Pileus Git - ~andy/linux/blob - drivers/staging/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
  33 #include "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         /* Make sure we are not connecting or connected */
  54         if (vmbus_connection.conn_state != DISCONNECTED)
  55                 return -EISCONN;
  56
  57         /* Initialize the vmbus connection */
  58         vmbus_connection.conn_state = CONNECTING;
  59         vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
  60         if (!vmbus_connection.work_queue) {
  61                 ret = -ENOMEM;
  62                 goto cleanup;
  63         }
  64
  65         INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
  66         spin_lock_init(&vmbus_connection.channelmsg_lock);
  67
  68         INIT_LIST_HEAD(&vmbus_connection.chn_list);
  69         spin_lock_init(&vmbus_connection.channel_lock);
  70
  71         /*
  72          * Setup the vmbus event connection for channel interrupt
  73          * abstraction stuff
  74          */
  75         vmbus_connection.int_page =
  76         (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
  77         if (vmbus_connection.int_page == NULL) {
  78                 ret = -ENOMEM;
  79                 goto cleanup;
  80         }
  81
  82         vmbus_connection.recv_int_page = vmbus_connection.int_page;
  83         vmbus_connection.send_int_page =
  84                 (void *)((unsigned long)vmbus_connection.int_page +
  85                         (PAGE_SIZE >> 1));
  86
  87         /*
  88          * Setup the monitor notification facility. The 1st page for
  89          * parent->child and the 2nd page for child->parent
  90          */
  91         vmbus_connection.monitor_pages =
  92         (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 1);
  93         if (vmbus_connection.monitor_pages == NULL) {
  94                 ret = -ENOMEM;
  95                 goto cleanup;
  96         }
  97
  98         msginfo = kzalloc(sizeof(*msginfo) +
  99                           sizeof(struct vmbus_channel_initiate_contact),
 100                           GFP_KERNEL);
 101         if (msginfo == NULL) {
 102                 ret = -ENOMEM;
 103                 goto cleanup;
 104         }
 105
 106         init_completion(&msginfo->waitevent);
 107
 108         msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
 109
 110         msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
 111         msg->vmbus_version_requested = VMBUS_REVISION_NUMBER;
 112         msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
 113         msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages);
 114         msg->monitor_page2 = virt_to_phys(
 115                         (void *)((unsigned long)vmbus_connection.monitor_pages +
 116                                  PAGE_SIZE));
 117
 118         /*
 119          * Add to list before we send the request since we may
 120          * receive the response before returning from this routine
 121          */
 122         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 123         list_add_tail(&msginfo->msglistentry,
 124                       &vmbus_connection.chn_msg_list);
 125
 126         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 127
 128         ret = vmbus_post_msg(msg,
 129                                sizeof(struct vmbus_channel_initiate_contact));
 130         if (ret != 0) {
 131                 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 132                 list_del(&msginfo->msglistentry);
 133                 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
 134                                         flags);
 135                 goto cleanup;
 136         }
 137
 138         /* Wait for the connection response */
 139         t =  wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 140         if (t == 0) {
 141                 spin_lock_irqsave(&vmbus_connection.channelmsg_lock,
 142                                 flags);
 143                 list_del(&msginfo->msglistentry);
 144                 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
 145                                         flags);
 146                 ret = -ETIMEDOUT;
 147                 goto cleanup;
 148         }
 149
 150         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 151         list_del(&msginfo->msglistentry);
 152         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 153
 154         /* Check if successful */
 155         if (msginfo->response.version_response.version_supported) {
 156                 vmbus_connection.conn_state = CONNECTED;
 157         } else {
 158                 pr_err("Unable to connect, "
 159                         "Version %d not supported by Hyper-V\n",
 160                         VMBUS_REVISION_NUMBER);
