writable) {
 546         vsc->guest_writable(port);
 547     }
 548 }
 549
 550 static uint64_t get_features(VirtIODevice *vdev, uint64_t features,
 551                              Error **errp)
 552 {
 553     VirtIOSerial *vser;
 554
 555     vser = VIRTIO_SERIAL(vdev);
 556
 557     features |= vser->host_features;
 558     if (vser->bus.max_nr_ports > 1) {
 559         virtio_add_feature(&features, VIRTIO_CONSOLE_F_MULTIPORT);
 560     }
 561     return features;
 562 }
 563
 564 /* Guest requested config info */
 565 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 566 {
 567     VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 568     struct virtio_console_config *config =
 569         (struct virtio_console_config *)config_data;
 570
 571     config->cols = 0;
 572     config->rows = 0;
 573     config->max_nr_ports = virtio_tswap32(vdev,
 574                                           vser->serial.max_virtserial_ports);
 575 }
 576
 577 /* Guest sent new config info */
 578 static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
 579 {
 580     VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 581     struct virtio_console_config *config =
 582         (struct virtio_console_config *)config_data;
 583     uint8_t emerg_wr_lo = le32_to_cpu(config->emerg_wr);
 584     VirtIOSerialPort *port = find_first_connected_console(vser);
 585     VirtIOSerialPortClass *vsc;
 586
 587     if (!config->emerg_wr) {
 588         return;
 589     }
 590     /* Make sure we don't misdetect an emergency write when the guest
 591      * does a short config write after an emergency write. */
 592     config->emerg_wr = 0;
 593     if (!port) {
 594         return;
 595     }
 596     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 597     (void)vsc->have_data(port, &emerg_wr_lo, 1);
 598 }
 599
 600 static void guest_reset(VirtIOSerial *vser)
 601 {
 602     VirtIOSerialPort *port;
 603     VirtIOSerialPortClass *vsc;
 604
 605     QTAILQ_FOREACH(port, &vser->ports, next) {
 606         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 607
 608         discard_throttle_data(port);
 609
 610         if (port->guest_connected) {
 611             port->guest_connected = false;
 612             if (vsc->set_guest_connected) {
 613                 vsc->set_guest_connected(port, false);
 614             }
 615         }
 616     }
 617 }
 618
 619 static void set_status(VirtIODevice *vdev, uint8_t status)
 620 {
 621     VirtIOSerial *vser;
 622     VirtIOSerialPort *port;
 623
 624     vser = VIRTIO_SERIAL(vdev);
 625     port = find_port_by_id(vser, 0);
 626
 627     if (port && !use_multiport(port->vser)
 628         && (status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 629         /*
 630          * Non-multiport guests won't be able to tell us guest
 631          * open/close status.  Such guests can only have a port at id
 632          * 0, so set guest_connected for such ports as soon as guest
 633          * is up.
 634          */
 635         port->guest_connected = true;
 636     }
 637     if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 638         guest_reset(vser);
 639     }
 640
 641     QTAILQ_FOREACH(port, &vser->ports, next) {
 642         VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 643         if (vsc->enable_backend) {
 644             vsc->enable_backend(port, vdev->vm_running);
 645         }
 646     }
 647 }
 648
 649 static void vser_reset(VirtIODevice *vdev)
 650 {
 651     VirtIOSerial *vser;
 652
 653     vser = VIRTIO_SERIAL(vdev);
 654     guest_reset(vser);
 655 }
 656
 657 static void virtio_serial_save_device(VirtIODevice *vdev, QEMUFile *f)
 658 {
 659     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 660     VirtIOSerialPort *port;
 661     uint32_t nr_active_ports;
 662     unsigned int i, max_nr_ports;
 663     struct virtio_console_config config;
 664
 665     /* The config space (ignored on the far end in current versions) */
 666     get_config(vdev, (uint8_t *)&config);
 667     qemu_put_be16s(f, &config.cols);
 668     qemu_put_be16s(f, &config.rows);
 669     qemu_put_be32s(f, &config.max_nr_ports);
 670
 671     /* The ports map */
 672     max_nr_ports = s->serial.max_virtserial_ports;
 673     for (i = 0; i < DIV_ROUND_UP(max_nr_ports, 32); i++) {
 674         qemu_put_be32s(f, &s->ports_map[i]);
 675     }
 676
 677     /* Ports */
 678
 679     nr_active_ports = 0;
 680     QTAILQ_FOREACH(port, &s->ports, next) {
 681         nr_active_ports++;
 682     }
 683
 684     qemu_put_be32s(f, &nr_active_ports);
 685
 686     /*
 687      * Items in struct VirtIOSerialPort.
