summaryrefslogtreecommitdiff
path: root/arch/arm64/kvm/hyp/nvhe/ffa.c
blob: 02746f9d0980f95d40e70f2c985d9e6051bc1ecf (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * FF-A v1.0 proxy to filter out invalid memory-sharing SMC calls issued by
 * the host. FF-A is a slightly more palatable abbreviation of "Arm Firmware
 * Framework for Arm A-profile", which is specified by Arm in document
 * number DEN0077.
 *
 * Copyright (C) 2022 - Google LLC
 * Author: Andrew Walbran <qwandor@google.com>
 *
 * This driver hooks into the SMC trapping logic for the host and intercepts
 * all calls falling within the FF-A range. Each call is either:
 *
 *	- Forwarded on unmodified to the SPMD at EL3
 *	- Rejected as "unsupported"
 *	- Accompanied by a host stage-2 page-table check/update and reissued
 *
 * Consequently, any attempts by the host to make guest memory pages
 * accessible to the secure world using FF-A will be detected either here
 * (in the case that the memory is already owned by the guest) or during
 * donation to the guest (in the case that the memory was previously shared
 * with the secure world).
 *
 * To allow the rolling-back of page-table updates and FF-A calls in the
 * event of failure, operations involving the RXTX buffers are locked for
 * the duration and are therefore serialised.
 */

#include <linux/arm-smccc.h>
#include <linux/arm_ffa.h>
#include <asm/kvm_pkvm.h>

#include <nvhe/ffa.h>
#include <nvhe/mem_protect.h>
#include <nvhe/memory.h>
#include <nvhe/trap_handler.h>
#include <nvhe/spinlock.h>

/*
 * "ID value 0 must be returned at the Non-secure physical FF-A instance"
 * We share this ID with the host.
 */
#define HOST_FFA_ID	0

/*
 * A buffer to hold the maximum descriptor size we can see from the host,
 * which is required when the SPMD returns a fragmented FFA_MEM_RETRIEVE_RESP
 * when resolving the handle on the reclaim path.
 */
struct kvm_ffa_descriptor_buffer {
	void	*buf;
	size_t	len;
};

static struct kvm_ffa_descriptor_buffer ffa_desc_buf;

struct kvm_ffa_buffers {
	hyp_spinlock_t lock;
	void *tx;
	void *rx;
};

/*
 * Note that we don't currently lock these buffers explicitly, instead
 * relying on the locking of the host FFA buffers as we only have one
 * client.
 */
static struct kvm_ffa_buffers hyp_buffers;
static struct kvm_ffa_buffers host_buffers;

static void ffa_to_smccc_error(struct arm_smccc_res *res, u64 ffa_errno)
{
	*res = (struct arm_smccc_res) {
		.a0	= FFA_ERROR,
		.a2	= ffa_errno,
	};
}

static void ffa_to_smccc_res_prop(struct arm_smccc_res *res, int ret, u64 prop)
{
	if (ret == FFA_RET_SUCCESS) {
		*res = (struct arm_smccc_res) { .a0 = FFA_SUCCESS,
						.a2 = prop };
	} else {
		ffa_to_smccc_error(res, ret);
	}
}

static void ffa_to_smccc_res(struct arm_smccc_res *res, int ret)
{
	ffa_to_smccc_res_prop(res, ret, 0);
}

static void ffa_set_retval(struct kvm_cpu_context *ctxt,
			   struct arm_smccc_res *res)
{
	cpu_reg(ctxt, 0) = res->a0;
	cpu_reg(ctxt, 1) = res->a1;
	cpu_reg(ctxt, 2) = res->a2;
	cpu_reg(ctxt, 3) = res->a3;
}

static bool is_ffa_call(u64 func_id)
{
	return ARM_SMCCC_IS_FAST_CALL(func_id) &&
	       ARM_SMCCC_OWNER_NUM(func_id) == ARM_SMCCC_OWNER_STANDARD &&
	       ARM_SMCCC_FUNC_NUM(func_id) >= FFA_MIN_FUNC_NUM &&
	       ARM_SMCCC_FUNC_NUM(func_id) <= FFA_MAX_FUNC_NUM;
}

static int ffa_map_hyp_buffers(u64 ffa_page_count)
{
	struct arm_smccc_res res;

