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 "qemu/module.h"
  25 #include "monitor/monitor.h"
  26 #include "qemu/error-report.h"
  27 #include "qemu/queue.h"
  28 #include "hw/sysbus.h"
  29 #include "trace.h"
  30 #include "hw/virtio/virtio-serial.h"
  31 #include "hw/virtio/virtio-access.h"
  32
  33 static struct VirtIOSerialDevices {
  34     QLIST_HEAD(, VirtIOSerial) devices;
  35 } vserdevices;
  36
  37 static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
  38 {
  39     VirtIOSerialPort *port;
  40
  41     if (id == VIRTIO_CONSOLE_BAD_ID) {
  42         return NULL;
  43     }
  44
  45     QTAILQ_FOREACH(port, &vser->ports, next) {
  46         if (port->id == id)
  47             return port;
  48     }
  49     return NULL;
  50 }
  51
  52 static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
  53 {
  54     VirtIOSerialPort *port;
  55
  56     QTAILQ_FOREACH(port, &vser->ports, next) {
  57         if (port->ivq == vq || port->ovq == vq)
  58             return port;
  59     }
  60     return NULL;
  61 }
  62
  63 static VirtIOSerialPort *find_port_by_name(char *name)
  64 {
  65     VirtIOSerial *vser;
  66
  67     QLIST_FOREACH(vser, &vserdevices.devices, next) {
  68         VirtIOSerialPort *port;
  69
  70         QTAILQ_FOREACH(port, &vser->ports, next) {
  71             if (port->name && !strcmp(port->name, name)) {
  72                 return port;
  73             }
  74         }
  75     }
  76     return NULL;
  77 }
  78
  79 static VirtIOSerialPort *find_first_connected_console(VirtIOSerial *vser)
  80 {
  81     VirtIOSerialPort *port;
  82
  83     QTAILQ_FOREACH(port, &vser->ports, next) {
  84         VirtIOSerialPortClass const *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
  85         if (vsc->is_console && port->host_connected) {
  86             return port;
  87         }
  88     }
  89     return NULL;
  90 }
  91
  92 static bool use_multiport(VirtIOSerial *vser)
  93 {
  94     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
  95     return virtio_vdev_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT);
  96 }
  97
  98 static size_t write_to_port(VirtIOSerialPort *port,
  99                             const uint8_t *buf, size_t size)
 100 {
 101     VirtQueueElement *elem;
 102     VirtQueue *vq;
 103     size_t offset;
 104
 105     vq = port->ivq;
 106     if (!virtio_queue_ready(vq)) {
 107         return 0;
 108     }
 109
 110     offset = 0;
 111     while (offset < size) {
 112         size_t len;
 113
 114         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 115         if (!elem) {
 116             break;
 117         }
 118
 119         len = iov_from_buf(elem->in_sg, elem->in_num, 0,
 120                            buf + offset, size - offset);
 121         offset += len;
 122
 123         virtqueue_push(vq, elem, len);
 124         g_free(elem);
 125     }
 126
 127     virtio_notify(VIRTIO_DEVICE(port->vser), vq);
 128     return offset;
 129 }
 130
 131 static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
 132 {
 133     VirtQueueElement *elem;
 134
 135     if (!virtio_queue_ready(vq)) {
 136         return;
 137     }
 138     for (;;) {
 139         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 140         if (!elem) {
 141             break;
 142         }
 143         virtqueue_push(vq, elem, 0);
 144         g_free(elem);
 145     }
 146     virtio_notify(vdev, vq);
 147 }
 148
 149 static void discard_throttle_data(VirtIOSerialPort *port)
 150 {
 151     if (port->elem) {
 152         virtqueue_detach_element(port->ovq, port->elem, 0);
 153         g_free(port->elem);
 154         port->elem = NULL;
 155     }
 156 }
 157
 158 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 159                                  VirtIODevice *vdev)
 160 {
 161     VirtIOSerialPortClass *vsc;
 162
 163     assert(port);
 164     assert(virtio_queue_ready(vq));
 165
 166     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 167
 168     while (!port->throttled) {
 169         unsigned int i;
 170
 171         /* Pop an elem only if we haven't left off a previous one mid-way */
 172         if (!port->elem) {
 173             port->elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 174             if (!port->elem) {
 175                 break;
 176             }
 177             port->iov_idx = 0;
 178             port->iov_offset = 0;
 179         }
 180
 181         for (i = port->iov_idx; i < port->elem->out_num; i++) {
 182             size_t buf_size;
 183             ssize_t ret;
 184
 185             buf_size = port->elem->out_sg[i].iov_len - port->iov_offset;
 186             ret = vsc->have_data(port,
 187                                   port->elem->out_sg[i].iov_base
 188                                   + port->iov_offset,
 189                                   buf_size);
 190             if (!port->elem) { /* bail if we got disconnected */
 191                 return;
 192             }
 193             if (port->throttled) {
 194                 port->iov_idx = i;
 195                 if (ret > 0) {
 196                     port->iov_offset += ret;
 197                 }
 198                 break;
 199             }
 200             port->iov_offset = 0;
 201         }
