summaryrefslogtreecommitdiffstats
path: root/drivers/misc/vmw_vmci/vmci_host.c
blob: 5acbf384ffa6495d9b7f3c8d63800df101067038 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
/*
 * VMware VMCI Driver
 *
 * Copyright (C) 2012 VMware, Inc. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation version 2 and no later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 */

#include <linux/vmw_vmci_defs.h>
#include <linux/vmw_vmci_api.h>
#include <linux/moduleparam.h>
#include <linux/miscdevice.h>
#include <linux/interrupt.h>
#include <linux/highmem.h>
#include <linux/atomic.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/cred.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/pci.h>
#include <linux/smp.h>
#include <linux/fs.h>
#include <linux/io.h>

#include "vmci_handle_array.h"
#include "vmci_queue_pair.h"
#include "vmci_datagram.h"
#include "vmci_doorbell.h"
#include "vmci_resource.h"
#include "vmci_context.h"
#include "vmci_driver.h"
#include "vmci_event.h"

#define VMCI_UTIL_NUM_RESOURCES 1

enum {
	VMCI_NOTIFY_RESOURCE_QUEUE_PAIR = 0,
	VMCI_NOTIFY_RESOURCE_DOOR_BELL = 1,
};

enum {
	VMCI_NOTIFY_RESOURCE_ACTION_NOTIFY = 0,
	VMCI_NOTIFY_RESOURCE_ACTION_CREATE = 1,
	VMCI_NOTIFY_RESOURCE_ACTION_DESTROY = 2,
};

/*
 * VMCI driver initialization. This block can also be used to
 * pass initial group membership etc.
 */
struct vmci_init_blk {
	u32 cid;
	u32 flags;
};

/* VMCIqueue_pairAllocInfo_VMToVM */
struct vmci_qp_alloc_info_vmvm {
	struct vmci_handle handle;
	u32 peer;
	u32 flags;
	u64 produce_size;
	u64 consume_size;
	u64 produce_page_file;	  /* User VA. */
	u64 consume_page_file;	  /* User VA. */
	u64 produce_page_file_size;  /* Size of the file name array. */
	u64 consume_page_file_size;  /* Size of the file name array. */
	s32 result;
	u32 _pad;
};

/* VMCISetNotifyInfo: Used to pass notify flag's address to the host driver. */
struct vmci_set_notify_info {
	u64 notify_uva;
	s32 result;
	u32 _pad;
};

/*
 * Per-instance host state
 */
struct vmci_host_dev {
	struct vmci_ctx *context;
	int user_version;
	enum vmci_obj_type ct_type;
	struct mutex lock;  /* Mutex lock for vmci context access */
};

static struct vmci_ctx *host_context;
static bool vmci_host_device_initialized;
static atomic_t vmci_host_active_users = ATOMIC_INIT(0);

/*
 * Determines whether the VMCI host personality is
 * available. Since the core functionality of the host driver is
 * always present, all guests could possibly use the host
 * personality. However, to minimize the deviation from the
 * pre-unified driver state of affairs, we only consider the host
 * device active if there is no active guest device or if there
 * are VMX'en with active VMCI contexts using the host device.
 */
bool vmci_host_code_active(void)
{
	return vmci_host_device_initialized &&
	    (!vmci_guest_code_active() ||
	     atomic_read(&vmci_host_active_users) > 0);
}

/*
 * Called on open of /dev/vmci.
 */
static int vmci_host_open(struct inode *inode, struct file *filp)
{
	struct vmci_host_dev *vmci_host_dev;

	vmci_host_dev = kzalloc(sizeof(struct vmci_host_dev), GFP_KERNEL);
	if (vmci_host_dev == NULL)
		return -ENOMEM;

	vmci_host_dev->ct_type = VMCIOBJ_NOT_SET;
	mutex_init(&vmci_host_dev->lock);
	filp->private_data = vmci_host_dev;

	return 0;
}

/*
 * Called on close of /dev/vmci, most often when the process
 * exits.
 */
static int vmci_host_close(struct inode *inode, struct file *filp)
{
	struct vmci_host_dev *vmci_host_dev = filp->private_data;

	if (vmci_host_dev->ct_type == VMCIOBJ_CONTEXT) {
		vmci_ctx_destroy(vmci_host_dev->context);
		vmci_host_dev->context = NULL;