	arm_smccc_1_1_smc(FFA_FN64_RXTX_MAP,
			  hyp_virt_to_phys(hyp_buffers.tx),
			  hyp_virt_to_phys(hyp_buffers.rx),
			  ffa_page_count,
			  0, 0, 0, 0,
			  &res);

	return res.a0 == FFA_SUCCESS ? FFA_RET_SUCCESS : res.a2;
}

static int ffa_unmap_hyp_buffers(void)
{
	struct arm_smccc_res res;

	arm_smccc_1_1_smc(FFA_RXTX_UNMAP,
			  HOST_FFA_ID,
			  0, 0, 0, 0, 0, 0,
			  &res);

	return res.a0 == FFA_SUCCESS ? FFA_RET_SUCCESS : res.a2;
}

static void ffa_mem_frag_tx(struct arm_smccc_res *res, u32 handle_lo,
			     u32 handle_hi, u32 fraglen, u32 endpoint_id)
{
	arm_smccc_1_1_smc(FFA_MEM_FRAG_TX,
			  handle_lo, handle_hi, fraglen, endpoint_id,
			  0, 0, 0,
			  res);
}

static void ffa_mem_frag_rx(struct arm_smccc_res *res, u32 handle_lo,
			     u32 handle_hi, u32 fragoff)
{
	arm_smccc_1_1_smc(FFA_MEM_FRAG_RX,
			  handle_lo, handle_hi, fragoff, HOST_FFA_ID,
			  0, 0, 0,
			  res);
}

static void ffa_mem_xfer(struct arm_smccc_res *res, u64 func_id, u32 len,
			  u32 fraglen)
{
	arm_smccc_1_1_smc(func_id, len, fraglen,
			  0, 0, 0, 0, 0,
			  res);
}

static void ffa_mem_reclaim(struct arm_smccc_res *res, u32 handle_lo,
			     u32 handle_hi, u32 flags)
{
	arm_smccc_1_1_smc(FFA_MEM_RECLAIM,
			  handle_lo, handle_hi, flags,
			  0, 0, 0, 0,
			  res);
}

static void ffa_retrieve_req(struct arm_smccc_res *res, u32 len)
{
	arm_smccc_1_1_smc(FFA_FN64_MEM_RETRIEVE_REQ,
			  len, len,
			  0, 0, 0, 0, 0,
			  res);
}

static void do_ffa_rxtx_map(struct arm_smccc_res *res,
			    struct kvm_cpu_context *ctxt)
{
	DECLARE_REG(phys_addr_t, tx, ctxt, 1);
	DECLARE_REG(phys_addr_t, rx, ctxt, 2);
	DECLARE_REG(u32, npages, ctxt, 3);
	int ret = 0;
	void *rx_virt, *tx_virt;

	if (npages != (KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE) / FFA_PAGE_SIZE) {
		ret = FFA_RET_INVALID_PARAMETERS;
		goto out;
	}

	if (!PAGE_ALIGNED(tx) || !PAGE_ALIGNED(rx)) {
		ret = FFA_RET_INVALID_PARAMETERS;
		goto out;
	}

	hyp_spin_lock(&host_buffers.lock);
	if (host_buffers.tx) {
		ret = FFA_RET_DENIED;
		goto out_unlock;
	}

	/*
	 * Map our hypervisor buffers into the SPMD before mapping and
	 * pinning the host buffers in our own address space.
	 */
	ret = ffa_map_hyp_buffers(npages);
	if (ret)
		goto out_unlock;

	ret = __pkvm_host_share_hyp(hyp_phys_to_pfn(tx));
	if (ret) {
		ret = FFA_RET_INVALID_PARAMETERS;
		goto err_unmap;
	}

	ret = __pkvm_host_share_hyp(hyp_phys_to_pfn(rx));
	if (ret) {
		ret = FFA_RET_INVALID_PARAMETERS;
		goto err_unshare_tx;
	}

	tx_virt = hyp_phys_to_virt(tx);
	ret = hyp_pin_shared_mem(tx_virt, tx_virt + 1);
	if (ret) {
		ret = FFA_RET_INVALID_PARAMETERS;
		goto err_unshare_rx;
	}

