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 <asm/mshyperv.h>
  36
  37 #include "hyperv_vmbus.h"
  38
  39
  40 struct vmbus_connection vmbus_connection = {
  41         .conn_state             = DISCONNECTED,
  42         .next_gpadl_handle      = ATOMIC_INIT(0xE1E10),
  43 };
  44 EXPORT_SYMBOL_GPL(vmbus_connection);
  45
  46 /*
  47  * Negotiated protocol version with the host.
  48  */
  49 __u32 vmbus_proto_version;
  50 EXPORT_SYMBOL_GPL(vmbus_proto_version);
  51
  52 static __u32 vmbus_get_next_version(__u32 current_version)
  53 {
  54         switch (current_version) {
  55         case (VERSION_WIN7):
  56                 return VERSION_WS2008;
  57
  58         case (VERSION_WIN8):
  59                 return VERSION_WIN7;
  60
  61         case (VERSION_WIN8_1):
  62                 return VERSION_WIN8;
  63
  64         case (VERSION_WIN10):
  65                 return VERSION_WIN8_1;
  66
  67         case (VERSION_WS2008):
  68         default:
  69                 return VERSION_INVAL;
  70         }
  71 }
  72
  73 static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
  74                                         __u32 version)
  75 {
  76         int ret = 0;
  77         unsigned int cur_cpu;
  78         struct vmbus_channel_initiate_contact *msg;
  79         unsigned long flags;
  80
  81         init_completion(&msginfo->waitevent);
  82
  83         msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
  84
  85         msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
  86         msg->vmbus_version_requested = version;
  87         msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
  88         msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
  89         msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
  90         /*
  91          * We want all channel messages to be delivered on CPU 0.
  92          * This has been the behavior pre-win8. This is not
  93          * perf issue and having all channel messages delivered on CPU 0
  94          * would be ok.
  95          * For post win8 hosts, we support receiving channel messagges on
  96          * all the CPUs. This is needed for kexec to work correctly where
  97          * the CPU attempting to connect may not be CPU 0.
  98          */
  99         if (version >= VERSION_WIN8_1) {
 100                 cur_cpu = get_cpu();
 101                 msg->target_vcpu = hv_cpu_number_to_vp_number(cur_cpu);
 102                 vmbus_connection.connect_cpu = cur_cpu;
 103                 put_cpu();
 104         } else {
 105                 msg->target_vcpu = 0;
 106                 vmbus_connection.connect_cpu = 0;
 107         }
 108
 109         /*
 110          * Add to list before we send the request since we may
 111          * receive the response before returning from this routine
 112          */
 113         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 114         list_add_tail(&msginfo->msglistentry,
 115                       &vmbus_connection.chn_msg_list);
 116
 117         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 118
 119         ret = vmbus_post_msg(msg,
 120                              sizeof(struct vmbus_channel_initiate_contact),
 121                              true);
 122
 123         trace_vmbus_negotiate_version(msg, ret);
 124
 125         if (ret != 0) {
 126                 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 127                 list_del(&msginfo->msglistentry);
 128                 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
 129                                         flags);
 130                 return ret;
 131         }
 132
 133         /* Wait for the connection response */
 134         wait_for_completion(&msginfo->waitevent);
 135
 136         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 137         list_del(&msginfo->msglistentry);
 138         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 139
 140         /* Check if successful */
 141         if (msginfo->response.version_response.version_supported) {
 142                 vmbus_connection.conn_state = CONNECTED;
 143         } else {
 144                 return -ECONNREFUSED;
 145         }
 146
 147         return ret;
 148 }
 149
 150 /*
 151  * vmbus_connect - Sends a connect request on the partition service connection
 152  */
 153 int vmbus_connect(void)
 154 {
 155         int ret = 0;
 156         struct vmbus_channel_msginfo *msginfo = NULL;
 157         __u32 version;
 158
 159         /* Initialize the vmbus connection */
 160         vmbus_connection.conn_state = CONNECTING;
 161         vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
 162         if (!vmbus_connection.work_queue) {
 163                 ret = -ENOMEM;
 164                 goto cleanup;
 165         }
 166
 167         vmbus_connection.handle_primary_chan_wq =
 168                 create_workqueue("hv_pri_chan");
 169         if (!vmbus_connection.handle_primary_chan_wq) {
 170                 ret = -ENOMEM;
 171                 goto cleanup;
