drivers/hv/connection.c

   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
  37 struct 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  */
  45 int 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
 164 cleanup:
 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  */
 190 struct 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  */
 211 static 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  */
 248 void 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  */
 283 int 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  */
 310 int 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 }