		/*
		 * The number of active contexts is used to track whether any
		 * VMX'en are using the host personality. It is incremented when
		 * a context is created through the IOCTL_VMCI_INIT_CONTEXT
		 * ioctl.
		 */
		atomic_dec(&vmci_host_active_users);
	}
	vmci_host_dev->ct_type = VMCIOBJ_NOT_SET;

	kfree(vmci_host_dev);
	filp->private_data = NULL;
	return 0;
}

/*
 * This is used to wake up the VMX when a VMCI call arrives, or
 * to wake up select() or poll() at the next clock tick.
 */
static __poll_t vmci_host_poll(struct file *filp, poll_table *wait)
{
	struct vmci_host_dev *vmci_host_dev = filp->private_data;
	struct vmci_ctx *context;
	__poll_t mask = 0;

	if (vmci_host_dev->ct_type == VMCIOBJ_CONTEXT) {
		/*
		 * Read context only if ct_type == VMCIOBJ_CONTEXT to make
		 * sure that context is initialized
		 */
		context = vmci_host_dev->context;

		/* Check for VMCI calls to this VM context. */
		if (wait)
			poll_wait(filp, &context->host_context.wait_queue,
				  wait);

		spin_lock(&context->lock);
		if (context->pending_datagrams > 0 ||
		    vmci_handle_arr_get_size(
				context->pending_doorbell_array) > 0) {
			mask = EPOLLIN;
		}
		spin_unlock(&context->lock);
	}
	return mask;
}

/*
 * Copies the handles of a handle array into a user buffer, and
 * returns the new length in userBufferSize. If the copy to the
 * user buffer fails, the functions still returns VMCI_SUCCESS,
 * but retval != 0.
 */
static int drv_cp_harray_to_user(void __user *user_buf_uva,
				 u64 *user_buf_size,
				 struct vmci_handle_arr *handle_array,
				 int *retval)
{
	u32 array_size = 0;
	struct vmci_handle *handles;

	if (handle_array)
		array_size = vmci_handle_arr_get_size(handle_array);

	if (array_size * sizeof(*handles) > *user_buf_size)
		return VMCI_ERROR_MORE_DATA;

	*user_buf_size = array_size * sizeof(*handles);
	if (*user_buf_size)
		*retval = copy_to_user(user_buf_uva,
				       vmci_handle_arr_get_handles
				       (handle_array), *user_buf_size);

	return VMCI_SUCCESS;
}

/*
 * Sets up a given context for notify to work. Maps the notify
 * boolean in user VA into kernel space.
 */
static int vmci_host_setup_notify(struct vmci_ctx *context,
				  unsigned long uva)
{
	int retval;

	if (context->notify_page) {
		pr_devel("%s: Notify mechanism is already set up\n", __func__);
		return VMCI_ERROR_DUPLICATE_ENTRY;
	}

	/*
	 * We are using 'bool' internally, but let's make sure we explicit
	 * about the size.
	 */
	BUILD_BUG_ON(sizeof(bool) != sizeof(u8));
	if (!access_ok(VERIFY_WRITE, (void __user *)uva, sizeof(u8)))
		return VMCI_ERROR_GENERIC;

	/*
	 * Lock physical page backing a given user VA.
	 */
	retval = get_user_pages_fast(uva, 1, 1, &context->notify_page);
	if (retval != 1) {
		context->notify_page = NULL;
		return VMCI_ERROR_GENERIC;
	}

	/*
	 * Map the locked page and set up notify pointer.
	 */
	context->notify = kmap(context->notify_page) + (uva & (PAGE_SIZE - 1));
	vmci_ctx_check_signal_notify(context);

	return VMCI_SUCCESS;
}

static int vmci_host_get_version(struct vmci_host_dev *vmci_host_dev,
				 unsigned int cmd, void __user *uptr)
{
	if (cmd == IOCTL_VMCI_VERSION2) {
		int __user *vptr = uptr;
		if (get_user(vmci_host_dev->user_version, vptr))
			return -EFAULT;
	}

	/*
	 * The basic logic here is:
	 *
	 * If the user sends in a version of 0 tell it our version.
	 * If the user didn't send in a version, tell it our version.
	 * If the user sent in an old version, tell it -its- version.
	 * If the user sent in an newer version, tell it our version.
	 *
	 * The rationale behind telling the caller its version is that
	 * Workstation 6.5 required that VMX and VMCI kernel module were
	 * version sync'd.  All new VMX users will be programmed to
	 * handle the VMCI kernel module version.
	 */

	if (vmci_host_dev->user_version > 0 &&
	    vmci_host_dev->user_version < VMCI_VERSION_HOSTQP) {
		return vmci_host_dev->user_version;
	}

	return VMCI_VERSION;
}

#define vmci_ioctl_err(fmt, ...)	\
	pr_devel("%s: " fmt, ioctl_name, ##__VA_ARGS__)

