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         struct vmbus_channel_msginfo *msginfo = NULL;
  49         struct vmbus_channel_initiate_contact *msg;
  50         unsigned long flags;
  51
  52         /* Initialize the vmbus connection */
  53         vmbus_connection.conn_state = CONNECTING;
  54         vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
  55         if (!vmbus_connection.work_queue) {
  56                 ret = -ENOMEM;
  57                 goto cleanup;
  58         }
  59
  60         INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
  61         spin_lock_init(&vmbus_connection.channelmsg_lock);
  62
  63         INIT_LIST_HEAD(&vmbus_connection.chn_list);
  64         spin_lock_init(&vmbus_connection.channel_lock);
  65
  66         /*
  67          * Setup the vmbus event connection for channel interrupt
  68          * abstraction stuff
  69          */
  70         vmbus_connection.int_page =
  71         (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
  72         if (vmbus_connection.int_page == NULL) {
  73                 ret = -ENOMEM;
  74                 goto cleanup;
  75         }
  76
  77         vmbus_connection.recv_int_page = vmbus_connection.int_page;
  78         vmbus_connection.send_int_page =
  79                 (void *)((unsigned long)vmbus_connection.int_page +
  80                         (PAGE_SIZE >> 1));
  81
  82         /*
  83          * Setup the monitor notification facility. The 1st page for
  84          * parent->child and the 2nd page for child->parent
  85          */
  86         vmbus_connection.monitor_pages =
  87         (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 1);
  88         if (vmbus_connection.monitor_pages == NULL) {
  89                 ret = -ENOMEM;
  90                 goto cleanup;
  91         }
  92
  93         msginfo = kzalloc(sizeof(*msginfo) +
  94                           sizeof(struct vmbus_channel_initiate_contact),
  95                           GFP_KERNEL);
  96         if (msginfo == NULL) {
  97                 ret = -ENOMEM;
  98                 goto cleanup;
  99         }
 100
 101         init_completion(&msginfo->waitevent);
 102
 103         msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
 104
 105         msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
 106         msg->vmbus_version_requested = VMBUS_REVISION_NUMBER;
 107         msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
 108         msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages);
 109         msg->monitor_page2 = virt_to_phys(
 110                         (void *)((unsigned long)vmbus_connection.monitor_pages +
 111                                  PAGE_SIZE));
 112
 113         /*
 114          * Add to list before we send the request since we may
 115          * receive the response before returning from this routine
 116          */
 117         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 118         list_add_tail(&msginfo->msglistentry,
 119                       &vmbus_connection.chn_msg_list);
 120
 121         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 122
 123         ret = vmbus_post_msg(msg,
 124                                sizeof(struct vmbus_channel_initiate_contact));
 125         if (ret != 0) {
 126                 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 127                 list_del(&msginfo->msglistentry);
 128                 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
 129                                         flags);
 130                 goto cleanup;
 131         }
 132
 133         /* Wait for the connection response */
 134         wait_for_completion(&msginfo->waitevent);
 135
 136         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 137         list_del(&msginfo->msglistentry);
 138         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 139
 140         /* Check if successful */
 141         if (msginfo->response.version_response.version_supported) {
 142                 vmbus_connection.conn_state = CONNECTED;
 143         } else {
 144                 pr_err("Unable to connect, "
 145                         "Version %d not supported by Hyper-V\n",
 146                         VMBUS_REVISION_NUMBER);
 147                 ret = -ECONNREFUSED;
 148                 goto cleanup;
 149         }
 150
 151         kfree(msginfo);
 152         return 0;
 153
 154 cleanup:
 155         vmbus_connection.conn_state = DISCONNECTED;
 156
 157         if (vmbus_connection.work_queue)
 158                 destroy_workqueue(vmbus_connection.work_queue);
 159
 160         if (vmbus_connection.int_page) {
 161                 free_pages((unsigned long)vmbus_connection.int_page, 0);
 162                 vmbus_connection.int_page = NULL;
 163         }
 164
 165         if (vmbus_connection.monitor_pages) {
 166                 free_pages((unsigned long)vmbus_connection.monitor_pages, 1);
 167                 vmbus_connection.monitor_pages = NULL;
 168         }
 169
 170         kfree(msginfo);
 171
 172         return ret;
 173 }
 174
 175