 688      */
 689     QTAILQ_FOREACH(port, &s->ports, next) {
 690         uint32_t elem_popped;
 691
 692         qemu_put_be32s(f, &port->id);
 693         qemu_put_byte(f, port->guest_connected);
 694         qemu_put_byte(f, port->host_connected);
 695
 696         elem_popped = 0;
 697         if (port->elem) {
 698             elem_popped = 1;
 699         }
 700         qemu_put_be32s(f, &elem_popped);
 701         if (elem_popped) {
 702             qemu_put_be32s(f, &port->iov_idx);
 703             qemu_put_be64s(f, &port->iov_offset);
 704             qemu_put_virtqueue_element(f, port->elem);
 705         }
 706     }
 707 }
 708
 709 static void virtio_serial_post_load_timer_cb(void *opaque)
 710 {
 711     uint32_t i;
 712     VirtIOSerial *s = VIRTIO_SERIAL(opaque);
 713     VirtIOSerialPort *port;
 714     uint8_t host_connected;
 715     VirtIOSerialPortClass *vsc;
 716
 717     if (!s->post_load) {
 718         return;
 719     }
 720     for (i = 0 ; i < s->post_load->nr_active_ports; ++i) {
 721         port = s->post_load->connected[i].port;
 722         host_connected = s->post_load->connected[i].host_connected;
 723         if (host_connected != port->host_connected) {
 724             /*
 725              * We have to let the guest know of the host connection
 726              * status change
 727              */
 728             send_control_event(s, port->id, VIRTIO_CONSOLE_PORT_OPEN,
 729                                port->host_connected);
 730         }
 731         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 732         if (vsc->set_guest_connected) {
 733             vsc->set_guest_connected(port, port->guest_connected);
 734         }
 735     }
 736     g_free(s->post_load->connected);
 737     timer_del(s->post_load->timer);
 738     timer_free(s->post_load->timer);
 739     g_free(s->post_load);
 740     s->post_load = NULL;
 741 }
 742
 743 static int fetch_active_ports_list(QEMUFile *f,
 744                                    VirtIOSerial *s, uint32_t nr_active_ports)
 745 {
 746     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 747     uint32_t i;
 748
 749     s->post_load = g_malloc0(sizeof(*s->post_load));
 750     s->post_load->nr_active_ports = nr_active_ports;
 751     s->post_load->connected =
 752         g_malloc0(sizeof(*s->post_load->connected) * nr_active_ports);
 753
 754     s->post_load->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
 755                                             virtio_serial_post_load_timer_cb,
 756                                             s);
 757
 758     /* Items in struct VirtIOSerialPort */
 759     for (i = 0; i < nr_active_ports; i++) {
 760         VirtIOSerialPort *port;
 761         uint32_t elem_popped;
 762         uint32_t id;
 763
 764         id = qemu_get_be32(f);
 765         port = find_port_by_id(s, id);
 766         if (!port) {
 767             return -EINVAL;
 768         }
 769
 770         port->guest_connected = qemu_get_byte(f);
 771         s->post_load->connected[i].port = port;
 772         s->post_load->connected[i].host_connected = qemu_get_byte(f);
 773
 774         qemu_get_be32s(f, &elem_popped);
 775         if (elem_popped) {
 776             qemu_get_be32s(f, &port->iov_idx);
 777             qemu_get_be64s(f, &port->iov_offset);
 778
 779             port->elem =
 780                 qemu_get_virtqueue_element(vdev, f, sizeof(VirtQueueElement));
 781
 782             /*
 783              *  Port was throttled on source machine.  Let's
 784              *  unthrottle it here so data starts flowing again.
