drivers/misc/vmw_vmci/vmci

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This source file includes following definitions.
ctx_signal_notify
ctx_clear_notify
ctx_clear_notify_call
vmci_ctx_check_signal_notify
vmci_ctx_create
vmci_ctx_destroy
ctx_fire_notification
vmci_ctx_pending_datagrams
vmci_ctx_enqueue_datagram
vmci_ctx_exists
vmci_ctx_get
ctx_free_ctx
vmci_ctx_put
vmci_ctx_dequeue_datagram
vmci_ctx_unset_notify
vmci_ctx_add_notification
vmci_ctx_remove_notification
vmci_ctx_get_chkpt_notifiers
vmci_ctx_get_chkpt_doorbells
vmci_ctx_get_chkpt_state
vmci_ctx_set_chkpt_state
vmci_ctx_rcv_notifications_get
vmci_ctx_rcv_notifications_release
vmci_ctx_dbell_create
vmci_ctx_dbell_destroy
vmci_ctx_dbell_destroy_all
vmci_ctx_notify_dbell
vmci_ctx_supports_host_qp
vmci_ctx_qp_create
vmci_ctx_qp_destroy
vmci_ctx_qp_exists
vmci_context_get_priv_flags
vmci_is_context_owner
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * VMware VMCI Driver
   4  *
   5  * Copyright (C) 2012 VMware, Inc. All rights reserved.
   6  */
   7 
   8 #include <linux/vmw_vmci_defs.h>
   9 #include <linux/vmw_vmci_api.h>
  10 #include <linux/highmem.h>
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/sched.h>
  14 #include <linux/cred.h>
  15 #include <linux/slab.h>
  16 
  17 #include "vmci_queue_pair.h"
  18 #include "vmci_datagram.h"
  19 #include "vmci_doorbell.h"
  20 #include "vmci_context.h"
  21 #include "vmci_driver.h"
  22 #include "vmci_event.h"
  23 
  24 /* Use a wide upper bound for the maximum contexts. */
  25 #define VMCI_MAX_CONTEXTS 2000
  26 
  27 /*
  28  * List of current VMCI contexts.  Contexts can be added by
  29  * vmci_ctx_create() and removed via vmci_ctx_destroy().
  30  * These, along with context lookup, are protected by the
  31  * list structure's lock.
  32  */
  33 static struct {
  34         struct list_head head;
  35         spinlock_t lock; /* Spinlock for context list operations */
  36 } ctx_list = {
  37         .head = LIST_HEAD_INIT(ctx_list.head),
  38         .lock = __SPIN_LOCK_UNLOCKED(ctx_list.lock),
  39 };
  40 
  41 /* Used by contexts that did not set up notify flag pointers */
  42 static bool ctx_dummy_notify;
  43 
  44 static void ctx_signal_notify(struct vmci_ctx *context)
  45 {
  46         *context->notify = true;
  47 }
  48 
  49 static void ctx_clear_notify(struct vmci_ctx *context)
  50 {
  51         *context->notify = false;
  52 }
  53 
  54 /*
  55  * If nothing requires the attention of the guest, clears both
  56  * notify flag and call.
  57  */
  58 static void ctx_clear_notify_call(struct vmci_ctx *context)
  59 {
  60         if (context->pending_datagrams == 0 &&
  61             vmci_handle_arr_get_size(context->pending_doorbell_array) == 0)
  62                 ctx_clear_notify(context);
  63 }
  64 
  65 /*
  66  * Sets the context's notify flag iff datagrams are pending for this
  67  * context.  Called from vmci_setup_notify().
  68  */
  69 void vmci_ctx_check_signal_notify(struct vmci_ctx *context)
  70 {
  71         spin_lock(&context->lock);
  72         if (context->pending_datagrams)
  73                 ctx_signal_notify(context);
  74         spin_unlock(&context->lock);
  75 }
  76 
  77 /*
  78  * Allocates and initializes a VMCI context.
  79  */
  80 struct vmci_ctx *vmci_ctx_create(u32 cid, u32 priv_flags,
  81                                  uintptr_t event_hnd,
  82                                  int user_version,
  83                                  const struct cred *cred)
  84 {
  85         struct vmci_ctx *context;
  86         int error;
  87 
  88         if (cid == VMCI_INVALID_ID) {
  89                 pr_devel("Invalid context ID for VMCI context\n");
  90                 error = -EINVAL;
  91                 goto err_out;
  92         }
  93 
  94         if (priv_flags & ~VMCI_PRIVILEGE_ALL_FLAGS) {
  95                 pr_devel("Invalid flag (flags=0x%x) for VMCI context\n",
  96                          priv_flags);
  97                 error = -EINVAL;
  98                 goto err_out;
  99         }
 100 
 101         if (user_version == 0) {
 102                 pr_devel("Invalid suer_version %d\n", user_version);
 103                 error = -EINVAL;
 104                 goto err_out;
 105         }
 106 
 107         context = kzalloc(sizeof(*context), GFP_KERNEL);
 108         if (!context) {
 109                 pr_warn("Failed to allocate memory for VMCI context\n");
 110                 error = -EINVAL;
 111                 goto err_out;
 112         }
 113 
 114         kref_init(&context->kref);
 115         spin_lock_init(&context->lock);
 116         INIT_LIST_HEAD(&context->list_item);
 117         INIT_LIST_HEAD(&context->datagram_queue);
 118         INIT_LIST_HEAD(&context->notifier_list);
 119 
 120         /* Initialize host-specific VMCI context. */
 121         init_waitqueue_head(&context->host_context.wait_queue);
 122 
 123         context->queue_pair_array =
 124                 vmci_handle_arr_create(0, VMCI_MAX_GUEST_QP_COUNT);
 125         if (!context->queue_pair_array) {
 126                 error = -ENOMEM;
 127                 goto err_free_ctx;
 128         }
 129 
 130         context->doorbell_array =
 131                 vmci_handle_arr_create(0, VMCI_MAX_GUEST_DOORBELL_COUNT);
 132         if (!context->doorbell_array) {
 133                 error = -ENOMEM;
 134                 goto err_free_qp_array;
 135         }
 136 
 137         context->pending_doorbell_array =
 138                 vmci_handle_arr_create(0, VMCI_MAX_GUEST_DOORBELL_COUNT);
 139         if (!context->pending_doorbell_array) {
 140                 error = -ENOMEM;
 141                 goto err_free_db_array;
 142         }
 143 
 144         context->user_version = user_version;
 145 
 146         context->priv_flags = priv_flags;
 147 
 148         if (cred)
 149                 context->cred = get_cred(cred);
 150 
 151         context->notify = &ctx_dummy_notify;
 152         context->notify_page = NULL;
 153 
 154         /*
 155          * If we collide with an existing context we generate a new
 156          * and use it instead. The VMX will determine if regeneration
 157          * is okay. Since there isn't 4B - 16 VMs running on a given
 158          * host, the below loop will terminate.
