hw/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-serial.h"
  27
  28 /* The virtio-serial bus on top of which the ports will ride as devices */
  29 struct VirtIOSerialBus {
  30     BusState qbus;
  31
  32     /* This is the parent device that provides the bus for ports. */
  33     VirtIOSerial *vser;
  34
  35     /* The maximum number of ports that can ride on top of this bus */
  36     uint32_t max_nr_ports;
  37 };
  38
  39 typedef struct VirtIOSerialPostLoad {
  40     QEMUTimer *timer;
  41     uint32_t nr_active_ports;
  42     struct {
  43         VirtIOSerialPort *port;
  44         uint8_t host_connected;
  45     } *connected;
  46 } VirtIOSerialPostLoad;
  47
  48 struct VirtIOSerial {
  49     VirtIODevice vdev;
  50
  51     VirtQueue *c_ivq, *c_ovq;
  52     /* Arrays of ivqs and ovqs: one per port */
  53     VirtQueue **ivqs, **ovqs;
  54
  55     VirtIOSerialBus bus;
  56
  57     DeviceState *qdev;
  58
  59     QTAILQ_HEAD(, VirtIOSerialPort) ports;
  60
  61     /* bitmap for identifying active ports */
  62     uint32_t *ports_map;
  63
  64     struct virtio_console_config config;
  65
  66     struct VirtIOSerialPostLoad *post_load;
  67 };
  68
  69 static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
  70 {
  71     VirtIOSerialPort *port;
  72
  73     if (id == VIRTIO_CONSOLE_BAD_ID) {
  74         return NULL;
  75     }
  76
  77     QTAILQ_FOREACH(port, &vser->ports, next) {
  78         if (port->id == id)
  79             return port;
  80     }
  81     return NULL;
  82 }
  83
  84 static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
  85 {
  86     VirtIOSerialPort *port;
  87
  88     QTAILQ_FOREACH(port, &vser->ports, next) {
  89         if (port->ivq == vq || port->ovq == vq)
  90             return port;
  91     }
  92     return NULL;
  93 }
  94
  95 static bool use_multiport(VirtIOSerial *vser)
  96 {
  97     return vser->vdev.guest_features & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
  98 }
  99
 100 static size_t write_to_port(VirtIOSerialPort *port,
 101                             const uint8_t *buf, size_t size)
 102 {
 103     VirtQueueElement elem;
 104     VirtQueue *vq;
 105     size_t offset;
 106
 107     vq = port->ivq;
 108     if (!virtio_queue_ready(vq)) {
 109         return 0;
 110     }
 111
 112     offset = 0;
 113     while (offset < size) {
 114         size_t len;
 115
 116         if (!virtqueue_pop(vq, &elem)) {
 117             break;
 118         }
 119
 120         len = iov_from_buf(elem.in_sg, elem.in_num, 0,
 121                            buf + offset, size - offset);
 122         offset += len;
 123
 124         virtqueue_push(vq, &elem, len);
 125     }
 126
 127     virtio_notify(&port->vser->vdev, 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     while (virtqueue_pop(vq, &elem)) {
 139         virtqueue_push(vq, &elem, 0);
 140     }
 141     virtio_notify(vdev, vq);
 142 }
 143
 144 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
 145                                  VirtIODevice *vdev)
 146 {
 147     VirtIOSerialPortClass *vsc;
 148
 149     assert(port);
 150     assert(virtio_queue_ready(vq));
 151
 152     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 153
 154     while (!port->throttled) {
 155         unsigned int i;
 156
 157         /* Pop an elem only if we haven't left off a previous one mid-way */
 158         if (!port->elem.out_num) {
 159             if (!virtqueue_pop(vq, &port->elem)) {
 160                 break;
 161             }
