summaryrefslogtreecommitdiffstats
path: root/arch/x86/kvm/xen.c
blob: 74be1fda58e34c34b3e821cf54c45480a460b55c (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
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright © 2019 Oracle and/or its affiliates. All rights reserved.
 * Copyright © 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * KVM Xen emulation
 */

#include "x86.h"
#include "xen.h"
#include "hyperv.h"

#include <linux/kvm_host.h>
#include <linux/sched/stat.h>

#include <trace/events/kvm.h>
#include <xen/interface/xen.h>
#include <xen/interface/vcpu.h>
#include <xen/interface/event_channel.h>

#include "trace.h"

DEFINE_STATIC_KEY_DEFERRED_FALSE(kvm_xen_enabled, HZ);

static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn)
{
	struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
	struct pvclock_wall_clock *wc;
	gpa_t gpa = gfn_to_gpa(gfn);
	u32 *wc_sec_hi;
	u32 wc_version;
	u64 wall_nsec;
	int ret = 0;
	int idx = srcu_read_lock(&kvm->srcu);

	if (gfn == GPA_INVALID) {
		kvm_gfn_to_pfn_cache_destroy(kvm, gpc);
		goto out;
	}

	do {
		ret = kvm_gfn_to_pfn_cache_init(kvm, gpc, NULL, false, true,
						gpa, PAGE_SIZE, false);
		if (ret)
			goto out;

		/*
		 * This code mirrors kvm_write_wall_clock() except that it writes
		 * directly through the pfn cache and doesn't mark the page dirty.
		 */
		wall_nsec = ktime_get_real_ns() - get_kvmclock_ns(kvm);

		/* It could be invalid again already, so we need to check */
		read_lock_irq(&gpc->lock);

		if (gpc->valid)
			break;

		read_unlock_irq(&gpc->lock);
	} while (1);

	/* Paranoia checks on the 32-bit struct layout */
	BUILD_BUG_ON(offsetof(struct compat_shared_info, wc) != 0x900);
	BUILD_BUG_ON(offsetof(struct compat_shared_info, arch.wc_sec_hi) != 0x924);
	BUILD_BUG_ON(offsetof(struct pvclock_vcpu_time_info, version) != 0);

#ifdef CONFIG_X86_64
	/* Paranoia checks on the 64-bit struct layout */
	BUILD_BUG_ON(offsetof(struct shared_info, wc) != 0xc00);
	BUILD_BUG_ON(offsetof(struct shared_info, wc_sec_hi) != 0xc0c);

	if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
		struct shared_info *shinfo = gpc->khva;

		wc_sec_hi = &shinfo->wc_sec_hi;
		wc = &shinfo->wc;
	} else
#endif
	{
		struct compat_shared_info *shinfo = gpc->khva;

		wc_sec_hi = &shinfo->arch.wc_sec_hi;
		wc = &shinfo->wc;
	}

	/* Increment and ensure an odd value */
	wc_version = wc->version = (wc->version + 1) | 1;
	smp_wmb();

	wc->nsec = do_div(wall_nsec,  1000000000);
	wc->sec = (u32)wall_nsec;
	*wc_sec_hi = wall_nsec >> 32;
	smp_wmb();

	wc->version = wc_version + 1;
	read_unlock_irq(&gpc->lock);

	kvm_make_all_cpus_request(kvm, KVM_REQ_MASTERCLOCK_UPDATE);

out:
	srcu_read_unlock(&kvm->srcu, idx);
	return ret;
}

static void kvm_xen_update_runstate(struct kvm_vcpu *v, int state)
{
	struct kvm_vcpu_xen *vx = &v->arch.xen;
	u64 now = get_kvmclock_ns(v->kvm);
	u64 delta_ns = now - vx->runstate_entry_time;
	u64 run_delay = current->sched_info.run_delay;

	if (unlikely(!vx->runstate_entry_time))
		vx->current_runstate = RUNSTATE_offline;

