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                 msg->msg_vtl = ms_hyperv.vtl;
 102                 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
 103         } else {
 104                 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
 105                 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;
 106         }
 107
 108         /*
 109          * shared_gpa_boundary is zero in non-SNP VMs, so it's safe to always
 110          * bitwise OR it
 111          */
 112         msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]) |
 113                                 ms_hyperv.shared_gpa_boundary;
 114         msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]) |
 115                                 ms_hyperv.shared_gpa_boundary;
 116
 117         msg->target_vcpu = hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU);
 118
 119         /*
 120          * Add to list before we send the request since we may
 121          * receive the response before returning from this routine
 122          */
 123         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 124         list_add_tail(&msginfo->msglistentry,
 125                       &vmbus_connection.chn_msg_list);
 126
 127         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 128
 129         ret = vmbus_post_msg(msg,
 130                              sizeof(struct vmbus_channel_initiate_contact),
 131                              true);
 132
 133         trace_vmbus_negotiate_version(msg, ret);
 134
 135         if (ret != 0) {
 136                 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 137                 list_del(&msginfo->msglistentry);
 138                 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
 139                                         flags);
 140                 return ret;
 141         }
 142
 143         /* Wait for the connection response */
 144         wait_for_completion(&msginfo->waitevent);
 145
 146         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 147         list_del(&msginfo->msglistentry);
 148         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 149
 150         /* Check if successful */
 151         if (msginfo->response.version_response.version_supported) {
 152                 vmbus_connection.conn_state = CONNECTED;
 153
 154                 if (version >= VERSION_WIN10_V5)
 155                         vmbus_connection.msg_conn_id =
 156                                 msginfo->response.version_response.msg_conn_id;
 157         } else {
 158                 return -ECONNREFUSED;
 159         }
 160
 161         return ret;
 162 }
 163
 164 /*
 165  * vmbus_connect - Sends a connect request on the partition service connection
 166  */
 167 int vmbus_connect(void)
 168 {
 169         struct vmbus_channel_msginfo *msginfo = NULL;
 170         int i, ret = 0;
 171         __u32 version;
 172
 173         /* Initialize the vmbus connection */
 174         vmbus_connection.conn_state = CONNECTING;
 175         vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
 176         if (!vmbus_connection.work_queue) {
 177                 ret = -ENOMEM;
 178                 goto cleanup;
 179         }
 180
 181         vmbus_connection.rescind_work_queue =
 182                 create_workqueue("hv_vmbus_rescind");
 183         if (!vmbus_connection.rescind_work_queue) {
 184                 ret = -ENOMEM;
 185                 goto cleanup;
 186         }
 187         vmbus_connection.ignore_any_offer_msg = false;
 188
 189         vmbus_connection.handle_primary_chan_wq =
 190                 create_workqueue("hv_pri_chan");
 191         if (!vmbus_connection.handle_primary_chan_wq) {
 192                 ret = -ENOMEM;
 193                 goto cleanup;
 194         }
 195
 196         vmbus_connection.handle_sub_chan_wq =
 197                 create_workqueue("hv_sub_chan");
 198         if (!vmbus_connection.handle_sub_chan_wq) {
 199                 ret = -ENOMEM;
 200                 goto cleanup;
 201         }
 202
 203         INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
 204         spin_lock_init(&vmbus_connection.channelmsg_lock);
 205
 206         INIT_LIST_HEAD(&vmbus_connection.chn_list);
 207         mutex_init(&vmbus_connection.channel_mutex);
 208
 209         /*
 210          * Setup the vmbus event connection for channel interrupt
 211          * abstraction stuff
 212          */
 213         vmbus_connection.int_page = hv_alloc_hyperv_zeroed_page();
 214         if (vmbus_connection.int_page == NULL) {
 215                 ret = -ENOMEM;
 216                 goto cleanup;
 217         }
 218
 219         vmbus_connection.recv_int_page = vmbus_connection.int_page;
 220         vmbus_connection.send_int_page =
 221                 (void *)((unsigned long)vmbus_connection.int_page +
 222                         (HV_HYP_PAGE_SIZE >> 1));
 223
 224         /*
 225          * Setup the monitor notification facility. The 1st page for
 226          * parent->child and the 2nd page for child->parent
 227          */
 228         vmbus_connection.monitor_pages[0] = hv_alloc_hyperv_page();
 229         vmbus_connection.monitor_pages[1] = hv_alloc_hyperv_page();
 230         if ((vmbus_connection.monitor_pages[0] == NULL) ||
 231             (vmbus_connection.monitor_pages[1] == NULL)) {
 232                 ret = -ENOMEM;
 233                 goto cleanup;
 234         }
 235
 236         ret = set_memory_decrypted((unsigned long)
 237                                 vmbus_connection.monitor_pages[0], 1);
 238         ret |= set_memory_decrypted((unsigned long)
 239                                 vmbus_connection.monitor_pages[1], 1);
 240         if (ret)
 241                 goto cleanup;
 242
 243         /*
 244          * Set_memory_decrypted() will change the memory contents if
 245          * decryption occurs, so zero monitor pages here.