static int vmci_host_do_init_context(struct vmci_host_dev *vmci_host_dev,
				     const char *ioctl_name,
				     void __user *uptr)
{
	struct vmci_init_blk init_block;
	const struct cred *cred;
	int retval;

	if (copy_from_user(&init_block, uptr, sizeof(init_block))) {
		vmci_ioctl_err("error reading init block\n");
		return -EFAULT;
	}

	mutex_lock(&vmci_host_dev->lock);

	if (vmci_host_dev->ct_type != VMCIOBJ_NOT_SET) {
		vmci_ioctl_err("received VMCI init on initialized handle\n");
		retval = -EINVAL;
		goto out;
	}

	if (init_block.flags & ~VMCI_PRIVILEGE_FLAG_RESTRICTED) {
		vmci_ioctl_err("unsupported VMCI restriction flag\n");
		retval = -EINVAL;
		goto out;
	}

	cred = get_current_cred();
	vmci_host_dev->context = vmci_ctx_create(init_block.cid,
						 init_block.flags, 0,
						 vmci_host_dev->user_version,
						 cred);
	put_cred(cred);
	if (IS_ERR(vmci_host_dev->context)) {
		retval = PTR_ERR(vmci_host_dev->context);
		vmci_ioctl_err("error initializing context\n");
		goto out;
	}

	/*
	 * Copy cid to userlevel, we do this to allow the VMX
	 * to enforce its policy on cid generation.
	 */
	init_block.cid = vmci_ctx_get_id(vmci_host_dev->context);
	if (copy_to_user(uptr, &init_block, sizeof(init_block))) {
		vmci_ctx_destroy(vmci_host_dev->context);
		vmci_host_dev->context = NULL;
		vmci_ioctl_err("error writing init block\n");
		retval = -EFAULT;
		goto out;
	}

	vmci_host_dev->ct_type = VMCIOBJ_CONTEXT;
	atomic_inc(&vmci_host_active_users);

	retval = 0;

out:
	mutex_unlock(&vmci_host_dev->lock);
	return retval;
}

static int vmci_host_do_send_datagram(struct vmci_host_dev *vmci_host_dev,
				      const char *ioctl_name,
				      void __user *uptr)
{
	struct vmci_datagram_snd_rcv_info send_info;
	struct vmci_datagram *dg = NULL;
	u32 cid;

	if (vmci_host_dev->ct_type != VMCIOBJ_CONTEXT) {
		vmci_ioctl_err("only valid for contexts\n");
		return -EINVAL;
	}

	if (copy_from_user(&send_info, uptr, sizeof(send_info)))
		return -EFAULT;

	if (send_info.len > VMCI_MAX_DG_SIZE) {
		vmci_ioctl_err("datagram is too big (size=%d)\n",
			       send_info.len);
		return -EINVAL;
	}

	if (send_info.len < sizeof(*dg)) {
		vmci_ioctl_err("datagram is too small (size=%d)\n",
			       send_info.len);
		return -EINVAL;
	}

	dg = memdup_user((void __user *)(uintptr_t)send_info.addr,
			 send_info.len);
	if (IS_ERR(dg)) {
		vmci_ioctl_err(
			"cannot allocate memory to dispatch datagram\n");
		return PTR_ERR(dg);
	}

	if (VMCI_DG_SIZE(dg) != send_info.len) {
		vmci_ioctl_err("datagram size mismatch\n");
		kfree(dg);
		return -EINVAL;
	}

	pr_devel("Datagram dst (handle=0x%x:0x%x) src (handle=0x%x:0x%x), payload (size=%llu bytes)\n",
		 dg->dst.context, dg->dst.resource,
		 dg->src.context, dg->src.resource,
		 (unsigned long long)dg->payload_size);

	/* Get source context id. */
	cid = vmci_ctx_get_id(vmci_host_dev->context);
	send_info.result = vmci_datagram_dispatch(cid, dg, true);
	kfree(dg);

	return copy_to_user(uptr, &send_info, sizeof(send_info)) ? -EFAULT : 0;
}

static int vmci_host_do_receive_datagram(struct vmci_host_dev *vmci_host_dev,
					 const char *ioctl_name,
					 void __user *uptr)
{
	struct vmci_datagram_snd_rcv_info recv_info;
	struct vmci_datagram *dg = NULL;
	int retval;
	size_t size;

	if (vmci_host_dev->ct_type != VMCIOBJ_CONTEXT) {
		vmci_ioctl_err("only valid for contexts\n");
		return -EINVAL;
	}

	if (copy_from_user(&recv_info, uptr, sizeof(recv_info)))
		return -EFAULT;