 159          */
 160         spin_lock(&ctx_list.lock);
 161 
 162         while (vmci_ctx_exists(cid)) {
 163                 /* We reserve the lowest 16 ids for fixed contexts. */
 164                 cid = max(cid, VMCI_RESERVED_CID_LIMIT - 1) + 1;
 165                 if (cid == VMCI_INVALID_ID)
 166                         cid = VMCI_RESERVED_CID_LIMIT;
 167         }
 168         context->cid = cid;
 169 
 170         list_add_tail_rcu(&context->list_item, &ctx_list.head);
 171         spin_unlock(&ctx_list.lock);
 172 
 173         return context;
 174 
 175  err_free_db_array:
 176         vmci_handle_arr_destroy(context->doorbell_array);
 177  err_free_qp_array:
 178         vmci_handle_arr_destroy(context->queue_pair_array);
 179  err_free_ctx:
 180         kfree(context);
 181  err_out:
 182         return ERR_PTR(error);
 183 }
 184 
 185 /*
 186  * Destroy VMCI context.
 187  */
 188 void vmci_ctx_destroy(struct vmci_ctx *context)
 189 {
 190         spin_lock(&ctx_list.lock);
 191         list_del_rcu(&context->list_item);
 192         spin_unlock(&ctx_list.lock);
 193         synchronize_rcu();
 194 
 195         vmci_ctx_put(context);
 196 }
 197 
 198 /*
 199  * Fire notification for all contexts interested in given cid.
 200  */
 201 static int ctx_fire_notification(u32 context_id, u32 priv_flags)
 202 {
 203         u32 i, array_size;
 204         struct vmci_ctx *sub_ctx;
 205         struct vmci_handle_arr *subscriber_array;
 206         struct vmci_handle context_handle =
 207                 vmci_make_handle(context_id, VMCI_EVENT_HANDLER);
 208 
 209         /*
 210          * We create an array to hold the subscribers we find when
 211          * scanning through all contexts.
 212          */
 213         subscriber_array = vmci_handle_arr_create(0, VMCI_MAX_CONTEXTS);
 214         if (subscriber_array == NULL)
 215                 return VMCI_ERROR_NO_MEM;
 216 
 217         /*
 218          * Scan all contexts to find who is interested in being
 219          * notified about given contextID.
 220          */
 221         rcu_read_lock();
 222         list_for_each_entry_rcu(sub_ctx, &ctx_list.head, list_item) {
 223                 struct vmci_handle_list *node;
 224 
 225                 /*
 226                  * We only deliver notifications of the removal of
 227                  * contexts, if the two contexts are allowed to
 228                  * interact.
 229                  */
 230                 if (vmci_deny_interaction(priv_flags, sub_ctx->priv_flags))
 231                         continue;
 232 
 233                 list_for_each_entry_rcu(node, &sub_ctx->notifier_list, node) {
 234                         if (!vmci_handle_is_equal(node->handle, context_handle))
 235                                 continue;
 236 
 237                         vmci_handle_arr_append_entry(&subscriber_array,
 238                                         vmci_make_handle(sub_ctx->cid,
 239                                                          VMCI_EVENT_HANDLER));
 240                 }
 241         }
 242         rcu_read_unlock();
 243 
 244         /* Fire event to all subscribers. */
 245         array_size = vmci_handle_arr_get_size(subscriber_array);
 246         for (i = 0; i < array_size; i++) {
 247                 int result;
 248                 struct vmci_event_ctx ev;
 249 
 250                 ev.msg.hdr.dst = vmci_handle_arr_get_entry(subscriber_array, i);
 251                 ev.msg.hdr.src = vmci_make_handle(VMCI_HYPERVISOR_CONTEXT_ID,
 252                                                   VMCI_CONTEXT_RESOURCE_ID);
 253                 ev.msg.hdr.payload_size = sizeof(ev) - sizeof(ev.msg.hdr);
 254                 ev.msg.event_data.event = VMCI_EVENT_CTX_REMOVED;
 255                 ev.payload.context_id = context_id;
 256 
 257                 result = vmci_datagram_dispatch(VMCI_HYPERVISOR_CONTEXT_ID,
 258                                                 &ev.msg.hdr, false);
 259                 if (result < VMCI_SUCCESS) {
 260                         pr_devel("Failed to enqueue event datagram (type=%d) for context (ID=0x%x)\n",
 261                                  ev.msg.event_data.event,
 262                                  ev.msg.hdr.dst.context);
 263                         /* We continue to enqueue on next subscriber. */
 264                 }
 265         }
 266         vmci_handle_arr_destroy(subscriber_array);
 267 
 268         return VMCI_SUCCESS;
 269 }
 270 
 271 /*
 272  * Returns the current number of pending datagrams. The call may
 273  * also serve as a synchronization point for the datagram queue,
 274  * as no enqueue operations can occur concurrently.