 246          */
 247         memset(vmbus_connection.monitor_pages[0], 0x00, HV_HYP_PAGE_SIZE);
 248         memset(vmbus_connection.monitor_pages[1], 0x00, HV_HYP_PAGE_SIZE);
 249
 250         msginfo = kzalloc(sizeof(*msginfo) +
 251                           sizeof(struct vmbus_channel_initiate_contact),
 252                           GFP_KERNEL);
 253         if (msginfo == NULL) {
 254                 ret = -ENOMEM;
 255                 goto cleanup;
 256         }
 257
 258         /*
 259          * Negotiate a compatible VMBUS version number with the
 260          * host. We start with the highest number we can support
 261          * and work our way down until we negotiate a compatible
 262          * version.
 263          */
 264
 265         for (i = 0; ; i++) {
 266                 if (i == ARRAY_SIZE(vmbus_versions)) {
 267                         ret = -EDOM;
 268                         goto cleanup;
 269                 }
 270
 271                 version = vmbus_versions[i];
 272                 if (version > max_version)
 273                         continue;
 274
 275                 ret = vmbus_negotiate_version(msginfo, version);
 276                 if (ret == -ETIMEDOUT)
 277                         goto cleanup;
 278
 279                 if (vmbus_connection.conn_state == CONNECTED)
 280                         break;
 281         }
 282
 283         if (hv_is_isolation_supported() && version < VERSION_WIN10_V5_2) {
 284                 pr_err("Invalid VMBus version %d.%d (expected >= %d.%d) from the host supporting isolation\n",
 285                        version >> 16, version & 0xFFFF, VERSION_WIN10_V5_2 >> 16, VERSION_WIN10_V5_2 & 0xFFFF);
 286                 ret = -EINVAL;
 287                 goto cleanup;
 288         }
 289
 290         vmbus_proto_version = version;
 291         pr_info("Vmbus version:%d.%d\n",
 292                 version >> 16, version & 0xFFFF);
 293
 294         vmbus_connection.channels = kcalloc(MAX_CHANNEL_RELIDS,
 295                                             sizeof(struct vmbus_channel *),
 296                                             GFP_KERNEL);
 297         if (vmbus_connection.channels == NULL) {
 298                 ret = -ENOMEM;
 299                 goto cleanup;
 300         }
 301
 302         kfree(msginfo);
 303         return 0;
 304
 305 cleanup:
 306         pr_err("Unable to connect to host\n");
 307
 308         vmbus_connection.conn_state = DISCONNECTED;
 309         vmbus_disconnect();
 310
 311         kfree(msginfo);
 312
 313         return ret;
 314 }
 315
 316 void vmbus_disconnect(void)
 317 {
 318         /*
 319          * First send the unload request to the host.
 320          */
 321         vmbus_initiate_unload(false);
 322
 323         if (vmbus_connection.handle_sub_chan_wq)
 324                 destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
 325
 326         if (vmbus_connection.handle_primary_chan_wq)
 327                 destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
 328
 329         if (vmbus_connection.rescind_work_queue)
 330                 destroy_workqueue(vmbus_connection.rescind_work_queue);
 331
 332         if (vmbus_connection.work_queue)
 333                 destroy_workqueue(vmbus_connection.work_queue);
 334
 335         if (vmbus_connection.int_page) {
 336                 hv_free_hyperv_page(vmbus_connection.int_page);
 337                 vmbus_connection.int_page = NULL;
 338         }
 339
 340         set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[0], 1);
 341         set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[1], 1);
 342
 343         hv_free_hyperv_page(vmbus_connection.monitor_pages[0]);
 344         hv_free_hyperv_page(vmbus_connection.monitor_pages[1]);
 345         vmbus_connection.monitor_pages[0] = NULL;
 346         vmbus_connection.monitor_pages[1] = NULL;
 347 }
 348
 349 /*
 350  * relid2channel - Get the channel object given its
 351  * child relative id (ie channel id)
 352  */
 353 struct vmbus_channel *relid2channel(u32 relid)
 354 {
 355         if (vmbus_connection.channels == NULL) {
 356                 pr_warn_once("relid2channel: relid=%d: No channels mapped!\n", relid);
 357                 return NULL;
 358         }
 359         if (WARN_ON(relid >= MAX_CHANNEL_RELIDS))
 360                 return NULL;
 361         return READ_ONCE(vmbus_connection.channels[relid]);
 362 }
 363
 364 /*
 365  * vmbus_on_event - Process a channel event notification
 366  *
 367  * For batched channels (default) optimize host to guest signaling
 368  * by ensuring:
 369  * 1. While reading the channel, we disable interrupts from host.