 162             port->iov_idx = 0;
 163             port->iov_offset = 0;
 164         }
 165
 166         for (i = port->iov_idx; i < port->elem.out_num; i++) {
 167             size_t buf_size;
 168             ssize_t ret;
 169
 170             buf_size = port->elem.out_sg[i].iov_len - port->iov_offset;
 171             ret = vsc->have_data(port,
 172                                   port->elem.out_sg[i].iov_base
 173                                   + port->iov_offset,
 174                                   buf_size);
 175             if (port->throttled) {
 176                 port->iov_idx = i;
 177                 if (ret > 0) {
 178                     port->iov_offset += ret;
 179                 }
 180                 break;
 181             }
 182             port->iov_offset = 0;
 183         }
 184         if (port->throttled) {
 185             break;
 186         }
 187         virtqueue_push(vq, &port->elem, 0);
 188         port->elem.out_num = 0;
 189     }
 190     virtio_notify(vdev, vq);
 191 }
 192
 193 static void flush_queued_data(VirtIOSerialPort *port)
 194 {
 195     assert(port);
 196
 197     if (!virtio_queue_ready(port->ovq)) {
 198         return;
 199     }
 200     do_flush_queued_data(port, port->ovq, &port->vser->vdev);
 201 }
 202
 203 static size_t send_control_msg(VirtIOSerial *vser, void *buf, size_t len)
 204 {
 205     VirtQueueElement elem;
 206     VirtQueue *vq;
 207
 208     vq = vser->c_ivq;
 209     if (!virtio_queue_ready(vq)) {
 210         return 0;
 211     }
 212     if (!virtqueue_pop(vq, &elem)) {
 213         return 0;
 214     }
 215
 216     memcpy(elem.in_sg[0].iov_base, buf, len);
 217
 218     virtqueue_push(vq, &elem, len);
 219     virtio_notify(&vser->vdev, vq);
 220     return len;
 221 }
 222
 223 static size_t send_control_event(VirtIOSerial *vser, uint32_t port_id,
 224                                  uint16_t event, uint16_t value)
 225 {
 226     struct virtio_console_control cpkt;
 227
 228     stl_p(&cpkt.id, port_id);
 229     stw_p(&cpkt.event, event);
 230     stw_p(&cpkt.value, value);
 231
 232     trace_virtio_serial_send_control_event(port_id, event, value);
 233     return send_control_msg(vser, &cpkt, sizeof(cpkt));
 234 }
 235
 236 /* Functions for use inside qemu to open and read from/write to ports */
 237 int virtio_serial_open(VirtIOSerialPort *port)
 238 {
 239     /* Don't allow opening an already-open port */
 240     if (port->host_connected) {
 241         return 0;
 242     }
 243     /* Send port open notification to the guest */
 244     port->host_connected = true;
 245     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 246
 247     return 0;
 248 }
 249
 250 int virtio_serial_close(VirtIOSerialPort *port)
 251 {
 252     port->host_connected = false;
 253     /*
 254      * If there's any data the guest sent which the app didn't
 255      * consume, reset the throttling flag and discard the data.
 256      */
 257     port->throttled = false;
 258     discard_vq_data(port->ovq, &port->vser->vdev);
 259
 260     send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 0);
 261
 262     return 0;
 263 }
 264
 265 /* Individual ports/apps call this function to write to the guest. */
 266 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 267                             size_t size)
 268 {
 269     if (!port || !port->host_connected || !port->guest_connected) {
 270         return 0;
 271     }
 272     return write_to_port(port, buf, size);
 273 }
 274
 275 /*
 276  * Readiness of the guest to accept data on a port.