 202         if (port->throttled) {
 203             break;
 204         }
 205         virtqueue_push(vq, port->elem, 0);
 206         g_free(port->elem);
 207         port->elem = NULL;
 208     }
 209     virtio_notify(vdev, vq);
 210 }
 211
 212 static void flush_queued_data(VirtIOSerialPort *port)
 213 {
 214     assert(port);
 215
 216     if (!virtio_queue_ready(port->ovq)) {
 217         return;
 218     }
 219     do_flush_queued_data(port, port->ovq, VIRTIO_DEVICE(port->vser));
 220 }
 221
 222 static size_t send_control_msg(VirtIOSerial *vser, void *buf, size_t len)
 223 {
 224     VirtQueueElement *elem;
 225     VirtQueue *vq;
 226
 227     vq = vser->c_ivq;
 228     if (!virtio_queue_ready(vq)) {
 229         return 0;
 230     }
 231
 232     elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 233     if (!elem) {
 234         return 0;
 235     }
 236
 237     /* TODO: detect a buffer that's too short, set NEEDS_RESET */
 238     iov_from_buf(elem->in_sg, elem->in_num, 0, buf, len);
 239
 240     virtqueue_push(vq, elem, len);
 241     virtio_notify(VIRTIO_DEVICE(vser), vq);
 242     g_free(elem);
 243
 244     return len;
 245 }
 246
 247 static size_t send_control_event(VirtIOSerial *vser, uint32_t port_id,
 248                                  uint16_t event, uint16_t value)
 249 {
 250     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 251     struct virtio_console_control cpkt;
 252
 253     virtio_stl_p(vdev, &cpkt.id, port_id);
 254     virtio_stw_p(vdev, &cpkt.event, event);
 255     virtio_stw_p(vdev, &cpkt.value, value);
 256
 257     trace_virtio_serial_send_control_event(port_id, event, value);
 258     return send_control_msg(vser, &cpkt, sizeof(cpkt));
 259 }
 260
 261 /* Functions for use inside qemu to open and read from/write to ports */
 262 int virtio_serial_open(VirtIOSerialPort *port)
 263 {
 264     /* Don't allow opening an already-open port */
 265     if (port->host_connected) {
 266         return 0;
 267     }
 268     /* Send port open notification to the guest */
 269     port->host_connected = true;
 270     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 271
 272     return 0;
 273 }
 274
 275 int virtio_serial_close(VirtIOSerialPort *port)
 276 {
 277     port->host_connected = false;
 278     /*
 279      * If there's any data the guest sent which the app didn't
 280      * consume, reset the throttling flag and discard the data.
 281      */
 282     port->throttled = false;
 283     discard_throttle_data(port);
 284     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 285
 286     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 0);
 287
 288     return 0;
 289 }
 290
 291 /* Individual ports/apps call this function to write to the guest. */
 292 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 293                             size_t size)
 294 {
 295     if (!port || !port->host_connected || !port->guest_connected) {
 296         return 0;
 297     }
 298     return write_to_port(port, buf, size);
 299 }
 300
 301 /*
 302  * Readiness of the guest to accept data on a port.
 303  * Returns max. data the guest can receive
 304  */
 305 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 306 {
 307     VirtIODevice *vdev = VIRTIO_DEVICE(port->vser);
 308     VirtQueue *vq = port->ivq;
 309     unsigned int bytes;
 310
 311     if (!virtio_queue_ready(vq) ||
 312         !(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 313         virtio_queue_empty(vq)) {
 314         return 0;
 315     }
 316     if (use_multiport(port->vser) && !port->guest_connected) {
 317         return 0;
 318     }
 319     virtqueue_get_avail_bytes(vq, &bytes, NULL, 4096, 0);
 320     return bytes;
 321 }
 322
 323 static void flush_queued_data_bh(void *opaque)
 324 {
 325     VirtIOSerialPort *port = opaque;
 326
 327     flush_queued_data(port);
 328 }
 329
 330 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 331 {
 332     if (!port) {
 333         return;
 334     }
 335
 336     trace_virtio_serial_throttle_port(port->id, throttle);
 337     port->throttled = throttle;
 338     if (throttle) {
 339         return;
 340     }
 341     qemu_bh_schedule(port->bh);
 342 }
 343
 344 /* Guest wants to notify us of some event */
 345 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 346 {
 347     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
 348     struct VirtIOSerialPort *port;
 349     VirtIOSerialPortClass *vsc;
 350     struct virtio_console_control cpkt, *gcpkt;
 351     uint8_t *buffer;
 352     size_t buffer_len;
 353
 354     gcpkt = buf;
 355
 356     if (len < sizeof(cpkt)) {
 357         /* The guest sent an invalid control packet */
 358         return;
 359     }
 360
 361     cpkt.event = virtio_lduw_p(vdev, &gcpkt->event);
 362     cpkt.value = virtio_lduw_p(vdev, &gcpkt->value);
 363
 364     trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 365
 366     if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 367         if (!cpkt.value) {
 368             error_report("virtio-serial-bus: Guest failure in adding device %s",
 369                          vser->bus.qbus.name);
 370             return;
 371         }
 372         /*
 373          * The device is up, we can now tell the device about all the
 374          * ports we have here.