	size = recv_info.len;
	recv_info.result = vmci_ctx_dequeue_datagram(vmci_host_dev->context,
						     &size, &dg);

	if (recv_info.result >= VMCI_SUCCESS) {
		void __user *ubuf = (void __user *)(uintptr_t)recv_info.addr;
		retval = copy_to_user(ubuf, dg, VMCI_DG_SIZE(dg));
		kfree(dg);
		if (retval != 0)
			return -EFAULT;
	}

	return copy_to_user(uptr, &recv_info, sizeof(recv_info)) ? -EFAULT : 0;
}

static int vmci_host_do_alloc_queuepair(struct vmci_host_dev *vmci_host_dev,
					const char *ioctl_name,
					void __user *uptr)
{
	struct vmci_handle handle;
	int vmci_status;
	int __user *retptr;
	u32 cid;

	if (vmci_host_dev->ct_type != VMCIOBJ_CONTEXT) {
		vmci_ioctl_err("only valid for contexts\n");
		return -EINVAL;
	}

	cid = vmci_ctx_get_id(vmci_host_dev->context);

	if (vmci_host_dev->user_version < VMCI_VERSION_NOVMVM) {
		struct vmci_qp_alloc_info_vmvm alloc_info;
		struct vmci_qp_alloc_info_vmvm __user *info = uptr;

		if (copy_from_user(&alloc_info, uptr, sizeof(alloc_info)))
			return -EFAULT;

		handle = alloc_info.handle;
		retptr = &info->result;

		vmci_status = vmci_qp_broker_alloc(alloc_info.handle,
						alloc_info.peer,
						alloc_info.flags,
						VMCI_NO_PRIVILEGE_FLAGS,
						alloc_info.produce_size,
						alloc_info.consume_size,
						NULL,
						vmci_host_dev->context);

		if (vmci_status == VMCI_SUCCESS)
			vmci_status = VMCI_SUCCESS_QUEUEPAIR_CREATE;
	} else {
		struct vmci_qp_alloc_info alloc_info;
		struct vmci_qp_alloc_info __user *info = uptr;
		struct vmci_qp_page_store page_store;

		if (copy_from_user(&alloc_info, uptr, sizeof(alloc_info)))
			return -EFAULT;

		handle = alloc_info.handle;
		retptr = &info->result;

		page_store.pages = alloc_info.ppn_va;
		page_store.len = alloc_info.num_ppns;

		vmci_status = vmci_qp_broker_alloc(alloc_info.handle,
						alloc_info.peer,
						alloc_info.flags,
						VMCI_NO_PRIVILEGE_FLAGS,
						alloc_info.produce_size,
						alloc_info.consume_size,
						&page_store,
						vmci_host_dev->context);
	}

	if (put_user(vmci_status, retptr)) {
		if (vmci_status >= VMCI_SUCCESS) {
			vmci_status = vmci_qp_broker_detach(handle,
							vmci_host_dev->context);
		}
		return -EFAULT;
	}

	return 0;
}

static int vmci_host_do_queuepair_setva(struct vmci_host_dev *vmci_host_dev,
					const char *ioctl_name,
					void __user *uptr)
{
	struct vmci_qp_set_va_info set_va_info;
	struct vmci_qp_set_va_info __user *info = uptr;
	s32 result;

	if (vmci_host_dev->ct_type != VMCIOBJ_CONTEXT) {
		vmci_ioctl_err("only valid for contexts\n");
		return -EINVAL;
	}

	if (vmci_host_dev->user_version < VMCI_VERSION_NOVMVM) {
		vmci_ioctl_err("is not allowed\n");
		return -EINVAL;
	}

	if (copy_from_user(&set_va_info, uptr, sizeof(set_va_info)))
		return -EFAULT;

	if (set_va_info.va) {
		/*
		 * VMX is passing down a new VA for the queue
		 * pair mapping.
		 */
		result = vmci_qp_broker_map(set_va_info.handle,
					    vmci_host_dev->context,
					    set_va_info.va);
	} else {
		/*
		 * The queue pair is about to be unmapped by
		 * the VMX.
		 */
		result = vmci_qp_broker_unmap(set_va_info.handle,
					 vmci_host_dev->context, 0);
	}

	return put_user(result, &info->result) ? -EFAULT : 0;
}

static int vmci_host_do_queuepair_setpf(struct vmci_host_dev *vmci_host_dev,
					const char *ioctl_name,
					void __user *uptr)
{
	struct vmci_qp_page_file_info page_file_info;
	struct vmci_qp_page_file_info __user *info = uptr;
	s32 result;

	if (vmci_host_dev->user_version < VMCI_VERSION_HOSTQP ||
	    vmci_host_dev->user_version >= VMCI_VERSION_NOVMVM) {
		vmci_ioctl_err("not supported on this VMX (version=%d)\n",
			       vmci_host_dev->user_version);
		return -EINVAL;
	}

	if (vmci_host_dev->ct_type != VMCIOBJ_CONTEXT) {
		vmci_ioctl_err("only valid for contexts\n");
		return -EINVAL;
	}

	if (copy_from_user(&page_file_info, uptr, sizeof(*info)))
		return -EFAULT;