 277  * Returns max. data the guest can receive
 278  */
 279 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 280 {
 281     VirtQueue *vq = port->ivq;
 282     unsigned int bytes;
 283
 284     if (!virtio_queue_ready(vq) ||
 285         !(port->vser->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK) ||
 286         virtio_queue_empty(vq)) {
 287         return 0;
 288     }
 289     if (use_multiport(port->vser) && !port->guest_connected) {
 290         return 0;
 291     }
 292     virtqueue_get_avail_bytes(vq, &bytes, NULL, 4096, 0);
 293     return bytes;
 294 }
 295
 296 static void flush_queued_data_bh(void *opaque)
 297 {
 298     VirtIOSerialPort *port = opaque;
 299
 300     flush_queued_data(port);
 301 }
 302
 303 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 304 {
 305     if (!port) {
 306         return;
 307     }
 308
 309     trace_virtio_serial_throttle_port(port->id, throttle);
 310     port->throttled = throttle;
 311     if (throttle) {
 312         return;
 313     }
 314     qemu_bh_schedule(port->bh);
 315 }
 316
 317 /* Guest wants to notify us of some event */
 318 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 319 {
 320     struct VirtIOSerialPort *port;
 321     VirtIOSerialPortClass *vsc;
 322     struct virtio_console_control cpkt, *gcpkt;
 323     uint8_t *buffer;
 324     size_t buffer_len;
 325
 326     gcpkt = buf;
 327
 328     if (len < sizeof(cpkt)) {
 329         /* The guest sent an invalid control packet */
 330         return;
 331     }
 332
 333     cpkt.event = lduw_p(&gcpkt->event);
 334     cpkt.value = lduw_p(&gcpkt->value);
 335
 336     trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
 337
 338     if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
 339         if (!cpkt.value) {
 340             error_report("virtio-serial-bus: Guest failure in adding device %s",
 341                          vser->bus.qbus.name);
 342             return;
 343         }
 344         /*
 345          * The device is up, we can now tell the device about all the
 346          * ports we have here.
 347          */
 348         QTAILQ_FOREACH(port, &vser->ports, next) {
 349             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_ADD, 1);
 350         }
 351         return;
 352     }
 353
 354     port = find_port_by_id(vser, ldl_p(&gcpkt->id));
 355     if (!port) {
 356         error_report("virtio-serial-bus: Unexpected port id %u for device %s",
 357                      ldl_p(&gcpkt->id), vser->bus.qbus.name);
 358         return;
 359     }
 360
 361     trace_virtio_serial_handle_control_message_port(port->id);
 362
 363     vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 364
 365     switch(cpkt.event) {
 366     case VIRTIO_CONSOLE_PORT_READY:
 367         if (!cpkt.value) {
 368             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
 369                          port->id, vser->bus.qbus.name);
 370             break;
 371         }
 372         /*
 373          * Now that we know the guest asked for the port name, we're
 374          * sure the guest has initialised whatever state is necessary
 375          * for this port. Now's a good time to let the guest know if
 376          * this port is a console port so that the guest can hook it
 377          * up to hvc.
 378          */
 379         if (vsc->is_console) {
 380             send_control_event(vser, port->id, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
 381         }
 382
 383         if (port->name) {
 384             stl_p(&cpkt.id, port->id);
 385             stw_p(&cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
 386             stw_p(&cpkt.value, 1);
 387
 388             buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
 389             buffer = g_malloc(buffer_len);
 390
 391             memcpy(buffer, &cpkt, sizeof(cpkt));
 392             memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
 393             buffer[buffer_len - 1] = 0;
 394
 395             send_control_msg(vser, buffer, buffer_len);
 396             g_free(buffer);
 397         }
 398
 399         if (port->host_connected) {
 400             send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
 401         }
 402
 403         /*
 404          * When the guest has asked us for this information it means
 405          * the guest is all setup and has its virtqueues
 406          * initialised. If some app is interested in knowing about
 407          * this event, let it know.