 375          */
 376         QTAILQ_FOREACH(port, &vser->ports, next) {
 377             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_ADD, 1);
 378         }
 379         return;
 380     }
 381
 382     port = find_port_by_id(vser, virtio_ldl_p(vdev, &gcpkt->id));
 383     if (!port) {
 384         error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 385                      virtio_ldl_p(vdev, &gcpkt->id), vser->bus.qbus.name);
 386         return;
 387     }
 388
 389     trace_virtio_serial_handle_control_message_port(port->id);
 390
 391     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 392
 393     switch(cpkt.event) {
 394     case VIRTIO_CONSOLE_PORT_READY:
 395         if (!cpkt.value) {
 396             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 397                          port->id, vser->bus.qbus.name);
 398             break;
 399         }
 400         /*
 401          * Now that we know the guest asked for the port name, we're
 402          * sure the guest has initialised whatever state is necessary
 403          * for this port. Now's a good time to let the guest know if
 404          * this port is a console port so that the guest can hook it
 405          * up to hvc.
 406          */
 407         if (vsc->is_console) {
 408             send_control_event(vser, port->id, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 409         }
 410
 411         if (port->name) {
 412             virtio_stl_p(vdev, &cpkt.id, port->id);
 413             virtio_stw_p(vdev, &cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 414             virtio_stw_p(vdev, &cpkt.value, 1);
 415
 416             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 417             buffer = g_malloc(buffer_len);
 418
 419             memcpy(buffer, &cpkt, sizeof(cpkt));
 420             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 421             buffer[buffer_len - 1] = 0;
 422
 423             send_control_msg(vser, buffer, buffer_len);
 424             g_free(buffer);
 425         }
 426
 427         if (port->host_connected) {
 428             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 429         }
 430
 431         /*
 432          * When the guest has asked us for this information it means
 433          * the guest is all setup and has its virtqueues
 434          * initialised. If some app is interested in knowing about
 435          * this event, let it know.
 436          */
 437         if (vsc->guest_ready) {
 438             vsc->guest_ready(port);
 439         }
 440         break;
 441
 442     case VIRTIO_CONSOLE_PORT_OPEN:
 443         port->guest_connected = cpkt.value;
 444         if (vsc->set_guest_connected) {
 445             /* Send the guest opened notification if an app is interested */
 446             vsc->set_guest_connected(port, cpkt.value);
 447         }
 448         break;
 449     }
 450 }
 451
 452 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 453 {
 454 }
 455
 456 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 457 {
 458     VirtQueueElement *elem;
 459     VirtIOSerial *vser;
 460     uint8_t *buf;
 461     size_t len;
 462
 463     vser = VIRTIO_SERIAL(vdev);
 464
 465     len = 0;
 466     buf = NULL;
 467     for (;;) {
 468         size_t cur_len;
 469
 470         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 471         if (!elem) {
 472             break;
 473         }
 474
 475         cur_len = iov_size(elem->out_sg, elem->out_num);
 476         /*
 477          * Allocate a new buf only if we didn't have one previously or
 478          * if the size of the buf differs
 479          */
 480         if (cur_len > len) {
 481             g_free(buf);
 482
 483             buf = g_malloc(cur_len);
 484             len = cur_len;
 485         }
 486         iov_to_buf(elem->out_sg, elem->out_num, 0, buf, cur_len);
 487
 488         handle_control_message(vser, buf, cur_len);
 489         virtqueue_push(vq, elem, 0);
 490         g_free(elem);
 491     }
 492     g_free(buf);
 493     virtio_notify(vdev, vq);
 494 }
 495
 496 /* Guest wrote something to some port. */
 497 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 498 {
 499     VirtIOSerial *vser;
 500     VirtIOSerialPort *port;
 501
 502     vser = VIRTIO_SERIAL(vdev);
 503     port = find_port_by_vq(vser, vq);
 504
 505     if (!port || !port->host_connected) {
 506         discard_vq_data(vq, vdev);
 507         return;
 508     }
 509
 510     if (!port->throttled) {
 511         do_flush_queued_data(port, vq, vdev);
 512         return;
 513     }
 514 }
 515
 516 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 517 {
 518     /*
 519      * Users of virtio-serial would like to know when guest becomes
 520      * writable again -- i.e. if a vq had stuff queued up and the
 521      * guest wasn't reading at all, the host would not be able to
 522      * write to the vq anymore.  Once the guest reads off something,
 523      * we can start queueing things up again.  However, this call is
 524      * made for each buffer addition by the guest -- even though free
 525      * buffers existed prior to the current buffer addition.  This is
 526      * done so as not to maintain previous state, which will need
 527      * additional live-migration-related changes.
