linux/drivers/char/virtio_console.c
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   1/*
   2 * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
   3 * Copyright (C) 2009, 2010, 2011 Red Hat, Inc.
   4 * Copyright (C) 2009, 2010, 2011 Amit Shah <amit.shah@redhat.com>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19 */
  20#include <linux/cdev.h>
  21#include <linux/debugfs.h>
  22#include <linux/completion.h>
  23#include <linux/device.h>
  24#include <linux/err.h>
  25#include <linux/freezer.h>
  26#include <linux/fs.h>
  27#include <linux/init.h>
  28#include <linux/list.h>
  29#include <linux/poll.h>
  30#include <linux/sched.h>
  31#include <linux/slab.h>
  32#include <linux/spinlock.h>
  33#include <linux/virtio.h>
  34#include <linux/virtio_console.h>
  35#include <linux/wait.h>
  36#include <linux/workqueue.h>
  37#include <linux/module.h>
  38#include "../tty/hvc/hvc_console.h"
  39
  40/*
  41 * This is a global struct for storing common data for all the devices
  42 * this driver handles.
  43 *
  44 * Mainly, it has a linked list for all the consoles in one place so
  45 * that callbacks from hvc for get_chars(), put_chars() work properly
  46 * across multiple devices and multiple ports per device.
  47 */
  48struct ports_driver_data {
  49        /* Used for registering chardevs */
  50        struct class *class;
  51
  52        /* Used for exporting per-port information to debugfs */
  53        struct dentry *debugfs_dir;
  54
  55        /* List of all the devices we're handling */
  56        struct list_head portdevs;
  57
  58        /* Number of devices this driver is handling */
  59        unsigned int index;
  60
  61        /*
  62         * This is used to keep track of the number of hvc consoles
  63         * spawned by this driver.  This number is given as the first
  64         * argument to hvc_alloc().  To correctly map an initial
  65         * console spawned via hvc_instantiate to the console being
  66         * hooked up via hvc_alloc, we need to pass the same vtermno.
  67         *
  68         * We also just assume the first console being initialised was
  69         * the first one that got used as the initial console.
  70         */
  71        unsigned int next_vtermno;
  72
  73        /* All the console devices handled by this driver */
  74        struct list_head consoles;
  75};
  76static struct ports_driver_data pdrvdata;
  77
  78DEFINE_SPINLOCK(pdrvdata_lock);
  79DECLARE_COMPLETION(early_console_added);
  80
  81/* This struct holds information that's relevant only for console ports */
  82struct console {
  83        /* We'll place all consoles in a list in the pdrvdata struct */
  84        struct list_head list;
  85
  86        /* The hvc device associated with this console port */
  87        struct hvc_struct *hvc;
  88
  89        /* The size of the console */
  90        struct winsize ws;
  91
  92        /*
  93         * This number identifies the number that we used to register
  94         * with hvc in hvc_instantiate() and hvc_alloc(); this is the
  95         * number passed on by the hvc callbacks to us to
  96         * differentiate between the other console ports handled by
  97         * this driver
  98         */
  99        u32 vtermno;
 100};
 101
 102struct port_buffer {
 103        char *buf;
 104
 105        /* size of the buffer in *buf above */
 106        size_t size;
 107
 108        /* used length of the buffer */
 109        size_t len;
 110        /* offset in the buf from which to consume data */
 111        size_t offset;
 112};
 113
 114/*
 115 * This is a per-device struct that stores data common to all the
 116 * ports for that device (vdev->priv).
 117 */
 118struct ports_device {
 119        /* Next portdev in the list, head is in the pdrvdata struct */
 120        struct list_head list;
 121
 122        /*
 123         * Workqueue handlers where we process deferred work after
 124         * notification
 125         */
 126        struct work_struct control_work;
 127
 128        struct list_head ports;
 129
 130        /* To protect the list of ports */
 131        spinlock_t ports_lock;
 132
 133        /* To protect the vq operations for the control channel */
 134        spinlock_t cvq_lock;
 135
 136        /* The current config space is stored here */
 137        struct virtio_console_config config;
 138
 139        /* The virtio device we're associated with */
 140        struct virtio_device *vdev;
 141
 142        /*
 143         * A couple of virtqueues for the control channel: one for
 144         * guest->host transfers, one for host->guest transfers
 145         */
 146        struct virtqueue *c_ivq, *c_ovq;
 147
 148        /* Array of per-port IO virtqueues */
 149        struct virtqueue **in_vqs, **out_vqs;
 150
 151        /* Used for numbering devices for sysfs and debugfs */
 152        unsigned int drv_index;
 153
 154        /* Major number for this device.  Ports will be created as minors. */
 155        int chr_major;
 156};
 157
 158struct port_stats {
 159        unsigned long bytes_sent, bytes_received, bytes_discarded;
 160};
 161
 162/* This struct holds the per-port data */
 163struct port {
 164        /* Next port in the list, head is in the ports_device */
 165        struct list_head list;
 166
 167        /* Pointer to the parent virtio_console device */
 168        struct ports_device *portdev;
 169
 170        /* The current buffer from which data has to be fed to readers */
 171        struct port_buffer *inbuf;
 172
 173        /*
 174         * To protect the operations on the in_vq associated with this
 175         * port.  Has to be a spinlock because it can be called from
 176         * interrupt context (get_char()).
 177         */
 178        spinlock_t inbuf_lock;
 179
 180        /* Protect the operations on the out_vq. */
 181        spinlock_t outvq_lock;
 182
 183        /* The IO vqs for this port */
 184        struct virtqueue *in_vq, *out_vq;
 185
 186        /* File in the debugfs directory that exposes this port's information */
 187        struct dentry *debugfs_file;
 188
 189        /*
 190         * Keep count of the bytes sent, received and discarded for
 191         * this port for accounting and debugging purposes.  These
 192         * counts are not reset across port open / close events.