	/*
	 * Communicate success pre-emptively to the caller.  Note that the
	 * basic premise is that it is incumbent upon the caller not to look at
	 * the info.result field until after the ioctl() returns.  And then,
	 * only if the ioctl() result indicates no error.  We send up the
	 * SUCCESS status before calling SetPageStore() store because failing
	 * to copy up the result code means unwinding the SetPageStore().
	 *
	 * It turns out the logic to unwind a SetPageStore() opens a can of
	 * worms.  For example, if a host had created the queue_pair and a
	 * guest attaches and SetPageStore() is successful but writing success
	 * fails, then ... the host has to be stopped from writing (anymore)
	 * data into the queue_pair.  That means an additional test in the
	 * VMCI_Enqueue() code path.  Ugh.
	 */

	if (put_user(VMCI_SUCCESS, &info->result)) {
		/*
		 * In this case, we can't write a result field of the
		 * caller's info block.  So, we don't even try to
		 * SetPageStore().
		 */
		return -EFAULT;
	}

	result = vmci_qp_broker_set_page_store(page_file_info.handle,
						page_file_info.produce_va,
						page_file_info.consume_va,
						vmci_host_dev->context);
	if (result < VMCI_SUCCESS) {
		if (put_user(result, &info->result)) {
			/*
			 * Note that in this case the SetPageStore()
			 * call failed but we were unable to
			 * communicate that to the caller (because the
			 * copy_to_user() call failed).  So, if we
			 * simply return an error (in this case
			 * -EFAULT) then the caller will know that the
			 *  SetPageStore failed even though we couldn't
			 *  put the result code in the result field and
			 *  indicate exactly why it failed.
			 *
			 * That says nothing about the issue where we
			 * were once able to write to the caller's info
			 * memory and now can't.  Something more
			 * serious is probably going on than the fact
			 * that SetPageStore() didn't work.
			 */
			return -EFAULT;
		}
	}

	return 0;
}

static int vmci_host_do_qp_detach(struct vmci_host_dev *vmci_host_dev,
				  const char *ioctl_name,
				  void __user *uptr)
{
	struct vmci_qp_dtch_info detach_info;
	struct vmci_qp_dtch_info __user *info = uptr;
	s32 result;

	if (vmci_host_dev->ct_type != VMCIOBJ_CONTEXT) {
		vmci_ioctl_err("only valid for contexts\n");
		return -EINVAL;
	}

	if (copy_from_user(&detach_info, uptr, sizeof(detach_info)))
		return -EFAULT;

	result = vmci_qp_broker_detach(detach_info.handle,
				       vmci_host_dev->context);
	if (result == VMCI_SUCCESS &&
	    vmci_host_dev->user_version < VMCI_VERSION_NOVMVM) {
		result = VMCI_SUCCESS_LAST_DETACH;
	}

	return put_user(result, &info->result) ? -EFAULT : 0;
}

static int vmci_host_do_ctx_add_notify(struct vmci_host_dev *vmci_host_dev,
				       const char *ioctl_name,
				       void __user *uptr)
{
	struct vmci_ctx_info ar_info;
	struct vmci_ctx_info __user *info = uptr;
	s32 result;
	u32 cid;

	if (vmci_host_dev->ct_type != VMCIOBJ_CONTEXT) {
		vmci_ioctl_err("only valid for contexts\n");
		return -EINVAL;
	}

	if (copy_from_user(&ar_info, uptr, sizeof(ar_info)))
		return -EFAULT;

	cid = vmci_ctx_get_id(vmci_host_dev->context);
	result = vmci_ctx_add_notification(cid, ar_info.remote_cid);

	return put_user(result, &info->result) ? -EFAULT : 0;
}

static int vmci_host_do_ctx_remove_notify(struct vmci_host_dev *vmci_host_dev,
					  const char *ioctl_name,
					  void __user *uptr)
{
	struct vmci_ctx_info ar_info;
	struct vmci_ctx_info __user *info = uptr;
	u32 cid;
	int result;