	/*
	 * Time waiting for the scheduler isn't "stolen" if the
	 * vCPU wasn't running anyway.
	 */
	if (vx->current_runstate == RUNSTATE_running) {
		u64 steal_ns = run_delay - vx->last_steal;

		delta_ns -= steal_ns;

		vx->runstate_times[RUNSTATE_runnable] += steal_ns;
	}
	vx->last_steal = run_delay;

	vx->runstate_times[vx->current_runstate] += delta_ns;
	vx->current_runstate = state;
	vx->runstate_entry_time = now;
}

void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, int state)
{
	struct kvm_vcpu_xen *vx = &v->arch.xen;
	struct gfn_to_hva_cache *ghc = &vx->runstate_cache;
	struct kvm_memslots *slots = kvm_memslots(v->kvm);
	bool atomic = (state == RUNSTATE_runnable);
	uint64_t state_entry_time;
	int __user *user_state;
	uint64_t __user *user_times;

	kvm_xen_update_runstate(v, state);

	if (!vx->runstate_set)
		return;

	if (unlikely(slots->generation != ghc->generation || kvm_is_error_hva(ghc->hva)) &&
	    kvm_gfn_to_hva_cache_init(v->kvm, ghc, ghc->gpa, ghc->len))
		return;

	/* We made sure it fits in a single page */
	BUG_ON(!ghc->memslot);

	if (atomic)
		pagefault_disable();

	/*
	 * The only difference between 32-bit and 64-bit versions of the
	 * runstate struct us the alignment of uint64_t in 32-bit, which
	 * means that the 64-bit version has an additional 4 bytes of
	 * padding after the first field 'state'.
	 *
	 * So we use 'int __user *user_state' to point to the state field,
	 * and 'uint64_t __user *user_times' for runstate_entry_time. So
	 * the actual array of time[] in each state starts at user_times[1].
	 */
	BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) != 0);
	BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state) != 0);
	user_state = (int __user *)ghc->hva;

	BUILD_BUG_ON(sizeof(struct compat_vcpu_runstate_info) != 0x2c);

	user_times = (uint64_t __user *)(ghc->hva +
					 offsetof(struct compat_vcpu_runstate_info,
						  state_entry_time));
#ifdef CONFIG_X86_64
	BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) !=
		     offsetof(struct compat_vcpu_runstate_info, state_entry_time) + 4);
	BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, time) !=
		     offsetof(struct compat_vcpu_runstate_info, time) + 4);

	if (v->kvm->arch.xen.long_mode)
		user_times = (uint64_t __user *)(ghc->hva +
						 offsetof(struct vcpu_runstate_info,
							  state_entry_time));
#endif
	/*
	 * First write the updated state_entry_time at the appropriate
	 * location determined by 'offset'.
	 */
	state_entry_time = vx->runstate_entry_time;
	state_entry_time |= XEN_RUNSTATE_UPDATE;

	BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state_entry_time) !=
		     sizeof(state_entry_time));
	BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state_entry_time) !=
		     sizeof(state_entry_time));

	if (__put_user(state_entry_time, user_times))
		goto out;
	smp_wmb();

	/*
	 * Next, write the new runstate. This is in the *same* place
	 * for 32-bit and 64-bit guests, asserted here for paranoia.
	 */
	BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) !=
		     offsetof(struct compat_vcpu_runstate_info, state));
	BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state) !=
		     sizeof(vx->current_runstate));
	BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state) !=
		     sizeof(vx->current_runstate));

	if (__put_user(vx->current_runstate, user_state))
		goto out;

	/*
	 * Write the actual runstate times immediately after the
	 * runstate_entry_time.
	 */
	BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) !=
		     offsetof(struct vcpu_runstate_info, time) - sizeof(u64));
	BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state_entry_time) !=
		     offsetof(struct compat_vcpu_runstate_info, time) - sizeof(u64));
	BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) !=
		     sizeof_field(struct compat_vcpu_runstate_info, time));
	BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) !=
		     sizeof(vx->runstate_times));

	if (__copy_to_user(user_times + 1, vx->runstate_times, sizeof(vx->runstate_times)))
		goto out;
	smp_wmb();

	/*
	 * Finally, clear the XEN_RUNSTATE_UPDATE bit in the guest's
	 * runstate_entry_time field.
	 */
	state_entry_time &= ~XEN_RUNSTATE_UPDATE;
	__put_user(state_entry_time, user_times);
	smp_wmb();

 out:
	mark_page_dirty_in_slot(v->kvm, ghc->memslot, ghc->gpa >> PAGE_SHIFT);

	if (atomic)
		pagefault_enable();
}

int __kvm_xen_has_interrupt(struct kvm_vcpu *v)
{
	unsigned long evtchn_pending_sel = READ_ONCE(v->arch.xen.evtchn_pending_sel);
	bool atomic = in_atomic() || !task_is_running(current);
	int err;
	u8 rc = 0;