 408          */
 409         if (vsc->guest_ready) {
 410             vsc->guest_ready(port);
 411         }
 412         break;
 413
 414     case VIRTIO_CONSOLE_PORT_OPEN:
 415         port->guest_connected = cpkt.value;
 416         if (cpkt.value && vsc->guest_open) {
 417             /* Send the guest opened notification if an app is interested */
 418             vsc->guest_open(port);
 419         }
 420
 421         if (!cpkt.value && vsc->guest_close) {
 422             /* Send the guest closed notification if an app is interested */
 423             vsc->guest_close(port);
 424         }
 425         break;
 426     }
 427 }
 428
 429 static void control_in(VirtIODevice *vdev, VirtQueue *vq)
 430 {
 431 }
 432
 433 static void control_out(VirtIODevice *vdev, VirtQueue *vq)
 434 {
 435     VirtQueueElement elem;
 436     VirtIOSerial *vser;
 437     uint8_t *buf;
 438     size_t len;
 439
 440     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 441
 442     len = 0;
 443     buf = NULL;
 444     while (virtqueue_pop(vq, &elem)) {
 445         size_t cur_len;
 446
 447         cur_len = iov_size(elem.out_sg, elem.out_num);
 448         /*
 449          * Allocate a new buf only if we didn't have one previously or
 450          * if the size of the buf differs
 451          */
 452         if (cur_len > len) {
 453             g_free(buf);
 454
 455             buf = g_malloc(cur_len);
 456             len = cur_len;
 457         }
 458         iov_to_buf(elem.out_sg, elem.out_num, 0, buf, cur_len);
 459
 460         handle_control_message(vser, buf, cur_len);
 461         virtqueue_push(vq, &elem, 0);
 462     }
 463     g_free(buf);
 464     virtio_notify(vdev, vq);
 465 }
 466
 467 /* Guest wrote something to some port. */
 468 static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 469 {
 470     VirtIOSerial *vser;
 471     VirtIOSerialPort *port;
 472
 473     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 474     port = find_port_by_vq(vser, vq);
 475
 476     if (!port || !port->host_connected) {
 477         discard_vq_data(vq, vdev);
 478         return;
 479     }
 480
 481     if (!port->throttled) {
 482         do_flush_queued_data(port, vq, vdev);
 483         return;
 484     }
 485 }
 486
 487 static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
 488 {
 489 }
 490
 491 static uint32_t get_features(VirtIODevice *vdev, uint32_t features)
 492 {
 493     VirtIOSerial *vser;
 494
 495     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 496
 497     if (vser->bus.max_nr_ports > 1) {
 498         features |= (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 499     }
 500     return features;
 501 }
 502
 503 /* Guest requested config info */
 504 static void get_config(VirtIODevice *vdev, uint8_t *config_data)
 505 {
 506     VirtIOSerial *vser;
 507
 508     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 509     memcpy(config_data, &vser->config, sizeof(struct virtio_console_config));
 510 }
 511
 512 static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
 513 {
 514     struct virtio_console_config config;
 515
 516     memcpy(&config, config_data, sizeof(config));
 517 }
 518
 519 static void guest_reset(VirtIOSerial *vser)
 520 {
 521     VirtIOSerialPort *port;
 522     VirtIOSerialPortClass *vsc;
 523
 524     QTAILQ_FOREACH(port, &vser->ports, next) {
 525         vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 526         if (port->guest_connected) {
 527             port->guest_connected = false;
 528
 529             if (vsc->guest_close)
 530                 vsc->guest_close(port);
 531         }
 532     }
 533 }
 534
 535 static void set_status(VirtIODevice *vdev, uint8_t status)
 536 {
 537     VirtIOSerial *vser;
 538     VirtIOSerialPort *port;
 539
 540     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 541     port = find_port_by_id(vser, 0);
 542
 543     if (port && !use_multiport(port->vser)
 544         && (status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 545         /*
 546          * Non-multiport guests won't be able to tell us guest
 547          * open/close status.  Such guests can only have a port at id
 548          * 0, so set guest_connected for such ports as soon as guest
 549          * is up.
 550          */
 551         port->guest_connected = true;
 552     }
 553     if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 554         guest_reset(vser);
 555     }
 556 }
 557
 558 static void vser_reset(VirtIODevice *vdev)
 559 {
 560     VirtIOSerial *vser;
 561
 562     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 563     guest_reset(vser);
 564 }
 565
 566 static void virtio_serial_save(QEMUFile *f, void *opaque)
 567 {
 568     VirtIOSerial *s = opaque;
 569     VirtIOSerialPort *port;
 570     uint32_t nr_active_ports;
 571     unsigned int i, max_nr_ports;
 572
 573     /* The virtio device */
 574     virtio_save(&s->vdev, f);
 575
 576     /* The config space */
 577     qemu_put_be16s(f, &s->config.cols);
 578     qemu_put_be16s(f, &s->config.rows);
 579
 580     qemu_put_be32s(f, &s->config.max_nr_ports);
 581
 582     /* The ports map */
 583     max_nr_ports = tswap32(s->config.max_nr_ports);
 584     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 585         qemu_put_be32s(f, &s->ports_map[i]);
 586     }
 587
 588     /* Ports */
 589
 590     nr_active_ports = 0;
 591     QTAILQ_FOREACH(port, &s->ports, next) {
 592         nr_active_ports++;
 593     }
 594
 595     qemu_put_be32s(f, &nr_active_ports);
 596
 597     /*
 598      * Items in struct VirtIOSerialPort.
