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 <linux/export.h>
  34 #include <asm/hyperv.h>
  35 #include "hyperv_vmbus.h"
  36
  37
  38 struct vmbus_connection vmbus_connection = {
  39         .conn_state             = DISCONNECTED,
  40         .next_gpadl_handle      = ATOMIC_INIT(0xE1E10),
  41 };
  42
  43 /*
  44  * Negotiated protocol version with the host.
  45  */
  46 __u32 vmbus_proto_version;
  47 EXPORT_SYMBOL_GPL(vmbus_proto_version);
  48
  49 static __u32 vmbus_get_next_version(__u32 current_version)
  50 {
  51         switch (current_version) {
  52         case (VERSION_WIN7):
  53                 return VERSION_WS2008;
  54
  55         case (VERSION_WIN8):
  56                 return VERSION_WIN7;
  57
  58         case (VERSION_WIN8_1):
  59                 return VERSION_WIN8;
  60
  61         case (VERSION_WS2008):
  62         default:
  63                 return VERSION_INVAL;
  64         }
  65 }
  66
  67 static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
  68                                         __u32 version)
  69 {
  70         int ret = 0;
  71         struct vmbus_channel_initiate_contact *msg;
  72         unsigned long flags;
  73
  74         init_completion(&msginfo->waitevent);
  75
  76         msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
  77
  78         msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
  79         msg->vmbus_version_requested = version;
  80         msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
  81         msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages);
  82         msg->monitor_page2 = virt_to_phys(
  83                         (void *)((unsigned long)vmbus_connection.monitor_pages +
  84                                  PAGE_SIZE));
  85
  86         if (version == VERSION_WIN8_1)
  87                 msg->target_vcpu = hv_context.vp_index[smp_processor_id()];
  88
  89         /*
  90          * Add to list before we send the request since we may
  91          * receive the response before returning from this routine
  92          */
  93         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
  94         list_add_tail(&msginfo->msglistentry,
  95                       &vmbus_connection.chn_msg_list);
  96
  97         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
  98
  99         ret = vmbus_post_msg(msg,
 100                                sizeof(struct vmbus_channel_initiate_contact));
 101         if (ret != 0) {
 102                 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 103                 list_del(&msginfo->msglistentry);
 104                 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
 105                                         flags);
 106                 return ret;
 107         }
 108
 109         /* Wait for the connection response */
 110         wait_for_completion(&msginfo->waitevent);
 111
 112         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 113         list_del(&msginfo->msglistentry);
 114         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 115
 116         /* Check if successful */
 117         if (msginfo->response.version_response.version_supported) {
 118                 vmbus_connection.conn_state = CONNECTED;
 119         } else {
 120                 return -ECONNREFUSED;
 121         }
 122
 123         return ret;
 124 }
 125
 126 /*
 127  * vmbus_connect - Sends a connect request on the partition service connection
 128  */
 129 int vmbus_connect(void)
 130 {
 131         int ret = 0;
 132         struct vmbus_channel_msginfo *msginfo = NULL;
 133         __u32 version;
 134
 135         /* Initialize the vmbus connection */
 136         vmbus_connection.conn_state = CONNECTING;
 137         vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
 138         if (!vmbus_connection.work_queue) {
 139                 ret = -ENOMEM;
 140                 goto cleanup;
 141         }
 142
 143         INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
 144         spin_lock_init(&vmbus_connection.channelmsg_lock);
 145
 146         INIT_LIST_HEAD(&vmbus_connection.chn_list);
 147         spin_lock_init(&vmbus_connection.channel_lock);
 148
 149         /*
 150          * Setup the vmbus event connection for channel interrupt
 151          * abstraction stuff
 152          */
 153         vmbus_connection.int_page =
 154         (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
 155         if (vmbus_connection.int_page == NULL) {
 156                 ret = -ENOMEM;
 157                 goto cleanup;
 158         }
 159
 160         vmbus_connection.recv_int_page = vmbus_connection.int_page;
 161         vmbus_connection.send_int_page =
 162                 (void *)((unsigned long)vmbus_connection.int_page +
 163                         (PAGE_SIZE >> 1));
 164
 165         /*
 166          * Setup the monitor notification facility. The 1st page for
 167          * parent->child and the 2nd page for child->parent
 168          */
 169         vmbus_connection.monitor_pages =
 170         (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 1);
 171         if (vmbus_connection.monitor_pages == NULL) {
 172                 ret = -ENOMEM;
 173                 goto cleanup;
 174         }
 175
 176         msginfo = kzalloc(sizeof(*msginfo) +
 177                           sizeof(struct vmbus_channel_initiate_contact),
 178                           GFP_KERNEL);
 179         if (msginfo == NULL) {
 180                 ret = -ENOMEM;
 181                 goto cleanup;
 182         }
 183
 184         /*
 185          * Negotiate a compatible VMBUS version number with the
 186          * host. We start with the highest number we can support
 187          * and work our way down until we negotiate a compatible
 188          * version.