	/*
	 * If the global upcall vector (HVMIRQ_callback_vector) is set and
	 * the vCPU's evtchn_upcall_pending flag is set, the IRQ is pending.
	 */
	struct gfn_to_hva_cache *ghc = &v->arch.xen.vcpu_info_cache;
	struct kvm_memslots *slots = kvm_memslots(v->kvm);
	bool ghc_valid = slots->generation == ghc->generation &&
		!kvm_is_error_hva(ghc->hva) && ghc->memslot;

	unsigned int offset = offsetof(struct vcpu_info, evtchn_upcall_pending);

	/* No need for compat handling here */
	BUILD_BUG_ON(offsetof(struct vcpu_info, evtchn_upcall_pending) !=
		     offsetof(struct compat_vcpu_info, evtchn_upcall_pending));
	BUILD_BUG_ON(sizeof(rc) !=
		     sizeof_field(struct vcpu_info, evtchn_upcall_pending));
	BUILD_BUG_ON(sizeof(rc) !=
		     sizeof_field(struct compat_vcpu_info, evtchn_upcall_pending));

	/*
	 * For efficiency, this mirrors the checks for using the valid
	 * cache in kvm_read_guest_offset_cached(), but just uses
	 * __get_user() instead. And falls back to the slow path.
	 */
	if (!evtchn_pending_sel && ghc_valid) {
		/* Fast path */
		pagefault_disable();
		err = __get_user(rc, (u8 __user *)ghc->hva + offset);
		pagefault_enable();
		if (!err)
			return rc;
	}

	/* Slow path */

	/*
	 * This function gets called from kvm_vcpu_block() after setting the
	 * task to TASK_INTERRUPTIBLE, to see if it needs to wake immediately
	 * from a HLT. So we really mustn't sleep. If the page ended up absent
	 * at that point, just return 1 in order to trigger an immediate wake,
	 * and we'll end up getting called again from a context where we *can*
	 * fault in the page and wait for it.
	 */
	if (atomic)
		return 1;

	if (!ghc_valid) {
		err = kvm_gfn_to_hva_cache_init(v->kvm, ghc, ghc->gpa, ghc->len);
		if (err || !ghc->memslot) {
			/*
			 * If this failed, userspace has screwed up the
			 * vcpu_info mapping. No interrupts for you.
			 */
			return 0;
		}
	}

	/*
	 * Now we have a valid (protected by srcu) userspace HVA in
	 * ghc->hva which points to the struct vcpu_info. If there
	 * are any bits in the in-kernel evtchn_pending_sel then
	 * we need to write those to the guest vcpu_info and set
	 * its evtchn_upcall_pending flag. If there aren't any bits
	 * to add, we only want to *check* evtchn_upcall_pending.
	 */
	if (evtchn_pending_sel) {
		bool long_mode = v->kvm->arch.xen.long_mode;

		if (!user_access_begin((void __user *)ghc->hva, sizeof(struct vcpu_info)))
			return 0;

		if (IS_ENABLED(CONFIG_64BIT) && long_mode) {
			struct vcpu_info __user *vi = (void __user *)ghc->hva;

			/* Attempt to set the evtchn_pending_sel bits in the
			 * guest, and if that succeeds then clear the same
			 * bits in the in-kernel version. */
			asm volatile("1:\t" LOCK_PREFIX "orq %0, %1\n"
				     "\tnotq %0\n"
				     "\t" LOCK_PREFIX "andq %0, %2\n"
				     "2:\n"
				     _ASM_EXTABLE_UA(1b, 2b)
				     : "=r" (evtchn_pending_sel),
				       "+m" (vi->evtchn_pending_sel),
				       "+m" (v->arch.xen.evtchn_pending_sel)
				     : "0" (evtchn_pending_sel));
		} else {
			struct compat_vcpu_info __user *vi = (void __user *)ghc->hva;
			u32 evtchn_pending_sel32 = evtchn_pending_sel;

			/* Attempt to set the evtchn_pending_sel bits in the
			 * guest, and if that succeeds then clear the same
			 * bits in the in-kernel version. */
			asm volatile("1:\t" LOCK_PREFIX "orl %0, %1\n"
				     "\tnotl %0\n"
				     "\t" LOCK_PREFIX "andl %0, %2\n"
				     "2:\n"
				     _ASM_EXTABLE_UA(1b, 2b)
				     : "=r" (evtchn_pending_sel32),
				       "+m" (vi->evtchn_pending_sel),
				       "+m" (v->arch.xen.evtchn_pending_sel)
				     : "0" (evtchn_pending_sel32));
		}
		rc = 1;
		unsafe_put_user(rc, (u8 __user *)ghc->hva + offset, err);