 275  */
 276 int vmci_ctx_pending_datagrams(u32 cid, u32 *pending)
 277 {
 278         struct vmci_ctx *context;
 279 
 280         context = vmci_ctx_get(cid);
 281         if (context == NULL)
 282                 return VMCI_ERROR_INVALID_ARGS;
 283 
 284         spin_lock(&context->lock);
 285         if (pending)
 286                 *pending = context->pending_datagrams;
 287         spin_unlock(&context->lock);
 288         vmci_ctx_put(context);
 289 
 290         return VMCI_SUCCESS;
 291 }
 292 
 293 /*
 294  * Queues a VMCI datagram for the appropriate target VM context.
 295  */
 296 int vmci_ctx_enqueue_datagram(u32 cid, struct vmci_datagram *dg)
 297 {
 298         struct vmci_datagram_queue_entry *dq_entry;
 299         struct vmci_ctx *context;
 300         struct vmci_handle dg_src;
 301         size_t vmci_dg_size;
 302 
 303         vmci_dg_size = VMCI_DG_SIZE(dg);
 304         if (vmci_dg_size > VMCI_MAX_DG_SIZE) {
 305                 pr_devel("Datagram too large (bytes=%zu)\n", vmci_dg_size);
 306                 return VMCI_ERROR_INVALID_ARGS;
 307         }
 308 
 309         /* Get the target VM's VMCI context. */
 310         context = vmci_ctx_get(cid);
 311         if (!context) {
 312                 pr_devel("Invalid context (ID=0x%x)\n", cid);
 313                 return VMCI_ERROR_INVALID_ARGS;
 314         }
 315 
 316         /* Allocate guest call entry and add it to the target VM's queue. */
 317         dq_entry = kmalloc(sizeof(*dq_entry), GFP_KERNEL);
 318         if (dq_entry == NULL) {
 319                 pr_warn("Failed to allocate memory for datagram\n");
 320                 vmci_ctx_put(context);
 321                 return VMCI_ERROR_NO_MEM;
 322         }
 323         dq_entry->dg = dg;
 324         dq_entry->dg_size = vmci_dg_size;
 325         dg_src = dg->src;
 326         INIT_LIST_HEAD(&dq_entry->list_item);
 327 
 328         spin_lock(&context->lock);
 329 
 330         /*
 331          * We put a higher limit on datagrams from the hypervisor.  If
 332          * the pending datagram is not from hypervisor, then we check
 333          * if enqueueing it would exceed the
 334          * VMCI_MAX_DATAGRAM_QUEUE_SIZE limit on the destination.  If
 335          * the pending datagram is from hypervisor, we allow it to be
 336          * queued at the destination side provided we don't reach the
 337          * VMCI_MAX_DATAGRAM_AND_EVENT_QUEUE_SIZE limit.
 338          */
 339         if (context->datagram_queue_size + vmci_dg_size >=
 340             VMCI_MAX_DATAGRAM_QUEUE_SIZE &&
 341             (!vmci_handle_is_equal(dg_src,
 342                                 vmci_make_handle
 343                                 (VMCI_HYPERVISOR_CONTEXT_ID,
 344                                  VMCI_CONTEXT_RESOURCE_ID)) ||
 345              context->datagram_queue_size + vmci_dg_size >=
 346              VMCI_MAX_DATAGRAM_AND_EVENT_QUEUE_SIZE)) {
 347                 spin_unlock(&context->lock);
 348                 vmci_ctx_put(context);
 349                 kfree(dq_entry);
 350                 pr_devel("Context (ID=0x%x) receive queue is full\n", cid);
 351                 return VMCI_ERROR_NO_RESOURCES;
 352         }
 353 
 354         list_add(&dq_entry->list_item, &context->datagram_queue);
 355         context->pending_datagrams++;
 356         context->datagram_queue_size += vmci_dg_size;
 357         ctx_signal_notify(context);
 358         wake_up(&context->host_context.wait_queue);
 359         spin_unlock(&context->lock);
 360         vmci_ctx_put(context);
 361 
 362         return vmci_dg_size;
 363 }
 364 
 365 /*
 366  * Verifies whether a context with the specified context ID exists.
 367  * FIXME: utility is dubious as no decisions can be reliably made
 368  * using this data as context can appear and disappear at any time.
 369  */
 370 bool vmci_ctx_exists(u32 cid)
 371 {
 372         struct vmci_ctx *context;
 373         bool exists = false;
 374 
 375         rcu_read_lock();
 376 
 377         list_for_each_entry_rcu(context, &ctx_list.head, list_item) {
 378                 if (context->cid == cid) {
 379                         exists = true;
 380                         break;
 381                 }
 382         }
 383 
 384         rcu_read_unlock();
 385         return exists;
 386 }
 387 
 388 /*
 389  * Retrieves VMCI context corresponding to the given cid.
 390  */
 391 struct vmci_ctx *vmci_ctx_get(u32 cid)
 392 {
 393         struct vmci_ctx *c, *context = NULL;
 394 
 395         if (cid == VMCI_INVALID_ID)
 396                 return NULL;
 397 
 398         rcu_read_lock();
 399         list_for_each_entry_rcu(c, &ctx_list.head, list_item) {
 400                 if (c->cid == cid) {
 401                         /*
 402                          * The context owner drops its own reference to the
 403                          * context only after removing it from the list and
 404                          * waiting for RCU grace period to expire. This
 405                          * means that we are not about to increase the
 406                          * reference count of something that is in the
 407                          * process of being destroyed.
 408                          */
 409                         context = c;
 410                         kref_get(&context->kref);
 411                         break;
 412                 }
 413         }
 414         rcu_read_unlock();
 415 
 416         return context;
 417 }
 418 
 419 /*
 420  * Deallocates all parts of a context data structure. This
 421  * function doesn't lock the context, because it assumes that
 422  * the caller was holding the last reference to context.
 423  */
 424 static void ctx_free_ctx(struct kref *kref)
 425 {
 426         struct vmci_ctx *context = container_of(kref, struct vmci_ctx, kref);
 427         struct vmci_datagram_queue_entry *dq_entry, *dq_entry_tmp;
 428         struct vmci_handle temp_handle;
 429         struct vmci_handle_list *notifier, *tmp;
 430 
 431         /*
 432          * Fire event to all contexts interested in knowing this
 433          * context is dying.