	if (vmci_host_dev->ct_type != VMCIOBJ_CONTEXT) {
		vmci_ioctl_err("only valid for contexts\n");
		return -EINVAL;
	}

	if (copy_from_user(&ar_info, uptr, sizeof(ar_info)))
		return -EFAULT;

	cid = vmci_ctx_get_id(vmci_host_dev->context);
	result = vmci_ctx_remove_notification(cid,
					      ar_info.remote_cid);

	return put_user(result, &info->result) ? -EFAULT : 0;
}

static int vmci_host_do_ctx_get_cpt_state(struct vmci_host_dev *vmci_host_dev,
					  const char *ioctl_name,
					  void __user *uptr)
{
	struct vmci_ctx_chkpt_buf_info get_info;
	u32 cid;
	void *cpt_buf;
	int retval;

	if (vmci_host_dev->ct_type != VMCIOBJ_CONTEXT) {
		vmci_ioctl_err("only valid for contexts\n");
		return -EINVAL;
	}

	if (copy_from_user(&get_info, uptr, sizeof(get_info)))
		return -EFAULT;

	cid = vmci_ctx_get_id(vmci_host_dev->context);
	get_info.result = vmci_ctx_get_chkpt_state(cid, get_info.cpt_type,
						&get_info.buf_size, &cpt_buf);
	if (get_info.result == VMCI_SUCCESS && get_info.buf_size) {
		void __user *ubuf = (void __user *)(uintptr_t)get_info.cpt_buf;
		retval = copy_to_user(ubuf, cpt_buf, get_info.buf_size);
		kfree(cpt_buf);

		if (retval)
			return -EFAULT;
	}

	return copy_to_user(uptr, &get_info, sizeof(get_info)) ? -EFAULT : 0;
}

static int vmci_host_do_ctx_set_cpt_state(struct vmci_host_dev *vmci_host_dev,
					  const char *ioctl_name,
					  void __user *uptr)
{
	struct vmci_ctx_chkpt_buf_info set_info;
	u32 cid;
	void *cpt_buf;
	int retval;

	if (vmci_host_dev->ct_type != VMCIOBJ_CONTEXT) {
		vmci_ioctl_err("only valid for contexts\n");
		return -EINVAL;
	}

	if (copy_from_user(&set_info, uptr, sizeof(set_info)))
		return -EFAULT;

	cpt_buf = kmalloc(set_info.buf_size, GFP_KERNEL);
	if (!cpt_buf) {
		vmci_ioctl_err(
			"cannot allocate memory to set cpt state (type=%d)\n",
			set_info.cpt_type);
		return -ENOMEM;
	}

	if (copy_from_user(cpt_buf, (void __user *)(uintptr_t)set_info.cpt_buf,
			   set_info.buf_size)) {
		retval = -EFAULT;
		goto out;
	}

	cid = vmci_ctx_get_id(vmci_host_dev->context);
	set_info.result = vmci_ctx_set_chkpt_state(cid, set_info.cpt_type,
						   set_info.buf_size, cpt_buf);

	retval = copy_to_user(uptr, &set_info, sizeof(set_info)) ? -EFAULT : 0;

out:
	kfree(cpt_buf);
	return retval;
}

static int vmci_host_do_get_context_id(struct vmci_host_dev *vmci_host_dev,
				       const char *ioctl_name,
				       void __user *uptr)
{
	u32 __user *u32ptr = uptr;

	return put_user(VMCI_HOST_CONTEXT_ID, u32ptr) ? -EFAULT : 0;
}

static int vmci_host_do_set_notify(struct vmci_host_dev *vmci_host_dev,
				   const char *ioctl_name,
				   void __user *uptr)
{
	struct vmci_set_notify_info notify_info;

	if (vmci_host_dev->ct_type != VMCIOBJ_CONTEXT) {
		vmci_ioctl_err("only valid for contexts\n");
		return -EINVAL;
	}

	if (copy_from_user(&notify_info, uptr, sizeof(notify_info)))
		return -EFAULT;

	if (notify_info.notify_uva) {
		notify_info.result =
			vmci_host_setup_notify(vmci_host_dev->context,
					       notify_info.notify_uva);
	} else {
		vmci_ctx_unset_notify(vmci_host_dev->context);
		notify_info.result = VMCI_SUCCESS;
	}

	return copy_to_user(uptr, &notify_info, sizeof(notify_info)) ?
		-EFAULT : 0;
}

static int vmci_host_do_notify_resource(struct vmci_host_dev *vmci_host_dev,
					const char *ioctl_name,
					void __user *uptr)
{
	struct vmci_dbell_notify_resource_info info;
	u32 cid;