	err:
		user_access_end();

		mark_page_dirty_in_slot(v->kvm, ghc->memslot, ghc->gpa >> PAGE_SHIFT);
	} else {
		__get_user(rc, (u8 __user *)ghc->hva + offset);
	}

	return rc;
}

int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
{
	int r = -ENOENT;

	mutex_lock(&kvm->lock);

	switch (data->type) {
	case KVM_XEN_ATTR_TYPE_LONG_MODE:
		if (!IS_ENABLED(CONFIG_64BIT) && data->u.long_mode) {
			r = -EINVAL;
		} else {
			kvm->arch.xen.long_mode = !!data->u.long_mode;
			r = 0;
		}
		break;

	case KVM_XEN_ATTR_TYPE_SHARED_INFO:
		r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn);
		break;

	case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
		if (data->u.vector && data->u.vector < 0x10)
			r = -EINVAL;
		else {
			kvm->arch.xen.upcall_vector = data->u.vector;
			r = 0;
		}
		break;

	default:
		break;
	}

	mutex_unlock(&kvm->lock);
	return r;
}

int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
{
	int r = -ENOENT;

	mutex_lock(&kvm->lock);

	switch (data->type) {
	case KVM_XEN_ATTR_TYPE_LONG_MODE:
		data->u.long_mode = kvm->arch.xen.long_mode;
		r = 0;
		break;

	case KVM_XEN_ATTR_TYPE_SHARED_INFO:
		if (kvm->arch.xen.shinfo_cache.active)
			data->u.shared_info.gfn = gpa_to_gfn(kvm->arch.xen.shinfo_cache.gpa);
		else
			data->u.shared_info.gfn = GPA_INVALID;
		r = 0;
		break;

	case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
		data->u.vector = kvm->arch.xen.upcall_vector;
		r = 0;
		break;

	default:
		break;
	}

	mutex_unlock(&kvm->lock);
	return r;
}

int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
{
	int idx, r = -ENOENT;

	mutex_lock(&vcpu->kvm->lock);
	idx = srcu_read_lock(&vcpu->kvm->srcu);

	switch (data->type) {
	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
		/* No compat necessary here. */
		BUILD_BUG_ON(sizeof(struct vcpu_info) !=
			     sizeof(struct compat_vcpu_info));
		BUILD_BUG_ON(offsetof(struct vcpu_info, time) !=
			     offsetof(struct compat_vcpu_info, time));

		if (data->u.gpa == GPA_INVALID) {
			vcpu->arch.xen.vcpu_info_set = false;
			r = 0;
			break;
		}

		/* It must fit within a single page */
		if ((data->u.gpa & ~PAGE_MASK) + sizeof(struct vcpu_info) > PAGE_SIZE) {
			r = -EINVAL;
			break;
		}

		r = kvm_gfn_to_hva_cache_init(vcpu->kvm,
					      &vcpu->arch.xen.vcpu_info_cache,
					      data->u.gpa,
					      sizeof(struct vcpu_info));
		if (!r) {
			vcpu->arch.xen.vcpu_info_set = true;
			kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
		}
		break;

	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
		if (data->u.gpa == GPA_INVALID) {
			vcpu->arch.xen.vcpu_time_info_set = false;
			r = 0;
			break;
		}

		/* It must fit within a single page */
		if ((data->u.gpa & ~PAGE_MASK) + sizeof(struct pvclock_vcpu_time_info) > PAGE_SIZE) {
			r = -EINVAL;
			break;
		}

		r = kvm_gfn_to_hva_cache_init(vcpu->kvm,
					      &vcpu->arch.xen.vcpu_time_info_cache,
					      data->u.gpa,
					      sizeof(struct pvclock_vcpu_time_info));
		if (!r) {
			vcpu->arch.xen.vcpu_time_info_set = true;
			kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
		}
		break;

	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR:
		if (!sched_info_on()) {
			r = -EOPNOTSUPP;
			break;
		}
		if (data->u.gpa == GPA_INVALID) {
			vcpu->arch.xen.runstate_set = false;
			r = 0;
			break;
		}

		/* It must fit within a single page */
		if ((data->u.gpa & ~PAGE_MASK) + sizeof(struct vcpu_runstate_info) > PAGE_SIZE) {
			r = -EINVAL;
			break;
		}

		r = kvm_gfn_to_hva_cache_init(vcpu->kvm,
					      &vcpu->arch.xen.runstate_cache,
					      data->u.gpa,
					      sizeof(struct vcpu_runstate_info));
		if (!r) {
			vcpu->arch.xen.runstate_set = true;
		}
		break;