 434          */
 435         ctx_fire_notification(context->cid, context->priv_flags);
 436 
 437         /*
 438          * Cleanup all queue pair resources attached to context.  If
 439          * the VM dies without cleaning up, this code will make sure
 440          * that no resources are leaked.
 441          */
 442         temp_handle = vmci_handle_arr_get_entry(context->queue_pair_array, 0);
 443         while (!vmci_handle_is_equal(temp_handle, VMCI_INVALID_HANDLE)) {
 444                 if (vmci_qp_broker_detach(temp_handle,
 445                                           context) < VMCI_SUCCESS) {
 446                         /*
 447                          * When vmci_qp_broker_detach() succeeds it
 448                          * removes the handle from the array.  If
 449                          * detach fails, we must remove the handle
 450                          * ourselves.
 451                          */
 452                         vmci_handle_arr_remove_entry(context->queue_pair_array,
 453                                                      temp_handle);
 454                 }
 455                 temp_handle =
 456                     vmci_handle_arr_get_entry(context->queue_pair_array, 0);
 457         }
 458 
 459         /*
 460          * It is fine to destroy this without locking the callQueue, as
 461          * this is the only thread having a reference to the context.
 462          */
 463         list_for_each_entry_safe(dq_entry, dq_entry_tmp,
 464                                  &context->datagram_queue, list_item) {
 465                 WARN_ON(dq_entry->dg_size != VMCI_DG_SIZE(dq_entry->dg));
 466                 list_del(&dq_entry->list_item);
 467                 kfree(dq_entry->dg);
 468                 kfree(dq_entry);
 469         }
 470 
 471         list_for_each_entry_safe(notifier, tmp,
 472                                  &context->notifier_list, node) {
 473                 list_del(&notifier->node);
 474                 kfree(notifier);
 475         }
 476 
 477         vmci_handle_arr_destroy(context->queue_pair_array);
 478         vmci_handle_arr_destroy(context->doorbell_array);
 479         vmci_handle_arr_destroy(context->pending_doorbell_array);
 480         vmci_ctx_unset_notify(context);
 481         if (context->cred)
 482                 put_cred(context->cred);
 483         kfree(context);
 484 }
 485 
 486 /*
 487  * Drops reference to VMCI context. If this is the last reference to
 488  * the context it will be deallocated. A context is created with
 489  * a reference count of one, and on destroy, it is removed from
 490  * the context list before its reference count is decremented. Thus,
 491  * if we reach zero, we are sure that nobody else are about to increment
 492  * it (they need the entry in the context list for that), and so there
 493  * is no need for locking.
 494  */
 495 void vmci_ctx_put(struct vmci_ctx *context)
 496 {
 497         kref_put(&context->kref, ctx_free_ctx);
 498 }
 499 
 500 /*
 501  * Dequeues the next datagram and returns it to caller.
 502  * The caller passes in a pointer to the max size datagram
 503  * it can handle and the datagram is only unqueued if the
 504  * size is less than max_size. If larger max_size is set to
 505  * the size of the datagram to give the caller a chance to
 506  * set up a larger buffer for the guestcall.
 507  */
 508 int vmci_ctx_dequeue_datagram(struct vmci_ctx *context,
 509                               size_t *max_size,
 510                               struct vmci_datagram **dg)
 511 {
 512         struct vmci_datagram_queue_entry *dq_entry;
 513         struct list_head *list_item;
 514         int rv;
 515 
 516         /* Dequeue the next datagram entry. */
 517         spin_lock(&context->lock);
 518         if (context->pending_datagrams == 0) {
 519                 ctx_clear_notify_call(context);
 520                 spin_unlock(&context->lock);
 521                 pr_devel("No datagrams pending\n");
 522                 return VMCI_ERROR_NO_MORE_DATAGRAMS;
 523         }
 524 
 525         list_item = context->datagram_queue.next;
 526 
 527         dq_entry =
 528             list_entry(list_item, struct vmci_datagram_queue_entry, list_item);
 529 
 530         /* Check size of caller's buffer. */
 531         if (*max_size < dq_entry->dg_size) {
 532                 *max_size = dq_entry->dg_size;
 533                 spin_unlock(&context->lock);
 534                 pr_devel("Caller's buffer should be at least (size=%u bytes)\n",
 535                          (u32) *max_size);
 536                 return VMCI_ERROR_NO_MEM;
 537         }
 538 
 539         list_del(list_item);
 540         context->pending_datagrams--;
 541         context->datagram_queue_size -= dq_entry->dg_size;
 542         if (context->pending_datagrams == 0) {
 543                 ctx_clear_notify_call(context);
 544                 rv = VMCI_SUCCESS;
 545         } else {
 546                 /*
 547                  * Return the size of the next datagram.
 548                  */
 549                 struct vmci_datagram_queue_entry *next_entry;
 550 
 551                 list_item = context->datagram_queue.next;
 552                 next_entry =
 553                     list_entry(list_item, struct vmci_datagram_queue_entry,
 554                                list_item);
 555 
 556                 /*
 557                  * The following size_t -> int truncation is fine as
 558                  * the maximum size of a (routable) datagram is 68KB.
 559                  */
 560                 rv = (int)next_entry->dg_size;
 561         }
 562         spin_unlock(&context->lock);
 563 
 564         /* Caller must free datagram. */
 565         *dg = dq_entry->dg;
 566         dq_entry->dg = NULL;
 567         kfree(dq_entry);
 568 
 569         return rv;
 570 }
 571 
 572 /*
 573  * Reverts actions set up by vmci_setup_notify().  Unmaps and unlocks the
 574  * page mapped/locked by vmci_setup_notify().
 575  */
 576 void vmci_ctx_unset_notify(struct vmci_ctx *context)
 577 {
 578         struct page *notify_page;
 579 
 580         spin_lock(&context->lock);
 581 
 582         notify_page = context->notify_page;
 583         context->notify = &ctx_dummy_notify;
 584         context->notify_page = NULL;
 585 
 586         spin_unlock(&context->lock);
 587 
 588         if (notify_page) {
 589                 kunmap(notify_page);
 590                 put_page(notify_page);
 591         }
 592 }
 593 
 594 /*
 595  * Add remote_cid to list of contexts current contexts wants
 596  * notifications from/about.