 189          */
 190
 191         version = VERSION_CURRENT;
 192
 193         do {
 194                 ret = vmbus_negotiate_version(msginfo, version);
 195                 if (ret == 0)
 196                         break;
 197
 198                 version = vmbus_get_next_version(version);
 199         } while (version != VERSION_INVAL);
 200
 201         if (version == VERSION_INVAL)
 202                 goto cleanup;
 203
 204         vmbus_proto_version = version;
 205         pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n",
 206                     host_info_eax, host_info_ebx >> 16,
 207                     host_info_ebx & 0xFFFF, host_info_ecx,
 208                     host_info_edx >> 24, host_info_edx & 0xFFFFFF,
 209                     version >> 16, version & 0xFFFF);
 210
 211         kfree(msginfo);
 212         return 0;
 213
 214 cleanup:
 215         pr_err("Unable to connect to host\n");
 216         vmbus_connection.conn_state = DISCONNECTED;
 217
 218         if (vmbus_connection.work_queue)
 219                 destroy_workqueue(vmbus_connection.work_queue);
 220
 221         if (vmbus_connection.int_page) {
 222                 free_pages((unsigned long)vmbus_connection.int_page, 0);
 223                 vmbus_connection.int_page = NULL;
 224         }
 225
 226         if (vmbus_connection.monitor_pages) {
 227                 free_pages((unsigned long)vmbus_connection.monitor_pages, 1);
 228                 vmbus_connection.monitor_pages = NULL;
 229         }
 230
 231         kfree(msginfo);
 232
 233         return ret;
 234 }
 235
 236
 237 /*
 238  * relid2channel - Get the channel object given its
 239  * child relative id (ie channel id)
 240  */
 241 struct vmbus_channel *relid2channel(u32 relid)
 242 {
 243         struct vmbus_channel *channel;
 244         struct vmbus_channel *found_channel  = NULL;
 245         unsigned long flags;
 246
 247         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 248         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 249                 if (channel->offermsg.child_relid == relid) {
 250                         found_channel = channel;
 251                         break;
 252                 }
 253         }
 254         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 255
 256         return found_channel;
 257 }
 258
 259 /*
 260  * process_chn_event - Process a channel event notification
 261  */
 262 static void process_chn_event(u32 relid)
 263 {
 264         struct vmbus_channel *channel;
 265         unsigned long flags;
 266         void *arg;
 267         bool read_state;
 268         u32 bytes_to_read;
 269
 270         /*
 271          * Find the channel based on this relid and invokes the
 272          * channel callback to process the event
 273          */
 274         channel = relid2channel(relid);
 275
 276         if (!channel) {
 277                 pr_err("channel not found for relid - %u\n", relid);
 278                 return;
 279         }
 280
 281         /*
 282          * A channel once created is persistent even when there
 283          * is no driver handling the device. An unloading driver
 284          * sets the onchannel_callback to NULL under the
 285          * protection of the channel inbound_lock. Thus, checking
 286          * and invoking the driver specific callback takes care of
 287          * orderly unloading of the driver.
 288          */
 289
 290         spin_lock_irqsave(&channel->inbound_lock, flags);
 291         if (channel->onchannel_callback != NULL) {
 292                 arg = channel->channel_callback_context;
 293                 read_state = channel->batched_reading;
 294                 /*
 295                  * This callback reads the messages sent by the host.
 296                  * We can optimize host to guest signaling by ensuring:
 297                  * 1. While reading the channel, we disable interrupts from
 298                  *    host.
 299                  * 2. Ensure that we process all posted messages from the host
 300                  *    before returning from this callback.
 301                  * 3. Once we return, enable signaling from the host. Once this
 302                  *    state is set we check to see if additional packets are
 303                  *    available to read. In this case we repeat the process.