	if (vmci_host_dev->user_version < VMCI_VERSION_NOTIFY) {
		vmci_ioctl_err("invalid for current VMX versions\n");
		return -EINVAL;
	}

	if (vmci_host_dev->ct_type != VMCIOBJ_CONTEXT) {
		vmci_ioctl_err("only valid for contexts\n");
		return -EINVAL;
	}

	if (copy_from_user(&info, uptr, sizeof(info)))
		return -EFAULT;

	cid = vmci_ctx_get_id(vmci_host_dev->context);

	switch (info.action) {
	case VMCI_NOTIFY_RESOURCE_ACTION_NOTIFY:
		if (info.resource == VMCI_NOTIFY_RESOURCE_DOOR_BELL) {
			u32 flags = VMCI_NO_PRIVILEGE_FLAGS;
			info.result = vmci_ctx_notify_dbell(cid, info.handle,
							    flags);
		} else {
			info.result = VMCI_ERROR_UNAVAILABLE;
		}
		break;

	case VMCI_NOTIFY_RESOURCE_ACTION_CREATE:
		info.result = vmci_ctx_dbell_create(cid, info.handle);
		break;

	case VMCI_NOTIFY_RESOURCE_ACTION_DESTROY:
		info.result = vmci_ctx_dbell_destroy(cid, info.handle);
		break;

	default:
		vmci_ioctl_err("got unknown action (action=%d)\n",
			       info.action);
		info.result = VMCI_ERROR_INVALID_ARGS;
	}

	return copy_to_user(uptr, &info, sizeof(info)) ? -EFAULT : 0;
}

static int vmci_host_do_recv_notifications(struct vmci_host_dev *vmci_host_dev,
					   const char *ioctl_name,
					   void __user *uptr)
{
	struct vmci_ctx_notify_recv_info info;
	struct vmci_handle_arr *db_handle_array;
	struct vmci_handle_arr *qp_handle_array;
	void __user *ubuf;
	u32 cid;
	int retval = 0;

	if (vmci_host_dev->ct_type != VMCIOBJ_CONTEXT) {
		vmci_ioctl_err("only valid for contexts\n");
		return -EINVAL;
	}

	if (vmci_host_dev->user_version < VMCI_VERSION_NOTIFY) {
		vmci_ioctl_err("not supported for the current vmx version\n");
		return -EINVAL;
	}

	if (copy_from_user(&info, uptr, sizeof(info)))
		return -EFAULT;

	if ((info.db_handle_buf_size && !info.db_handle_buf_uva) ||
	    (info.qp_handle_buf_size && !info.qp_handle_buf_uva)) {
		return -EINVAL;
	}

	cid = vmci_ctx_get_id(vmci_host_dev->context);

	info.result = vmci_ctx_rcv_notifications_get(cid,
				&db_handle_array, &qp_handle_array);
	if (info.result != VMCI_SUCCESS)
		return copy_to_user(uptr, &info, sizeof(info)) ? -EFAULT : 0;

	ubuf = (void __user *)(uintptr_t)info.db_handle_buf_uva;
	info.result = drv_cp_harray_to_user(ubuf, &info.db_handle_buf_size,
					    db_handle_array, &retval);
	if (info.result == VMCI_SUCCESS && !retval) {
		ubuf = (void __user *)(uintptr_t)info.qp_handle_buf_uva;
		info.result = drv_cp_harray_to_user(ubuf,
						    &info.qp_handle_buf_size,
						    qp_handle_array, &retval);
	}

	if (!retval && copy_to_user(uptr, &info, sizeof(info)))
		retval = -EFAULT;

	vmci_ctx_rcv_notifications_release(cid,
				db_handle_array, qp_handle_array,
				info.result == VMCI_SUCCESS && !retval);

	return retval;
}

static long vmci_host_unlocked_ioctl(struct file *filp,
				     unsigned int iocmd, unsigned long ioarg)
{
#define VMCI_DO_IOCTL(ioctl_name, ioctl_fn) do {			\
		char *name = __stringify(IOCTL_VMCI_ ## ioctl_name);	\
		return vmci_host_do_ ## ioctl_fn(			\
			vmci_host_dev, name, uptr);			\
	} while (0)

	struct vmci_host_dev *vmci_host_dev = filp->private_data;
	void __user *uptr = (void __user *)ioarg;

