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/mm.h>
  29 #include <linux/slab.h>
  30 #include <linux/vmalloc.h>
  31
  32 #include "hyperv.h"
  33 #include "hyperv_vmbus.h"
  34
  35
  36 struct vmbus_connection vmbus_connection = {
  37         .conn_state             = DISCONNECTED,
  38         .next_gpadl_handle      = ATOMIC_INIT(0xE1E10),
  39 };
  40
  41 /*
  42  * vmbus_connect - Sends a connect request on the partition service connection
  43  */
  44 int vmbus_connect(void)
  45 {
  46         int ret = 0;
  47         int t;
  48         struct vmbus_channel_msginfo *msginfo = NULL;
  49         struct vmbus_channel_initiate_contact *msg;
  50         unsigned long flags;
  51
  52         /* Make sure we are not connecting or connected */
  53         if (vmbus_connection.conn_state != DISCONNECTED)
  54                 return -1;
  55
  56         /* Initialize the vmbus connection */
  57         vmbus_connection.conn_state = CONNECTING;
  58         vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
  59         if (!vmbus_connection.work_queue) {
  60                 ret = -1;
  61                 goto cleanup;
  62         }
  63
  64         INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
  65         spin_lock_init(&vmbus_connection.channelmsg_lock);
  66
  67         INIT_LIST_HEAD(&vmbus_connection.chn_list);
  68         spin_lock_init(&vmbus_connection.channel_lock);
  69
  70         /*
  71          * Setup the vmbus event connection for channel interrupt
  72          * abstraction stuff
  73          */
  74         vmbus_connection.int_page =
  75         (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
  76         if (vmbus_connection.int_page == NULL) {
  77                 ret = -1;
  78                 goto cleanup;
  79         }
  80
  81         vmbus_connection.recv_int_page = vmbus_connection.int_page;
  82         vmbus_connection.send_int_page =
  83                 (void *)((unsigned long)vmbus_connection.int_page +
  84                         (PAGE_SIZE >> 1));
  85
  86         /*
  87          * Setup the monitor notification facility. The 1st page for
  88          * parent->child and the 2nd page for child->parent
  89          */
  90         vmbus_connection.monitor_pages =
  91         (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 1);
  92         if (vmbus_connection.monitor_pages == NULL) {
  93                 ret = -1;
  94                 goto cleanup;
  95         }
  96
  97         msginfo = kzalloc(sizeof(*msginfo) +
  98                           sizeof(struct vmbus_channel_initiate_contact),
  99                           GFP_KERNEL);
 100         if (msginfo == NULL) {
 101                 ret = -ENOMEM;
 102                 goto cleanup;
 103         }
 104
 105         init_completion(&msginfo->waitevent);
 106
 107         msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
 108
 109         msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
 110         msg->vmbus_version_requested = VMBUS_REVISION_NUMBER;
 111         msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
 112         msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages);
 113         msg->monitor_page2 = virt_to_phys(
 114                         (void *)((unsigned long)vmbus_connection.monitor_pages +
 115                                  PAGE_SIZE));
 116
 117         /*
 118          * Add to list before we send the request since we may
 119          * receive the response before returning from this routine
 120          */
 121         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 122         list_add_tail(&msginfo->msglistentry,
 123                       &vmbus_connection.chn_msg_list);
 124
 125         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 126
 127         ret = vmbus_post_msg(msg,
 128                                sizeof(struct vmbus_channel_initiate_contact));
 129         if (ret != 0) {
 130                 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 131                 list_del(&msginfo->msglistentry);
 132                 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
 133                                         flags);
 134                 goto cleanup;
 135         }
 136
 137         /* Wait for the connection response */
 138         t =  wait_for_completion_timeout(&msginfo->waitevent, HZ);
 139         if (t == 0) {
 140                 spin_lock_irqsave(&vmbus_connection.channelmsg_lock,
 141                                 flags);
 142                 list_del(&msginfo->msglistentry);
 143                 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
 144                                         flags);
 145                 ret = -ETIMEDOUT;
 146                 goto cleanup;
 147         }
 148
 149         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 150         list_del(&msginfo->msglistentry);
 151         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 152
 153         /* Check if successful */
 154         if (msginfo->response.version_response.version_supported) {
 155                 vmbus_connection.conn_state = CONNECTED;
 156         } else {
 157                 pr_err("Unable to connect, "
 158                         "Version %d not supported by Hyper-V\n",
 159                         VMBUS_REVISION_NUMBER);
 160                 ret = -1;
 161                 goto cleanup;
 162         }