 785              */
 786             virtio_serial_throttle_port(port, false);
 787         }
 788     }
 789     timer_mod(s->post_load->timer, 1);
 790     return 0;
 791 }
 792
 793 static int virtio_serial_load_device(VirtIODevice *vdev, QEMUFile *f,
 794                                      int version_id)
 795 {
 796     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 797     uint32_t max_nr_ports, nr_active_ports, ports_map;
 798     unsigned int i;
 799     int ret;
 800     uint32_t tmp;
 801
 802     /* Unused */
 803     qemu_get_be16s(f, (uint16_t *) &tmp);
 804     qemu_get_be16s(f, (uint16_t *) &tmp);
 805     qemu_get_be32s(f, &tmp);
 806
 807     max_nr_ports = s->serial.max_virtserial_ports;
 808     for (i = 0; i < DIV_ROUND_UP(max_nr_ports, 32); i++) {
 809         qemu_get_be32s(f, &ports_map);
 810
 811         if (ports_map != s->ports_map[i]) {
 812             /*
 813              * Ports active on source and destination don't
 814              * match. Fail migration.
 815              */
 816             return -EINVAL;
 817         }
 818     }
 819
 820     qemu_get_be32s(f, &nr_active_ports);
 821
 822     if (nr_active_ports) {
 823         ret = fetch_active_ports_list(f, s, nr_active_ports);
 824         if (ret) {
 825             return ret;
 826         }
 827     }
 828     return 0;
 829 }
 830
 831 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 832
 833 static Property virtser_props[] = {
 834     DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 835     DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 836     DEFINE_PROP_END_OF_LIST()
 837 };
 838
 839 #define TYPE_VIRTIO_SERIAL_BUS "virtio-serial-bus"
 840 #define VIRTIO_SERIAL_BUS(obj) \
 841       OBJECT_CHECK(VirtIOSerialBus, (obj), TYPE_VIRTIO_SERIAL_BUS)
 842
 843 static void virtser_bus_class_init(ObjectClass *klass, void *data)
 844 {
 845     BusClass *k = BUS_CLASS(klass);
 846     k->print_dev = virtser_bus_dev_print;
 847 }
 848
 849 static const TypeInfo virtser_bus_info = {
 850     .name = TYPE_VIRTIO_SERIAL_BUS,
 851     .parent = TYPE_BUS,
 852     .instance_size = sizeof(VirtIOSerialBus),
 853     .class_init = virtser_bus_class_init,
 854 };
 855
 856 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 857 {
 858     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(qdev);
 859
 860     monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 861                    indent, "", port->id,
 862                    port->guest_connected ? "on" : "off",
 863                    port->host_connected ? "on" : "off",
 864                    port->throttled ? "on" : "off");
 865 }
 866
 867 /* This function is only used if a port id is not provided by the user */
 868 static uint32_t find_free_port_id(VirtIOSerial *vser)
 869 {
 870     unsigned int i, max_nr_ports;
 871
 872     max_nr_ports = vser->serial.max_virtserial_ports;
 873     for (i = 0; i < DIV_ROUND_UP(max_nr_ports, 32); i++) {
 874         uint32_t map, zeroes;
 875
 876         map = vser->ports_map[i];
 877         zeroes = ctz32(~map);
 878         if (zeroes != 32) {
 879             return zeroes + i * 32;
 880         }
 881     }
 882     return VIRTIO_CONSOLE_BAD_ID;
 883 }
 884
 885 static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 886 {
 887     unsigned int i;
 888
 889     i = port_id / 32;
 890     vser->ports_map[i] |= 1U << (port_id % 32);
 891 }
 892
 893 static void add_port(VirtIOSerial *vser, uint32_t port_id)
 894 {
 895     mark_port_added(vser, port_id);
 896     send_control_event(vser, port_id, VIRTIO_CONSOLE_PORT_ADD, 1);
 897 }
 898
 899 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 900 {
 901     VirtIOSerialPort *port;
 902
 903     /*
 904      * Don't mark port 0 removed -- we explicitly reserve it for
 905      * backward compat with older guests, ensure a virtconsole device
 906      * unplug retains the reservation.