 172         }
 173
 174         vmbus_connection.handle_sub_chan_wq =
 175                 create_workqueue("hv_sub_chan");
 176         if (!vmbus_connection.handle_sub_chan_wq) {
 177                 ret = -ENOMEM;
 178                 goto cleanup;
 179         }
 180
 181         INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
 182         spin_lock_init(&vmbus_connection.channelmsg_lock);
 183
 184         INIT_LIST_HEAD(&vmbus_connection.chn_list);
 185         mutex_init(&vmbus_connection.channel_mutex);
 186
 187         /*
 188          * Setup the vmbus event connection for channel interrupt
 189          * abstraction stuff
 190          */
 191         vmbus_connection.int_page =
 192         (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
 193         if (vmbus_connection.int_page == NULL) {
 194                 ret = -ENOMEM;
 195                 goto cleanup;
 196         }
 197
 198         vmbus_connection.recv_int_page = vmbus_connection.int_page;
 199         vmbus_connection.send_int_page =
 200                 (void *)((unsigned long)vmbus_connection.int_page +
 201                         (PAGE_SIZE >> 1));
 202
 203         /*
 204          * Setup the monitor notification facility. The 1st page for
 205          * parent->child and the 2nd page for child->parent
 206          */
 207         vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
 208         vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
 209         if ((vmbus_connection.monitor_pages[0] == NULL) ||
 210             (vmbus_connection.monitor_pages[1] == NULL)) {
 211                 ret = -ENOMEM;
 212                 goto cleanup;
 213         }
 214
 215         msginfo = kzalloc(sizeof(*msginfo) +
 216                           sizeof(struct vmbus_channel_initiate_contact),
 217                           GFP_KERNEL);
 218         if (msginfo == NULL) {
 219                 ret = -ENOMEM;
 220                 goto cleanup;
 221         }
 222
 223         /*
 224          * Negotiate a compatible VMBUS version number with the
 225          * host. We start with the highest number we can support
 226          * and work our way down until we negotiate a compatible
 227          * version.
 228          */
 229
 230         version = VERSION_CURRENT;
 231
 232         do {
 233                 ret = vmbus_negotiate_version(msginfo, version);
 234                 if (ret == -ETIMEDOUT)
 235                         goto cleanup;
 236
 237                 if (vmbus_connection.conn_state == CONNECTED)
 238                         break;
 239
 240                 version = vmbus_get_next_version(version);
 241         } while (version != VERSION_INVAL);
 242
 243         if (version == VERSION_INVAL)
 244                 goto cleanup;
 245
 246         vmbus_proto_version = version;
 247         pr_info("Vmbus version:%d.%d\n",
 248                 version >> 16, version & 0xFFFF);
 249
 250         kfree(msginfo);
 251         return 0;
 252
 253 cleanup:
 254         pr_err("Unable to connect to host\n");
 255
 256         vmbus_connection.conn_state = DISCONNECTED;
 257         vmbus_disconnect();
 258
 259         kfree(msginfo);
 260
 261         return ret;
 262 }
 263
 264 void vmbus_disconnect(void)
 265 {
 266         /*
 267          * First send the unload request to the host.
 268          */
 269         vmbus_initiate_unload(false);
 270
 271         if (vmbus_connection.handle_sub_chan_wq)
 272                 destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
 273
 274         if (vmbus_connection.handle_primary_chan_wq)
 275                 destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
 276
 277         if (vmbus_connection.work_queue)
 278                 destroy_workqueue(vmbus_connection.work_queue);
 279
 280         if (vmbus_connection.int_page) {
 281                 free_pages((unsigned long)vmbus_connection.int_page, 0);
 282                 vmbus_connection.int_page = NULL;
 283         }
 284
 285         free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
 286         free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
 287         vmbus_connection.monitor_pages[0] = NULL;
 288         vmbus_connection.monitor_pages[1] = NULL;
 289 }
 290
 291 /*
 292  * relid2channel - Get the channel object given its
 293  * child relative id (ie channel id)
 294  */
 295 struct vmbus_channel *relid2channel(u32 relid)
 296 {
 297         struct vmbus_channel *channel;
 298         struct vmbus_channel *found_channel  = NULL;
 299         struct list_head *cur, *tmp;
 300         struct vmbus_channel *cur_sc;
 301
 302         BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));
 303
 304         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 305                 if (channel->offermsg.child_relid == relid) {
 306                         found_channel = channel;
 307                         break;
 308                 } else if (!list_empty(&channel->sc_list)) {
 309                         /*
 310                          * Deal with sub-channels.