 163
 164         kfree(msginfo);
 165         return 0;
 166
 167 cleanup:
 168         vmbus_connection.conn_state = DISCONNECTED;
 169
 170         if (vmbus_connection.work_queue)
 171                 destroy_workqueue(vmbus_connection.work_queue);
 172
 173         if (vmbus_connection.int_page) {
 174                 free_pages((unsigned long)vmbus_connection.int_page, 0);
 175                 vmbus_connection.int_page = NULL;
 176         }
 177
 178         if (vmbus_connection.monitor_pages) {
 179                 free_pages((unsigned long)vmbus_connection.monitor_pages, 1);
 180                 vmbus_connection.monitor_pages = NULL;
 181         }
 182
 183         kfree(msginfo);
 184
 185         return ret;
 186 }
 187
 188 /*
 189  * vmbus_disconnect -
 190  * Sends a disconnect request on the partition service connection
 191  */
 192 int vmbus_disconnect(void)
 193 {
 194         int ret = 0;
 195         struct vmbus_channel_message_header *msg;
 196
 197         /* Make sure we are connected */
 198         if (vmbus_connection.conn_state != CONNECTED)
 199                 return -1;
 200
 201         msg = kzalloc(sizeof(struct vmbus_channel_message_header), GFP_KERNEL);
 202         if (!msg)
 203                 return -ENOMEM;
 204
 205         msg->msgtype = CHANNELMSG_UNLOAD;
 206
 207         ret = vmbus_post_msg(msg,
 208                                sizeof(struct vmbus_channel_message_header));
 209         if (ret != 0)
 210                 goto cleanup;
 211
 212         free_pages((unsigned long)vmbus_connection.int_page, 0);
 213         free_pages((unsigned long)vmbus_connection.monitor_pages, 1);
 214
 215         /* TODO: iterate thru the msg list and free up */
 216         destroy_workqueue(vmbus_connection.work_queue);
 217
 218         vmbus_connection.conn_state = DISCONNECTED;
 219
 220         pr_info("hv_vmbus disconnected\n");
 221
 222 cleanup:
 223         kfree(msg);
 224         return ret;
 225 }
 226
 227 /*
 228  * relid2channel - Get the channel object given its
 229  * child relative id (ie channel id)
 230  */
 231 struct vmbus_channel *relid2channel(u32 relid)
 232 {
 233         struct vmbus_channel *channel;
 234         struct vmbus_channel *found_channel  = NULL;
 235         unsigned long flags;
 236
 237         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 238         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 239                 if (channel->offermsg.child_relid == relid) {
 240                         found_channel = channel;
 241                         break;
 242                 }
 243         }
 244         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 245
 246         return found_channel;
 247 }
 248
 249 /*
 250  * process_chn_event - Process a channel event notification
 251  */
 252 static void process_chn_event(u32 relid)
 253 {
 254         struct vmbus_channel *channel;
 255
 256         /* ASSERT(relId > 0); */
 257
 258         /*
 259          * Find the channel based on this relid and invokes the
 260          * channel callback to process the event
 261          */
 262         channel = relid2channel(relid);
 263
 264         if (channel) {
 265                 vmbus_onchannel_event(channel);
 266         } else {
 267                 pr_err("channel not found for relid - %u\n", relid);
 268         }
 269 }
 270
 271 /*
 272  * vmbus_on_event - Handler for events
 273  */
 274 void vmbus_on_event(unsigned long data)
 275 {
 276         u32 dword;
 277         u32 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
 278         int bit;
 279         u32 relid;
 280         u32 *recv_int_page = vmbus_connection.recv_int_page;
 281
 282         /* Check events */
 283         if (!recv_int_page)
 284                 return;
 285         for (dword = 0; dword < maxdword; dword++) {
 286                 if (!recv_int_page[dword])
 287                         continue;
 288                 for (bit = 0; bit < 32; bit++) {
 289                         if (sync_test_and_clear_bit(bit, (unsigned long *)&recv_int_page[dword])) {
 290                                 relid = (dword << 5) + bit;
 291
 292                                 if (relid == 0) {
 293                                         /*
 294                                          * Special case - vmbus
 295                                          * channel protocol msg
 296                                          */
 297                                         continue;
 298                                 }
 299                                 process_chn_event(relid);
 300                         }
 301                 }
 302         }
 303 }
 304
 305 /*
 306  * vmbus_post_msg - Send a msg on the vmbus's message connection
 307  */
 308 int vmbus_post_msg(void *buffer, size_t buflen)
 309 {
 310         union hv_connection_id conn_id;
 311
 312         conn_id.asu32 = 0;
 313         conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
 314         return hv_post_message(conn_id, 1, buffer, buflen);
 315 }
 316
 317 /*
 318  * vmbus_set_event - Send an event notification to the parent
 319  */
 320 int vmbus_set_event(u32 child_relid)
 321 {
 322         /* Each u32 represents 32 channels */
 323         sync_set_bit(child_relid & 31,
 324                 (unsigned long *)vmbus_connection.send_int_page +
 325                 (child_relid >> 5));
 326
 327         return hv_signal_event();
 328 }