	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
		if (!sched_info_on()) {
			r = -EOPNOTSUPP;
			break;
		}
		if (data->u.runstate.state > RUNSTATE_offline) {
			r = -EINVAL;
			break;
		}

		kvm_xen_update_runstate(vcpu, data->u.runstate.state);
		r = 0;
		break;

	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
		if (!sched_info_on()) {
			r = -EOPNOTSUPP;
			break;
		}
		if (data->u.runstate.state > RUNSTATE_offline) {
			r = -EINVAL;
			break;
		}
		if (data->u.runstate.state_entry_time !=
		    (data->u.runstate.time_running +
		     data->u.runstate.time_runnable +
		     data->u.runstate.time_blocked +
		     data->u.runstate.time_offline)) {
			r = -EINVAL;
			break;
		}
		if (get_kvmclock_ns(vcpu->kvm) <
		    data->u.runstate.state_entry_time) {
			r = -EINVAL;
			break;
		}

		vcpu->arch.xen.current_runstate = data->u.runstate.state;
		vcpu->arch.xen.runstate_entry_time =
			data->u.runstate.state_entry_time;
		vcpu->arch.xen.runstate_times[RUNSTATE_running] =
			data->u.runstate.time_running;
		vcpu->arch.xen.runstate_times[RUNSTATE_runnable] =
			data->u.runstate.time_runnable;
		vcpu->arch.xen.runstate_times[RUNSTATE_blocked] =
			data->u.runstate.time_blocked;
		vcpu->arch.xen.runstate_times[RUNSTATE_offline] =
			data->u.runstate.time_offline;
		vcpu->arch.xen.last_steal = current->sched_info.run_delay;
		r = 0;
		break;

	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
		if (!sched_info_on()) {
			r = -EOPNOTSUPP;
			break;
		}
		if (data->u.runstate.state > RUNSTATE_offline &&
		    data->u.runstate.state != (u64)-1) {
			r = -EINVAL;
			break;
		}
		/* The adjustment must add up */
		if (data->u.runstate.state_entry_time !=
		    (data->u.runstate.time_running +
		     data->u.runstate.time_runnable +
		     data->u.runstate.time_blocked +
		     data->u.runstate.time_offline)) {
			r = -EINVAL;
			break;
		}

		if (get_kvmclock_ns(vcpu->kvm) <
		    (vcpu->arch.xen.runstate_entry_time +
		     data->u.runstate.state_entry_time)) {
			r = -EINVAL;
			break;
		}

		vcpu->arch.xen.runstate_entry_time +=
			data->u.runstate.state_entry_time;
		vcpu->arch.xen.runstate_times[RUNSTATE_running] +=
			data->u.runstate.time_running;
		vcpu->arch.xen.runstate_times[RUNSTATE_runnable] +=
			data->u.runstate.time_runnable;
		vcpu->arch.xen.runstate_times[RUNSTATE_blocked] +=
			data->u.runstate.time_blocked;
		vcpu->arch.xen.runstate_times[RUNSTATE_offline] +=
			data->u.runstate.time_offline;

		if (data->u.runstate.state <= RUNSTATE_offline)
			kvm_xen_update_runstate(vcpu, data->u.runstate.state);
		r = 0;
		break;

	default:
		break;
	}

	srcu_read_unlock(&vcpu->kvm->srcu, idx);
	mutex_unlock(&vcpu->kvm->lock);
	return r;
}

int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
{
	int r = -ENOENT;

	mutex_lock(&vcpu->kvm->lock);

	switch (data->type) {
	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
		if (vcpu->arch.xen.vcpu_info_set)
			data->u.gpa = vcpu->arch.xen.vcpu_info_cache.gpa;
		else
			data->u.gpa = GPA_INVALID;
		r = 0;
		break;

	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
		if (vcpu->arch.xen.vcpu_time_info_set)
			data->u.gpa = vcpu->arch.xen.vcpu_time_info_cache.gpa;
		else
			data->u.gpa = GPA_INVALID;
		r = 0;
		break;

	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR:
		if (!sched_info_on()) {
			r = -EOPNOTSUPP;
			break;
		}
		if (vcpu->arch.xen.runstate_set) {
			data->u.gpa = vcpu->arch.xen.runstate_cache.gpa;
			r = 0;
		}
		break;

	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
		if (!sched_info_on()) {
			r = -EOPNOTSUPP;
			break;
		}
		data->u.runstate.state = vcpu->arch.xen.current_runstate;
		r = 0;
		break;