 528      */
 529     VirtIOSerial *vser;
 530     VirtIOSerialPort *port;
 531     VirtIOSerialPortClass *vsc;
 532
 533     vser = VIRTIO_SERIAL(vdev);
 534     port = find_port_by_vq(vser, vq);
 535
 536     if (!port) {
 537         return;
 538     }
 539     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 540
 541     /*
 542      * If guest_connected is false, this call is being made by the
 543      * early-boot queueing up of descriptors, which is just noise for
 544      * the host apps -- don't disturb them in that case.
 545      */
 546     if (port->guest_connected && port->host_connected && vsc->guest_writable) {
 547         vsc->guest_writable(port);
 548     }
 549 }
 550
 551 static uint64_t get_features(VirtIODevice *vdev, uint64_t features,
 552                              Error **errp)
 553 {
 554     VirtIOSerial *vser;
 555
 556     vser = VIRTIO_SERIAL(vdev);
 557
 558     features |= vser->host_features;
 559     if (vser->bus.max_nr_ports > 1) {
 560         virtio_add_feature(&features, VIRTIO_CONSOLE_F_MULTIPORT);
 561     }
 562     return features;
 563 }
 564
 565 /* Guest requested config info */
 566 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 567 {
 568     VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 569     struct virtio_console_config *config =
 570         (struct virtio_console_config *)config_data;
 571
 572     config->cols = 0;
 573     config->rows = 0;
 574     config->max_nr_ports = virtio_tswap32(vdev,
 575                                           vser->serial.max_virtserial_ports);
 576 }
 577
 578 /* Guest sent new config info */
 579 static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
 580 {
 581     VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
 582     struct virtio_console_config *config =
 583         (struct virtio_console_config *)config_data;
 584     VirtIOSerialPort *port = find_first_connected_console(vser);
 585     VirtIOSerialPortClass *vsc;
 586     uint8_t emerg_wr_lo;
 587
 588     if (!virtio_has_feature(vser->host_features,
 589         VIRTIO_CONSOLE_F_EMERG_WRITE) || !config->emerg_wr) {
 590         return;
 591     }
 592
 593     emerg_wr_lo = le32_to_cpu(config->emerg_wr);
 594     /* Make sure we don't misdetect an emergency write when the guest
 595      * does a short config write after an emergency write. */
 596     config->emerg_wr = 0;
 597     if (!port) {
 598         return;
 599     }
 600     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 601     (void)vsc->have_data(port, &emerg_wr_lo, 1);
 602 }
 603
 604 static void guest_reset(VirtIOSerial *vser)
 605 {
 606     VirtIOSerialPort *port;
 607     VirtIOSerialPortClass *vsc;
 608
 609     QTAILQ_FOREACH(port, &vser->ports, next) {
 610         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 611
 612         discard_throttle_data(port);
 613
 614         if (port->guest_connected) {
 615             port->guest_connected = false;
 616             if (vsc->set_guest_connected) {
 617                 vsc->set_guest_connected(port, false);
 618             }
 619         }
 620     }
 621 }
 622
 623 static void set_status(VirtIODevice *vdev, uint8_t status)
 624 {
 625     VirtIOSerial *vser;
 626     VirtIOSerialPort *port;
 627
 628     vser = VIRTIO_SERIAL(vdev);
 629     port = find_port_by_id(vser, 0);
 630
 631     if (port && !use_multiport(port->vser)
 632         && (status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 633         /*
 634          * Non-multiport guests won't be able to tell us guest
 635          * open/close status.  Such guests can only have a port at id
 636          * 0, so set guest_connected for such ports as soon as guest
 637          * is up.
 638          */
 639         port->guest_connected = true;
 640     }
 641     if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 642         guest_reset(vser);
 643     }
 644
 645     QTAILQ_FOREACH(port, &vser->ports, next) {
 646         VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 647         if (vsc->enable_backend) {
 648             vsc->enable_backend(port, vdev->vm_running);
 649         }
 650     }
 651 }
 652
 653 static void vser_reset(VirtIODevice *vdev)
 654 {
 655     VirtIOSerial *vser;
 656
 657     vser = VIRTIO_SERIAL(vdev);
 658     guest_reset(vser);
 659 }
 660
 661 static void virtio_serial_save_device(VirtIODevice *vdev, QEMUFile *f)
 662 {
 663     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 664     VirtIOSerialPort *port;
 665     uint32_t nr_active_ports;
 666     unsigned int i, max_nr_ports;
 667     struct virtio_console_config config;
 668
 669     /* The config space (ignored on the far end in current versions) */
 670     get_config(vdev, (uint8_t *)&config);
 671     qemu_put_be16(f, config.cols);
 672     qemu_put_be16(f, config.rows);
 673     qemu_put_be32(f, config.max_nr_ports);
 674
 675     /* The ports map */
 676     max_nr_ports = s->serial.max_virtserial_ports;
 677     for (i = 0; i < DIV_ROUND_UP(max_nr_ports, 32); i++) {
 678         qemu_put_be32s(f, &s->ports_map[i]);
 679     }
 680
 681     /* Ports */
 682
 683     nr_active_ports = 0;
 684     QTAILQ_FOREACH(port, &s->ports, next) {
 685         nr_active_ports++;
 686     }
 687
 688     qemu_put_be32s(f, &nr_active_ports);
 689
 690     /*
 691      * Items in struct VirtIOSerialPort.
