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_WS2008):
  59         default:
  60                 return VERSION_INVAL;
  61         }
  62 }
  63
  64 static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
  65                                         __u32 version)
  66 {
  67         int ret = 0;
  68         struct vmbus_channel_initiate_contact *msg;
  69         unsigned long flags;
  70         int t;
  71
  72         init_completion(&msginfo->waitevent);
  73
  74         msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
  75
  76         msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
  77         msg->vmbus_version_requested = version;
  78         msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
  79         msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
  80         msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
  81
  82         /*
  83          * Add to list before we send the request since we may
  84          * receive the response before returning from this routine
  85          */
  86         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
  87         list_add_tail(&msginfo->msglistentry,
  88                       &vmbus_connection.chn_msg_list);
  89
  90         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
  91
  92         ret = vmbus_post_msg(msg,
  93                                sizeof(struct vmbus_channel_initiate_contact));
  94         if (ret != 0) {
  95                 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
  96                 list_del(&msginfo->msglistentry);
  97                 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
  98                                         flags);
  99                 return ret;
 100         }
 101
 102         /* Wait for the connection response */
 103         t =  wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 104         if (t == 0) {
 105                 spin_lock_irqsave(&vmbus_connection.channelmsg_lock,
 106                                 flags);
 107                 list_del(&msginfo->msglistentry);
 108                 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
 109                                         flags);
 110                 return -ETIMEDOUT;
 111         }
 112
 113         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 114         list_del(&msginfo->msglistentry);
 115         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 116
 117         /* Check if successful */
 118         if (msginfo->response.version_response.version_supported) {
 119                 vmbus_connection.conn_state = CONNECTED;
 120         } else {
 121                 return -ECONNREFUSED;
 122         }
 123
 124         return ret;
 125 }
 126
 127 /*
 128  * vmbus_connect - Sends a connect request on the partition service connection
 129  */
 130 int vmbus_connect(void)
 131 {
 132         int ret = 0;
 133         struct vmbus_channel_msginfo *msginfo = NULL;
 134         __u32 version;
 135
 136         /* Initialize the vmbus connection */
 137         vmbus_connection.conn_state = CONNECTING;
 138         vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
 139         if (!vmbus_connection.work_queue) {
 140                 ret = -ENOMEM;
 141                 goto cleanup;
 142         }
 143
 144         INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
 145         spin_lock_init(&vmbus_connection.channelmsg_lock);
 146
 147         INIT_LIST_HEAD(&vmbus_connection.chn_list);
 148         spin_lock_init(&vmbus_connection.channel_lock);
 149
 150         /*
 151          * Setup the vmbus event connection for channel interrupt
 152          * abstraction stuff
 153          */
 154         vmbus_connection.int_page =
 155         (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
 156         if (vmbus_connection.int_page == NULL) {
 157                 ret = -ENOMEM;
 158                 goto cleanup;
 159         }
 160
 161         vmbus_connection.recv_int_page = vmbus_connection.int_page;
 162         vmbus_connection.send_int_page =
 163                 (void *)((unsigned long)vmbus_connection.int_page +
 164                         (PAGE_SIZE >> 1));
 165
 166         /*
 167          * Setup the monitor notification facility. The 1st page for
 168          * parent->child and the 2nd page for child->parent
 169          */
 170         vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
 171         vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
 172         if ((vmbus_connection.monitor_pages[0] == NULL) ||
 173             (vmbus_connection.monitor_pages[1] == NULL)) {
 174                 ret = -ENOMEM;
 175                 goto cleanup;
 176         }
 177
 178         msginfo = kzalloc(sizeof(*msginfo) +
 179                           sizeof(struct vmbus_channel_initiate_contact),
 180                           GFP_KERNEL);
 181         if (msginfo == NULL) {
 182                 ret = -ENOMEM;
 183                 goto cleanup;
 184         }
 185
 186         /*
 187          * Negotiate a compatible VMBUS version number with the
 188          * host. We start with the highest number we can support
 189          * and work our way down until we negotiate a compatible
 190          * version.
