linux/drivers/hv/connection.c
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   1/*
   2 *
   3 * Copyright (c) 2009, Microsoft Corporation.
   4 *
   5 * This program is free software; you can redistribute it and/or modify it
   6 * under the terms and conditions of the GNU General Public License,
   7 * version 2, as published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope it will be useful, but WITHOUT
  10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12 * more details.
  13 *
  14 * You should have received a copy of the GNU General Public License along with
  15 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  16 * Place - Suite 330, Boston, MA 02111-1307 USA.
  17 *
  18 * Authors:
  19 *   Haiyang Zhang <haiyangz@microsoft.com>
  20 *   Hank Janssen  <hjanssen@microsoft.com>
  21 *
  22 */
  23#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  24
  25#include <linux/kernel.h>
  26#include <linux/sched.h>
  27#include <linux/wait.h>
  28#include <linux/delay.h>
  29#include <linux/mm.h>
  30#include <linux/slab.h>
  31#include <linux/vmalloc.h>
  32#include <linux/hyperv.h>
  33#include <asm/hyperv.h>
  34#include "hyperv_vmbus.h"
  35
  36
  37struct vmbus_connection vmbus_connection = {
  38        .conn_state             = DISCONNECTED,
  39        .next_gpadl_handle      = ATOMIC_INIT(0xE1E10),
  40};
  41
  42/*
  43 * vmbus_connect - Sends a connect request on the partition service connection
  44 */
  45int vmbus_connect(void)
  46{
  47        int ret = 0;
  48        int t;
  49        struct vmbus_channel_msginfo *msginfo = NULL;
  50        struct vmbus_channel_initiate_contact *msg;
  51        unsigned long flags;
  52
  53        /* Initialize the vmbus connection */
  54        vmbus_connection.conn_state = CONNECTING;
  55        vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
  56        if (!vmbus_connection.work_queue) {
  57                ret = -ENOMEM;
  58                goto cleanup;
  59        }
  60
  61        INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
  62        spin_lock_init(&vmbus_connection.channelmsg_lock);
  63
  64        INIT_LIST_HEAD(&vmbus_connection.chn_list);
  65        spin_lock_init(&vmbus_connection.channel_lock);
  66
  67        /*
  68         * Setup the vmbus event connection for channel interrupt
  69         * abstraction stuff
  70         */
  71        vmbus_connection.int_page =
  72        (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
  73        if (vmbus_connection.int_page == NULL) {
  74                ret = -ENOMEM;
  75                goto cleanup;
  76        }
  77
  78        vmbus_connection.recv_int_page = vmbus_connection.int_page;
  79        vmbus_connection.send_int_page =
  80                (void *)((unsigned long)vmbus_connection.int_page +
  81                        (PAGE_SIZE >> 1));
  82
  83        /*
  84         * Setup the monitor notification facility. The 1st page for
  85         * parent->child and the 2nd page for child->parent
  86         */
  87        vmbus_connection.monitor_pages =
  88        (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 1);
  89        if (vmbus_connection.monitor_pages == NULL) {
  90                ret = -ENOMEM;
  91                goto cleanup;
  92        }
  93
  94        msginfo = kzalloc(sizeof(*msginfo) +
  95                          sizeof(struct vmbus_channel_initiate_contact),
  96                          GFP_KERNEL);
  97        if (msginfo == NULL) {
  98                ret = -ENOMEM;
  99                goto cleanup;
 100        }
 101
 102        init_completion(&msginfo->waitevent);
 103
 104        msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
 105
 106        msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
 107        msg->vmbus_version_requested = VMBUS_REVISION_NUMBER;
 108        msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
 109        msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages);
 110        msg->monitor_page2 = virt_to_phys(
 111                        (void *)((unsigned long)vmbus_connection.monitor_pages +
 112                                 PAGE_SIZE));
 113
 114        /*
 115         * Add to list before we send the request since we may
 116         * receive the response before returning from this routine
 117         */
 118        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 119        list_add_tail(&msginfo->msglistentry,
 120                      &vmbus_connection.chn_msg_list);
 121
 122        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 123
 124        ret = vmbus_post_msg(msg,
 125                               sizeof(struct vmbus_channel_initiate_contact));
 126        if (ret != 0) {
 127                spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 128                list_del(&msginfo->msglistentry);
 129                spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
 130                                        flags);
 131                goto cleanup;
 132        }
 133
 134        /* Wait for the connection response */
 135        t =  wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 136        if (t == 0) {
 137                spin_lock_irqsave(&vmbus_connection.channelmsg_lock,
 138                                flags);
 139                list_del(&msginfo->msglistentry);
 140                spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
 141                                        flags);
 142                ret = -ETIMEDOUT;
 143                goto cleanup;
 144        }
 145
 146        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 147        list_del(&msginfo->msglistentry);
 148        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 149
 150        /* Check if successful */
