drivers/hv/connection.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *
   4  * Copyright (c) 2009, Microsoft Corporation.
   5  *
   6  * Authors:
   7  *   Haiyang Zhang <haiyangz@microsoft.com>
   8  *   Hank Janssen  <hjanssen@microsoft.com>
   9  */
  10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/kernel.h>
  13 #include <linux/sched.h>
  14 #include <linux/wait.h>
  15 #include <linux/delay.h>
  16 #include <linux/mm.h>
  17 #include <linux/module.h>
  18 #include <linux/slab.h>
  19 #include <linux/vmalloc.h>
  20 #include <linux/hyperv.h>
  21 #include <linux/export.h>
  22 #include <linux/io.h>
  23 #include <linux/set_memory.h>
  24 #include <asm/mshyperv.h>
  25
  26 #include "hyperv_vmbus.h"
  27
  28
  29 struct vmbus_connection vmbus_connection = {
  30         .conn_state             = DISCONNECTED,
  31         .unload_event           = COMPLETION_INITIALIZER(
  32                                   vmbus_connection.unload_event),
  33         .next_gpadl_handle      = ATOMIC_INIT(0xE1E10),
  34
  35         .ready_for_suspend_event = COMPLETION_INITIALIZER(
  36                                   vmbus_connection.ready_for_suspend_event),
  37         .ready_for_resume_event = COMPLETION_INITIALIZER(
  38                                   vmbus_connection.ready_for_resume_event),
  39 };
  40 EXPORT_SYMBOL_GPL(vmbus_connection);
  41
  42 /*
  43  * Negotiated protocol version with the host.
  44  */
  45 __u32 vmbus_proto_version;
  46 EXPORT_SYMBOL_GPL(vmbus_proto_version);
  47
  48 /*
  49  * Table of VMBus versions listed from newest to oldest.
  50  * VERSION_WIN7 and VERSION_WS2008 are no longer supported in
  51  * Linux guests and are not listed.
  52  */
  53 static __u32 vmbus_versions[] = {
  54         VERSION_WIN10_V5_3,
  55         VERSION_WIN10_V5_2,
  56         VERSION_WIN10_V5_1,
  57         VERSION_WIN10_V5,
  58         VERSION_WIN10_V4_1,
  59         VERSION_WIN10,
  60         VERSION_WIN8_1,
  61         VERSION_WIN8
  62 };
  63
  64 /*
  65  * Maximal VMBus protocol version guests can negotiate.  Useful to cap the
  66  * VMBus version for testing and debugging purpose.
  67  */
  68 static uint max_version = VERSION_WIN10_V5_3;
  69
  70 module_param(max_version, uint, S_IRUGO);
  71 MODULE_PARM_DESC(max_version,
  72                  "Maximal VMBus protocol version which can be negotiated");
  73
  74 int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
  75 {
  76         int ret = 0;
  77         struct vmbus_channel_initiate_contact *msg;
  78         unsigned long flags;
  79
  80         init_completion(&msginfo->waitevent);
  81
  82         msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
  83
  84         memset(msg, 0, sizeof(*msg));
  85         msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
  86         msg->vmbus_version_requested = version;
  87
  88         /*
  89          * VMBus protocol 5.0 (VERSION_WIN10_V5) and higher require that we must
  90          * use VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
  91          * and for subsequent messages, we must use the Message Connection ID
  92          * field in the host-returned Version Response Message. And, with
  93          * VERSION_WIN10_V5 and higher, we don't use msg->interrupt_page, but we
  94          * tell the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
  95          * compatibility.
  96          *
  97          * On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).