	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
		if (!sched_info_on()) {
			r = -EOPNOTSUPP;
			break;
		}
		data->u.runstate.state = vcpu->arch.xen.current_runstate;
		data->u.runstate.state_entry_time =
			vcpu->arch.xen.runstate_entry_time;
		data->u.runstate.time_running =
			vcpu->arch.xen.runstate_times[RUNSTATE_running];
		data->u.runstate.time_runnable =
			vcpu->arch.xen.runstate_times[RUNSTATE_runnable];
		data->u.runstate.time_blocked =
			vcpu->arch.xen.runstate_times[RUNSTATE_blocked];
		data->u.runstate.time_offline =
			vcpu->arch.xen.runstate_times[RUNSTATE_offline];
		r = 0;
		break;

	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
		r = -EINVAL;
		break;

	default:
		break;
	}

	mutex_unlock(&vcpu->kvm->lock);
	return r;
}

int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data)
{
	struct kvm *kvm = vcpu->kvm;
	u32 page_num = data & ~PAGE_MASK;
	u64 page_addr = data & PAGE_MASK;
	bool lm = is_long_mode(vcpu);

	/* Latch long_mode for shared_info pages etc. */
	vcpu->kvm->arch.xen.long_mode = lm;

	/*
	 * If Xen hypercall intercept is enabled, fill the hypercall
	 * page with VMCALL/VMMCALL instructions since that's what
	 * we catch. Else the VMM has provided the hypercall pages
	 * with instructions of its own choosing, so use those.
	 */
	if (kvm_xen_hypercall_enabled(kvm)) {
		u8 instructions[32];
		int i;

		if (page_num)
			return 1;

		/* mov imm32, %eax */
		instructions[0] = 0xb8;

		/* vmcall / vmmcall */
		kvm_x86_ops.patch_hypercall(vcpu, instructions + 5);

		/* ret */
		instructions[8] = 0xc3;

		/* int3 to pad */
		memset(instructions + 9, 0xcc, sizeof(instructions) - 9);

		for (i = 0; i < PAGE_SIZE / sizeof(instructions); i++) {
			*(u32 *)&instructions[1] = i;
			if (kvm_vcpu_write_guest(vcpu,
						 page_addr + (i * sizeof(instructions)),
						 instructions, sizeof(instructions)))
				return 1;
		}
	} else {
		/*
		 * Note, truncation is a non-issue as 'lm' is guaranteed to be
		 * false for a 32-bit kernel, i.e. when hva_t is only 4 bytes.
		 */
		hva_t blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64
				     : kvm->arch.xen_hvm_config.blob_addr_32;
		u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64
				  : kvm->arch.xen_hvm_config.blob_size_32;
		u8 *page;

		if (page_num >= blob_size)
			return 1;

		blob_addr += page_num * PAGE_SIZE;

		page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE);
		if (IS_ERR(page))
			return PTR_ERR(page);

		if (kvm_vcpu_write_guest(vcpu, page_addr, page, PAGE_SIZE)) {
			kfree(page);
			return 1;
		}
	}
	return 0;
}

int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc)
{
	if (xhc->flags & ~KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL)
		return -EINVAL;

	/*
	 * With hypercall interception the kernel generates its own
	 * hypercall page so it must not be provided.
	 */
	if ((xhc->flags & KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL) &&
	    (xhc->blob_addr_32 || xhc->blob_addr_64 ||
	     xhc->blob_size_32 || xhc->blob_size_64))
		return -EINVAL;

	mutex_lock(&kvm->lock);

	if (xhc->msr && !kvm->arch.xen_hvm_config.msr)
		static_branch_inc(&kvm_xen_enabled.key);
	else if (!xhc->msr && kvm->arch.xen_hvm_config.msr)
		static_branch_slow_dec_deferred(&kvm_xen_enabled);

	memcpy(&kvm->arch.xen_hvm_config, xhc, sizeof(*xhc));

	mutex_unlock(&kvm->lock);
	return 0;
}

void kvm_xen_init_vm(struct kvm *kvm)
{
}

void kvm_xen_destroy_vm(struct kvm *kvm)
{
	kvm_gfn_to_pfn_cache_destroy(kvm, &kvm->arch.xen.shinfo_cache);

	if (kvm->arch.xen_hvm_config.msr)
		static_branch_slow_dec_deferred(&kvm_xen_enabled);
}

static int kvm_xen_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)
{
	kvm_rax_write(vcpu, result);
	return kvm_skip_emulated_instruction(vcpu);
}

static int kvm_xen_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
{
	struct kvm_run *run = vcpu->run;

	if (unlikely(!kvm_is_linear_rip(vcpu, vcpu->arch.xen.hypercall_rip)))
		return 1;

	return kvm_xen_hypercall_set_result(vcpu, run->xen.u.hcall.result);
}

int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
{
	bool longmode;
	u64 input, params[6];

	input = (u64)kvm_register_read(vcpu, VCPU_REGS_RAX);