 599      */
 600     QTAILQ_FOREACH(port, &s->ports, next) {
 601         uint32_t elem_popped;
 602
 603         qemu_put_be32s(f, &port->id);
 604         qemu_put_byte(f, port->guest_connected);
 605         qemu_put_byte(f, port->host_connected);
 606
 607         elem_popped = 0;
 608         if (port->elem.out_num) {
 609             elem_popped = 1;
 610         }
 611         qemu_put_be32s(f, &elem_popped);
 612         if (elem_popped) {
 613             qemu_put_be32s(f, &port->iov_idx);
 614             qemu_put_be64s(f, &port->iov_offset);
 615
 616             qemu_put_buffer(f, (unsigned char *)&port->elem,
 617                             sizeof(port->elem));
 618         }
 619     }
 620 }
 621
 622 static void virtio_serial_post_load_timer_cb(void *opaque)
 623 {
 624     uint32_t i;
 625     VirtIOSerial *s = opaque;
 626     VirtIOSerialPort *port;
 627     uint8_t host_connected;
 628
 629     if (!s->post_load) {
 630         return;
 631     }
 632     for (i = 0 ; i < s->post_load->nr_active_ports; ++i) {
 633         port = s->post_load->connected[i].port;
 634         host_connected = s->post_load->connected[i].host_connected;
 635         if (host_connected != port->host_connected) {
 636             /*
 637              * We have to let the guest know of the host connection
 638              * status change
 639              */
 640             send_control_event(s, port->id, VIRTIO_CONSOLE_PORT_OPEN,
 641                                port->host_connected);
 642         }
 643     }
 644     g_free(s->post_load->connected);
 645     qemu_free_timer(s->post_load->timer);
 646     g_free(s->post_load);
 647     s->post_load = NULL;
 648 }
 649
 650 static int fetch_active_ports_list(QEMUFile *f, int version_id,
 651                                    VirtIOSerial *s, uint32_t nr_active_ports)
 652 {
 653     uint32_t i;
 654
 655     s->post_load = g_malloc0(sizeof(*s->post_load));
 656     s->post_load->nr_active_ports = nr_active_ports;
 657     s->post_load->connected =
 658         g_malloc0(sizeof(*s->post_load->connected) * nr_active_ports);
 659
 660     s->post_load->timer = qemu_new_timer_ns(vm_clock,
 661                                             virtio_serial_post_load_timer_cb,
 662                                             s);
 663
 664     /* Items in struct VirtIOSerialPort */
 665     for (i = 0; i < nr_active_ports; i++) {
 666         VirtIOSerialPort *port;
 667         uint32_t id;
 668
 669         id = qemu_get_be32(f);
 670         port = find_port_by_id(s, id);
 671         if (!port) {
 672             return -EINVAL;
 673         }
 674
 675         port->guest_connected = qemu_get_byte(f);
 676         s->post_load->connected[i].port = port;
 677         s->post_load->connected[i].host_connected = qemu_get_byte(f);
 678
 679         if (version_id > 2) {
 680             uint32_t elem_popped;
 681
 682             qemu_get_be32s(f, &elem_popped);
 683             if (elem_popped) {
 684                 qemu_get_be32s(f, &port->iov_idx);
 685                 qemu_get_be64s(f, &port->iov_offset);
 686
 687                 qemu_get_buffer(f, (unsigned char *)&port->elem,
 688                                 sizeof(port->elem));
 689                 virtqueue_map_sg(port->elem.in_sg, port->elem.in_addr,
 690                                  port->elem.in_num, 1);
 691                 virtqueue_map_sg(port->elem.out_sg, port->elem.out_addr,
 692                                  port->elem.out_num, 1);
 693
 694                 /*
 695                  *  Port was throttled on source machine.  Let's
 696                  *  unthrottle it here so data starts flowing again.