 692      */
 693     QTAILQ_FOREACH(port, &s->ports, next) {
 694         uint32_t elem_popped;
 695
 696         qemu_put_be32s(f, &port->id);
 697         qemu_put_byte(f, port->guest_connected);
 698         qemu_put_byte(f, port->host_connected);
 699
 700         elem_popped = 0;
 701         if (port->elem) {
 702             elem_popped = 1;
 703         }
 704         qemu_put_be32s(f, &elem_popped);
 705         if (elem_popped) {
 706             qemu_put_be32s(f, &port->iov_idx);
 707             qemu_put_be64s(f, &port->iov_offset);
 708             qemu_put_virtqueue_element(f, port->elem);
 709         }
 710     }
 711 }
 712
 713 static void virtio_serial_post_load_timer_cb(void *opaque)
 714 {
 715     uint32_t i;
 716     VirtIOSerial *s = VIRTIO_SERIAL(opaque);
 717     VirtIOSerialPort *port;
 718     uint8_t host_connected;
 719     VirtIOSerialPortClass *vsc;
 720
 721     if (!s->post_load) {
 722         return;
 723     }
 724     for (i = 0 ; i < s->post_load->nr_active_ports; ++i) {
 725         port = s->post_load->connected[i].port;
 726         host_connected = s->post_load->connected[i].host_connected;
 727         if (host_connected != port->host_connected) {
 728             /*
 729              * We have to let the guest know of the host connection
 730              * status change
 731              */
 732             send_control_event(s, port->id, VIRTIO_CONSOLE_PORT_OPEN,
 733                                port->host_connected);
 734         }
 735         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 736         if (vsc->set_guest_connected) {
 737             vsc->set_guest_connected(port, port->guest_connected);
 738         }
 739     }
 740     g_free(s->post_load->connected);
 741     timer_del(s->post_load->timer);
 742     timer_free(s->post_load->timer);
 743     g_free(s->post_load);
 744     s->post_load = NULL;
 745 }
 746
 747 static int fetch_active_ports_list(QEMUFile *f,
 748                                    VirtIOSerial *s, uint32_t nr_active_ports)
 749 {
 750     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 751     uint32_t i;
 752
 753     s->post_load = g_malloc0(sizeof(*s->post_load));
 754     s->post_load->nr_active_ports = nr_active_ports;
 755     s->post_load->connected =
 756         g_malloc0(sizeof(*s->post_load->connected) * nr_active_ports);
 757
 758     s->post_load->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
 759                                             virtio_serial_post_load_timer_cb,
 760                                             s);
 761
 762     /* Items in struct VirtIOSerialPort */
 763     for (i = 0; i < nr_active_ports; i++) {
 764         VirtIOSerialPort *port;
 765         uint32_t elem_popped;
 766         uint32_t id;
 767
 768         id = qemu_get_be32(f);
 769         port = find_port_by_id(s, id);
 770         if (!port) {
 771             return -EINVAL;
 772         }
 773
 774         port->guest_connected = qemu_get_byte(f);
 775         s->post_load->connected[i].port = port;
 776         s->post_load->connected[i].host_connected = qemu_get_byte(f);
 777
 778         qemu_get_be32s(f, &elem_popped);
 779         if (elem_popped) {
 780             qemu_get_be32s(f, &port->iov_idx);
 781             qemu_get_be64s(f, &port->iov_offset);
 782
 783             port->elem =
 784                 qemu_get_virtqueue_element(vdev, f, sizeof(VirtQueueElement));
 785
 786             /*
 787              *  Port was throttled on source machine.  Let's
 788              *  unthrottle it here so data starts flowing again.