 193         */
 194        struct port_stats stats;
 195
 196        /*
 197         * The entries in this struct will be valid if this port is
 198         * hooked up to an hvc console
 199         */
 200        struct console cons;
 201
 202        /* Each port associates with a separate char device */
 203        struct cdev *cdev;
 204        struct device *dev;
 205
 206        /* Reference-counting to handle port hot-unplugs and file operations */
 207        struct kref kref;
 208
 209        /* A waitqueue for poll() or blocking read operations */
 210        wait_queue_head_t waitqueue;
 211
 212        /* The 'name' of the port that we expose via sysfs properties */
 213        char *name;
 214
 215        /* We can notify apps of host connect / disconnect events via SIGIO */
 216        struct fasync_struct *async_queue;
 217
 218        /* The 'id' to identify the port with the Host */
 219        u32 id;
 220
 221        bool outvq_full;
 222
 223        /* Is the host device open */
 224        bool host_connected;
 225
 226        /* We should allow only one process to open a port */
 227        bool guest_connected;
 228};
 229
 230/* This is the very early arch-specified put chars function. */
 231static int (*early_put_chars)(u32, const char *, int);
 232
 233static struct port *find_port_by_vtermno(u32 vtermno)
 234{
 235        struct port *port;
 236        struct console *cons;
 237        unsigned long flags;
 238
 239        spin_lock_irqsave(&pdrvdata_lock, flags);
 240        list_for_each_entry(cons, &pdrvdata.consoles, list) {
 241                if (cons->vtermno == vtermno) {
 242                        port = container_of(cons, struct port, cons);
 243                        goto out;
 244                }
 245        }
 246        port = NULL;
 247out:
 248        spin_unlock_irqrestore(&pdrvdata_lock, flags);
 249        return port;
 250}
 251
 252static struct port *find_port_by_devt_in_portdev(struct ports_device *portdev,
 253                                                 dev_t dev)
 254{
 255        struct port *port;
 256        unsigned long flags;
 257
 258        spin_lock_irqsave(&portdev->ports_lock, flags);
 259        list_for_each_entry(port, &portdev->ports, list)
 260                if (port->cdev->dev == dev)
 261                        goto out;
 262        port = NULL;
 263out:
 264        spin_unlock_irqrestore(&portdev->ports_lock, flags);
 265
 266        return port;
 267}
 268
 269static struct port *find_port_by_devt(dev_t dev)
 270{
 271        struct ports_device *portdev;
 272        struct port *port;
 273        unsigned long flags;
 274
 275        spin_lock_irqsave(&pdrvdata_lock, flags);
 276        list_for_each_entry(portdev, &pdrvdata.portdevs, list) {
 277                port = find_port_by_devt_in_portdev(portdev, dev);
 278                if (port)
 279                        goto out;
 280        }
 281        port = NULL;
 282out:
 283        spin_unlock_irqrestore(&pdrvdata_lock, flags);
 284        return port;
 285}
 286
 287static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
 288{
 289        struct port *port;
 290        unsigned long flags;
 291
 292        spin_lock_irqsave(&portdev->ports_lock, flags);
 293        list_for_each_entry(port, &portdev->ports, list)
 294                if (port->id == id)
 295                        goto out;
 296        port = NULL;
 297out:
 298        spin_unlock_irqrestore(&portdev->ports_lock, flags);
 299
 300        return port;
 301}
 302
 303static struct port *find_port_by_vq(struct ports_device *portdev,
 304                                    struct virtqueue *vq)
 305{
 306        struct port *port;
 307        unsigned long flags;
 308
 309        spin_lock_irqsave(&portdev->ports_lock, flags);
 310        list_for_each_entry(port, &portdev->ports, list)
 311                if (port->in_vq == vq || port->out_vq == vq)
 312                        goto out;
 313        port = NULL;
 314out:
 315        spin_unlock_irqrestore(&portdev->ports_lock, flags);
 316        return port;
 317}
 318
 319static bool is_console_port(struct port *port)
 320{
 321        if (port->cons.hvc)
 322                return true;
 323        return false;
 324}
 325
 326static inline bool use_multiport(struct ports_device *portdev)
 327{
 328        /*
 329         * This condition can be true when put_chars is called from
 330         * early_init
 331         */
 332        if (!portdev->vdev)
 333                return 0;
 334        return portdev->vdev->features[0] & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 335}
 336
 337static void free_buf(struct port_buffer *buf)
 338{
 339        kfree(buf->buf);
 340        kfree(buf);
 341}
 342
 343static struct port_buffer *alloc_buf(size_t buf_size)
 344{
 345        struct port_buffer *buf;
 346
 347        buf = kmalloc(sizeof(*buf), GFP_KERNEL);
 348        if (!buf)
 349                goto fail;
 350        buf->buf = kzalloc(buf_size, GFP_KERNEL);
 351        if (!buf->buf)
 352                goto free_buf;
 353        buf->len = 0;
 354        buf->offset = 0;
 355        buf->size = buf_size;
 356        return buf;
 357
 358free_buf:
 359        kfree(buf);
 360fail:
 361        return NULL;
 362}
 363
 364/* Callers should take appropriate locks */
 365static struct port_buffer *get_inbuf(struct port *port)
 366{
 367        struct port_buffer *buf;
 368        unsigned int len;
 369
 370        if (port->inbuf)
 371                return port->inbuf;
 372
 373        buf = virtqueue_get_buf(port->in_vq, &len);
 374        if (buf) {
 375                buf->len = len;
 376                buf->offset = 0;
 377                port->stats.bytes_received += len;
 378        }
 379        return buf;
 380}
 381
 382/*
 383 * Create a scatter-gather list representing our input buffer and put
 384 * it in the queue.
 385 *
 386 * Callers should take appropriate locks.
 387 */
 388static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
 389{
 390        struct scatterlist sg[1];
 391        int ret;
 392
 393        sg_init_one(sg, buf->buf, buf->size);
 394
 395        ret = virtqueue_add_buf(vq, sg, 0, 1, buf, GFP_ATOMIC);
 396        virtqueue_kick(vq);
 397        return ret;
 398}
 399
 400/* Discard any unread data this port has. Callers lockers. */
 401static void discard_port_data(struct port *port)
 402{
 403        struct port_buffer *buf;
 404        unsigned int err;
 405
 406        if (!port->portdev) {
 407                /* Device has been unplugged.  vqs are already gone. */
 408                return;
 409        }
 410        buf = get_inbuf(port);
 411
 412        err = 0;
 413        while (buf) {
 414                port->stats.bytes_discarded += buf->len - buf->offset;
 415                if (add_inbuf(port->in_vq, buf) < 0) {
 416                        err++;
 417                        free_buf(buf);
 418                }
 419                port->inbuf = NULL;
 420                buf = get_inbuf(port);
 421        }
 422        if (err)
 423                dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
 424                         err);
 425}
 426
 427static bool port_has_data(struct port *port)
 428{
 429        unsigned long flags;
 430        bool ret;
 431
 432        ret = false;
 433        spin_lock_irqsave(&port->inbuf_lock, flags);
 434        port->inbuf = get_inbuf(port);
 435        if (port->inbuf)
 436                ret = true;
 437
 438        spin_unlock_irqrestore(&port->inbuf_lock, flags);
 439        return ret;
 440}
 441
 442static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
 443                                  unsigned int event, unsigned int value)
 444{
 445        struct scatterlist sg[1];
 446        struct virtio_console_control cpkt;
 447        struct virtqueue *vq;
 448        unsigned int len;
 449
 450        if (!use_multiport(portdev))
 451                return 0;
 452
 453        cpkt.id = port_id;
 454        cpkt.event = event;
 455        cpkt.value = value;
 456
 457        vq = portdev->c_ovq;
 458
 459        sg_init_one(sg, &cpkt, sizeof(cpkt));
 460        if (virtqueue_add_buf(vq, sg, 1, 0, &cpkt, GFP_ATOMIC) >= 0) {
 461                virtqueue_kick(vq);
 462                while (!virtqueue_get_buf(vq, &len))
 463                        cpu_relax();
 464        }
 465        return 0;
 466}
 467
 468static ssize_t send_control_msg(struct port *port, unsigned int event,
 469                                unsigned int value)
 470{
 471        /* Did the port get unplugged before userspace closed it? */
 472        if (port->portdev)
 473                return __send_control_msg(port->portdev, port->id, event, value);
 474        return 0;
 475}
 476
 477/* Callers must take the port->outvq_lock */
 478static void reclaim_consumed_buffers(struct port *port)
 479{
 480        void *buf;
 481        unsigned int len;
 482
 483        if (!port->portdev) {
 484                /* Device has been unplugged.  vqs are already gone. */
 485                return;
 486        }
 487        while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
 488                kfree(buf);
 489                port->outvq_full = false;
 490        }
 491}
 492
 493static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count,
 494                        bool nonblock)
 495{
 496        struct scatterlist sg[1];
 497        struct virtqueue *out_vq;
 498        ssize_t ret;
 499        unsigned long flags;
 500        unsigned int len;
 501
 502        out_vq = port->out_vq;
 503
 504        spin_lock_irqsave(&port->outvq_lock, flags);
 505
 506        reclaim_consumed_buffers(port);
 507
 508        sg_init_one(sg, in_buf, in_count);
 509        ret = virtqueue_add_buf(out_vq, sg, 1, 0, in_buf, GFP_ATOMIC);
 510
 511        /* Tell Host to go! */
 512        virtqueue_kick(out_vq);
 513
 514        if (ret < 0) {
 515                in_count = 0;
 516                goto done;
 517        }
 518
 519        if (ret == 0)
 520                port->outvq_full = true;
 521
 522        if (nonblock)
 523                goto done;
 524
 525        /*
 526         * Wait till the host acknowledges it pushed out the data we
 527         * sent.  This is done for data from the hvc_console; the tty
 528         * operations are performed with spinlocks held so we can't
 529         * sleep here.  An alternative would be to copy the data to a
 530         * buffer and relax the spinning requirement.  The downside is
 531         * we need to kmalloc a GFP_ATOMIC buffer each time the
 532         * console driver writes something out.