	/* Hyper-V hypercalls get bit 31 set in EAX */
	if ((input & 0x80000000) &&
	    kvm_hv_hypercall_enabled(vcpu))
		return kvm_hv_hypercall(vcpu);

	longmode = is_64_bit_hypercall(vcpu);
	if (!longmode) {
		params[0] = (u32)kvm_rbx_read(vcpu);
		params[1] = (u32)kvm_rcx_read(vcpu);
		params[2] = (u32)kvm_rdx_read(vcpu);
		params[3] = (u32)kvm_rsi_read(vcpu);
		params[4] = (u32)kvm_rdi_read(vcpu);
		params[5] = (u32)kvm_rbp_read(vcpu);
	}
#ifdef CONFIG_X86_64
	else {
		params[0] = (u64)kvm_rdi_read(vcpu);
		params[1] = (u64)kvm_rsi_read(vcpu);
		params[2] = (u64)kvm_rdx_read(vcpu);
		params[3] = (u64)kvm_r10_read(vcpu);
		params[4] = (u64)kvm_r8_read(vcpu);
		params[5] = (u64)kvm_r9_read(vcpu);
	}
#endif
	trace_kvm_xen_hypercall(input, params[0], params[1], params[2],
				params[3], params[4], params[5]);

	vcpu->run->exit_reason = KVM_EXIT_XEN;
	vcpu->run->xen.type = KVM_EXIT_XEN_HCALL;
	vcpu->run->xen.u.hcall.longmode = longmode;
	vcpu->run->xen.u.hcall.cpl = kvm_x86_ops.get_cpl(vcpu);
	vcpu->run->xen.u.hcall.input = input;
	vcpu->run->xen.u.hcall.params[0] = params[0];
	vcpu->run->xen.u.hcall.params[1] = params[1];
	vcpu->run->xen.u.hcall.params[2] = params[2];
	vcpu->run->xen.u.hcall.params[3] = params[3];
	vcpu->run->xen.u.hcall.params[4] = params[4];
	vcpu->run->xen.u.hcall.params[5] = params[5];
	vcpu->arch.xen.hypercall_rip = kvm_get_linear_rip(vcpu);
	vcpu->arch.complete_userspace_io =
		kvm_xen_hypercall_complete_userspace;

	return 0;
}

static inline int max_evtchn_port(struct kvm *kvm)
{
	if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode)
		return EVTCHN_2L_NR_CHANNELS;
	else
		return COMPAT_EVTCHN_2L_NR_CHANNELS;
}

/*
 * This follows the kvm_set_irq() API, so it returns:
 *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
 *  = 0   Interrupt was coalesced (previous irq is still pending)
 *  > 0   Number of CPUs interrupt was delivered to
 */
int kvm_xen_set_evtchn_fast(struct kvm_kernel_irq_routing_entry *e,
			    struct kvm *kvm)
{
	struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
	struct kvm_vcpu *vcpu;
	unsigned long *pending_bits, *mask_bits;
	unsigned long flags;
	int port_word_bit;
	bool kick_vcpu = false;
	int idx;
	int rc;

	vcpu = kvm_get_vcpu_by_id(kvm, e->xen_evtchn.vcpu);
	if (!vcpu)
		return -1;

	if (!vcpu->arch.xen.vcpu_info_set)
		return -1;

	if (e->xen_evtchn.port >= max_evtchn_port(kvm))
		return -1;

	rc = -EWOULDBLOCK;
	read_lock_irqsave(&gpc->lock, flags);

	idx = srcu_read_lock(&kvm->srcu);
	if (!kvm_gfn_to_pfn_cache_check(kvm, gpc, gpc->gpa, PAGE_SIZE))
		goto out_rcu;

	if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
		struct shared_info *shinfo = gpc->khva;
		pending_bits = (unsigned long *)&shinfo->evtchn_pending;
		mask_bits = (unsigned long *)&shinfo->evtchn_mask;
		port_word_bit = e->xen_evtchn.port / 64;
	} else {
		struct compat_shared_info *shinfo = gpc->khva;
		pending_bits = (unsigned long *)&shinfo->evtchn_pending;
		mask_bits = (unsigned long *)&shinfo->evtchn_mask;
		port_word_bit = e->xen_evtchn.port / 32;
	}