 697                  */
 698                 virtio_serial_throttle_port(port, false);
 699             }
 700         }
 701     }
 702     qemu_mod_timer(s->post_load->timer, 1);
 703     return 0;
 704 }
 705
 706 static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
 707 {
 708     VirtIOSerial *s = opaque;
 709     uint32_t max_nr_ports, nr_active_ports, ports_map;
 710     unsigned int i;
 711     int ret;
 712
 713     if (version_id > 3) {
 714         return -EINVAL;
 715     }
 716
 717     /* The virtio device */
 718     ret = virtio_load(&s->vdev, f);
 719     if (ret) {
 720         return ret;
 721     }
 722
 723     if (version_id < 2) {
 724         return 0;
 725     }
 726
 727     /* The config space */
 728     qemu_get_be16s(f, &s->config.cols);
 729     qemu_get_be16s(f, &s->config.rows);
 730
 731     qemu_get_be32s(f, &max_nr_ports);
 732     tswap32s(&max_nr_ports);
 733     if (max_nr_ports > tswap32(s->config.max_nr_ports)) {
 734         /* Source could have had more ports than us. Fail migration. */
 735         return -EINVAL;
 736     }
 737
 738     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 739         qemu_get_be32s(f, &ports_map);
 740
 741         if (ports_map != s->ports_map[i]) {
 742             /*
 743              * Ports active on source and destination don't
 744              * match. Fail migration.
 745              */
 746             return -EINVAL;
 747         }
 748     }
 749
 750     qemu_get_be32s(f, &nr_active_ports);
 751
 752     if (nr_active_ports) {
 753         ret = fetch_active_ports_list(f, version_id, s, nr_active_ports);
 754         if (ret) {
 755             return ret;
 756         }
 757     }
 758     return 0;
 759 }
 760
 761 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 762
 763 static Property virtser_props[] = {
 764     DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
 765     DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
 766     DEFINE_PROP_END_OF_LIST()
 767 };
 768
 769 #define TYPE_VIRTIO_SERIAL_BUS "virtio-serial-bus"
 770 #define VIRTIO_SERIAL_BUS(obj) \
 771       OBJECT_CHECK(VirtIOSerialBus, (obj), TYPE_VIRTIO_SERIAL_BUS)
 772
 773 static void virtser_bus_class_init(ObjectClass *klass, void *data)
 774 {
 775     BusClass *k = BUS_CLASS(klass);
 776     k->print_dev = virtser_bus_dev_print;
 777 }
 778
 779 static const TypeInfo virtser_bus_info = {
 780     .name = TYPE_VIRTIO_SERIAL_BUS,
 781     .parent = TYPE_BUS,
 782     .instance_size = sizeof(VirtIOSerialBus),
 783     .class_init = virtser_bus_class_init,
 784 };
 785
 786 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 787 {
 788     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 789
 790     monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
 791                    indent, "", port->id,
 792                    port->guest_connected ? "on" : "off",
 793                    port->host_connected ? "on" : "off",
 794                    port->throttled ? "on" : "off");
 795 }
 796
 797 /* This function is only used if a port id is not provided by the user */
 798 static uint32_t find_free_port_id(VirtIOSerial *vser)
 799 {
 800     unsigned int i, max_nr_ports;
 801
 802     max_nr_ports = tswap32(vser->config.max_nr_ports);
 803     for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
 804         uint32_t map, bit;
 805
 806         map = vser->ports_map[i];
 807         bit = ffs(~map);
 808         if (bit) {
 809             return (bit - 1) + i * 32;
 810         }
 811     }
 812     return VIRTIO_CONSOLE_BAD_ID;
 813 }
 814
 815 static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
 816 {
 817     unsigned int i;
 818
 819     i = port_id / 32;
 820     vser->ports_map[i] |= 1U << (port_id % 32);
 821 }
 822
 823 static void add_port(VirtIOSerial *vser, uint32_t port_id)
 824 {
 825     mark_port_added(vser, port_id);
 826     send_control_event(vser, port_id, VIRTIO_CONSOLE_PORT_ADD, 1);
 827 }
 828
 829 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 830 {
 831     VirtIOSerialPort *port;
 832     unsigned int i;
 833
 834     i = port_id / 32;
 835     vser->ports_map[i] &= ~(1U << (port_id % 32));
 836
 837     port = find_port_by_id(vser, port_id);
 838     /*
 839      * This function is only called from qdev's unplug callback; if we
 840      * get a NULL port here, we're in trouble.