 533         */
 534        while (!virtqueue_get_buf(out_vq, &len))
 535                cpu_relax();
 536done:
 537        spin_unlock_irqrestore(&port->outvq_lock, flags);
 538
 539        port->stats.bytes_sent += in_count;
 540        /*
 541         * We're expected to return the amount of data we wrote -- all
 542         * of it
 543         */
 544        return in_count;
 545}
 546
 547/*
 548 * Give out the data that's requested from the buffer that we have
 549 * queued up.
 550 */
 551static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count,
 552                            bool to_user)
 553{
 554        struct port_buffer *buf;
 555        unsigned long flags;
 556
 557        if (!out_count || !port_has_data(port))
 558                return 0;
 559
 560        buf = port->inbuf;
 561        out_count = min(out_count, buf->len - buf->offset);
 562
 563        if (to_user) {
 564                ssize_t ret;
 565
 566                ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count);
 567                if (ret)
 568                        return -EFAULT;
 569        } else {
 570                memcpy(out_buf, buf->buf + buf->offset, out_count);
 571        }
 572
 573        buf->offset += out_count;
 574
 575        if (buf->offset == buf->len) {
 576                /*
 577                 * We're done using all the data in this buffer.
 578                 * Re-queue so that the Host can send us more data.
 579                 */
 580                spin_lock_irqsave(&port->inbuf_lock, flags);
 581                port->inbuf = NULL;
 582
 583                if (add_inbuf(port->in_vq, buf) < 0)
 584                        dev_warn(port->dev, "failed add_buf\n");
 585
 586                spin_unlock_irqrestore(&port->inbuf_lock, flags);
 587        }
 588        /* Return the number of bytes actually copied */
 589        return out_count;
 590}
 591
 592/* The condition that must be true for polling to end */
 593static bool will_read_block(struct port *port)
 594{
 595        if (!port->guest_connected) {
 596                /* Port got hot-unplugged. Let's exit. */
 597                return false;
 598        }
 599        return !port_has_data(port) && port->host_connected;
 600}
 601
 602static bool will_write_block(struct port *port)
 603{
 604        bool ret;
 605
 606        if (!port->guest_connected) {
 607                /* Port got hot-unplugged. Let's exit. */
 608                return false;
 609        }
 610        if (!port->host_connected)
 611                return true;
 612
 613        spin_lock_irq(&port->outvq_lock);
 614        /*
 615         * Check if the Host has consumed any buffers since we last
 616         * sent data (this is only applicable for nonblocking ports).
 617         */
 618        reclaim_consumed_buffers(port);
 619        ret = port->outvq_full;
 620        spin_unlock_irq(&port->outvq_lock);
 621
 622        return ret;
 623}
 624
 625static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
 626                              size_t count, loff_t *offp)
 627{
 628        struct port *port;
 629        ssize_t ret;
 630
 631        port = filp->private_data;
 632
 633        if (!port_has_data(port)) {
 634                /*
 635                 * If nothing's connected on the host just return 0 in
 636                 * case of list_empty; this tells the userspace app
 637                 * that there's no connection
 638                 */
 639                if (!port->host_connected)
 640                        return 0;
 641                if (filp->f_flags & O_NONBLOCK)
 642                        return -EAGAIN;
 643
 644                ret = wait_event_freezable(port->waitqueue,
 645                                           !will_read_block(port));
 646                if (ret < 0)
 647                        return ret;
 648        }
 649        /* Port got hot-unplugged. */
 650        if (!port->guest_connected)
 651                return -ENODEV;
 652        /*
 653         * We could've received a disconnection message while we were
 654         * waiting for more data.
 655         *
 656         * This check is not clubbed in the if() statement above as we
 657         * might receive some data as well as the host could get
 658         * disconnected after we got woken up from our wait.  So we
 659         * really want to give off whatever data we have and only then
 660         * check for host_connected.
 661         */
 662        if (!port_has_data(port) && !port->host_connected)
 663                return 0;
 664
 665        return fill_readbuf(port, ubuf, count, true);
 666}
 667
 668static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
 669                               size_t count, loff_t *offp)
 670{
 671        struct port *port;
 672        char *buf;
 673        ssize_t ret;
 674        bool nonblock;
 675
 676        /* Userspace could be out to fool us */
 677        if (!count)
 678                return 0;
 679
 680        port = filp->private_data;
 681
 682        nonblock = filp->f_flags & O_NONBLOCK;
 683
 684        if (will_write_block(port)) {
 685                if (nonblock)
 686                        return -EAGAIN;
 687
 688                ret = wait_event_freezable(port->waitqueue,
 689                                           !will_write_block(port));
 690                if (ret < 0)
 691                        return ret;
 692        }
 693        /* Port got hot-unplugged. */
 694        if (!port->guest_connected)
 695                return -ENODEV;
 696
 697        count = min((size_t)(32 * 1024), count);
 698
 699        buf = kmalloc(count, GFP_KERNEL);
 700        if (!buf)
 701                return -ENOMEM;
 702
 703        ret = copy_from_user(buf, ubuf, count);
 704        if (ret) {
 705                ret = -EFAULT;
 706                goto free_buf;
 707        }
 708
 709        /*
 710         * We now ask send_buf() to not spin for generic ports -- we
 711         * can re-use the same code path that non-blocking file
 712         * descriptors take for blocking file descriptors since the
 713         * wait is already done and we're certain the write will go
 714         * through to the host.
 715         */
 716        nonblock = true;
 717        ret = send_buf(port, buf, count, nonblock);
 718
 719        if (nonblock && ret > 0)
 720                goto out;
 721
 722free_buf:
 723        kfree(buf);
 724out:
 725        return ret;
 726}
 727
 728static unsigned int port_fops_poll(struct file *filp, poll_table *wait)
 729{
 730        struct port *port;
 731        unsigned int ret;
 732
 733        port = filp->private_data;
 734        poll_wait(filp, &port->waitqueue, wait);
 735
 736        if (!port->guest_connected) {
 737                /* Port got unplugged */
 738                return POLLHUP;
 739        }
 740        ret = 0;
 741        if (!will_read_block(port))
 742                ret |= POLLIN | POLLRDNORM;
 743        if (!will_write_block(port))
 744                ret |= POLLOUT;
 745        if (!port->host_connected)
 746                ret |= POLLHUP;
 747
 748        return ret;
 749}
 750
 751static void remove_port(struct kref *kref);
 752
 753static int port_fops_release(struct inode *inode, struct file *filp)
 754{
 755        struct port *port;
 756
 757        port = filp->private_data;
 758
 759        /* Notify host of port being closed */
 760        send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
 761
 762        spin_lock_irq(&port->inbuf_lock);
 763        port->guest_connected = false;
 764
 765        discard_port_data(port);
 766
 767        spin_unlock_irq(&port->inbuf_lock);
 768
 769        spin_lock_irq(&port->outvq_lock);
 770        reclaim_consumed_buffers(port);
 771        spin_unlock_irq(&port->outvq_lock);
 772
 773        /*
 774         * Locks aren't necessary here as a port can't be opened after
 775         * unplug, and if a port isn't unplugged, a kref would already
 776         * exist for the port.  Plus, taking ports_lock here would
 777         * create a dependency on other locks taken by functions
 778         * inside remove_port if we're the last holder of the port,
 779         * creating many problems.