  98          */
  99         if (version >= VERSION_WIN10_V5) {
 100                 msg->msg_sint = VMBUS_MESSAGE_SINT;
 101                 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
 102         } else {
 103                 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
 104                 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;
 105         }
 106
 107         msg->monitor_page1 = vmbus_connection.monitor_pages_pa[0];
 108         msg->monitor_page2 = vmbus_connection.monitor_pages_pa[1];
 109
 110         msg->target_vcpu = hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU);
 111
 112         /*
 113          * Add to list before we send the request since we may
 114          * receive the response before returning from this routine
 115          */
 116         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 117         list_add_tail(&msginfo->msglistentry,
 118                       &vmbus_connection.chn_msg_list);
 119
 120         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 121
 122         ret = vmbus_post_msg(msg,
 123                              sizeof(struct vmbus_channel_initiate_contact),
 124                              true);
 125
 126         trace_vmbus_negotiate_version(msg, ret);
 127
 128         if (ret != 0) {
 129                 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 130                 list_del(&msginfo->msglistentry);
 131                 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
 132                                         flags);
 133                 return ret;
 134         }
 135
 136         /* Wait for the connection response */
 137         wait_for_completion(&msginfo->waitevent);
 138
 139         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 140         list_del(&msginfo->msglistentry);
 141         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 142
 143         /* Check if successful */
 144         if (msginfo->response.version_response.version_supported) {
 145                 vmbus_connection.conn_state = CONNECTED;
 146
 147                 if (version >= VERSION_WIN10_V5)
 148                         vmbus_connection.msg_conn_id =
 149                                 msginfo->response.version_response.msg_conn_id;
 150         } else {
 151                 return -ECONNREFUSED;
 152         }
 153
 154         return ret;
 155 }
 156
 157 /*
 158  * vmbus_connect - Sends a connect request on the partition service connection
 159  */
 160 int vmbus_connect(void)
 161 {
 162         struct vmbus_channel_msginfo *msginfo = NULL;
 163         int i, ret = 0;
 164         __u32 version;
 165
 166         /* Initialize the vmbus connection */
 167         vmbus_connection.conn_state = CONNECTING;
 168         vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
 169         if (!vmbus_connection.work_queue) {
 170                 ret = -ENOMEM;
 171                 goto cleanup;
 172         }
 173
 174         vmbus_connection.handle_primary_chan_wq =
 175                 create_workqueue("hv_pri_chan");
 176         if (!vmbus_connection.handle_primary_chan_wq) {
 177                 ret = -ENOMEM;
 178                 goto cleanup;
 179         }
 180
 181         vmbus_connection.handle_sub_chan_wq =
 182                 create_workqueue("hv_sub_chan");
 183         if (!vmbus_connection.handle_sub_chan_wq) {
 184                 ret = -ENOMEM;
 185                 goto cleanup;
 186         }
 187
 188         INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
 189         spin_lock_init(&vmbus_connection.channelmsg_lock);
 190
 191         INIT_LIST_HEAD(&vmbus_connection.chn_list);
 192         mutex_init(&vmbus_connection.channel_mutex);
 193
 194         /*
 195          * Setup the vmbus event connection for channel interrupt
 196          * abstraction stuff
 197          */
 198         vmbus_connection.int_page =
 199         (void *)hv_alloc_hyperv_zeroed_page();
 200         if (vmbus_connection.int_page == NULL) {
 201                 ret = -ENOMEM;
 202                 goto cleanup;
 203         }
 204
 205         vmbus_connection.recv_int_page = vmbus_connection.int_page;
 206         vmbus_connection.send_int_page =
 207                 (void *)((unsigned long)vmbus_connection.int_page +
 208                         (HV_HYP_PAGE_SIZE >> 1));
 209
 210         /*
 211          * Setup the monitor notification facility. The 1st page for
 212          * parent->child and the 2nd page for child->parent
 213          */
 214         vmbus_connection.monitor_pages[0] = (void *)hv_alloc_hyperv_zeroed_page();
 215         vmbus_connection.monitor_pages[1] = (void *)hv_alloc_hyperv_zeroed_page();
 216         if ((vmbus_connection.monitor_pages[0] == NULL) ||
 217             (vmbus_connection.monitor_pages[1] == NULL)) {
 218                 ret = -ENOMEM;
 219                 goto cleanup;
 220         }
 221
 222         vmbus_connection.monitor_pages_original[0]
 223                 = vmbus_connection.monitor_pages[0];
 224         vmbus_connection.monitor_pages_original[1]
 225                 = vmbus_connection.monitor_pages[1];
 226         vmbus_connection.monitor_pages_pa[0]
 227                 = virt_to_phys(vmbus_connection.monitor_pages[0]);
 228         vmbus_connection.monitor_pages_pa[1]
 229                 = virt_to_phys(vmbus_connection.monitor_pages[1]);
 230
 231         if (hv_is_isolation_supported()) {
 232                 ret = set_memory_decrypted((unsigned long)
 233                                            vmbus_connection.monitor_pages[0],
 234                                            1);
 235                 ret |= set_memory_decrypted((unsigned long)
 236                                             vmbus_connection.monitor_pages[1],
 237                                             1);
 238                 if (ret)
 239                         goto cleanup;
 240
 241                 /*
 242                  * Isolation VM with AMD SNP needs to access monitor page via
 243                  * address space above shared gpa boundary.