 311                          */
 312                         list_for_each_safe(cur, tmp, &channel->sc_list) {
 313                                 cur_sc = list_entry(cur, struct vmbus_channel,
 314                                                         sc_list);
 315                                 if (cur_sc->offermsg.child_relid == relid) {
 316                                         found_channel = cur_sc;
 317                                         break;
 318                                 }
 319                         }
 320                 }
 321         }
 322
 323         return found_channel;
 324 }
 325
 326 /*
 327  * vmbus_on_event - Process a channel event notification
 328  *
 329  * For batched channels (default) optimize host to guest signaling
 330  * by ensuring:
 331  * 1. While reading the channel, we disable interrupts from host.
 332  * 2. Ensure that we process all posted messages from the host
 333  *    before returning from this callback.
 334  * 3. Once we return, enable signaling from the host. Once this
 335  *    state is set we check to see if additional packets are
 336  *    available to read. In this case we repeat the process.
 337  *    If this tasklet has been running for a long time
 338  *    then reschedule ourselves.
 339  */
 340 void vmbus_on_event(unsigned long data)
 341 {
 342         struct vmbus_channel *channel = (void *) data;
 343         unsigned long time_limit = jiffies + 2;
 344
 345         trace_vmbus_on_event(channel);
 346
 347         do {
 348                 void (*callback_fn)(void *);
 349
 350                 /* A channel once created is persistent even when
 351                  * there is no driver handling the device. An
 352                  * unloading driver sets the onchannel_callback to NULL.
 353                  */
 354                 callback_fn = READ_ONCE(channel->onchannel_callback);
 355                 if (unlikely(callback_fn == NULL))
 356                         return;
 357
 358                 (*callback_fn)(channel->channel_callback_context);
 359
 360                 if (channel->callback_mode != HV_CALL_BATCHED)
 361                         return;
 362
 363                 if (likely(hv_end_read(&channel->inbound) == 0))
 364                         return;
 365
 366                 hv_begin_read(&channel->inbound);
 367         } while (likely(time_before(jiffies, time_limit)));
 368
 369         /* The time limit (2 jiffies) has been reached */
 370         tasklet_schedule(&channel->callback_event);
 371 }
 372
 373 /*
 374  * vmbus_post_msg - Send a msg on the vmbus's message connection
 375  */
 376 int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
 377 {
 378         union hv_connection_id conn_id;
 379         int ret = 0;
 380         int retries = 0;
 381         u32 usec = 1;
 382
 383         conn_id.asu32 = 0;
 384         conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
 385
 386         /*
 387          * hv_post_message() can have transient failures because of
 388          * insufficient resources. Retry the operation a couple of
 389          * times before giving up.
 390          */
 391         while (retries < 100) {
 392                 ret = hv_post_message(conn_id, 1, buffer, buflen);
 393
 394                 switch (ret) {
 395                 case HV_STATUS_INVALID_CONNECTION_ID:
 396                         /*
 397                          * We could get this if we send messages too
 398                          * frequently.
 399                          */
 400                         ret = -EAGAIN;
 401                         break;
 402                 case HV_STATUS_INSUFFICIENT_MEMORY:
 403                 case HV_STATUS_INSUFFICIENT_BUFFERS:
 404                         ret = -ENOBUFS;
 405                         break;
 406                 case HV_STATUS_SUCCESS:
 407                         return ret;
 408                 default:
 409                         pr_err("hv_post_msg() failed; error code:%d\n", ret);
 410                         return -EINVAL;
 411                 }
 412
 413                 retries++;
 414                 if (can_sleep && usec > 1000)
 415                         msleep(usec / 1000);
 416                 else if (usec < MAX_UDELAY_MS * 1000)
 417                         udelay(usec);
 418                 else
 419                         mdelay(usec / 1000);
 420
 421                 if (retries < 22)
 422                         usec *= 2;
 423         }
 424         return ret;
 425 }
 426
 427 /*
 428  * vmbus_set_event - Send an event notification to the parent
 429  */
 430 void vmbus_set_event(struct vmbus_channel *channel)
 431 {
 432         u32 child_relid = channel->offermsg.child_relid;
 433
 434         if (!channel->is_dedicated_interrupt)
 435                 vmbus_send_interrupt(child_relid);
 436
 437         ++channel->sig_events;
 438
 439         hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
 440 }
 441 EXPORT_SYMBOL_GPL(vmbus_set_event);