 161                 ret = -ECONNREFUSED;
 162                 goto cleanup;
 163         }
 164
 165         kfree(msginfo);
 166         return 0;
 167
 168 cleanup:
 169         vmbus_connection.conn_state = DISCONNECTED;
 170
 171         if (vmbus_connection.work_queue)
 172                 destroy_workqueue(vmbus_connection.work_queue);
 173
 174         if (vmbus_connection.int_page) {
 175                 free_pages((unsigned long)vmbus_connection.int_page, 0);
 176                 vmbus_connection.int_page = NULL;
 177         }
 178
 179         if (vmbus_connection.monitor_pages) {
 180                 free_pages((unsigned long)vmbus_connection.monitor_pages, 1);
 181                 vmbus_connection.monitor_pages = NULL;
 182         }
 183
 184         kfree(msginfo);
 185
 186         return ret;
 187 }
 188
 189
 190 /*
 191  * relid2channel - Get the channel object given its
 192  * child relative id (ie channel id)
 193  */
 194 struct vmbus_channel *relid2channel(u32 relid)
 195 {
 196         struct vmbus_channel *channel;
 197         struct vmbus_channel *found_channel  = NULL;
 198         unsigned long flags;
 199
 200         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 201         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 202                 if (channel->offermsg.child_relid == relid) {
 203                         found_channel = channel;
 204                         break;
 205                 }
 206         }
 207         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 208
 209         return found_channel;
 210 }
 211
 212 /*
 213  * process_chn_event - Process a channel event notification
 214  */
 215 static void process_chn_event(u32 relid)
 216 {
 217         struct vmbus_channel *channel;
 218
 219         /*
 220          * Find the channel based on this relid and invokes the
 221          * channel callback to process the event
 222          */
 223         channel = relid2channel(relid);
 224
 225         if (channel && (channel->onchannel_callback != NULL)) {
 226                 channel->onchannel_callback(channel->channel_callback_context);
 227         } else {
 228                 pr_err("channel not found for relid - %u\n", relid);
 229         }
 230 }
 231
 232 /*
 233  * vmbus_on_event - Handler for events
 234  */
 235 void vmbus_on_event(unsigned long data)
 236 {
 237         u32 dword;
 238         u32 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
 239         int bit;
 240         u32 relid;
 241         u32 *recv_int_page = vmbus_connection.recv_int_page;
 242
 243         /* Check events */
 244         if (!recv_int_page)
 245                 return;
 246         for (dword = 0; dword < maxdword; dword++) {
 247                 if (!recv_int_page[dword])
 248                         continue;
 249                 for (bit = 0; bit < 32; bit++) {
 250                         if (sync_test_and_clear_bit(bit, (unsigned long *)&recv_int_page[dword])) {
 251                                 relid = (dword << 5) + bit;
 252
 253                                 if (relid == 0) {
 254                                         /*
 255                                          * Special case - vmbus
 256                                          * channel protocol msg
 257                                          */
 258                                         continue;
 259                                 }
 260                                 process_chn_event(relid);
 261                         }
 262                 }
 263         }
 264 }
 265
 266 /*
 267  * vmbus_post_msg - Send a msg on the vmbus's message connection
 268  */
 269 int vmbus_post_msg(void *buffer, size_t buflen)
 270 {
 271         union hv_connection_id conn_id;
 272         int ret = 0;
 273         int retries = 0;
 274
 275         conn_id.asu32 = 0;
 276         conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
 277
 278         /*
 279          * hv_post_message() can have transient failures because of
 280          * insufficient resources. Retry the operation a couple of
 281          * times before giving up.
 282          */
 283         while (retries < 3) {
 284                 ret =  hv_post_message(conn_id, 1, buffer, buflen);
 285                 if (ret != HV_STATUS_INSUFFICIENT_BUFFERS)
 286                         return ret;
 287                 retries++;
 288                 msleep(100);
 289         }
 290         return ret;
 291 }
 292
 293 /*
 294  * vmbus_set_event - Send an event notification to the parent
 295  */
 296 int vmbus_set_event(u32 child_relid)
 297 {
 298         /* Each u32 represents 32 channels */
 299         sync_set_bit(child_relid & 31,
 300                 (unsigned long *)vmbus_connection.send_int_page +
 301                 (child_relid >> 5));
 302
 303         return hv_signal_event();
 304 }