 597  */
 598 int vmci_ctx_add_notification(u32 context_id, u32 remote_cid)
 599 {
 600         struct vmci_ctx *context;
 601         struct vmci_handle_list *notifier, *n;
 602         int result;
 603         bool exists = false;
 604 
 605         context = vmci_ctx_get(context_id);
 606         if (!context)
 607                 return VMCI_ERROR_NOT_FOUND;
 608 
 609         if (VMCI_CONTEXT_IS_VM(context_id) && VMCI_CONTEXT_IS_VM(remote_cid)) {
 610                 pr_devel("Context removed notifications for other VMs not supported (src=0x%x, remote=0x%x)\n",
 611                          context_id, remote_cid);
 612                 result = VMCI_ERROR_DST_UNREACHABLE;
 613                 goto out;
 614         }
 615 
 616         if (context->priv_flags & VMCI_PRIVILEGE_FLAG_RESTRICTED) {
 617                 result = VMCI_ERROR_NO_ACCESS;
 618                 goto out;
 619         }
 620 
 621         notifier = kmalloc(sizeof(struct vmci_handle_list), GFP_KERNEL);
 622         if (!notifier) {
 623                 result = VMCI_ERROR_NO_MEM;
 624                 goto out;
 625         }
 626 
 627         INIT_LIST_HEAD(&notifier->node);
 628         notifier->handle = vmci_make_handle(remote_cid, VMCI_EVENT_HANDLER);
 629 
 630         spin_lock(&context->lock);
 631 
 632         if (context->n_notifiers < VMCI_MAX_CONTEXTS) {
 633                 list_for_each_entry(n, &context->notifier_list, node) {
 634                         if (vmci_handle_is_equal(n->handle, notifier->handle)) {
 635                                 exists = true;
 636                                 break;
 637                         }
 638                 }
 639 
 640                 if (exists) {
 641                         kfree(notifier);
 642                         result = VMCI_ERROR_ALREADY_EXISTS;
 643                 } else {
 644                         list_add_tail_rcu(&notifier->node,
 645                                           &context->notifier_list);
 646                         context->n_notifiers++;
 647                         result = VMCI_SUCCESS;
 648                 }
 649         } else {
 650                 kfree(notifier);
 651                 result = VMCI_ERROR_NO_MEM;
 652         }
 653 
 654         spin_unlock(&context->lock);
 655 
 656  out:
 657         vmci_ctx_put(context);
 658         return result;
 659 }
 660 
 661 /*
 662  * Remove remote_cid from current context's list of contexts it is
 663  * interested in getting notifications from/about.
 664  */
 665 int vmci_ctx_remove_notification(u32 context_id, u32 remote_cid)
 666 {
 667         struct vmci_ctx *context;
 668         struct vmci_handle_list *notifier, *tmp;
 669         struct vmci_handle handle;
 670         bool found = false;
 671 
 672         context = vmci_ctx_get(context_id);
 673         if (!context)
 674                 return VMCI_ERROR_NOT_FOUND;
 675 
 676         handle = vmci_make_handle(remote_cid, VMCI_EVENT_HANDLER);
 677 
 678         spin_lock(&context->lock);
 679         list_for_each_entry_safe(notifier, tmp,
 680                                  &context->notifier_list, node) {
 681                 if (vmci_handle_is_equal(notifier->handle, handle)) {
 682                         list_del_rcu(&notifier->node);
 683                         context->n_notifiers--;
 684                         found = true;
 685                         break;
 686                 }
 687         }
 688         spin_unlock(&context->lock);
 689 
 690         if (found) {
 691                 synchronize_rcu();
 692                 kfree(notifier);
 693         }
 694 
 695         vmci_ctx_put(context);
 696 
 697         return found ? VMCI_SUCCESS : VMCI_ERROR_NOT_FOUND;
 698 }
 699 
 700 static int vmci_ctx_get_chkpt_notifiers(struct vmci_ctx *context,
 701                                         u32 *buf_size, void **pbuf)
 702 {
 703         u32 *notifiers;
 704         size_t data_size;
 705         struct vmci_handle_list *entry;
 706         int i = 0;
 707 
 708         if (context->n_notifiers == 0) {
 709                 *buf_size = 0;
 710                 *pbuf = NULL;
 711                 return VMCI_SUCCESS;
 712         }
 713 
 714         data_size = context->n_notifiers * sizeof(*notifiers);
 715         if (*buf_size < data_size) {
 716                 *buf_size = data_size;
 717                 return VMCI_ERROR_MORE_DATA;
 718         }
 719 
 720         notifiers = kmalloc(data_size, GFP_ATOMIC); /* FIXME: want GFP_KERNEL */
 721         if (!notifiers)
 722                 return VMCI_ERROR_NO_MEM;
 723 
 724         list_for_each_entry(entry, &context->notifier_list, node)
 725                 notifiers[i++] = entry->handle.context;
 726 
 727         *buf_size = data_size;
 728         *pbuf = notifiers;
 729         return VMCI_SUCCESS;
 730 }
 731 
 732 static int vmci_ctx_get_chkpt_doorbells(struct vmci_ctx *context,
 733                                         u32 *buf_size, void **pbuf)
 734 {
 735         struct dbell_cpt_state *dbells;
 736         u32 i, n_doorbells;
 737 
 738         n_doorbells = vmci_handle_arr_get_size(context->doorbell_array);
 739         if (n_doorbells > 0) {
 740                 size_t data_size = n_doorbells * sizeof(*dbells);
 741                 if (*buf_size < data_size) {
 742                         *buf_size = data_size;
 743                         return VMCI_ERROR_MORE_DATA;
 744                 }
 745 
 746                 dbells = kmalloc(data_size, GFP_ATOMIC);
 747                 if (!dbells)
 748                         return VMCI_ERROR_NO_MEM;
 749 
 750                 for (i = 0; i < n_doorbells; i++)
 751                         dbells[i].handle = vmci_handle_arr_get_entry(
 752                                                 context->doorbell_array, i);
 753 
 754                 *buf_size = data_size;
 755                 *pbuf = dbells;
 756         } else {
 757                 *buf_size = 0;
 758                 *pbuf = NULL;
 759         }
 760 
 761         return VMCI_SUCCESS;
 762 }
 763 
 764 /*
 765  * Get current context's checkpoint state of given type.