 780         */
 781        kref_put(&port->kref, remove_port);
 782
 783        return 0;
 784}
 785
 786static int port_fops_open(struct inode *inode, struct file *filp)
 787{
 788        struct cdev *cdev = inode->i_cdev;
 789        struct port *port;
 790        int ret;
 791
 792        port = find_port_by_devt(cdev->dev);
 793        filp->private_data = port;
 794
 795        /* Prevent against a port getting hot-unplugged at the same time */
 796        spin_lock_irq(&port->portdev->ports_lock);
 797        kref_get(&port->kref);
 798        spin_unlock_irq(&port->portdev->ports_lock);
 799
 800        /*
 801         * Don't allow opening of console port devices -- that's done
 802         * via /dev/hvc
 803         */
 804        if (is_console_port(port)) {
 805                ret = -ENXIO;
 806                goto out;
 807        }
 808
 809        /* Allow only one process to open a particular port at a time */
 810        spin_lock_irq(&port->inbuf_lock);
 811        if (port->guest_connected) {
 812                spin_unlock_irq(&port->inbuf_lock);
 813                ret = -EMFILE;
 814                goto out;
 815        }
 816
 817        port->guest_connected = true;
 818        spin_unlock_irq(&port->inbuf_lock);
 819
 820        spin_lock_irq(&port->outvq_lock);
 821        /*
 822         * There might be a chance that we missed reclaiming a few
 823         * buffers in the window of the port getting previously closed
 824         * and opening now.
 825         */
 826        reclaim_consumed_buffers(port);
 827        spin_unlock_irq(&port->outvq_lock);
 828
 829        nonseekable_open(inode, filp);
 830
 831        /* Notify host of port being opened */
 832        send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
 833
 834        return 0;
 835out:
 836        kref_put(&port->kref, remove_port);
 837        return ret;
 838}
 839
 840static int port_fops_fasync(int fd, struct file *filp, int mode)
 841{
 842        struct port *port;
 843
 844        port = filp->private_data;
 845        return fasync_helper(fd, filp, mode, &port->async_queue);
 846}
 847
 848/*
 849 * The file operations that we support: programs in the guest can open
 850 * a console device, read from it, write to it, poll for data and
 851 * close it.  The devices are at
 852 *   /dev/vport<device number>p<port number>
 853 */
 854static const struct file_operations port_fops = {
 855        .owner = THIS_MODULE,
 856        .open  = port_fops_open,
 857        .read  = port_fops_read,
 858        .write = port_fops_write,
 859        .poll  = port_fops_poll,
 860        .release = port_fops_release,
 861        .fasync = port_fops_fasync,
 862        .llseek = no_llseek,
 863};
 864
 865/*
 866 * The put_chars() callback is pretty straightforward.
 867 *
 868 * We turn the characters into a scatter-gather list, add it to the
 869 * output queue and then kick the Host.  Then we sit here waiting for
 870 * it to finish: inefficient in theory, but in practice
 871 * implementations will do it immediately (lguest's Launcher does).
 872 */
 873static int put_chars(u32 vtermno, const char *buf, int count)
 874{
 875        struct port *port;
 876
 877        if (unlikely(early_put_chars))
 878                return early_put_chars(vtermno, buf, count);
 879
 880        port = find_port_by_vtermno(vtermno);
 881        if (!port)
 882                return -EPIPE;
 883
 884        return send_buf(port, (void *)buf, count, false);
 885}
 886
 887/*
 888 * get_chars() is the callback from the hvc_console infrastructure
 889 * when an interrupt is received.
 890 *
 891 * We call out to fill_readbuf that gets us the required data from the
 892 * buffers that are queued up.
 893 */
 894static int get_chars(u32 vtermno, char *buf, int count)
 895{
 896        struct port *port;
 897
 898        /* If we've not set up the port yet, we have no input to give. */
 899        if (unlikely(early_put_chars))
 900                return 0;
 901
 902        port = find_port_by_vtermno(vtermno);
 903        if (!port)
 904                return -EPIPE;
 905
 906        /* If we don't have an input queue yet, we can't get input. */
 907        BUG_ON(!port->in_vq);
 908
 909        return fill_readbuf(port, buf, count, false);
 910}
 911
 912static void resize_console(struct port *port)
 913{
 914        struct virtio_device *vdev;
 915
 916        /* The port could have been hot-unplugged */
 917        if (!port || !is_console_port(port))
 918                return;
 919
 920        vdev = port->portdev->vdev;
 921        if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
 922                hvc_resize(port->cons.hvc, port->cons.ws);
 923}
 924
 925/* We set the configuration at this point, since we now have a tty */
 926static int notifier_add_vio(struct hvc_struct *hp, int data)
 927{
 928        struct port *port;
 929
 930        port = find_port_by_vtermno(hp->vtermno);
 931        if (!port)
 932                return -EINVAL;
 933
 934        hp->irq_requested = 1;
 935        resize_console(port);
 936
 937        return 0;
 938}
 939
 940static void notifier_del_vio(struct hvc_struct *hp, int data)
 941{
 942        hp->irq_requested = 0;
 943}
 944
 945/* The operations for console ports. */
 946static const struct hv_ops hv_ops = {
 947        .get_chars = get_chars,
 948        .put_chars = put_chars,
 949        .notifier_add = notifier_add_vio,
 950        .notifier_del = notifier_del_vio,
 951        .notifier_hangup = notifier_del_vio,
 952};
 953
 954/*
 955 * Console drivers are initialized very early so boot messages can go
 956 * out, so we do things slightly differently from the generic virtio
 957 * initialization of the net and block drivers.
 958 *
 959 * At this stage, the console is output-only.  It's too early to set
 960 * up a virtqueue, so we let the drivers do some boutique early-output
 961 * thing.
 962 */
 963int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
 964{
 965        early_put_chars = put_chars;
 966        return hvc_instantiate(0, 0, &hv_ops);
 967}
 968
 969int init_port_console(struct port *port)
 970{
 971        int ret;
 972
 973        /*
 974         * The Host's telling us this port is a console port.  Hook it
 975         * up with an hvc console.
 976         *
 977         * To set up and manage our virtual console, we call
 978         * hvc_alloc().
 979         *
 980         * The first argument of hvc_alloc() is the virtual console
 981         * number.  The second argument is the parameter for the
 982         * notification mechanism (like irq number).  We currently
 983         * leave this as zero, virtqueues have implicit notifications.
 984         *
 985         * The third argument is a "struct hv_ops" containing the
 986         * put_chars() get_chars(), notifier_add() and notifier_del()
 987         * pointers.  The final argument is the output buffer size: we
 988         * can do any size, so we put PAGE_SIZE here.
 989         */
 990        port->cons.vtermno = pdrvdata.next_vtermno;
 991
 992        port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
 993        if (IS_ERR(port->cons.hvc)) {
 994                ret = PTR_ERR(port->cons.hvc);
 995                dev_err(port->dev,
 996                        "error %d allocating hvc for port\n", ret);
 997                port->cons.hvc = NULL;
 998                return ret;
 999        }
1000        spin_lock_irq(&pdrvdata_lock);
1001        pdrvdata.next_vtermno++;
1002        list_add_tail(&port->cons.list, &pdrvdata.consoles);
1003        spin_unlock_irq(&pdrvdata_lock);
1004        port->guest_connected = true;
1005
1006        /*
1007         * Start using the new console output if this is the first
1008         * console to come up.