 304                  */
 305
 306                 do {
 307                         if (read_state)
 308                                 hv_begin_read(&channel->inbound);
 309                         channel->onchannel_callback(arg);
 310                         if (read_state)
 311                                 bytes_to_read = hv_end_read(&channel->inbound);
 312                         else
 313                                 bytes_to_read = 0;
 314                 } while (read_state && (bytes_to_read != 0));
 315         } else {
 316                 pr_err("no channel callback for relid - %u\n", relid);
 317         }
 318
 319         spin_unlock_irqrestore(&channel->inbound_lock, flags);
 320 }
 321
 322 /*
 323  * vmbus_on_event - Handler for events
 324  */
 325 void vmbus_on_event(unsigned long data)
 326 {
 327         u32 dword;
 328         u32 maxdword;
 329         int bit;
 330         u32 relid;
 331         u32 *recv_int_page = NULL;
 332         void *page_addr;
 333         int cpu = smp_processor_id();
 334         union hv_synic_event_flags *event;
 335
 336         if ((vmbus_proto_version == VERSION_WS2008) ||
 337                 (vmbus_proto_version == VERSION_WIN7)) {
 338                 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
 339                 recv_int_page = vmbus_connection.recv_int_page;
 340         } else {
 341                 /*
 342                  * When the host is win8 and beyond, the event page
 343                  * can be directly checked to get the id of the channel
 344                  * that has the interrupt pending.
 345                  */
 346                 maxdword = HV_EVENT_FLAGS_DWORD_COUNT;
 347                 page_addr = hv_context.synic_event_page[cpu];
 348                 event = (union hv_synic_event_flags *)page_addr +
 349                                                  VMBUS_MESSAGE_SINT;
 350                 recv_int_page = event->flags32;
 351         }
 352
 353
 354
 355         /* Check events */
 356         if (!recv_int_page)
 357                 return;
 358         for (dword = 0; dword < maxdword; dword++) {
 359                 if (!recv_int_page[dword])
 360                         continue;
 361                 for (bit = 0; bit < 32; bit++) {
 362                         if (sync_test_and_clear_bit(bit,
 363                                 (unsigned long *)&recv_int_page[dword])) {
 364                                 relid = (dword << 5) + bit;
 365
 366                                 if (relid == 0)
 367                                         /*
 368                                          * Special case - vmbus
 369                                          * channel protocol msg
 370                                          */
 371                                         continue;
 372
 373                                 process_chn_event(relid);
 374                         }
 375                 }
 376         }
 377 }
 378
 379 /*
 380  * vmbus_post_msg - Send a msg on the vmbus's message connection
 381  */
 382 int vmbus_post_msg(void *buffer, size_t buflen)
 383 {
 384         union hv_connection_id conn_id;
 385         int ret = 0;
 386         int retries = 0;
 387
 388         conn_id.asu32 = 0;
 389         conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
 390
 391         /*
 392          * hv_post_message() can have transient failures because of
 393          * insufficient resources. Retry the operation a couple of
 394          * times before giving up.
 395          */
 396         while (retries < 10) {
 397                 ret = hv_post_message(conn_id, 1, buffer, buflen);
 398
 399                 switch (ret) {
 400                 case HV_STATUS_INSUFFICIENT_BUFFERS:
 401                         ret = -ENOMEM;
 402                 case -ENOMEM:
 403                         break;
 404                 case HV_STATUS_SUCCESS:
 405                         return ret;
 406                 default:
 407                         pr_err("hv_post_msg() failed; error code:%d\n", ret);
 408                         return -EINVAL;
 409                 }
 410
 411                 retries++;
 412                 msleep(100);
 413         }
 414         return ret;
 415 }
 416
 417 /*
 418  * vmbus_set_event - Send an event notification to the parent
 419  */
 420 int vmbus_set_event(struct vmbus_channel *channel)
 421 {
 422         u32 child_relid = channel->offermsg.child_relid;
 423
 424         if (!channel->is_dedicated_interrupt) {
 425                 /* Each u32 represents 32 channels */
 426                 sync_set_bit(child_relid & 31,
 427                         (unsigned long *)vmbus_connection.send_int_page +
 428                         (child_relid >> 5));
 429         }
 430
 431         return hv_signal_event(channel->sig_event);
 432 }