 766  */
 767 int vmci_ctx_get_chkpt_state(u32 context_id,
 768                              u32 cpt_type,
 769                              u32 *buf_size,
 770                              void **pbuf)
 771 {
 772         struct vmci_ctx *context;
 773         int result;
 774 
 775         context = vmci_ctx_get(context_id);
 776         if (!context)
 777                 return VMCI_ERROR_NOT_FOUND;
 778 
 779         spin_lock(&context->lock);
 780 
 781         switch (cpt_type) {
 782         case VMCI_NOTIFICATION_CPT_STATE:
 783                 result = vmci_ctx_get_chkpt_notifiers(context, buf_size, pbuf);
 784                 break;
 785 
 786         case VMCI_WELLKNOWN_CPT_STATE:
 787                 /*
 788                  * For compatibility with VMX'en with VM to VM communication, we
 789                  * always return zero wellknown handles.
 790                  */
 791 
 792                 *buf_size = 0;
 793                 *pbuf = NULL;
 794                 result = VMCI_SUCCESS;
 795                 break;
 796 
 797         case VMCI_DOORBELL_CPT_STATE:
 798                 result = vmci_ctx_get_chkpt_doorbells(context, buf_size, pbuf);
 799                 break;
 800 
 801         default:
 802                 pr_devel("Invalid cpt state (type=%d)\n", cpt_type);
 803                 result = VMCI_ERROR_INVALID_ARGS;
 804                 break;
 805         }
 806 
 807         spin_unlock(&context->lock);
 808         vmci_ctx_put(context);
 809 
 810         return result;
 811 }
 812 
 813 /*
 814  * Set current context's checkpoint state of given type.
 815  */
 816 int vmci_ctx_set_chkpt_state(u32 context_id,
 817                              u32 cpt_type,
 818                              u32 buf_size,
 819                              void *cpt_buf)
 820 {
 821         u32 i;
 822         u32 current_id;
 823         int result = VMCI_SUCCESS;
 824         u32 num_ids = buf_size / sizeof(u32);
 825 
 826         if (cpt_type == VMCI_WELLKNOWN_CPT_STATE && num_ids > 0) {
 827                 /*
 828                  * We would end up here if VMX with VM to VM communication
 829                  * attempts to restore a checkpoint with wellknown handles.
 830                  */
 831                 pr_warn("Attempt to restore checkpoint with obsolete wellknown handles\n");
 832                 return VMCI_ERROR_OBSOLETE;
 833         }
 834 
 835         if (cpt_type != VMCI_NOTIFICATION_CPT_STATE) {
 836                 pr_devel("Invalid cpt state (type=%d)\n", cpt_type);
 837                 return VMCI_ERROR_INVALID_ARGS;
 838         }
 839 
 840         for (i = 0; i < num_ids && result == VMCI_SUCCESS; i++) {
 841                 current_id = ((u32 *)cpt_buf)[i];
 842                 result = vmci_ctx_add_notification(context_id, current_id);
 843                 if (result != VMCI_SUCCESS)
 844                         break;
 845         }
 846         if (result != VMCI_SUCCESS)
 847                 pr_devel("Failed to set cpt state (type=%d) (error=%d)\n",
 848                          cpt_type, result);
 849 
 850         return result;
 851 }
 852 
 853 /*
 854  * Retrieves the specified context's pending notifications in the
 855  * form of a handle array. The handle arrays returned are the
 856  * actual data - not a copy and should not be modified by the
 857  * caller. They must be released using
 858  * vmci_ctx_rcv_notifications_release.
 859  */
 860 int vmci_ctx_rcv_notifications_get(u32 context_id,
 861                                    struct vmci_handle_arr **db_handle_array,
 862                                    struct vmci_handle_arr **qp_handle_array)
 863 {
 864         struct vmci_ctx *context;
 865         int result = VMCI_SUCCESS;
 866 
 867         context = vmci_ctx_get(context_id);
 868         if (context == NULL)
 869                 return VMCI_ERROR_NOT_FOUND;
 870 
 871         spin_lock(&context->lock);
 872 
 873         *db_handle_array = context->pending_doorbell_array;
 874         context->pending_doorbell_array =
 875                 vmci_handle_arr_create(0, VMCI_MAX_GUEST_DOORBELL_COUNT);
 876         if (!context->pending_doorbell_array) {
 877                 context->pending_doorbell_array = *db_handle_array;
 878                 *db_handle_array = NULL;
 879                 result = VMCI_ERROR_NO_MEM;
 880         }
 881         *qp_handle_array = NULL;
 882 
 883         spin_unlock(&context->lock);
 884         vmci_ctx_put(context);
 885 
 886         return result;
 887 }
 888 
 889 /*
 890  * Releases handle arrays with pending notifications previously
 891  * retrieved using vmci_ctx_rcv_notifications_get. If the
 892  * notifications were not successfully handed over to the guest,
 893  * success must be false.
 894  */
 895 void vmci_ctx_rcv_notifications_release(u32 context_id,
 896                                         struct vmci_handle_arr *db_handle_array,
 897                                         struct vmci_handle_arr *qp_handle_array,
 898                                         bool success)
 899 {
 900         struct vmci_ctx *context = vmci_ctx_get(context_id);
 901 
 902         spin_lock(&context->lock);
 903         if (!success) {
 904                 struct vmci_handle handle;
 905 
 906                 /*
 907                  * New notifications may have been added while we were not
 908                  * holding the context lock, so we transfer any new pending
 909                  * doorbell notifications to the old array, and reinstate the
 910                  * old array.