 841      */
 842     assert(port);
 843
 844     /* Flush out any unconsumed buffers first */
 845     discard_vq_data(port->ovq, &port->vser->vdev);
 846
 847     send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 848 }
 849
 850 static int virtser_port_qdev_init(DeviceState *qdev)
 851 {
 852     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 853     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 854     VirtIOSerialBus *bus = DO_UPCAST(VirtIOSerialBus, qbus, qdev->parent_bus);
 855     int ret, max_nr_ports;
 856     bool plugging_port0;
 857
 858     port->vser = bus->vser;
 859     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 860
 861     assert(vsc->have_data);
 862
 863     /*
 864      * Is the first console port we're seeing? If so, put it up at
 865      * location 0. This is done for backward compatibility (old
 866      * kernel, new qemu).
 867      */
 868     plugging_port0 = vsc->is_console && !find_port_by_id(port->vser, 0);
 869
 870     if (find_port_by_id(port->vser, port->id)) {
 871         error_report("virtio-serial-bus: A port already exists at id %u",
 872                      port->id);
 873         return -1;
 874     }
 875
 876     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 877         if (plugging_port0) {
 878             port->id = 0;
 879         } else {
 880             port->id = find_free_port_id(port->vser);
 881             if (port->id == VIRTIO_CONSOLE_BAD_ID) {
 882                 error_report("virtio-serial-bus: Maximum port limit for this device reached");
 883                 return -1;
 884             }
 885         }
 886     }
 887
 888     max_nr_ports = tswap32(port->vser->config.max_nr_ports);
 889     if (port->id >= max_nr_ports) {
 890         error_report("virtio-serial-bus: Out-of-range port id specified, max. allowed: %u",
 891                      max_nr_ports - 1);
 892         return -1;
 893     }
 894
 895     ret = vsc->init(port);
 896     if (ret) {
 897         return ret;
 898     }
 899
 900     port->elem.out_num = 0;
 901
 902     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
 903     port->ivq = port->vser->ivqs[port->id];
 904     port->ovq = port->vser->ovqs[port->id];
 905
 906     add_port(port->vser, port->id);
 907
 908     /* Send an update to the guest about this new port added */
 909     virtio_notify_config(&port->vser->vdev);
 910
 911     return ret;
 912 }
 913
 914 static int virtser_port_qdev_exit(DeviceState *qdev)
 915 {
 916     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
 917     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 918     VirtIOSerial *vser = port->vser;
 919
 920     qemu_bh_delete(port->bh);
 921     remove_port(port->vser, port->id);
 922
 923     QTAILQ_REMOVE(&vser->ports, port, next);
 924
 925     if (vsc->exit) {
 926         vsc->exit(port);
 927     }
 928     return 0;
 929 }
 930
 931 VirtIODevice *virtio_serial_init(DeviceState *dev, virtio_serial_conf *conf)
 932 {
 933     VirtIOSerial *vser;
 934     VirtIODevice *vdev;
 935     uint32_t i, max_supported_ports;
 936
 937     if (!conf->max_virtserial_ports)
 938         return NULL;
 939
 940     /* Each port takes 2 queues, and one pair is for the control queue */
 941     max_supported_ports = VIRTIO_PCI_QUEUE_MAX / 2 - 1;
 942
 943     if (conf->max_virtserial_ports > max_supported_ports) {
 944         error_report("maximum ports supported: %u", max_supported_ports);
 945         return NULL;
 946     }
 947
 948     vdev = virtio_common_init("virtio-serial", VIRTIO_ID_CONSOLE,
 949                               sizeof(struct virtio_console_config),
 950                               sizeof(VirtIOSerial));
 951
 952     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 953
 954     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
 955     qbus_create_inplace(&vser->bus.qbus, TYPE_VIRTIO_SERIAL_BUS, dev, NULL);