1009         */
1010        if (early_put_chars)
1011                early_put_chars = NULL;
1012
1013        /* Notify host of port being opened */
1014        send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1015
1016        return 0;
1017}
1018
1019static ssize_t show_port_name(struct device *dev,
1020                              struct device_attribute *attr, char *buffer)
1021{
1022        struct port *port;
1023
1024        port = dev_get_drvdata(dev);
1025
1026        return sprintf(buffer, "%s\n", port->name);
1027}
1028
1029static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
1030
1031static struct attribute *port_sysfs_entries[] = {
1032        &dev_attr_name.attr,
1033        NULL
1034};
1035
1036static struct attribute_group port_attribute_group = {
1037        .name = NULL,           /* put in device directory */
1038        .attrs = port_sysfs_entries,
1039};
1040
1041static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
1042                            size_t count, loff_t *offp)
1043{
1044        struct port *port;
1045        char *buf;
1046        ssize_t ret, out_offset, out_count;
1047
1048        out_count = 1024;
1049        buf = kmalloc(out_count, GFP_KERNEL);
1050        if (!buf)
1051                return -ENOMEM;
1052
1053        port = filp->private_data;
1054        out_offset = 0;
1055        out_offset += snprintf(buf + out_offset, out_count,
1056                               "name: %s\n", port->name ? port->name : "");
1057        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1058                               "guest_connected: %d\n", port->guest_connected);
1059        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1060                               "host_connected: %d\n", port->host_connected);
1061        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1062                               "outvq_full: %d\n", port->outvq_full);
1063        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1064                               "bytes_sent: %lu\n", port->stats.bytes_sent);
1065        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1066                               "bytes_received: %lu\n",
1067                               port->stats.bytes_received);
1068        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1069                               "bytes_discarded: %lu\n",
1070                               port->stats.bytes_discarded);
1071        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1072                               "is_console: %s\n",
1073                               is_console_port(port) ? "yes" : "no");
1074        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1075                               "console_vtermno: %u\n", port->cons.vtermno);
1076
1077        ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
1078        kfree(buf);
1079        return ret;
1080}
1081
1082static const struct file_operations port_debugfs_ops = {
1083        .owner = THIS_MODULE,
1084        .open  = simple_open,
1085        .read  = debugfs_read,
1086};
1087
1088static void set_console_size(struct port *port, u16 rows, u16 cols)
1089{
1090        if (!port || !is_console_port(port))
1091                return;
1092
1093        port->cons.ws.ws_row = rows;
1094        port->cons.ws.ws_col = cols;
1095}
1096
1097static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
1098{
1099        struct port_buffer *buf;
1100        unsigned int nr_added_bufs;
1101        int ret;
1102
1103        nr_added_bufs = 0;
1104        do {
1105                buf = alloc_buf(PAGE_SIZE);
1106                if (!buf)
1107                        break;
1108
1109                spin_lock_irq(lock);
1110                ret = add_inbuf(vq, buf);
1111                if (ret < 0) {
1112                        spin_unlock_irq(lock);
1113                        free_buf(buf);
1114                        break;
1115                }
1116                nr_added_bufs++;
1117                spin_unlock_irq(lock);
1118        } while (ret > 0);
1119
1120        return nr_added_bufs;
1121}
1122
1123static void send_sigio_to_port(struct port *port)
1124{
1125        if (port->async_queue && port->guest_connected)
1126                kill_fasync(&port->async_queue, SIGIO, POLL_OUT);
1127}
1128
1129static int add_port(struct ports_device *portdev, u32 id)
1130{
1131        char debugfs_name[16];
1132        struct port *port;
1133        struct port_buffer *buf;
1134        dev_t devt;
1135        unsigned int nr_added_bufs;
1136        int err;
1137
1138        port = kmalloc(sizeof(*port), GFP_KERNEL);
1139        if (!port) {
1140                err = -ENOMEM;
1141                goto fail;
1142        }
1143        kref_init(&port->kref);
1144
1145        port->portdev = portdev;
1146        port->id = id;
1147
1148        port->name = NULL;
1149        port->inbuf = NULL;
1150        port->cons.hvc = NULL;
1151        port->async_queue = NULL;
1152
1153        port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
1154
1155        port->host_connected = port->guest_connected = false;
1156        port->stats = (struct port_stats) { 0 };
1157
1158        port->outvq_full = false;
1159
1160        port->in_vq = portdev->in_vqs[port->id];
1161        port->out_vq = portdev->out_vqs[port->id];
1162
1163        port->cdev = cdev_alloc();
1164        if (!port->cdev) {
1165                dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
1166                err = -ENOMEM;
1167                goto free_port;
1168        }
1169        port->cdev->ops = &port_fops;
1170
1171        devt = MKDEV(portdev->chr_major, id);
1172        err = cdev_add(port->cdev, devt, 1);
1173        if (err < 0) {
1174                dev_err(&port->portdev->vdev->dev,
1175                        "Error %d adding cdev for port %u\n", err, id);
1176                goto free_cdev;
1177        }
1178        port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
1179                                  devt, port, "vport%up%u",
1180                                  port->portdev->drv_index, id);
1181        if (IS_ERR(port->dev)) {
1182                err = PTR_ERR(port->dev);
1183                dev_err(&port->portdev->vdev->dev,
1184                        "Error %d creating device for port %u\n",
1185                        err, id);
1186                goto free_cdev;
1187        }
1188
1189        spin_lock_init(&port->inbuf_lock);
1190        spin_lock_init(&port->outvq_lock);
1191        init_waitqueue_head(&port->waitqueue);
1192
1193        /* Fill the in_vq with buffers so the host can send us data. */
1194        nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
1195        if (!nr_added_bufs) {
1196                dev_err(port->dev, "Error allocating inbufs\n");
1197                err = -ENOMEM;
1198                goto free_device;
1199        }
1200
1201        /*
1202         * If we're not using multiport support, this has to be a console port
1203         */
1204        if (!use_multiport(port->portdev)) {
1205                err = init_port_console(port);
1206                if (err)
1207                        goto free_inbufs;
1208        }
1209
1210        spin_lock_irq(&portdev->ports_lock);
1211        list_add_tail(&port->list, &port->portdev->ports);
1212        spin_unlock_irq(&portdev->ports_lock);
1213
1214        /*
1215         * Tell the Host we're set so that it can send us various
1216         * configuration parameters for this port (eg, port name,
1217         * caching, whether this is a console port, etc.)
1218         */
1219        send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1220
1221        if (pdrvdata.debugfs_dir) {
1222                /*
1223                 * Finally, create the debugfs file that we can use to
1224                 * inspect a port's state at any time
1225                 */
1226                sprintf(debugfs_name, "vport%up%u",
1227                        port->portdev->drv_index, id);
1228                port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
1229                                                         pdrvdata.debugfs_dir,
1230                                                         port,
1231                                                         &port_debugfs_ops);
1232        }
1233        return 0;
1234
1235free_inbufs:
1236        while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1237                free_buf(buf);
1238free_device:
1239        device_destroy(pdrvdata.class, port->dev->devt);
1240free_cdev:
1241        cdev_del(port->cdev);
1242free_port:
1243        kfree(port);
1244fail:
1245        /* The host might want to notify management sw about port add failure */
1246        __send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
1247        return err;
1248}
1249
1250/* No users remain, remove all port-specific data. */
1251static void remove_port(struct kref *kref)
1252{
1253        struct port *port;
1254
1255        port = container_of(kref, struct port, kref);
1256
1257        sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
1258        device_destroy(pdrvdata.class, port->dev->devt);
1259        cdev_del(port->cdev);
1260
1261        kfree(port->name);
1262
1263        debugfs_remove(port->debugfs_file);
1264
1265        kfree(port);
1266}
1267
1268static void remove_port_data(struct port *port)
1269{
1270        struct port_buffer *buf;
1271
1272        /* Remove unused data this port might have received. */
1273        discard_port_data(port);
1274
1275        reclaim_consumed_buffers(port);
1276
1277        /* Remove buffers we queued up for the Host to send us data in. */
1278        while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1279                free_buf(buf);
1280}
1281
1282/*
1283 * Port got unplugged.  Remove port from portdev's list and drop the
1284 * kref reference.  If no userspace has this port opened, it will
1285 * result in immediate removal the port.