 911                  */
 912 
 913                 handle = vmci_handle_arr_remove_tail(
 914                                         context->pending_doorbell_array);
 915                 while (!vmci_handle_is_invalid(handle)) {
 916                         if (!vmci_handle_arr_has_entry(db_handle_array,
 917                                                        handle)) {
 918                                 vmci_handle_arr_append_entry(
 919                                                 &db_handle_array, handle);
 920                         }
 921                         handle = vmci_handle_arr_remove_tail(
 922                                         context->pending_doorbell_array);
 923                 }
 924                 vmci_handle_arr_destroy(context->pending_doorbell_array);
 925                 context->pending_doorbell_array = db_handle_array;
 926                 db_handle_array = NULL;
 927         } else {
 928                 ctx_clear_notify_call(context);
 929         }
 930         spin_unlock(&context->lock);
 931         vmci_ctx_put(context);
 932 
 933         if (db_handle_array)
 934                 vmci_handle_arr_destroy(db_handle_array);
 935 
 936         if (qp_handle_array)
 937                 vmci_handle_arr_destroy(qp_handle_array);
 938 }
 939 
 940 /*
 941  * Registers that a new doorbell handle has been allocated by the
 942  * context. Only doorbell handles registered can be notified.
 943  */
 944 int vmci_ctx_dbell_create(u32 context_id, struct vmci_handle handle)
 945 {
 946         struct vmci_ctx *context;
 947         int result;
 948 
 949         if (context_id == VMCI_INVALID_ID || vmci_handle_is_invalid(handle))
 950                 return VMCI_ERROR_INVALID_ARGS;
 951 
 952         context = vmci_ctx_get(context_id);
 953         if (context == NULL)
 954                 return VMCI_ERROR_NOT_FOUND;
 955 
 956         spin_lock(&context->lock);
 957         if (!vmci_handle_arr_has_entry(context->doorbell_array, handle))
 958                 result = vmci_handle_arr_append_entry(&context->doorbell_array,
 959                                                       handle);
 960         else
 961                 result = VMCI_ERROR_DUPLICATE_ENTRY;
 962 
 963         spin_unlock(&context->lock);
 964         vmci_ctx_put(context);
 965 
 966         return result;
 967 }
 968 
 969 /*
 970  * Unregisters a doorbell handle that was previously registered
 971  * with vmci_ctx_dbell_create.
 972  */
 973 int vmci_ctx_dbell_destroy(u32 context_id, struct vmci_handle handle)
 974 {
 975         struct vmci_ctx *context;
 976         struct vmci_handle removed_handle;
 977 
 978         if (context_id == VMCI_INVALID_ID || vmci_handle_is_invalid(handle))
 979                 return VMCI_ERROR_INVALID_ARGS;
 980 
 981         context = vmci_ctx_get(context_id);
 982         if (context == NULL)
 983                 return VMCI_ERROR_NOT_FOUND;
 984 
 985         spin_lock(&context->lock);
 986         removed_handle =
 987             vmci_handle_arr_remove_entry(context->doorbell_array, handle);
 988         vmci_handle_arr_remove_entry(context->pending_doorbell_array, handle);
 989         spin_unlock(&context->lock);
 990 
 991         vmci_ctx_put(context);
 992 
 993         return vmci_handle_is_invalid(removed_handle) ?
 994             VMCI_ERROR_NOT_FOUND : VMCI_SUCCESS;
 995 }
 996 
 997 /*
 998  * Unregisters all doorbell handles that were previously
 999  * registered with vmci_ctx_dbell_create.
1000  */
1001 int vmci_ctx_dbell_destroy_all(u32 context_id)
1002 {
1003         struct vmci_ctx *context;
1004         struct vmci_handle handle;
1005 
1006         if (context_id == VMCI_INVALID_ID)
1007                 return VMCI_ERROR_INVALID_ARGS;
1008 
1009         context = vmci_ctx_get(context_id);
1010         if (context == NULL)
1011                 return VMCI_ERROR_NOT_FOUND;
1012 
1013         spin_lock(&context->lock);
1014         do {
1015                 struct vmci_handle_arr *arr = context->doorbell_array;
1016                 handle = vmci_handle_arr_remove_tail(arr);
1017         } while (!vmci_handle_is_invalid(handle));
1018         do {
1019                 struct vmci_handle_arr *arr = context->pending_doorbell_array;
1020                 handle = vmci_handle_arr_remove_tail(arr);
1021         } while (!vmci_handle_is_invalid(handle));
1022         spin_unlock(&context->lock);
1023 
1024         vmci_ctx_put(context);
1025 
1026         return VMCI_SUCCESS;
1027 }
1028 
1029 /*
1030  * Registers a notification of a doorbell handle initiated by the
1031  * specified source context. The notification of doorbells are
1032  * subject to the same isolation rules as datagram delivery. To
1033  * allow host side senders of notifications a finer granularity
1034  * of sender rights than those assigned to the sending context
1035  * itself, the host context is required to specify a different
1036  * set of privilege flags that will override the privileges of
1037  * the source context.