 789              */
 790             virtio_serial_throttle_port(port, false);
 791         }
 792     }
 793     timer_mod(s->post_load->timer, 1);
 794     return 0;
 795 }
 796
 797 static int virtio_serial_load_device(VirtIODevice *vdev, QEMUFile *f,
 798                                      int version_id)
 799 {
 800     VirtIOSerial *s = VIRTIO_SERIAL(vdev);
 801     uint32_t max_nr_ports, nr_active_ports, ports_map;
 802     unsigned int i;
 803     int ret;
 804     uint32_t tmp;
 805
 806     /* Unused */
 807     qemu_get_be16s(f, (uint16_t *) &tmp);
 808     qemu_get_be16s(f, (uint16_t *) &tmp);
 809     qemu_get_be32s(f, &tmp);
 810
 811     max_nr_ports = s->serial.max_virtserial_ports;
 812     for (i = 0; i < DIV_ROUND_UP(max_nr_ports, 32); i++) {
 813         qemu_get_be32s(f, &ports_map);
 814
 815         if (ports_map != s->ports_map[i]) {
 816             /*
 817              * Ports active on source and destination don't
 818              * match. Fail migration.
 819              */
 820             return -EINVAL;
 821         }
 822     }
 823
 824     qemu_get_be32s(f, &nr_active_ports);
 825
 826     if (nr_active_ports) {
 827         ret = fetch_active_ports_list(f, s, nr_active_ports);
 828         if (ret) {
 829             return ret;
 830         }
 831     }
 832     return 0;
 833 }
 834
 835 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 836
 837 static Property virtser_props[] = {
 838     DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 839     DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 840     DEFINE_PROP_END_OF_LIST()
 841 };
 842
 843 #define TYPE_VIRTIO_SERIAL_BUS "virtio-serial-bus"
 844 #define VIRTIO_SERIAL_BUS(obj) \
 845       OBJECT_CHECK(VirtIOSerialBus, (obj), TYPE_VIRTIO_SERIAL_BUS)
 846
 847 static void virtser_bus_class_init(ObjectClass *klass, void *data)
 848 {
 849     BusClass *k = BUS_CLASS(klass);
 850     k->print_dev = virtser_bus_dev_print;
 851 }
 852
 853 static const TypeInfo virtser_bus_info = {
 854     .name = TYPE_VIRTIO_SERIAL_BUS,
 855     .parent = TYPE_BUS,
 856     .instance_size = sizeof(VirtIOSerialBus),
 857     .class_init = virtser_bus_class_init,
 858 };
 859
 860 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 861 {
 862     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(qdev);
 863
 864     monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 865                    indent, "", port->id,
 866                    port->guest_connected ? "on" : "off",
 867                    port->host_connected ? "on" : "off",
 868                    port->throttled ? "on" : "off");
 869 }
 870
 871 /* This function is only used if a port id is not provided by the user */
 872 static uint32_t find_free_port_id(VirtIOSerial *vser)
 873 {
 874     unsigned int i, max_nr_ports;
 875
 876     max_nr_ports = vser->serial.max_virtserial_ports;
 877     for (i = 0; i < DIV_ROUND_UP(max_nr_ports, 32); i++) {
 878         uint32_t map, zeroes;
 879
 880         map = vser->ports_map[i];
 881         zeroes = ctz32(~map);
 882         if (zeroes != 32) {
 883             return zeroes + i * 32;
 884         }
 885     }
 886     return VIRTIO_CONSOLE_BAD_ID;
 887 }
 888
 889 static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 890 {
 891     unsigned int i;
 892
 893     i = port_id / 32;
 894     vser->ports_map[i] |= 1U << (port_id % 32);
 895 }
 896
 897 static void add_port(VirtIOSerial *vser, uint32_t port_id)
 898 {
 899     mark_port_added(vser, port_id);
 900     send_control_event(vser, port_id, VIRTIO_CONSOLE_PORT_ADD, 1);
 901 }
 902
 903 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 904 {
 905     VirtIOSerialPort *port;
 906
 907     /*
 908      * Don't mark port 0 removed -- we explicitly reserve it for
 909      * backward compat with older guests, ensure a virtconsole device
 910      * unplug retains the reservation.
 911      */
 912     if (port_id) {
 913         unsigned int i;
 914
 915         i = port_id / 32;
 916         vser->ports_map[i] &= ~(1U << (port_id % 32));
 917     }
 918
 919     port = find_port_by_id(vser, port_id);
 920     /*
 921      * This function is only called from qdev's unplug callback; if we
 922      * get a NULL port here, we're in trouble.
 923      */
 924     assert(port);
 925
 926     /* Flush out any unconsumed buffers first */
 927     discard_throttle_data(port);
 928     discard_vq_data(port->ovq, VIRTIO_DEVICE(port->vser));
 929
 930     send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 931 }
 932
 933 static void virtser_port_device_realize(DeviceState *dev, Error **errp)
 934 {
 935     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 936     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 937     VirtIOSerialBus *bus = VIRTIO_SERIAL_BUS(qdev_get_parent_bus(dev));
 938     int max_nr_ports;
 939     bool plugging_port0;
 940     Error *err = NULL;
 941
 942     port->vser = bus->vser;
 943     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 944
 945     assert(vsc->have_data);
 946
 947     /*
 948      * Is the first console port we're seeing? If so, put it up at
 949      * location 0. This is done for backward compatibility (old
 950      * kernel, new qemu).