 956     vser->bus.qbus.allow_hotplug = 1;
 957     vser->bus.vser = vser;
 958     QTAILQ_INIT(&vser->ports);
 959
 960     vser->bus.max_nr_ports = conf->max_virtserial_ports;
 961     vser->ivqs = g_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 962     vser->ovqs = g_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 963
 964     /* Add a queue for host to guest transfers for port 0 (backward compat) */
 965     vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
 966     /* Add a queue for guest to host transfers for port 0 (backward compat) */
 967     vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
 968
 969     /* TODO: host to guest notifications can get dropped
 970      * if the queue fills up. Implement queueing in host,
 971      * this might also make it possible to reduce the control
 972      * queue size: as guest preposts buffers there,
 973      * this will save 4Kbyte of guest memory per entry. */
 974
 975     /* control queue: host to guest */
 976     vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
 977     /* control queue: guest to host */
 978     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
 979
 980     for (i = 1; i < vser->bus.max_nr_ports; i++) {
 981         /* Add a per-port queue for host to guest transfers */
 982         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
 983         /* Add a per-per queue for guest to host transfers */
 984         vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
 985     }
 986
 987     vser->config.max_nr_ports = tswap32(conf->max_virtserial_ports);
 988     vser->ports_map = g_malloc0(((conf->max_virtserial_ports + 31) / 32)
 989         * sizeof(vser->ports_map[0]));
 990     /*
 991      * Reserve location 0 for a console port for backward compat
 992      * (old kernel, new qemu)
 993      */
 994     mark_port_added(vser, 0);
 995
 996     vser->vdev.get_features = get_features;
 997     vser->vdev.get_config = get_config;
 998     vser->vdev.set_config = set_config;
 999     vser->vdev.set_status = set_status;
1000     vser->vdev.reset = vser_reset;
1001
1002     vser->qdev = dev;
1003
1004     vser->post_load = NULL;
1005
1006     /*
1007      * Register for the savevm section with the virtio-console name
1008      * to preserve backward compat
1009      */
1010     register_savevm(dev, "virtio-console", -1, 3, virtio_serial_save,
1011                     virtio_serial_load, vser);
1012
1013     return vdev;
1014 }
1015
1016 void virtio_serial_exit(VirtIODevice *vdev)
1017 {
1018     VirtIOSerial *vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
1019
1020     unregister_savevm(vser->qdev, "virtio-console", vser);
1021
1022     g_free(vser->ivqs);
1023     g_free(vser->ovqs);
1024     g_free(vser->ports_map);
1025     if (vser->post_load) {
1026         g_free(vser->post_load->connected);
1027         qemu_del_timer(vser->post_load->timer);
1028         qemu_free_timer(vser->post_load->timer);
1029         g_free(vser->post_load);
1030     }
1031     virtio_cleanup(vdev);
1032 }
1033
1034 static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
1035 {
1036     DeviceClass *k = DEVICE_CLASS(klass);
1037     k->init = virtser_port_qdev_init;
1038     k->bus_type = TYPE_VIRTIO_SERIAL_BUS;
1039     k->exit = virtser_port_qdev_exit;
1040     k->unplug = qdev_simple_unplug_cb;
1041     k->props = virtser_props;
1042 }
1043
1044 static const TypeInfo virtio_serial_port_type_info = {
1045     .name = TYPE_VIRTIO_SERIAL_PORT,
1046     .parent = TYPE_DEVICE,
1047     .instance_size = sizeof(VirtIOSerialPort),
1048     .abstract = true,
1049     .class_size = sizeof(VirtIOSerialPortClass),
1050     .class_init = virtio_serial_port_class_init,
1051 };
1052
1053 static void virtio_serial_register_types(void)
1054 {
1055     type_register_static(&virtser_bus_info);
1056     type_register_static(&virtio_serial_port_type_info);
1057 }
1058
1059 type_init(virtio_serial_register_types)