1038  */
1039 int vmci_ctx_notify_dbell(u32 src_cid,
1040                           struct vmci_handle handle,
1041                           u32 src_priv_flags)
1042 {
1043         struct vmci_ctx *dst_context;
1044         int result;
1045 
1046         if (vmci_handle_is_invalid(handle))
1047                 return VMCI_ERROR_INVALID_ARGS;
1048 
1049         /* Get the target VM's VMCI context. */
1050         dst_context = vmci_ctx_get(handle.context);
1051         if (!dst_context) {
1052                 pr_devel("Invalid context (ID=0x%x)\n", handle.context);
1053                 return VMCI_ERROR_NOT_FOUND;
1054         }
1055 
1056         if (src_cid != handle.context) {
1057                 u32 dst_priv_flags;
1058 
1059                 if (VMCI_CONTEXT_IS_VM(src_cid) &&
1060                     VMCI_CONTEXT_IS_VM(handle.context)) {
1061                         pr_devel("Doorbell notification from VM to VM not supported (src=0x%x, dst=0x%x)\n",
1062                                  src_cid, handle.context);
1063                         result = VMCI_ERROR_DST_UNREACHABLE;
1064                         goto out;
1065                 }
1066 
1067                 result = vmci_dbell_get_priv_flags(handle, &dst_priv_flags);
1068                 if (result < VMCI_SUCCESS) {
1069                         pr_warn("Failed to get privilege flags for destination (handle=0x%x:0x%x)\n",
1070                                 handle.context, handle.resource);
1071                         goto out;
1072                 }
1073 
1074                 if (src_cid != VMCI_HOST_CONTEXT_ID ||
1075                     src_priv_flags == VMCI_NO_PRIVILEGE_FLAGS) {
1076                         src_priv_flags = vmci_context_get_priv_flags(src_cid);
1077                 }
1078 
1079                 if (vmci_deny_interaction(src_priv_flags, dst_priv_flags)) {
1080                         result = VMCI_ERROR_NO_ACCESS;
1081                         goto out;
1082                 }
1083         }
1084 
1085         if (handle.context == VMCI_HOST_CONTEXT_ID) {
1086                 result = vmci_dbell_host_context_notify(src_cid, handle);
1087         } else {
1088                 spin_lock(&dst_context->lock);
1089 
1090                 if (!vmci_handle_arr_has_entry(dst_context->doorbell_array,
1091                                                handle)) {
1092                         result = VMCI_ERROR_NOT_FOUND;
1093                 } else {
1094                         if (!vmci_handle_arr_has_entry(
1095                                         dst_context->pending_doorbell_array,
1096                                         handle)) {
1097                                 result = vmci_handle_arr_append_entry(
1098                                         &dst_context->pending_doorbell_array,
1099                                         handle);
1100                                 if (result == VMCI_SUCCESS) {
1101                                         ctx_signal_notify(dst_context);
1102                                         wake_up(&dst_context->host_context.wait_queue);
1103                                 }
1104                         } else {
1105                                 result = VMCI_SUCCESS;
1106                         }
1107                 }
1108                 spin_unlock(&dst_context->lock);
1109         }
1110 
1111  out:
1112         vmci_ctx_put(dst_context);
1113 
1114         return result;
1115 }
1116 
1117 bool vmci_ctx_supports_host_qp(struct vmci_ctx *context)
1118 {
1119         return context && context->user_version >= VMCI_VERSION_HOSTQP;
1120 }
1121 
1122 /*
1123  * Registers that a new queue pair handle has been allocated by
1124  * the context.
1125  */
1126 int vmci_ctx_qp_create(struct vmci_ctx *context, struct vmci_handle handle)
1127 {
1128         int result;
1129 
1130         if (context == NULL || vmci_handle_is_invalid(handle))
1131                 return VMCI_ERROR_INVALID_ARGS;
1132 
1133         if (!vmci_handle_arr_has_entry(context->queue_pair_array, handle))
1134                 result = vmci_handle_arr_append_entry(
1135                         &context->queue_pair_array, handle);
1136         else
1137                 result = VMCI_ERROR_DUPLICATE_ENTRY;
1138 
1139         return result;
1140 }
1141 
1142 /*
1143  * Unregisters a queue pair handle that was previously registered
1144  * with vmci_ctx_qp_create.
1145  */
1146 int vmci_ctx_qp_destroy(struct vmci_ctx *context, struct vmci_handle handle)
1147 {
1148         struct vmci_handle hndl;
1149 
1150         if (context == NULL || vmci_handle_is_invalid(handle))
1151                 return VMCI_ERROR_INVALID_ARGS;
1152 
1153         hndl = vmci_handle_arr_remove_entry(context->queue_pair_array, handle);
1154 
1155         return vmci_handle_is_invalid(hndl) ?
1156                 VMCI_ERROR_NOT_FOUND : VMCI_SUCCESS;
1157 }
1158 
1159 /*
1160  * Determines whether a given queue pair handle is registered
1161  * with the given context.
1162  */
1163 bool vmci_ctx_qp_exists(struct vmci_ctx *context, struct vmci_handle handle)
1164 {
1165         if (context == NULL || vmci_handle_is_invalid(handle))
1166                 return false;
1167 
1168         return vmci_handle_arr_has_entry(context->queue_pair_array, handle);
1169 }
1170 
1171 /*
1172  * vmci_context_get_priv_flags() - Retrieve privilege flags.
1173  * @context_id: The context ID of the VMCI context.
1174  *
1175  * Retrieves privilege flags of the given VMCI context ID.
1176  */
1177 u32 vmci_context_get_priv_flags(u32 context_id)
1178 {
1179         if (vmci_host_code_active()) {
1180                 u32 flags;
1181                 struct vmci_ctx *context;
1182 
1183                 context = vmci_ctx_get(context_id);
1184                 if (!context)
1185                         return VMCI_LEAST_PRIVILEGE_FLAGS;
1186 
1187                 flags = context->priv_flags;
1188                 vmci_ctx_put(context);
1189                 return flags;
1190         }
1191         return VMCI_NO_PRIVILEGE_FLAGS;
1192 }
1193 EXPORT_SYMBOL_GPL(vmci_context_get_priv_flags);
1194 
1195 /*
1196  * vmci_is_context_owner() - Determimnes if user is the context owner
1197  * @context_id: The context ID of the VMCI context.
1198  * @uid:        The host user id (real kernel value).
1199  *
1200  * Determines whether a given UID is the owner of given VMCI context.
1201  */
1202 bool vmci_is_context_owner(u32 context_id, kuid_t uid)
1203 {
1204         bool is_owner = false;
1205 
1206         if (vmci_host_code_active()) {
1207                 struct vmci_ctx *context = vmci_ctx_get(context_id);
1208                 if (context) {
1209                         if (context->cred)
1210                                 is_owner = uid_eq(context->cred->uid, uid);
1211                         vmci_ctx_put(context);
1212                 }
1213         }
1214 
1215         return is_owner;
1216 }
1217 EXPORT_SYMBOL_GPL(vmci_is_context_owner);
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/misc/vmw_vmci/vmci_context.c

DEFINITIONS