 176 /*
 177  * relid2channel - Get the channel object given its
 178  * child relative id (ie channel id)
 179  */
 180 struct vmbus_channel *relid2channel(u32 relid)
 181 {
 182         struct vmbus_channel *channel;
 183         struct vmbus_channel *found_channel  = NULL;
 184         unsigned long flags;
 185
 186         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 187         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 188                 if (channel->offermsg.child_relid == relid) {
 189                         found_channel = channel;
 190                         break;
 191                 }
 192         }
 193         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 194
 195         return found_channel;
 196 }
 197
 198 /*
 199  * process_chn_event - Process a channel event notification
 200  */
 201 static void process_chn_event(u32 relid)
 202 {
 203         struct vmbus_channel *channel;
 204         unsigned long flags;
 205
 206         /*
 207          * Find the channel based on this relid and invokes the
 208          * channel callback to process the event
 209          */
 210         channel = relid2channel(relid);
 211
 212         if (!channel) {
 213                 pr_err("channel not found for relid - %u\n", relid);
 214                 return;
 215         }
 216
 217         /*
 218          * A channel once created is persistent even when there
 219          * is no driver handling the device. An unloading driver
 220          * sets the onchannel_callback to NULL under the
 221          * protection of the channel inbound_lock. Thus, checking
 222          * and invoking the driver specific callback takes care of
 223          * orderly unloading of the driver.
 224          */
 225
 226         spin_lock_irqsave(&channel->inbound_lock, flags);
 227         if (channel->onchannel_callback != NULL)
 228                 channel->onchannel_callback(channel->channel_callback_context);
 229         else
 230                 pr_err("no channel callback for relid - %u\n", relid);
 231
 232         spin_unlock_irqrestore(&channel->inbound_lock, flags);
 233 }
 234
 235 /*
 236  * vmbus_on_event - Handler for events
 237  */
 238 void vmbus_on_event(unsigned long data)
 239 {
 240         u32 dword;
 241         u32 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
 242         int bit;
 243         u32 relid;
 244         u32 *recv_int_page = vmbus_connection.recv_int_page;
 245
 246         /* Check events */
 247         if (!recv_int_page)
 248                 return;
 249         for (dword = 0; dword < maxdword; dword++) {
 250                 if (!recv_int_page[dword])
 251                         continue;
 252                 for (bit = 0; bit < 32; bit++) {
 253                         if (sync_test_and_clear_bit(bit,
 254                                 (unsigned long *)&recv_int_page[dword])) {
 255                                 relid = (dword << 5) + bit;
 256
 257                                 if (relid == 0)
 258                                         /*
 259                                          * Special case - vmbus
 260                                          * channel protocol msg
 261                                          */
 262                                         continue;
 263
 264                                 process_chn_event(relid);
 265                         }
 266                 }
 267         }
 268 }
 269
 270 /*
 271  * vmbus_post_msg - Send a msg on the vmbus's message connection
 272  */
 273 int vmbus_post_msg(void *buffer, size_t buflen)
 274 {
 275         union hv_connection_id conn_id;
 276         int ret = 0;
 277         int retries = 0;
 278
 279         conn_id.asu32 = 0;
 280         conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
 281
 282         /*
 283          * hv_post_message() can have transient failures because of
 284          * insufficient resources. Retry the operation a couple of
 285          * times before giving up.
 286          */
 287         while (retries < 10) {
 288                 ret = hv_post_message(conn_id, 1, buffer, buflen);
 289
 290                 switch (ret) {
 291                 case HV_STATUS_INSUFFICIENT_BUFFERS:
 292                         ret = -ENOMEM;
 293                 case -ENOMEM:
 294                         break;
 295                 case HV_STATUS_SUCCESS:
 296                         return ret;
 297                 default:
 298                         pr_err("hv_post_msg() failed; error code:%d\n", ret);
 299                         return -EINVAL;
 300                 }
 301
 302                 retries++;
 303                 msleep(100);
 304         }
 305         return ret;
 306 }
 307
 308 /*
 309  * vmbus_set_event - Send an event notification to the parent
 310  */
 311 int vmbus_set_event(u32 child_relid)
 312 {
 313         /* Each u32 represents 32 channels */
 314         sync_set_bit(child_relid & 31,
 315                 (unsigned long *)vmbus_connection.send_int_page +
 316                 (child_relid >> 5));
 317
 318         return hv_signal_event();
 319 }