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 -EISCONN;
  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 = -ENOMEM;
  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 = -ENOMEM;
  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 = -ENOMEM;
  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, 5*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 = -ECONNREFUSED;
 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 /*
 190  * relid2channel - Get the channel object given its
 191  * child relative id (ie channel id)
 192  */
 193 struct vmbus_channel *relid2channel(u32 relid)
 194 {
 195         struct vmbus_channel *channel;
 196         struct vmbus_channel *found_channel  = NULL;
 197         unsigned long flags;
 198
 199         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 200         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 201                 if (channel->offermsg.child_relid == relid) {
 202                         found_channel = channel;
 203                         break;
 204                 }
 205         }
 206         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 207
 208         return found_channel;
 209 }
 210
 211 /*
 212  * process_chn_event - Process a channel event notification
 213  */
 214 static void process_chn_event(u32 relid)
 215 {
 216         struct vmbus_channel *channel;
 217
 218         /* ASSERT(relId > 0); */
 219
 220         /*
 221          * Find the channel based on this relid and invokes the
 222          * channel callback to process the event
 223          */
 224         channel = relid2channel(relid);
 225
 226         if (channel) {
 227                 channel->onchannel_callback(channel->channel_callback_context);
 228         } else {
 229                 pr_err("channel not found for relid - %u\n", relid);
 230         }
 231 }
 232
 233 /*
 234  * vmbus_on_event - Handler for events
 235  */
 236 void vmbus_on_event(unsigned long data)
 237 {
 238         u32 dword;
 239         u32 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
 240         int bit;
 241         u32 relid;
 242         u32 *recv_int_page = vmbus_connection.recv_int_page;
 243
 244         /* Check events */
 245         if (!recv_int_page)
 246                 return;
 247         for (dword = 0; dword < maxdword; dword++) {
 248                 if (!recv_int_page[dword])
 249                         continue;
 250                 for (bit = 0; bit < 32; bit++) {
 251                         if (sync_test_and_clear_bit(bit, (unsigned long *)&recv_int_page[dword])) {
 252                                 relid = (dword << 5) + bit;
 253
 254                                 if (relid == 0) {
 255                                         /*
 256                                          * Special case - vmbus
 257                                          * channel protocol msg
 258                                          */
 259                                         continue;
 260                                 }
 261                                 process_chn_event(relid);
 262                         }
 263                 }
 264         }
 265 }
 266
 267 /*
 268  * vmbus_post_msg - Send a msg on the vmbus's message connection
 269  */
 270 int vmbus_post_msg(void *buffer, size_t buflen)
 271 {
 272         union hv_connection_id conn_id;
 273
 274         conn_id.asu32 = 0;
 275         conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
 276         return hv_post_message(conn_id, 1, buffer, buflen);
 277 }
 278
 279 /*
 280  * vmbus_set_event - Send an event notification to the parent
 281  */
 282 int vmbus_set_event(u32 child_relid)
 283 {
 284         /* Each u32 represents 32 channels */
 285         sync_set_bit(child_relid & 31,
 286                 (unsigned long *)vmbus_connection.send_int_page +
 287                 (child_relid >> 5));
 288
 289         return hv_signal_event();
 290 }