 244                  */
 245                 if (hv_isolation_type_snp()) {
 246                         vmbus_connection.monitor_pages_pa[0] +=
 247                                 ms_hyperv.shared_gpa_boundary;
 248                         vmbus_connection.monitor_pages_pa[1] +=
 249                                 ms_hyperv.shared_gpa_boundary;
 250
 251                         vmbus_connection.monitor_pages[0]
 252                                 = memremap(vmbus_connection.monitor_pages_pa[0],
 253                                            HV_HYP_PAGE_SIZE,
 254                                            MEMREMAP_WB);
 255                         if (!vmbus_connection.monitor_pages[0]) {
 256                                 ret = -ENOMEM;
 257                                 goto cleanup;
 258                         }
 259
 260                         vmbus_connection.monitor_pages[1]
 261                                 = memremap(vmbus_connection.monitor_pages_pa[1],
 262                                            HV_HYP_PAGE_SIZE,
 263                                            MEMREMAP_WB);
 264                         if (!vmbus_connection.monitor_pages[1]) {
 265                                 ret = -ENOMEM;
 266                                 goto cleanup;
 267                         }
 268                 }
 269
 270                 /*
 271                  * Set memory host visibility hvcall smears memory
 272                  * and so zero monitor pages here.
 273                  */
 274                 memset(vmbus_connection.monitor_pages[0], 0x00,
 275                        HV_HYP_PAGE_SIZE);
 276                 memset(vmbus_connection.monitor_pages[1], 0x00,
 277                        HV_HYP_PAGE_SIZE);
 278
 279         }
 280
 281         msginfo = kzalloc(sizeof(*msginfo) +
 282                           sizeof(struct vmbus_channel_initiate_contact),
 283                           GFP_KERNEL);
 284         if (msginfo == NULL) {
 285                 ret = -ENOMEM;
 286                 goto cleanup;
 287         }
 288
 289         /*
 290          * Negotiate a compatible VMBUS version number with the
 291          * host. We start with the highest number we can support
 292          * and work our way down until we negotiate a compatible
 293          * version.
 294          */
 295
 296         for (i = 0; ; i++) {
 297                 if (i == ARRAY_SIZE(vmbus_versions)) {
 298                         ret = -EDOM;
 299                         goto cleanup;
 300                 }
 301
 302                 version = vmbus_versions[i];
 303                 if (version > max_version)
 304                         continue;
 305
 306                 ret = vmbus_negotiate_version(msginfo, version);
 307                 if (ret == -ETIMEDOUT)
 308                         goto cleanup;
 309
 310                 if (vmbus_connection.conn_state == CONNECTED)
 311                         break;
 312         }
 313
 314         if (hv_is_isolation_supported() && version < VERSION_WIN10_V5_2) {
 315                 pr_err("Invalid VMBus version %d.%d (expected >= %d.%d) from the host supporting isolation\n",
 316                        version >> 16, version & 0xFFFF, VERSION_WIN10_V5_2 >> 16, VERSION_WIN10_V5_2 & 0xFFFF);
 317                 ret = -EINVAL;
 318                 goto cleanup;
 319         }
 320
 321         vmbus_proto_version = version;
 322         pr_info("Vmbus version:%d.%d\n",
 323                 version >> 16, version & 0xFFFF);
 324
 325         vmbus_connection.channels = kcalloc(MAX_CHANNEL_RELIDS,
 326                                             sizeof(struct vmbus_channel *),
 327                                             GFP_KERNEL);
 328         if (vmbus_connection.channels == NULL) {
 329                 ret = -ENOMEM;
 330                 goto cleanup;
 331         }
 332
 333         kfree(msginfo);
 334         return 0;
 335
 336 cleanup:
 337         pr_err("Unable to connect to host\n");
 338
 339         vmbus_connection.conn_state = DISCONNECTED;
 340         vmbus_disconnect();
 341
 342         kfree(msginfo);
 343
 344         return ret;
 345 }
 346
 347 void vmbus_disconnect(void)
 348 {
 349         /*
 350          * First send the unload request to the host.