	switch (iocmd) {
	case IOCTL_VMCI_INIT_CONTEXT:
		VMCI_DO_IOCTL(INIT_CONTEXT, init_context);
	case IOCTL_VMCI_DATAGRAM_SEND:
		VMCI_DO_IOCTL(DATAGRAM_SEND, send_datagram);
	case IOCTL_VMCI_DATAGRAM_RECEIVE:
		VMCI_DO_IOCTL(DATAGRAM_RECEIVE, receive_datagram);
	case IOCTL_VMCI_QUEUEPAIR_ALLOC:
		VMCI_DO_IOCTL(QUEUEPAIR_ALLOC, alloc_queuepair);
	case IOCTL_VMCI_QUEUEPAIR_SETVA:
		VMCI_DO_IOCTL(QUEUEPAIR_SETVA, queuepair_setva);
	case IOCTL_VMCI_QUEUEPAIR_SETPAGEFILE:
		VMCI_DO_IOCTL(QUEUEPAIR_SETPAGEFILE, queuepair_setpf);
	case IOCTL_VMCI_QUEUEPAIR_DETACH:
		VMCI_DO_IOCTL(QUEUEPAIR_DETACH, qp_detach);
	case IOCTL_VMCI_CTX_ADD_NOTIFICATION:
		VMCI_DO_IOCTL(CTX_ADD_NOTIFICATION, ctx_add_notify);
	case IOCTL_VMCI_CTX_REMOVE_NOTIFICATION:
		VMCI_DO_IOCTL(CTX_REMOVE_NOTIFICATION, ctx_remove_notify);
	case IOCTL_VMCI_CTX_GET_CPT_STATE:
		VMCI_DO_IOCTL(CTX_GET_CPT_STATE, ctx_get_cpt_state);
	case IOCTL_VMCI_CTX_SET_CPT_STATE:
		VMCI_DO_IOCTL(CTX_SET_CPT_STATE, ctx_set_cpt_state);
	case IOCTL_VMCI_GET_CONTEXT_ID:
		VMCI_DO_IOCTL(GET_CONTEXT_ID, get_context_id);
	case IOCTL_VMCI_SET_NOTIFY:
		VMCI_DO_IOCTL(SET_NOTIFY, set_notify);
	case IOCTL_VMCI_NOTIFY_RESOURCE:
		VMCI_DO_IOCTL(NOTIFY_RESOURCE, notify_resource);
	case IOCTL_VMCI_NOTIFICATIONS_RECEIVE:
		VMCI_DO_IOCTL(NOTIFICATIONS_RECEIVE, recv_notifications);

	case IOCTL_VMCI_VERSION:
	case IOCTL_VMCI_VERSION2:
		return vmci_host_get_version(vmci_host_dev, iocmd, uptr);

	default:
		pr_devel("%s: Unknown ioctl (iocmd=%d)\n", __func__, iocmd);
		return -EINVAL;
	}

#undef VMCI_DO_IOCTL
}

static const struct file_operations vmuser_fops = {
	.owner		= THIS_MODULE,
	.open		= vmci_host_open,
	.release	= vmci_host_close,
	.poll		= vmci_host_poll,
	.unlocked_ioctl	= vmci_host_unlocked_ioctl,
	.compat_ioctl	= vmci_host_unlocked_ioctl,
};

static struct miscdevice vmci_host_miscdev = {
	 .name = "vmci",
	 .minor = MISC_DYNAMIC_MINOR,
	 .fops = &vmuser_fops,
};

int __init vmci_host_init(void)
{
	int error;

	host_context = vmci_ctx_create(VMCI_HOST_CONTEXT_ID,
					VMCI_DEFAULT_PROC_PRIVILEGE_FLAGS,
					-1, VMCI_VERSION, NULL);
	if (IS_ERR(host_context)) {
		error = PTR_ERR(host_context);
		pr_warn("Failed to initialize VMCIContext (error%d)\n",
			error);
		return error;
	}

	error = misc_register(&vmci_host_miscdev);
	if (error) {
		pr_warn("Module registration error (name=%s, major=%d, minor=%d, err=%d)\n",
			vmci_host_miscdev.name,
			MISC_MAJOR, vmci_host_miscdev.minor,
			error);
		pr_warn("Unable to initialize host personality\n");
		vmci_ctx_destroy(host_context);
		return error;
	}

	pr_info("VMCI host device registered (name=%s, major=%d, minor=%d)\n",
		vmci_host_miscdev.name, MISC_MAJOR, vmci_host_miscdev.minor);

	vmci_host_device_initialized = true;
	return 0;
}

void __exit vmci_host_exit(void)
{
	vmci_host_device_initialized = false;

	misc_deregister(&vmci_host_miscdev);
	vmci_ctx_destroy(host_context);
	vmci_qp_broker_exit();

	pr_debug("VMCI host driver module unloaded\n");
}