	/*
	 * If this port wasn't already set, and if it isn't masked, then
	 * we try to set the corresponding bit in the in-kernel shadow of
	 * evtchn_pending_sel for the target vCPU. And if *that* wasn't
	 * already set, then we kick the vCPU in question to write to the
	 * *real* evtchn_pending_sel in its own guest vcpu_info struct.
	 */
	if (test_and_set_bit(e->xen_evtchn.port, pending_bits)) {
		rc = 0; /* It was already raised */
	} else if (test_bit(e->xen_evtchn.port, mask_bits)) {
		rc = -1; /* Masked */
	} else {
		rc = 1; /* Delivered. But was the vCPU waking already? */
		if (!test_and_set_bit(port_word_bit, &vcpu->arch.xen.evtchn_pending_sel))
			kick_vcpu = true;
	}

 out_rcu:
	srcu_read_unlock(&kvm->srcu, idx);
	read_unlock_irqrestore(&gpc->lock, flags);

	if (kick_vcpu) {
		kvm_make_request(KVM_REQ_EVENT, vcpu);
		kvm_vcpu_kick(vcpu);
	}

	return rc;
}

/* This is the version called from kvm_set_irq() as the .set function */
static int evtchn_set_fn(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm,
			 int irq_source_id, int level, bool line_status)
{
	bool mm_borrowed = false;
	int rc;

	if (!level)
		return -1;

	rc = kvm_xen_set_evtchn_fast(e, kvm);
	if (rc != -EWOULDBLOCK)
		return rc;

	if (current->mm != kvm->mm) {
		/*
		 * If not on a thread which already belongs to this KVM,
		 * we'd better be in the irqfd workqueue.
		 */
		if (WARN_ON_ONCE(current->mm))
			return -EINVAL;

		kthread_use_mm(kvm->mm);
		mm_borrowed = true;
	}

	/*
	 * For the irqfd workqueue, using the main kvm->lock mutex is
	 * fine since this function is invoked from kvm_set_irq() with
	 * no other lock held, no srcu. In future if it will be called
	 * directly from a vCPU thread (e.g. on hypercall for an IPI)
	 * then it may need to switch to using a leaf-node mutex for
	 * serializing the shared_info mapping.
	 */
	mutex_lock(&kvm->lock);

	/*
	 * It is theoretically possible for the page to be unmapped
	 * and the MMU notifier to invalidate the shared_info before
	 * we even get to use it. In that case, this looks like an
	 * infinite loop. It was tempting to do it via the userspace
	 * HVA instead... but that just *hides* the fact that it's
	 * an infinite loop, because if a fault occurs and it waits
	 * for the page to come back, it can *still* immediately
	 * fault and have to wait again, repeatedly.
	 *
	 * Conversely, the page could also have been reinstated by
	 * another thread before we even obtain the mutex above, so
	 * check again *first* before remapping it.
	 */
	do {
		struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
		int idx;

		rc = kvm_xen_set_evtchn_fast(e, kvm);
		if (rc != -EWOULDBLOCK)
			break;

		idx = srcu_read_lock(&kvm->srcu);
		rc = kvm_gfn_to_pfn_cache_refresh(kvm, gpc, gpc->gpa,
						  PAGE_SIZE, false);
		srcu_read_unlock(&kvm->srcu, idx);
	} while(!rc);

	mutex_unlock(&kvm->lock);

	if (mm_borrowed)
		kthread_unuse_mm(kvm->mm);

	return rc;
}

int kvm_xen_setup_evtchn(struct kvm *kvm,
			 struct kvm_kernel_irq_routing_entry *e,
			 const struct kvm_irq_routing_entry *ue)

{
	if (ue->u.xen_evtchn.port >= max_evtchn_port(kvm))
		return -EINVAL;

	/* We only support 2 level event channels for now */
	if (ue->u.xen_evtchn.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
		return -EINVAL;

	e->xen_evtchn.port = ue->u.xen_evtchn.port;
	e->xen_evtchn.vcpu = ue->u.xen_evtchn.vcpu;
	e->xen_evtchn.priority = ue->u.xen_evtchn.priority;
	e->set = evtchn_set_fn;

	return 0;
}