	rx_virt = hyp_phys_to_virt(rx);
	ret = hyp_pin_shared_mem(rx_virt, rx_virt + 1);
	if (ret) {
		ret = FFA_RET_INVALID_PARAMETERS;
		goto err_unpin_tx;
	}

	host_buffers.tx = tx_virt;
	host_buffers.rx = rx_virt;

out_unlock:
	hyp_spin_unlock(&host_buffers.lock);
out:
	ffa_to_smccc_res(res, ret);
	return;

err_unpin_tx:
	hyp_unpin_shared_mem(tx_virt, tx_virt + 1);
err_unshare_rx:
	__pkvm_host_unshare_hyp(hyp_phys_to_pfn(rx));
err_unshare_tx:
	__pkvm_host_unshare_hyp(hyp_phys_to_pfn(tx));
err_unmap:
	ffa_unmap_hyp_buffers();
	goto out_unlock;
}

static void do_ffa_rxtx_unmap(struct arm_smccc_res *res,
			      struct kvm_cpu_context *ctxt)
{
	DECLARE_REG(u32, id, ctxt, 1);
	int ret = 0;

	if (id != HOST_FFA_ID) {
		ret = FFA_RET_INVALID_PARAMETERS;
		goto out;
	}

	hyp_spin_lock(&host_buffers.lock);
	if (!host_buffers.tx) {
		ret = FFA_RET_INVALID_PARAMETERS;
		goto out_unlock;
	}

	hyp_unpin_shared_mem(host_buffers.tx, host_buffers.tx + 1);
	WARN_ON(__pkvm_host_unshare_hyp(hyp_virt_to_pfn(host_buffers.tx)));
	host_buffers.tx = NULL;

	hyp_unpin_shared_mem(host_buffers.rx, host_buffers.rx + 1);
	WARN_ON(__pkvm_host_unshare_hyp(hyp_virt_to_pfn(host_buffers.rx)));
	host_buffers.rx = NULL;

	ffa_unmap_hyp_buffers();

out_unlock:
	hyp_spin_unlock(&host_buffers.lock);
out:
	ffa_to_smccc_res(res, ret);
}

static u32 __ffa_host_share_ranges(struct ffa_mem_region_addr_range *ranges,
				   u32 nranges)
{
	u32 i;

	for (i = 0; i < nranges; ++i) {
		struct ffa_mem_region_addr_range *range = &ranges[i];
		u64 sz = (u64)range->pg_cnt * FFA_PAGE_SIZE;
		u64 pfn = hyp_phys_to_pfn(range->address);

		if (!PAGE_ALIGNED(sz))
			break;

		if (__pkvm_host_share_ffa(pfn, sz / PAGE_SIZE))
			break;
	}

	return i;
}

static u32 __ffa_host_unshare_ranges(struct ffa_mem_region_addr_range *ranges,
				     u32 nranges)
{
	u32 i;

	for (i = 0; i < nranges; ++i) {
		struct ffa_mem_region_addr_range *range = &ranges[i];
		u64 sz = (u64)range->pg_cnt * FFA_PAGE_SIZE;
		u64 pfn = hyp_phys_to_pfn(range->address);

		if (!PAGE_ALIGNED(sz))
			break;

		if (__pkvm_host_unshare_ffa(pfn, sz / PAGE_SIZE))
			break;
	}

	return i;
}

static int ffa_host_share_ranges(struct ffa_mem_region_addr_range *ranges,
				 u32 nranges)
{
	u32 nshared = __ffa_host_share_ranges(ranges, nranges);
	int ret = 0;

	if (nshared != nranges) {
		WARN_ON(__ffa_host_unshare_ranges(ranges, nshared) != nshared);
		ret = FFA_RET_DENIED;
	}

	return ret;
}

static int ffa_host_unshare_ranges(struct ffa_mem_region_addr_range *ranges,
				   u32 nranges)
{
	u32 nunshared = __ffa_host_unshare_ranges(ranges, nranges);
	int ret = 0;

	if (nunshared != nranges) {
		WARN_ON(__ffa_host_share_ranges(ranges, nunshared) != nunshared);
		ret = FFA_RET_DENIED;
	}