1286 */
1287static void unplug_port(struct port *port)
1288{
1289        spin_lock_irq(&port->portdev->ports_lock);
1290        list_del(&port->list);
1291        spin_unlock_irq(&port->portdev->ports_lock);
1292
1293        if (port->guest_connected) {
1294                port->guest_connected = false;
1295                port->host_connected = false;
1296                wake_up_interruptible(&port->waitqueue);
1297
1298                /* Let the app know the port is going down. */
1299                send_sigio_to_port(port);
1300        }
1301
1302        if (is_console_port(port)) {
1303                spin_lock_irq(&pdrvdata_lock);
1304                list_del(&port->cons.list);
1305                spin_unlock_irq(&pdrvdata_lock);
1306                hvc_remove(port->cons.hvc);
1307        }
1308
1309        remove_port_data(port);
1310
1311        /*
1312         * We should just assume the device itself has gone off --
1313         * else a close on an open port later will try to send out a
1314         * control message.
1315         */
1316        port->portdev = NULL;
1317
1318        /*
1319         * Locks around here are not necessary - a port can't be
1320         * opened after we removed the port struct from ports_list
1321         * above.
1322         */
1323        kref_put(&port->kref, remove_port);
1324}
1325
1326/* Any private messages that the Host and Guest want to share */
1327static void handle_control_message(struct ports_device *portdev,
1328                                   struct port_buffer *buf)
1329{
1330        struct virtio_console_control *cpkt;
1331        struct port *port;
1332        size_t name_size;
1333        int err;
1334
1335        cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
1336
1337        port = find_port_by_id(portdev, cpkt->id);
1338        if (!port && cpkt->event != VIRTIO_CONSOLE_PORT_ADD) {
1339                /* No valid header at start of buffer.  Drop it. */
1340                dev_dbg(&portdev->vdev->dev,
1341                        "Invalid index %u in control packet\n", cpkt->id);
1342                return;
1343        }
1344
1345        switch (cpkt->event) {
1346        case VIRTIO_CONSOLE_PORT_ADD:
1347                if (port) {
1348                        dev_dbg(&portdev->vdev->dev,
1349                                "Port %u already added\n", port->id);
1350                        send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1351                        break;
1352                }
1353                if (cpkt->id >= portdev->config.max_nr_ports) {
1354                        dev_warn(&portdev->vdev->dev,
1355                                "Request for adding port with out-of-bound id %u, max. supported id: %u\n",
1356                                cpkt->id, portdev->config.max_nr_ports - 1);
1357                        break;
1358                }
1359                add_port(portdev, cpkt->id);
1360                break;
1361        case VIRTIO_CONSOLE_PORT_REMOVE:
1362                unplug_port(port);
1363                break;
1364        case VIRTIO_CONSOLE_CONSOLE_PORT:
1365                if (!cpkt->value)
1366                        break;
1367                if (is_console_port(port))
1368                        break;
1369
1370                init_port_console(port);
1371                complete(&early_console_added);
1372                /*
1373                 * Could remove the port here in case init fails - but
1374                 * have to notify the host first.
1375                 */
1376                break;
1377        case VIRTIO_CONSOLE_RESIZE: {
1378                struct {
1379                        __u16 rows;
1380                        __u16 cols;
1381                } size;
1382
1383                if (!is_console_port(port))
1384                        break;
1385
1386                memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
1387                       sizeof(size));
1388                set_console_size(port, size.rows, size.cols);
1389
1390                port->cons.hvc->irq_requested = 1;
1391                resize_console(port);
1392                break;
1393        }
1394        case VIRTIO_CONSOLE_PORT_OPEN:
1395                port->host_connected = cpkt->value;
1396                wake_up_interruptible(&port->waitqueue);
1397                /*
1398                 * If the host port got closed and the host had any
1399                 * unconsumed buffers, we'll be able to reclaim them
1400                 * now.
1401                 */
1402                spin_lock_irq(&port->outvq_lock);
1403                reclaim_consumed_buffers(port);
1404                spin_unlock_irq(&port->outvq_lock);
1405
1406                /*
1407                 * If the guest is connected, it'll be interested in
1408                 * knowing the host connection state changed.
1409                 */
1410                send_sigio_to_port(port);
1411                break;
1412        case VIRTIO_CONSOLE_PORT_NAME:
1413                /*
1414                 * If we woke up after hibernation, we can get this
1415                 * again.  Skip it in that case.
1416                 */
1417                if (port->name)
1418                        break;
1419
1420                /*
1421                 * Skip the size of the header and the cpkt to get the size
1422                 * of the name that was sent
1423                 */
1424                name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
1425
1426                port->name = kmalloc(name_size, GFP_KERNEL);
1427                if (!port->name) {
1428                        dev_err(port->dev,
1429                                "Not enough space to store port name\n");
1430                        break;
1431                }
1432                strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
1433                        name_size - 1);
1434                port->name[name_size - 1] = 0;
1435
1436                /*
1437                 * Since we only have one sysfs attribute, 'name',
1438                 * create it only if we have a name for the port.
1439                 */
1440                err = sysfs_create_group(&port->dev->kobj,
1441                                         &port_attribute_group);
1442                if (err) {
1443                        dev_err(port->dev,
1444                                "Error %d creating sysfs device attributes\n",
1445                                err);
1446                } else {
1447                        /*
1448                         * Generate a udev event so that appropriate
1449                         * symlinks can be created based on udev
1450                         * rules.
1451                         */
1452                        kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
1453                }
1454                break;
1455        }
1456}
1457
1458static void control_work_handler(struct work_struct *work)
1459{
1460        struct ports_device *portdev;
1461        struct virtqueue *vq;
1462        struct port_buffer *buf;
1463        unsigned int len;
1464
1465        portdev = container_of(work, struct ports_device, control_work);
1466        vq = portdev->c_ivq;
1467
1468        spin_lock(&portdev->cvq_lock);
1469        while ((buf = virtqueue_get_buf(vq, &len))) {
1470                spin_unlock(&portdev->cvq_lock);
1471
1472                buf->len = len;
1473                buf->offset = 0;
1474
1475                handle_control_message(portdev, buf);
1476
1477                spin_lock(&portdev->cvq_lock);
1478                if (add_inbuf(portdev->c_ivq, buf) < 0) {
1479                        dev_warn(&portdev->vdev->dev,
1480                                 "Error adding buffer to queue\n");
1481                        free_buf(buf);
1482                }
1483        }
1484        spin_unlock(&portdev->cvq_lock);
1485}
1486
1487static void out_intr(struct virtqueue *vq)
1488{
1489        struct port *port;
1490
1491        port = find_port_by_vq(vq->vdev->priv, vq);
1492        if (!port)
1493                return;
1494
1495        wake_up_interruptible(&port->waitqueue);
1496}
1497
1498static void in_intr(struct virtqueue *vq)
1499{
1500        struct port *port;
1501        unsigned long flags;
1502
1503        port = find_port_by_vq(vq->vdev->priv, vq);
1504        if (!port)
1505                return;
1506
1507        spin_lock_irqsave(&port->inbuf_lock, flags);
1508        port->inbuf = get_inbuf(port);
1509
1510        /*
1511         * Don't queue up data when port is closed.  This condition
1512         * can be reached when a console port is not yet connected (no
1513         * tty is spawned) and the host sends out data to console
1514         * ports.  For generic serial ports, the host won't
1515         * (shouldn't) send data till the guest is connected.