 191          */
 192
 193         version = VERSION_CURRENT;
 194
 195         do {
 196                 ret = vmbus_negotiate_version(msginfo, version);
 197                 if (ret == -ETIMEDOUT)
 198                         goto cleanup;
 199
 200                 if (vmbus_connection.conn_state == CONNECTED)
 201                         break;
 202
 203                 version = vmbus_get_next_version(version);
 204         } while (version != VERSION_INVAL);
 205
 206         if (version == VERSION_INVAL)
 207                 goto cleanup;
 208
 209         vmbus_proto_version = version;
 210         pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n",
 211                     host_info_eax, host_info_ebx >> 16,
 212                     host_info_ebx & 0xFFFF, host_info_ecx,
 213                     host_info_edx >> 24, host_info_edx & 0xFFFFFF,
 214                     version >> 16, version & 0xFFFF);
 215
 216         kfree(msginfo);
 217         return 0;
 218
 219 cleanup:
 220         pr_err("Unable to connect to host\n");
 221         vmbus_connection.conn_state = DISCONNECTED;
 222
 223         if (vmbus_connection.work_queue)
 224                 destroy_workqueue(vmbus_connection.work_queue);
 225
 226         if (vmbus_connection.int_page) {
 227                 free_pages((unsigned long)vmbus_connection.int_page, 0);
 228                 vmbus_connection.int_page = NULL;
 229         }
 230
 231         free_pages((unsigned long)vmbus_connection.monitor_pages[0], 1);
 232         free_pages((unsigned long)vmbus_connection.monitor_pages[1], 1);
 233         vmbus_connection.monitor_pages[0] = NULL;
 234         vmbus_connection.monitor_pages[1] = NULL;
 235
 236         kfree(msginfo);
 237
 238         return ret;
 239 }
 240
 241
 242 /*
 243  * relid2channel - Get the channel object given its
 244  * child relative id (ie channel id)
 245  */
 246 struct vmbus_channel *relid2channel(u32 relid)
 247 {
 248         struct vmbus_channel *channel;
 249         struct vmbus_channel *found_channel  = NULL;
 250         unsigned long flags;
 251         struct list_head *cur, *tmp;
 252         struct vmbus_channel *cur_sc;
 253
 254         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 255         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 256                 if (channel->offermsg.child_relid == relid) {
 257                         found_channel = channel;
 258                         break;
 259                 } else if (!list_empty(&channel->sc_list)) {
 260                         /*
 261                          * Deal with sub-channels.
 262                          */
 263                         list_for_each_safe(cur, tmp, &channel->sc_list) {
 264                                 cur_sc = list_entry(cur, struct vmbus_channel,
 265                                                         sc_list);
 266                                 if (cur_sc->offermsg.child_relid == relid) {
 267                                         found_channel = cur_sc;
 268                                         break;
 269                                 }
 270                         }
 271                 }
 272         }
 273         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 274
 275         return found_channel;
 276 }
 277
 278 /*
 279  * process_chn_event - Process a channel event notification
 280  */
 281 static void process_chn_event(u32 relid)
 282 {
 283         struct vmbus_channel *channel;
 284         unsigned long flags;
 285         void *arg;
 286         bool read_state;
 287         u32 bytes_to_read;
 288
 289         /*
 290          * Find the channel based on this relid and invokes the
 291          * channel callback to process the event
 292          */
 293         channel = relid2channel(relid);
 294
 295         if (!channel) {
 296                 pr_err("channel not found for relid - %u\n", relid);
 297                 return;
 298         }
 299
 300         /*
 301          * A channel once created is persistent even when there
 302          * is no driver handling the device. An unloading driver
 303          * sets the onchannel_callback to NULL under the
 304          * protection of the channel inbound_lock. Thus, checking
 305          * and invoking the driver specific callback takes care of
 306          * orderly unloading of the driver.
 307          */
 308
 309         spin_lock_irqsave(&channel->inbound_lock, flags);
 310         if (channel->onchannel_callback != NULL) {
 311                 arg = channel->channel_callback_context;
 312                 read_state = channel->batched_reading;
 313                 /*
 314                  * This callback reads the messages sent by the host.
 315                  * We can optimize host to guest signaling by ensuring:
 316                  * 1. While reading the channel, we disable interrupts from
 317                  *    host.