 351          */
 352         vmbus_initiate_unload(false);
 353
 354         if (vmbus_connection.handle_sub_chan_wq)
 355                 destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
 356
 357         if (vmbus_connection.handle_primary_chan_wq)
 358                 destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
 359
 360         if (vmbus_connection.work_queue)
 361                 destroy_workqueue(vmbus_connection.work_queue);
 362
 363         if (vmbus_connection.int_page) {
 364                 hv_free_hyperv_page((unsigned long)vmbus_connection.int_page);
 365                 vmbus_connection.int_page = NULL;
 366         }
 367
 368         if (hv_is_isolation_supported()) {
 369                 /*
 370                  * memunmap() checks input address is ioremap address or not
 371                  * inside. It doesn't unmap any thing in the non-SNP CVM and
 372                  * so not check CVM type here.
 373                  */
 374                 memunmap(vmbus_connection.monitor_pages[0]);
 375                 memunmap(vmbus_connection.monitor_pages[1]);
 376
 377                 set_memory_encrypted((unsigned long)
 378                         vmbus_connection.monitor_pages_original[0],
 379                         1);
 380                 set_memory_encrypted((unsigned long)
 381                         vmbus_connection.monitor_pages_original[1],
 382                         1);
 383         }
 384
 385         hv_free_hyperv_page((unsigned long)
 386                 vmbus_connection.monitor_pages_original[0]);
 387         hv_free_hyperv_page((unsigned long)
 388                 vmbus_connection.monitor_pages_original[1]);
 389         vmbus_connection.monitor_pages_original[0] =
 390                 vmbus_connection.monitor_pages[0] = NULL;
 391         vmbus_connection.monitor_pages_original[1] =
 392                 vmbus_connection.monitor_pages[1] = NULL;
 393 }
 394
 395 /*
 396  * relid2channel - Get the channel object given its
 397  * child relative id (ie channel id)
 398  */
 399 struct vmbus_channel *relid2channel(u32 relid)
 400 {
 401         if (WARN_ON(relid >= MAX_CHANNEL_RELIDS))
 402                 return NULL;
 403         return READ_ONCE(vmbus_connection.channels[relid]);
 404 }
 405
 406 /*
 407  * vmbus_on_event - Process a channel event notification
 408  *
 409  * For batched channels (default) optimize host to guest signaling
 410  * by ensuring:
 411  * 1. While reading the channel, we disable interrupts from host.
 412  * 2. Ensure that we process all posted messages from the host
 413  *    before returning from this callback.
 414  * 3. Once we return, enable signaling from the host. Once this
 415  *    state is set we check to see if additional packets are
 416  *    available to read. In this case we repeat the process.
 417  *    If this tasklet has been running for a long time
 418  *    then reschedule ourselves.