 907      */
 908     if (port_id) {
 909         unsigned int i;
 910
 911         i = port_id / 32;
 912         vser->ports_map[i] &= ~(1U << (port_id % 32));
 913     }
 914
 915     port = find_port_by_id(vser, port_id);
 916     /*
 917      * This function is only called from qdev's unplug callback; if we
 918      * get a NULL port here, we're in trouble.
 919      */
 920     assert(port);
 921
 922     /* Flush out any unconsumed buffers first */
 923     discard_throttle_data(port);
 924     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 925
 926     send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 927 }
 928
 929 static void virtser_port_device_realize(DeviceState *dev, Error **errp)
 930 {
 931     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 932     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 933     VirtIOSerialBus *bus = VIRTIO_SERIAL_BUS(qdev_get_parent_bus(dev));
 934     int max_nr_ports;
 935     bool plugging_port0;
 936     Error *err = NULL;
 937
 938     port->vser = bus->vser;
 939     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 940
 941     assert(vsc->have_data);
 942
 943     /*
 944      * Is the first console port we're seeing? If so, put it up at
 945      * location 0. This is done for backward compatibility (old
 946      * kernel, new qemu).
 947      */
 948     plugging_port0 = vsc->is_console && !find_port_by_id(port->vser, 0);
 949
 950     if (find_port_by_id(port->vser, port->id)) {
 951         error_setg(errp, "virtio-serial-bus: A port already exists at id %u",
 952                    port->id);
 953         return;
 954     }
 955
 956     if (port->name != NULL && find_port_by_name(port->name)) {
 957         error_setg(errp, "virtio-serial-bus: A port already exists by name %s",
 958                    port->name);
 959         return;
 960     }
 961
 962     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 963         if (plugging_port0) {
 964             port->id = 0;
 965         } else {
 966             port->id = find_free_port_id(port->vser);
 967             if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 968                 error_setg(errp, "virtio-serial-bus: Maximum port limit for "
 969                                  "this device reached");
 970                 return;
 971             }
 972         }
 973     }
 974
 975     max_nr_ports = port->vser->serial.max_virtserial_ports;
 976     if (port->id >= max_nr_ports) {
 977         error_setg(errp, "virtio-serial-bus: Out-of-range port id specified, "
 978                          "max. allowed: %u", max_nr_ports - 1);
 979         return;
 980     }
 981
 982     vsc->realize(dev, &err);
 983     if (err != NULL) {
 984         error_propagate(errp, err);
 985         return;
 986     }
 987
 988     port->elem = NULL;
 989 }
 990
 991 static void virtser_port_device_plug(HotplugHandler *hotplug_dev,
 992                                      DeviceState *dev, Error **errp)
 993 {
 994     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 995
 996     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
 997     port->ivq = port->vser->ivqs[port->id];
 998     port->ovq = port->vser->ovqs[port->id];
 999
1000     add_port(port->vser, port->id);
1001
1002     /* Send an update to the guest about this new port added */
1003     virtio_notify_config(VIRTIO_DEVICE(hotplug_dev));
1004 }
1005
1006 static void virtser_port_device_unrealize(DeviceState *dev, Error **errp)
1007 {
1008     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
1009     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(dev);
1010     VirtIOSerial *vser = port->vser;