 318                  * 2. Ensure that we process all posted messages from the host
 319                  *    before returning from this callback.
 320                  * 3. Once we return, enable signaling from the host. Once this
 321                  *    state is set we check to see if additional packets are
 322                  *    available to read. In this case we repeat the process.
 323                  */
 324
 325                 do {
 326                         hv_begin_read(&channel->inbound);
 327                         channel->onchannel_callback(arg);
 328                         bytes_to_read = hv_end_read(&channel->inbound);
 329                 } while (read_state && (bytes_to_read != 0));
 330         } else {
 331                 pr_err("no channel callback for relid - %u\n", relid);
 332         }
 333
 334         spin_unlock_irqrestore(&channel->inbound_lock, flags);
 335 }
 336
 337 /*
 338  * vmbus_on_event - Handler for events
 339  */
 340 void vmbus_on_event(unsigned long data)
 341 {
 342         u32 dword;
 343         u32 maxdword;
 344         int bit;
 345         u32 relid;
 346         u32 *recv_int_page = NULL;
 347         void *page_addr;
 348         int cpu = smp_processor_id();
 349         union hv_synic_event_flags *event;
 350
 351         if ((vmbus_proto_version == VERSION_WS2008) ||
 352                 (vmbus_proto_version == VERSION_WIN7)) {
 353                 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
 354                 recv_int_page = vmbus_connection.recv_int_page;
 355         } else {
 356                 /*
 357                  * When the host is win8 and beyond, the event page
 358                  * can be directly checked to get the id of the channel
 359                  * that has the interrupt pending.
 360                  */
 361                 maxdword = HV_EVENT_FLAGS_DWORD_COUNT;
 362                 page_addr = hv_context.synic_event_page[cpu];
 363                 event = (union hv_synic_event_flags *)page_addr +
 364                                                  VMBUS_MESSAGE_SINT;
 365                 recv_int_page = event->flags32;
 366         }
 367
 368
 369
 370         /* Check events */
 371         if (!recv_int_page)
 372                 return;
 373         for (dword = 0; dword < maxdword; dword++) {
 374                 if (!recv_int_page[dword])
 375                         continue;
 376                 for (bit = 0; bit < 32; bit++) {
 377                         if (sync_test_and_clear_bit(bit,
 378                                 (unsigned long *)&recv_int_page[dword])) {
 379                                 relid = (dword << 5) + bit;
 380
 381                                 if (relid == 0)
 382                                         /*
 383                                          * Special case - vmbus
 384                                          * channel protocol msg
 385                                          */
 386                                         continue;
 387
 388                                 process_chn_event(relid);
 389                         }
 390                 }
 391         }
 392 }
 393
 394 /*
 395  * vmbus_post_msg - Send a msg on the vmbus's message connection
 396  */
 397 int vmbus_post_msg(void *buffer, size_t buflen)
 398 {
 399         union hv_connection_id conn_id;
 400         int ret = 0;
 401         int retries = 0;
 402
 403         conn_id.asu32 = 0;
 404         conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
 405
 406         /*
 407          * hv_post_message() can have transient failures because of
 408          * insufficient resources. Retry the operation a couple of
 409          * times before giving up.
 410          */
 411         while (retries < 3) {
 412                 ret =  hv_post_message(conn_id, 1, buffer, buflen);
 413                 if (ret != HV_STATUS_INSUFFICIENT_BUFFERS)
 414                         return ret;
 415                 retries++;
 416                 msleep(100);
 417         }
 418         return ret;
 419 }
 420
 421 /*
 422  * vmbus_set_event - Send an event notification to the parent
 423  */
 424 int vmbus_set_event(struct vmbus_channel *channel)
 425 {
 426         u32 child_relid = channel->offermsg.child_relid;
 427
 428         if (!channel->is_dedicated_interrupt) {
 429                 /* Each u32 represents 32 channels */
 430                 sync_set_bit(child_relid & 31,
 431                         (unsigned long *)vmbus_connection.send_int_page +
 432                         (child_relid >> 5));
 433         }
 434
 435         return hv_signal_event(channel->sig_event);
 436 }