 151        if (msginfo->response.version_response.version_supported) {
 152                vmbus_connection.conn_state = CONNECTED;
 153        } else {
 154                pr_err("Unable to connect, "
 155                        "Version %d not supported by Hyper-V\n",
 156                        VMBUS_REVISION_NUMBER);
 157                ret = -ECONNREFUSED;
 158                goto cleanup;
 159        }
 160
 161        kfree(msginfo);
 162        return 0;
 163
 164cleanup:
 165        vmbus_connection.conn_state = DISCONNECTED;
 166
 167        if (vmbus_connection.work_queue)
 168                destroy_workqueue(vmbus_connection.work_queue);
 169
 170        if (vmbus_connection.int_page) {
 171                free_pages((unsigned long)vmbus_connection.int_page, 0);
 172                vmbus_connection.int_page = NULL;
 173        }
 174
 175        if (vmbus_connection.monitor_pages) {
 176                free_pages((unsigned long)vmbus_connection.monitor_pages, 1);
 177                vmbus_connection.monitor_pages = NULL;
 178        }
 179
 180        kfree(msginfo);
 181
 182        return ret;
 183}
 184
 185
 186/*
 187 * relid2channel - Get the channel object given its
 188 * child relative id (ie channel id)
 189 */
 190struct vmbus_channel *relid2channel(u32 relid)
 191{
 192        struct vmbus_channel *channel;
 193        struct vmbus_channel *found_channel  = NULL;
 194        unsigned long flags;
 195
 196        spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 197        list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 198                if (channel->offermsg.child_relid == relid) {
 199                        found_channel = channel;
 200                        break;
 201                }
 202        }
 203        spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 204
 205        return found_channel;
 206}
 207
 208/*
 209 * process_chn_event - Process a channel event notification
 210 */
 211static void process_chn_event(u32 relid)
 212{
 213        struct vmbus_channel *channel;
 214        unsigned long flags;
 215
 216        /*
 217         * Find the channel based on this relid and invokes the
 218         * channel callback to process the event
 219         */
 220        channel = relid2channel(relid);
 221
 222        if (!channel) {
 223                pr_err("channel not found for relid - %u\n", relid);
 224                return;
 225        }
 226
 227        /*
 228         * A channel once created is persistent even when there
 229         * is no driver handling the device. An unloading driver
 230         * sets the onchannel_callback to NULL under the
 231         * protection of the channel inbound_lock. Thus, checking
 232         * and invoking the driver specific callback takes care of
 233         * orderly unloading of the driver.
 234         */
 235
 236        spin_lock_irqsave(&channel->inbound_lock, flags);
 237        if (channel->onchannel_callback != NULL)
 238                channel->onchannel_callback(channel->channel_callback_context);
 239        else
 240                pr_err("no channel callback for relid - %u\n", relid);
 241
 242        spin_unlock_irqrestore(&channel->inbound_lock, flags);
 243}
 244
 245/*
 246 * vmbus_on_event - Handler for events
 247 */
 248void vmbus_on_event(unsigned long data)
 249{
 250        u32 dword;
 251        u32 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
 252        int bit;
 253        u32 relid;
 254        u32 *recv_int_page = vmbus_connection.recv_int_page;
 255
 256        /* Check events */
 257        if (!recv_int_page)
 258                return;
 259        for (dword = 0; dword < maxdword; dword++) {
 260                if (!recv_int_page[dword])
 261                        continue;
 262                for (bit = 0; bit < 32; bit++) {
 263                        if (sync_test_and_clear_bit(bit,
 264                                (unsigned long *)&recv_int_page[dword])) {
 265                                relid = (dword << 5) + bit;
 266
 267                                if (relid == 0)
 268                                        /*
 269                                         * Special case - vmbus
 270                                         * channel protocol msg
 271                                         */
 272                                        continue;
 273
 274                                process_chn_event(relid);
 275                        }
 276                }
 277        }
 278}
 279
 280/*
 281 * vmbus_post_msg - Send a msg on the vmbus's message connection
 282 */
 283int vmbus_post_msg(void *buffer, size_t buflen)
 284{
 285        union hv_connection_id conn_id;
 286        int ret = 0;
 287        int retries = 0;
 288
 289        conn_id.asu32 = 0;
 290        conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
 291
 292        /*
 293         * hv_post_message() can have transient failures because of
 294         * insufficient resources. Retry the operation a couple of
 295         * times before giving up.
 296         */
 297        while (retries < 3) {
 298                ret =  hv_post_message(conn_id, 1, buffer, buflen);
 299                if (ret != HV_STATUS_INSUFFICIENT_BUFFERS)
 300                        return ret;
 301                retries++;
 302                msleep(100);
 303        }
 304        return ret;
 305}
 306
 307/*
 308 * vmbus_set_event - Send an event notification to the parent
 309 */
 310int vmbus_set_event(u32 child_relid)
 311{
 312        /* Each u32 represents 32 channels */
 313        sync_set_bit(child_relid & 31,
 314                (unsigned long *)vmbus_connection.send_int_page +
 315                (child_relid >> 5));
 316
 317        return hv_signal_event();
 318}
 319
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