1011
1012     qemu_bh_delete(port->bh);
1013     remove_port(port->vser, port->id);
1014
1015     QTAILQ_REMOVE(&vser->ports, port, next);
1016
1017     if (vsc->unrealize) {
1018         vsc->unrealize(dev, errp);
1019     }
1020 }
1021
1022 static void virtio_serial_device_realize(DeviceState *dev, Error **errp)
1023 {
1024     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1025     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1026     uint32_t i, max_supported_ports;
1027     size_t config_size = sizeof(struct virtio_console_config);
1028
1029     if (!vser->serial.max_virtserial_ports) {
1030         error_setg(errp, "Maximum number of serial ports not specified");
1031         return;
1032     }
1033
1034     /* Each port takes 2 queues, and one pair is for the control queue */
1035     max_supported_ports = VIRTIO_QUEUE_MAX / 2 - 1;
1036
1037     if (vser->serial.max_virtserial_ports > max_supported_ports) {
1038         error_setg(errp, "maximum ports supported: %u", max_supported_ports);
1039         return;
1040     }
1041
1042     if (!virtio_has_feature(vser->host_features,
1043                             VIRTIO_CONSOLE_F_EMERG_WRITE)) {
1044         config_size = offsetof(struct virtio_console_config, emerg_wr);
1045     }
1046     virtio_init(vdev, "virtio-serial", VIRTIO_ID_CONSOLE,
1047                 config_size);
1048
1049     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
1050     qbus_create_inplace(&vser->bus, sizeof(vser->bus), TYPE_VIRTIO_SERIAL_BUS,
1051                         dev, vdev->bus_name);
1052     qbus_set_hotplug_handler(BUS(&vser->bus), DEVICE(vser), errp);
1053     vser->bus.vser = vser;
1054     QTAILQ_INIT(&vser->ports);
1055
1056     vser->bus.max_nr_ports = vser->serial.max_virtserial_ports;
1057     vser->ivqs = g_malloc(vser->serial.max_virtserial_ports
1058                           * sizeof(VirtQueue *));
1059     vser->ovqs = g_malloc(vser->serial.max_virtserial_ports
1060                           * sizeof(VirtQueue *));
1061
1062     /* Add a queue for host to guest transfers for port 0 (backward compat) */
1063     vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
1064     /* Add a queue for guest to host transfers for port 0 (backward compat) */
1065     vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
1066
1067     /* TODO: host to guest notifications can get dropped
1068      * if the queue fills up. Implement queueing in host,
1069      * this might also make it possible to reduce the control
1070      * queue size: as guest preposts buffers there,
1071      * this will save 4Kbyte of guest memory per entry. */
1072
1073     /* control queue: host to guest */
1074     vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
1075     /* control queue: guest to host */
1076     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
1077
1078     for (i = 1; i < vser->bus.max_nr_ports; i++) {
1079         /* Add a per-port queue for host to guest transfers */
1080         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
1081         /* Add a per-per queue for guest to host transfers */
1082         vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
1083     }
1084
1085     vser->ports_map = g_malloc0((DIV_ROUND_UP(vser->serial.max_virtserial_ports, 32))
1086         * sizeof(vser->ports_map[0]));
1087     /*
1088      * Reserve location 0 for a console port for backward compat
1089      * (old kernel, new qemu)
1090      */
1091     mark_port_added(vser, 0);
1092
1093     vser->post_load = NULL;
1094
1095     QLIST_INSERT_HEAD(&vserdevices.devices, vser, next);
1096 }
1097
1098 static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