 951      */
 952     plugging_port0 = vsc->is_console && !find_port_by_id(port->vser, 0);
 953
 954     if (find_port_by_id(port->vser, port->id)) {
 955         error_setg(errp, "virtio-serial-bus: A port already exists at id %u",
 956                    port->id);
 957         return;
 958     }
 959
 960     if (port->name != NULL && find_port_by_name(port->name)) {
 961         error_setg(errp, "virtio-serial-bus: A port already exists by name %s",
 962                    port->name);
 963         return;
 964     }
 965
 966     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 967         if (plugging_port0) {
 968             port->id = 0;
 969         } else {
 970             port->id = find_free_port_id(port->vser);
 971             if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 972                 error_setg(errp, "virtio-serial-bus: Maximum port limit for "
 973                                  "this device reached");
 974                 return;
 975             }
 976         }
 977     }
 978
 979     max_nr_ports = port->vser->serial.max_virtserial_ports;
 980     if (port->id >= max_nr_ports) {
 981         error_setg(errp, "virtio-serial-bus: Out-of-range port id specified, "
 982                          "max. allowed: %u", max_nr_ports - 1);
 983         return;
 984     }
 985
 986     vsc->realize(dev, &err);
 987     if (err != NULL) {
 988         error_propagate(errp, err);
 989         return;
 990     }
 991
 992     port->elem = NULL;
 993 }
 994
 995 static void virtser_port_device_plug(HotplugHandler *hotplug_dev,
 996                                      DeviceState *dev, Error **errp)
 997 {
 998     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 999
1000     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
1001     port->ivq = port->vser->ivqs[port->id];
1002     port->ovq = port->vser->ovqs[port->id];
1003
1004     add_port(port->vser, port->id);
1005
1006     /* Send an update to the guest about this new port added */
1007     virtio_notify_config(VIRTIO_DEVICE(hotplug_dev));
1008 }
1009
1010 static void virtser_port_device_unrealize(DeviceState *dev, Error **errp)
1011 {
1012     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
1013     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(dev);
1014     VirtIOSerial *vser = port->vser;
1015
1016     qemu_bh_delete(port->bh);
1017     remove_port(port->vser, port->id);
1018
1019     QTAILQ_REMOVE(&vser->ports, port, next);
1020
1021     if (vsc->unrealize) {
1022         vsc->unrealize(dev, errp);
1023     }
1024 }
1025
1026 static void virtio_serial_device_realize(DeviceState *dev, Error **errp)
1027 {
1028     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1029     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1030     uint32_t i, max_supported_ports;
1031     size_t config_size = sizeof(struct virtio_console_config);
1032
1033     if (!vser->serial.max_virtserial_ports) {
1034         error_setg(errp, "Maximum number of serial ports not specified");
1035         return;
1036     }
1037
1038     /* Each port takes 2 queues, and one pair is for the control queue */
1039     max_supported_ports = VIRTIO_QUEUE_MAX / 2 - 1;
1040
1041     if (vser->serial.max_virtserial_ports > max_supported_ports) {
1042         error_setg(errp, "maximum ports supported: %u", max_supported_ports);
1043         return;
1044     }
1045
1046     if (!virtio_has_feature(vser->host_features,
1047                             VIRTIO_CONSOLE_F_EMERG_WRITE)) {
1048         config_size = offsetof(struct virtio_console_config, emerg_wr);
1049     }
1050     virtio_init(vdev, "virtio-serial", VIRTIO_ID_CONSOLE,
1051                 config_size);
1052
1053     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
1054     qbus_create_inplace(&vser->bus, sizeof(vser->bus), TYPE_VIRTIO_SERIAL_BUS,
1055                         dev, vdev->bus_name);
1056     qbus_set_hotplug_handler(BUS(&vser->bus), OBJECT(vser), errp);
1057     vser->bus.vser = vser;
1058     QTAILQ_INIT(&vser->ports);
1059
1060     vser->bus.max_nr_ports = vser->serial.max_virtserial_ports;
1061     vser->ivqs = g_malloc(vser->serial.max_virtserial_ports
1062                           * sizeof(VirtQueue *));
1063     vser->ovqs = g_malloc(vser->serial.max_virtserial_ports
1064                           * sizeof(VirtQueue *));
1065
1066     /* Add a queue for host to guest transfers for port 0 (backward compat) */
1067     vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
1068     /* Add a queue for guest to host transfers for port 0 (backward compat) */
1069     vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
1070
1071     /* TODO: host to guest notifications can get dropped
1072      * if the queue fills up. Implement queueing in host,
1073      * this might also make it possible to reduce the control