 370  * 2. Ensure that we process all posted messages from the host
 371  *    before returning from this callback.
 372  * 3. Once we return, enable signaling from the host. Once this
 373  *    state is set we check to see if additional packets are
 374  *    available to read. In this case we repeat the process.
 375  *    If this tasklet has been running for a long time
 376  *    then reschedule ourselves.
 377  */
 378 void vmbus_on_event(unsigned long data)
 379 {
 380         struct vmbus_channel *channel = (void *) data;
 381         void (*callback_fn)(void *context);
 382
 383         trace_vmbus_on_event(channel);
 384
 385         hv_debug_delay_test(channel, INTERRUPT_DELAY);
 386
 387         /* A channel once created is persistent even when
 388          * there is no driver handling the device. An
 389          * unloading driver sets the onchannel_callback to NULL.
 390          */
 391         callback_fn = READ_ONCE(channel->onchannel_callback);
 392         if (unlikely(!callback_fn))
 393                 return;
 394
 395         (*callback_fn)(channel->channel_callback_context);
 396
 397         if (channel->callback_mode != HV_CALL_BATCHED)
 398                 return;
 399
 400         if (likely(hv_end_read(&channel->inbound) == 0))
 401                 return;
 402
 403         hv_begin_read(&channel->inbound);
 404         tasklet_schedule(&channel->callback_event);
 405 }
 406
 407 /*
 408  * vmbus_post_msg - Send a msg on the vmbus's message connection
 409  */
 410 int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
 411 {
 412         struct vmbus_channel_message_header *hdr;
 413         union hv_connection_id conn_id;
 414         int ret = 0;
 415         int retries = 0;
 416         u32 usec = 1;
 417
 418         conn_id.asu32 = 0;
 419         conn_id.u.id = vmbus_connection.msg_conn_id;
 420
 421         /*
 422          * hv_post_message() can have transient failures because of
 423          * insufficient resources. Retry the operation a couple of
 424          * times before giving up.
 425          */
 426         while (retries < 100) {
 427                 ret = hv_post_message(conn_id, 1, buffer, buflen);
 428
 429                 switch (ret) {
 430                 case HV_STATUS_INVALID_CONNECTION_ID:
 431                         /*
 432                          * See vmbus_negotiate_version(): VMBus protocol 5.0
 433                          * and higher require that we must use
 434                          * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
 435                          * Contact message, but on old hosts that only
 436                          * support VMBus protocol 4.0 or lower, here we get
 437                          * HV_STATUS_INVALID_CONNECTION_ID and we should
 438                          * return an error immediately without retrying.
 439                          */
 440                         hdr = buffer;
 441                         if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)
 442                                 return -EINVAL;
 443                         /*
 444                          * We could get this if we send messages too
 445                          * frequently.
 446                          */
 447                         ret = -EAGAIN;
 448                         break;
 449                 case HV_STATUS_INSUFFICIENT_MEMORY:
 450                 case HV_STATUS_INSUFFICIENT_BUFFERS:
 451                         ret = -ENOBUFS;
 452                         break;
 453                 case HV_STATUS_SUCCESS:
 454                         return ret;
 455                 default:
 456                         pr_err("hv_post_msg() failed; error code:%d\n", ret);
 457                         return -EINVAL;
 458                 }
 459
 460                 retries++;
 461                 if (can_sleep && usec > 1000)
 462                         msleep(usec / 1000);
 463                 else if (usec < MAX_UDELAY_MS * 1000)
 464                         udelay(usec);
 465                 else
 466                         mdelay(usec / 1000);
 467
 468                 if (retries < 22)
 469                         usec *= 2;
 470         }
 471         return ret;
 472 }
 473
 474 /*
 475  * vmbus_set_event - Send an event notification to the parent
 476  */
 477 void vmbus_set_event(struct vmbus_channel *channel)
 478 {
 479         u32 child_relid = channel->offermsg.child_relid;
 480
 481         if (!channel->is_dedicated_interrupt)
 482                 vmbus_send_interrupt(child_relid);
 483
 484         ++channel->sig_events;
 485
 486         if (ms_hyperv.paravisor_present) {
 487                 if (hv_isolation_type_snp())
 488                         hv_ghcb_hypercall(HVCALL_SIGNAL_EVENT, &channel->sig_event,
 489                                           NULL, sizeof(channel->sig_event));
 490                 else if (hv_isolation_type_tdx())
 491                         hv_tdx_hypercall(HVCALL_SIGNAL_EVENT | HV_HYPERCALL_FAST_BIT,
 492                                          channel->sig_event, 0);
 493                 else
 494                         WARN_ON_ONCE(1);
 495         } else {
 496                 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
 497         }
 498 }
 499 EXPORT_SYMBOL_GPL(vmbus_set_event);