1099 {
1100     DeviceClass *k = DEVICE_CLASS(klass);
1101
1102     set_bit(DEVICE_CATEGORY_INPUT, k->categories);
1103     k->bus_type = TYPE_VIRTIO_SERIAL_BUS;
1104     k->realize = virtser_port_device_realize;
1105     k->unrealize = virtser_port_device_unrealize;
1106     k->props = virtser_props;
1107 }
1108
1109 static const TypeInfo virtio_serial_port_type_info = {
1110     .name = TYPE_VIRTIO_SERIAL_PORT,
1111     .parent = TYPE_DEVICE,
1112     .instance_size = sizeof(VirtIOSerialPort),
1113     .abstract = true,
1114     .class_size = sizeof(VirtIOSerialPortClass),
1115     .class_init = virtio_serial_port_class_init,
1116 };
1117
1118 static void virtio_serial_device_unrealize(DeviceState *dev, Error **errp)
1119 {
1120     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1121     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1122
1123     QLIST_REMOVE(vser, next);
1124
1125     g_free(vser->ivqs);
1126     g_free(vser->ovqs);
1127     g_free(vser->ports_map);
1128     if (vser->post_load) {
1129         g_free(vser->post_load->connected);
1130         timer_del(vser->post_load->timer);
1131         timer_free(vser->post_load->timer);
1132         g_free(vser->post_load);
1133     }
1134
1135     qbus_set_hotplug_handler(BUS(&vser->bus), NULL, errp);
1136
1137     virtio_cleanup(vdev);
1138 }
1139
1140 /* Note: 'console' is used for backwards compatibility */
1141 static const VMStateDescription vmstate_virtio_console = {
1142     .name = "virtio-console",
1143     .minimum_version_id = 3,
1144     .version_id = 3,
1145     .fields = (VMStateField[]) {
1146         VMSTATE_VIRTIO_DEVICE,
1147         VMSTATE_END_OF_LIST()
1148     },
1149 };
1150
1151 static Property virtio_serial_properties[] = {
1152     DEFINE_PROP_UINT32("max_ports", VirtIOSerial, serial.max_virtserial_ports,
1153                                                   31),
1154     DEFINE_PROP_BIT64("emergency-write", VirtIOSerial, host_features,
1155                       VIRTIO_CONSOLE_F_EMERG_WRITE, true),
1156     DEFINE_PROP_END_OF_LIST(),
1157 };
1158
1159 static void virtio_serial_class_init(ObjectClass *klass, void *data)
1160 {
1161     DeviceClass *dc = DEVICE_CLASS(klass);
1162     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1163     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
1164
1165     QLIST_INIT(&vserdevices.devices);
1166
1167     dc->props = virtio_serial_properties;
1168     dc->vmsd = &vmstate_virtio_console;
1169     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
1170     vdc->realize = virtio_serial_device_realize;
1171     vdc->unrealize = virtio_serial_device_unrealize;
1172     vdc->get_features = get_features;
1173     vdc->get_config = get_config;
1174     vdc->set_config = set_config;
1175     vdc->set_status = set_status;
1176     vdc->reset = vser_reset;
1177     vdc->save = virtio_serial_save_device;
1178     vdc->load = virtio_serial_load_device;
1179     hc->plug = virtser_port_device_plug;
1180     hc->unplug = qdev_simple_device_unplug_cb;
1181 }
1182
1183 static const TypeInfo virtio_device_info = {
1184     .name = TYPE_VIRTIO_SERIAL,
1185     .parent = TYPE_VIRTIO_DEVICE,
1186     .instance_size = sizeof(VirtIOSerial),
1187     .class_init = virtio_serial_class_init,
1188     .interfaces = (InterfaceInfo[]) {
1189         { TYPE_HOTPLUG_HANDLER },
1190         { }
1191     }
1192 };
1193
1194 static void virtio_serial_register_types(void)
1195 {
1196     type_register_static(&virtser_bus_info);
1197     type_register_static(&virtio_serial_port_type_info);
1198     type_register_static(&virtio_device_info);
1199 }
1200
1201 type_init(virtio_serial_register_types)