 419  */
 420 void vmbus_on_event(unsigned long data)
 421 {
 422         struct vmbus_channel *channel = (void *) data;
 423         unsigned long time_limit = jiffies + 2;
 424
 425         trace_vmbus_on_event(channel);
 426
 427         hv_debug_delay_test(channel, INTERRUPT_DELAY);
 428         do {
 429                 void (*callback_fn)(void *);
 430
 431                 /* A channel once created is persistent even when
 432                  * there is no driver handling the device. An
 433                  * unloading driver sets the onchannel_callback to NULL.
 434                  */
 435                 callback_fn = READ_ONCE(channel->onchannel_callback);
 436                 if (unlikely(callback_fn == NULL))
 437                         return;
 438
 439                 (*callback_fn)(channel->channel_callback_context);
 440
 441                 if (channel->callback_mode != HV_CALL_BATCHED)
 442                         return;
 443
 444                 if (likely(hv_end_read(&channel->inbound) == 0))
 445                         return;
 446
 447                 hv_begin_read(&channel->inbound);
 448         } while (likely(time_before(jiffies, time_limit)));
 449
 450         /* The time limit (2 jiffies) has been reached */
 451         tasklet_schedule(&channel->callback_event);
 452 }
 453
 454 /*
 455  * vmbus_post_msg - Send a msg on the vmbus's message connection
 456  */
 457 int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
 458 {
 459         struct vmbus_channel_message_header *hdr;
 460         union hv_connection_id conn_id;
 461         int ret = 0;
 462         int retries = 0;
 463         u32 usec = 1;
 464
 465         conn_id.asu32 = 0;
 466         conn_id.u.id = vmbus_connection.msg_conn_id;
 467
 468         /*
 469          * hv_post_message() can have transient failures because of
 470          * insufficient resources. Retry the operation a couple of
 471          * times before giving up.
 472          */
 473         while (retries < 100) {
 474                 ret = hv_post_message(conn_id, 1, buffer, buflen);
 475
 476                 switch (ret) {
 477                 case HV_STATUS_INVALID_CONNECTION_ID:
 478                         /*
 479                          * See vmbus_negotiate_version(): VMBus protocol 5.0
 480                          * and higher require that we must use
 481                          * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
 482                          * Contact message, but on old hosts that only
 483                          * support VMBus protocol 4.0 or lower, here we get
 484                          * HV_STATUS_INVALID_CONNECTION_ID and we should
 485                          * return an error immediately without retrying.
 486                          */
 487                         hdr = buffer;
 488                         if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)
 489                                 return -EINVAL;
 490                         /*
 491                          * We could get this if we send messages too
 492                          * frequently.
 493                          */
 494                         ret = -EAGAIN;
 495                         break;
 496                 case HV_STATUS_INSUFFICIENT_MEMORY:
 497                 case HV_STATUS_INSUFFICIENT_BUFFERS:
 498                         ret = -ENOBUFS;
 499                         break;
 500                 case HV_STATUS_SUCCESS:
 501                         return ret;
 502                 default:
 503                         pr_err("hv_post_msg() failed; error code:%d\n", ret);
 504                         return -EINVAL;
 505                 }
 506
 507                 retries++;
 508                 if (can_sleep && usec > 1000)
 509                         msleep(usec / 1000);
 510                 else if (usec < MAX_UDELAY_MS * 1000)
 511                         udelay(usec);
 512                 else
 513                         mdelay(usec / 1000);
 514
 515                 if (retries < 22)
 516                         usec *= 2;
 517         }
 518         return ret;
 519 }
 520
 521 /*
 522  * vmbus_set_event - Send an event notification to the parent
 523  */
 524 void vmbus_set_event(struct vmbus_channel *channel)
 525 {
 526         u32 child_relid = channel->offermsg.child_relid;
 527
 528         if (!channel->is_dedicated_interrupt)
 529                 vmbus_send_interrupt(child_relid);
 530
 531         ++channel->sig_events;
 532
 533         if (hv_isolation_type_snp())
 534                 hv_ghcb_hypercall(HVCALL_SIGNAL_EVENT, &channel->sig_event,
 535                                 NULL, sizeof(channel->sig_event));
 536         else
 537                 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
 538 }
 539 EXPORT_SYMBOL_GPL(vmbus_set_event);