1074      * queue size: as guest preposts buffers there,
1075      * this will save 4Kbyte of guest memory per entry. */
1076
1077     /* control queue: host to guest */
1078     vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
1079     /* control queue: guest to host */
1080     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
1081
1082     for (i = 1; i < vser->bus.max_nr_ports; i++) {
1083         /* Add a per-port queue for host to guest transfers */
1084         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
1085         /* Add a per-per queue for guest to host transfers */
1086         vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
1087     }
1088
1089     vser->ports_map = g_malloc0((DIV_ROUND_UP(vser->serial.max_virtserial_ports, 32))
1090         * sizeof(vser->ports_map[0]));
1091     /*
1092      * Reserve location 0 for a console port for backward compat
1093      * (old kernel, new qemu)
1094      */
1095     mark_port_added(vser, 0);
1096
1097     vser->post_load = NULL;
1098
1099     QLIST_INSERT_HEAD(&vserdevices.devices, vser, next);
1100 }
1101
1102 static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
1103 {
1104     DeviceClass *k = DEVICE_CLASS(klass);
1105
1106     set_bit(DEVICE_CATEGORY_INPUT, k->categories);
1107     k->bus_type = TYPE_VIRTIO_SERIAL_BUS;
1108     k->realize = virtser_port_device_realize;
1109     k->unrealize = virtser_port_device_unrealize;
1110     k->props = virtser_props;
1111 }
1112
1113 static const TypeInfo virtio_serial_port_type_info = {
1114     .name = TYPE_VIRTIO_SERIAL_PORT,
1115     .parent = TYPE_DEVICE,
1116     .instance_size = sizeof(VirtIOSerialPort),
1117     .abstract = true,
1118     .class_size = sizeof(VirtIOSerialPortClass),
1119     .class_init = virtio_serial_port_class_init,
1120 };
1121
1122 static void virtio_serial_device_unrealize(DeviceState *dev, Error **errp)
1123 {
1124     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
1125     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
1126
1127     QLIST_REMOVE(vser, next);
1128
1129     g_free(vser->ivqs);
1130     g_free(vser->ovqs);
1131     g_free(vser->ports_map);
1132     if (vser->post_load) {
1133         g_free(vser->post_load->connected);
1134         timer_del(vser->post_load->timer);
1135         timer_free(vser->post_load->timer);
1136         g_free(vser->post_load);
1137     }
1138
1139     qbus_set_hotplug_handler(BUS(&vser->bus), NULL, errp);
1140
1141     virtio_cleanup(vdev);
1142 }
1143
1144 /* Note: 'console' is used for backwards compatibility */
1145 static const VMStateDescription vmstate_virtio_console = {
1146     .name = "virtio-console",
1147     .minimum_version_id = 3,
1148     .version_id = 3,
1149     .fields = (VMStateField[]) {
1150         VMSTATE_VIRTIO_DEVICE,
1151         VMSTATE_END_OF_LIST()
1152     },
1153 };
1154
1155 static Property virtio_serial_properties[] = {
1156     DEFINE_PROP_UINT32("max_ports", VirtIOSerial, serial.max_virtserial_ports,
1157                                                   31),
1158     DEFINE_PROP_BIT64("emergency-write", VirtIOSerial, host_features,
1159                       VIRTIO_CONSOLE_F_EMERG_WRITE, true),
1160     DEFINE_PROP_END_OF_LIST(),
1161 };
1162
1163 static void virtio_serial_class_init(ObjectClass *klass, void *data)
1164 {
1165     DeviceClass *dc = DEVICE_CLASS(klass);
1166     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
1167     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
1168
1169     QLIST_INIT(&vserdevices.devices);
1170
1171     dc->props = virtio_serial_properties;
1172     dc->vmsd = &vmstate_virtio_console;
1173     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
1174     vdc->realize = virtio_serial_device_realize;
1175     vdc->unrealize = virtio_serial_device_unrealize;
1176     vdc->get_features = get_features;
1177     vdc->get_config = get_config;
1178     vdc->set_config = set_config;
1179     vdc->set_status = set_status;
1180     vdc->reset = vser_reset;
1181     vdc->save = virtio_serial_save_device;
1182     vdc->load = virtio_serial_load_device;
1183     hc->plug = virtser_port_device_plug;
1184     hc->unplug = qdev_simple_device_unplug_cb;
1185 }
1186
1187 static const TypeInfo virtio_device_info = {
1188     .name = TYPE_VIRTIO_SERIAL,
1189     .parent = TYPE_VIRTIO_DEVICE,
1190     .instance_size = sizeof(VirtIOSerial),
1191     .class_init = virtio_serial_class_init,
1192     .interfaces = (InterfaceInfo[]) {
1193         { TYPE_HOTPLUG_HANDLER },
1194         { }
1195     }
1196 };
1197
1198 static void virtio_serial_register_types(void)
1199 {
1200     type_register_static(&virtser_bus_info);
1201     type_register_static(&virtio_serial_port_type_info);
1202     type_register_static(&virtio_device_info);
1203 }
1204
1205 type_init(virtio_serial_register_types)