1516         */
1517        if (!port->guest_connected)
1518                discard_port_data(port);
1519
1520        spin_unlock_irqrestore(&port->inbuf_lock, flags);
1521
1522        wake_up_interruptible(&port->waitqueue);
1523
1524        /* Send a SIGIO indicating new data in case the process asked for it */
1525        send_sigio_to_port(port);
1526
1527        if (is_console_port(port) && hvc_poll(port->cons.hvc))
1528                hvc_kick();
1529}
1530
1531static void control_intr(struct virtqueue *vq)
1532{
1533        struct ports_device *portdev;
1534
1535        portdev = vq->vdev->priv;
1536        schedule_work(&portdev->control_work);
1537}
1538
1539static void config_intr(struct virtio_device *vdev)
1540{
1541        struct ports_device *portdev;
1542
1543        portdev = vdev->priv;
1544
1545        if (!use_multiport(portdev)) {
1546                struct port *port;
1547                u16 rows, cols;
1548
1549                vdev->config->get(vdev,
1550                                  offsetof(struct virtio_console_config, cols),
1551                                  &cols, sizeof(u16));
1552                vdev->config->get(vdev,
1553                                  offsetof(struct virtio_console_config, rows),
1554                                  &rows, sizeof(u16));
1555
1556                port = find_port_by_id(portdev, 0);
1557                set_console_size(port, rows, cols);
1558
1559                /*
1560                 * We'll use this way of resizing only for legacy
1561                 * support.  For newer userspace
1562                 * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1563                 * to indicate console size changes so that it can be
1564                 * done per-port.
1565                 */
1566                resize_console(port);
1567        }
1568}
1569
1570static int init_vqs(struct ports_device *portdev)
1571{
1572        vq_callback_t **io_callbacks;
1573        char **io_names;
1574        struct virtqueue **vqs;
1575        u32 i, j, nr_ports, nr_queues;
1576        int err;
1577
1578        nr_ports = portdev->config.max_nr_ports;
1579        nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
1580
1581        vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL);
1582        io_callbacks = kmalloc(nr_queues * sizeof(vq_callback_t *), GFP_KERNEL);
1583        io_names = kmalloc(nr_queues * sizeof(char *), GFP_KERNEL);
1584        portdev->in_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1585                                  GFP_KERNEL);
1586        portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1587                                   GFP_KERNEL);
1588        if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
1589            !portdev->out_vqs) {
1590                err = -ENOMEM;
1591                goto free;
1592        }
1593
1594        /*
1595         * For backward compat (newer host but older guest), the host
1596         * spawns a console port first and also inits the vqs for port
1597         * 0 before others.
1598         */
1599        j = 0;
1600        io_callbacks[j] = in_intr;
1601        io_callbacks[j + 1] = out_intr;
1602        io_names[j] = "input";
1603        io_names[j + 1] = "output";
1604        j += 2;
1605
1606        if (use_multiport(portdev)) {
1607                io_callbacks[j] = control_intr;
1608                io_callbacks[j + 1] = NULL;
1609                io_names[j] = "control-i";
1610                io_names[j + 1] = "control-o";
1611
1612                for (i = 1; i < nr_ports; i++) {
1613                        j += 2;
1614                        io_callbacks[j] = in_intr;
1615                        io_callbacks[j + 1] = out_intr;
1616                        io_names[j] = "input";
1617                        io_names[j + 1] = "output";
1618                }
1619        }
1620        /* Find the queues. */
1621        err = portdev->vdev->config->find_vqs(portdev->vdev, nr_queues, vqs,
1622                                              io_callbacks,
1623                                              (const char **)io_names);
1624        if (err)
1625                goto free;
1626
1627        j = 0;
1628        portdev->in_vqs[0] = vqs[0];
1629        portdev->out_vqs[0] = vqs[1];
1630        j += 2;
1631        if (use_multiport(portdev)) {
1632                portdev->c_ivq = vqs[j];
1633                portdev->c_ovq = vqs[j + 1];
1634
1635                for (i = 1; i < nr_ports; i++) {
1636                        j += 2;
1637                        portdev->in_vqs[i] = vqs[j];
1638                        portdev->out_vqs[i] = vqs[j + 1];
1639                }
1640        }
1641        kfree(io_names);
1642        kfree(io_callbacks);
1643        kfree(vqs);
1644
1645        return 0;
1646
1647free:
1648        kfree(portdev->out_vqs);
1649        kfree(portdev->in_vqs);
1650        kfree(io_names);
1651        kfree(io_callbacks);
1652        kfree(vqs);
1653
1654        return err;
1655}
1656
1657static const struct file_operations portdev_fops = {
1658        .owner = THIS_MODULE,
1659};
1660
1661static void remove_vqs(struct ports_device *portdev)
1662{
1663        portdev->vdev->config->del_vqs(portdev->vdev);
1664        kfree(portdev->in_vqs);
1665        kfree(portdev->out_vqs);
1666}
1667
1668static void remove_controlq_data(struct ports_device *portdev)
1669{
1670        struct port_buffer *buf;
1671        unsigned int len;
1672
1673        if (!use_multiport(portdev))
1674                return;
1675
1676        while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
1677                free_buf(buf);
1678
1679        while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
1680                free_buf(buf);
1681}
1682
1683/*
1684 * Once we're further in boot, we get probed like any other virtio
1685 * device.
1686 *
1687 * If the host also supports multiple console ports, we check the
1688 * config space to see how many ports the host has spawned.  We
1689 * initialize each port found.
1690 */
1691static int __devinit virtcons_probe(struct virtio_device *vdev)
1692{
1693        struct ports_device *portdev;
1694        int err;
1695        bool multiport;
1696        bool early = early_put_chars != NULL;
1697
1698        /* Ensure to read early_put_chars now */
1699        barrier();
1700
1701        portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
1702        if (!portdev) {
1703                err = -ENOMEM;
1704                goto fail;
1705        }
1706
1707        /* Attach this portdev to this virtio_device, and vice-versa. */
1708        portdev->vdev = vdev;
1709        vdev->priv = portdev;
1710
1711        spin_lock_irq(&pdrvdata_lock);
1712        portdev->drv_index = pdrvdata.index++;
1713        spin_unlock_irq(&pdrvdata_lock);
1714
1715        portdev->chr_major = register_chrdev(0, "virtio-portsdev",
1716                                             &portdev_fops);
1717        if (portdev->chr_major < 0) {
1718                dev_err(&vdev->dev,
1719                        "Error %d registering chrdev for device %u\n",
1720                        portdev->chr_major, portdev->drv_index);
1721                err = portdev->chr_major;
1722                goto free;
1723        }
1724
1725        multiport = false;
1726        portdev->config.max_nr_ports = 1;
1727        if (virtio_config_val(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
1728                              offsetof(struct virtio_console_config,
1729                                       max_nr_ports),
1730                              &portdev->config.max_nr_ports) == 0)
1731                multiport = true;
1732
1733        err = init_vqs(portdev);
1734        if (err < 0) {
1735                dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
1736                goto free_chrdev;
1737        }
1738
1739        spin_lock_init(&portdev->ports_lock);
1740        INIT_LIST_HEAD(&portdev->ports);
1741
1742        if (multiport) {
1743                unsigned int nr_added_bufs;
1744
1745                spin_lock_init(&portdev->cvq_lock);
1746                INIT_WORK(&portdev->control_work, &control_work_handler);
1747
1748                nr_added_bufs = fill_queue(portdev->c_ivq, &portdev->cvq_lock);
1749                if (!nr_added_bufs) {
1750                        dev_err(&vdev->dev,
1751                                "Error allocating buffers for control queue\n");
1752                        err = -ENOMEM;
1753                        goto free_vqs;
1754                }
1755        } else {
1756                /*
1757                 * For backward compatibility: Create a console port
1758                 * if we're running on older host.
