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