1759                 */
1760                add_port(portdev, 0);
1761        }
1762
1763        spin_lock_irq(&pdrvdata_lock);
1764        list_add_tail(&portdev->list, &pdrvdata.portdevs);
1765        spin_unlock_irq(&pdrvdata_lock);
1766
1767        __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
1768                           VIRTIO_CONSOLE_DEVICE_READY, 1);
1769
1770        /*
1771         * If there was an early virtio console, assume that there are no
1772         * other consoles. We need to wait until the hvc_alloc matches the
1773         * hvc_instantiate, otherwise tty_open will complain, resulting in
1774         * a "Warning: unable to open an initial console" boot failure.
1775         * Without multiport this is done in add_port above. With multiport
1776         * this might take some host<->guest communication - thus we have to
1777         * wait.
1778         */
1779        if (multiport && early)
1780                wait_for_completion(&early_console_added);
1781
1782        return 0;
1783
1784free_vqs:
1785        /* The host might want to notify mgmt sw about device add failure */
1786        __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
1787                           VIRTIO_CONSOLE_DEVICE_READY, 0);
1788        remove_vqs(portdev);
1789free_chrdev:
1790        unregister_chrdev(portdev->chr_major, "virtio-portsdev");
1791free:
1792        kfree(portdev);
1793fail:
1794        return err;
1795}
1796
1797static void virtcons_remove(struct virtio_device *vdev)
1798{
1799        struct ports_device *portdev;
1800        struct port *port, *port2;
1801
1802        portdev = vdev->priv;
1803
1804        spin_lock_irq(&pdrvdata_lock);
1805        list_del(&portdev->list);
1806        spin_unlock_irq(&pdrvdata_lock);
1807
1808        /* Disable interrupts for vqs */
1809        vdev->config->reset(vdev);
1810        /* Finish up work that's lined up */
1811        cancel_work_sync(&portdev->control_work);
1812
1813        list_for_each_entry_safe(port, port2, &portdev->ports, list)
1814                unplug_port(port);
1815
1816        unregister_chrdev(portdev->chr_major, "virtio-portsdev");
1817
1818        /*
1819         * When yanking out a device, we immediately lose the
1820         * (device-side) queues.  So there's no point in keeping the
1821         * guest side around till we drop our final reference.  This
1822         * also means that any ports which are in an open state will
1823         * have to just stop using the port, as the vqs are going
1824         * away.
1825         */
1826        remove_controlq_data(portdev);
1827        remove_vqs(portdev);
1828        kfree(portdev);
1829}
1830
1831static struct virtio_device_id id_table[] = {
1832        { VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
1833        { 0 },
1834};
1835
1836static unsigned int features[] = {
1837        VIRTIO_CONSOLE_F_SIZE,
1838        VIRTIO_CONSOLE_F_MULTIPORT,
1839};
1840
1841#ifdef CONFIG_PM
1842static int virtcons_freeze(struct virtio_device *vdev)
1843{
1844        struct ports_device *portdev;
1845        struct port *port;
1846
1847        portdev = vdev->priv;
1848
1849        vdev->config->reset(vdev);
1850
1851        virtqueue_disable_cb(portdev->c_ivq);
1852        cancel_work_sync(&portdev->control_work);
1853        /*
1854         * Once more: if control_work_handler() was running, it would
1855         * enable the cb as the last step.
1856         */
1857        virtqueue_disable_cb(portdev->c_ivq);
1858        remove_controlq_data(portdev);
1859
1860        list_for_each_entry(port, &portdev->ports, list) {
1861                virtqueue_disable_cb(port->in_vq);
1862                virtqueue_disable_cb(port->out_vq);
1863                /*
1864                 * We'll ask the host later if the new invocation has
1865                 * the port opened or closed.
1866                 */
1867                port->host_connected = false;
1868                remove_port_data(port);
1869        }
1870        remove_vqs(portdev);
1871
1872        return 0;
1873}
1874
1875static int virtcons_restore(struct virtio_device *vdev)
1876{
1877        struct ports_device *portdev;
1878        struct port *port;
1879        int ret;
1880
1881        portdev = vdev->priv;
1882
1883        ret = init_vqs(portdev);
1884        if (ret)
1885                return ret;
1886
1887        if (use_multiport(portdev))
1888                fill_queue(portdev->c_ivq, &portdev->cvq_lock);
1889
1890        list_for_each_entry(port, &portdev->ports, list) {
1891                port->in_vq = portdev->in_vqs[port->id];
1892                port->out_vq = portdev->out_vqs[port->id];
1893
1894                fill_queue(port->in_vq, &port->inbuf_lock);
1895
1896                /* Get port open/close status on the host */
1897                send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1898
1899                /*
1900                 * If a port was open at the time of suspending, we
1901                 * have to let the host know that it's still open.
1902                 */
1903                if (port->guest_connected)
1904                        send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1905        }
1906        return 0;
1907}
1908#endif
1909
1910static struct virtio_driver virtio_console = {
1911        .feature_table = features,
1912        .feature_table_size = ARRAY_SIZE(features),
1913        .driver.name =  KBUILD_MODNAME,
1914        .driver.owner = THIS_MODULE,
1915        .id_table =     id_table,
1916        .probe =        virtcons_probe,
1917        .remove =       virtcons_remove,
1918        .config_changed = config_intr,
1919#ifdef CONFIG_PM
1920        .freeze =       virtcons_freeze,
1921        .restore =      virtcons_restore,
1922#endif
1923};
1924
1925static int __init init(void)
1926{
1927        int err;
1928
1929        pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
1930        if (IS_ERR(pdrvdata.class)) {
1931                err = PTR_ERR(pdrvdata.class);
1932                pr_err("Error %d creating virtio-ports class\n", err);
1933                return err;
1934        }
1935
1936        pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
1937        if (!pdrvdata.debugfs_dir) {
1938                pr_warning("Error %ld creating debugfs dir for virtio-ports\n",
1939                           PTR_ERR(pdrvdata.debugfs_dir));
1940        }
1941        INIT_LIST_HEAD(&pdrvdata.consoles);
1942        INIT_LIST_HEAD(&pdrvdata.portdevs);
1943
1944        return register_virtio_driver(&virtio_console);
1945}
1946
1947static void __exit fini(void)
1948{
1949        unregister_virtio_driver(&virtio_console);
1950
1951        class_destroy(pdrvdata.class);
1952        if (pdrvdata.debugfs_dir)
1953                debugfs_remove_recursive(pdrvdata.debugfs_dir);
1954}
1955module_init(init);
1956module_exit(fini);
1957
1958MODULE_DEVICE_TABLE(virtio, id_table);
1959MODULE_DESCRIPTION("Virtio console driver");
1960MODULE_LICENSE("GPL");
1961
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