	return ret;
}

static void do_ffa_mem_frag_tx(struct arm_smccc_res *res,
			       struct kvm_cpu_context *ctxt)
{
	DECLARE_REG(u32, handle_lo, ctxt, 1);
	DECLARE_REG(u32, handle_hi, ctxt, 2);
	DECLARE_REG(u32, fraglen, ctxt, 3);
	DECLARE_REG(u32, endpoint_id, ctxt, 4);
	struct ffa_mem_region_addr_range *buf;
	int ret = FFA_RET_INVALID_PARAMETERS;
	u32 nr_ranges;

	if (fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE)
		goto out;

	if (fraglen % sizeof(*buf))
		goto out;

	hyp_spin_lock(&host_buffers.lock);
	if (!host_buffers.tx)
		goto out_unlock;

	buf = hyp_buffers.tx;
	memcpy(buf, host_buffers.tx, fraglen);
	nr_ranges = fraglen / sizeof(*buf);

	ret = ffa_host_share_ranges(buf, nr_ranges);
	if (ret) {
		/*
		 * We're effectively aborting the transaction, so we need
		 * to restore the global state back to what it was prior to
		 * transmission of the first fragment.
		 */
		ffa_mem_reclaim(res, handle_lo, handle_hi, 0);
		WARN_ON(res->a0 != FFA_SUCCESS);
		goto out_unlock;
	}

	ffa_mem_frag_tx(res, handle_lo, handle_hi, fraglen, endpoint_id);
	if (res->a0 != FFA_SUCCESS && res->a0 != FFA_MEM_FRAG_RX)
		WARN_ON(ffa_host_unshare_ranges(buf, nr_ranges));

out_unlock:
	hyp_spin_unlock(&host_buffers.lock);
out:
	if (ret)
		ffa_to_smccc_res(res, ret);

	/*
	 * If for any reason this did not succeed, we're in trouble as we have
	 * now lost the content of the previous fragments and we can't rollback
	 * the host stage-2 changes. The pages previously marked as shared will
	 * remain stuck in that state forever, hence preventing the host from
	 * sharing/donating them again and may possibly lead to subsequent
	 * failures, but this will not compromise confidentiality.
	 */
	return;
}

static __always_inline void do_ffa_mem_xfer(const u64 func_id,
					    struct arm_smccc_res *res,
					    struct kvm_cpu_context *ctxt)
{
	DECLARE_REG(u32, len, ctxt, 1);
	DECLARE_REG(u32, fraglen, ctxt, 2);
	DECLARE_REG(u64, addr_mbz, ctxt, 3);
	DECLARE_REG(u32, npages_mbz, ctxt, 4);
	struct ffa_mem_region_attributes *ep_mem_access;
	struct ffa_composite_mem_region *reg;
	struct ffa_mem_region *buf;
	u32 offset, nr_ranges;
	int ret = 0;

	BUILD_BUG_ON(func_id != FFA_FN64_MEM_SHARE &&
		     func_id != FFA_FN64_MEM_LEND);

	if (addr_mbz || npages_mbz || fraglen > len ||
	    fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE) {
		ret = FFA_RET_INVALID_PARAMETERS;
		goto out;
	}

	if (fraglen < sizeof(struct ffa_mem_region) +
		      sizeof(struct ffa_mem_region_attributes)) {
		ret = FFA_RET_INVALID_PARAMETERS;
		goto out;
	}

	hyp_spin_lock(&host_buffers.lock);
	if (!host_buffers.tx) {
		ret = FFA_RET_INVALID_PARAMETERS;
		goto out_unlock;
	}

	buf = hyp_buffers.tx;
	memcpy(buf, host_buffers.tx, fraglen);

	ep_mem_access = (void *)buf +
			ffa_mem_desc_offset(buf, 0, FFA_VERSION_1_0);
	offset = ep_mem_access->composite_off;
	if (!offset || buf->ep_count != 1 || buf->sender_id != HOST_FFA_ID) {
		ret = FFA_RET_INVALID_PARAMETERS;
		goto out_unlock;
	}

	if (fraglen < offset + sizeof(struct ffa_composite_mem_region)) {
		ret = FFA_RET_INVALID_PARAMETERS;
		goto out_unlock;
	}

	reg = (void *)buf + offset;
	nr_ranges = ((void *)buf + fraglen) - (void *)reg->constituents;
	if (nr_ranges % sizeof(reg->constituents[0])) {
		ret = FFA_RET_INVALID_PARAMETERS;
		goto out_unlock;
	}

	nr_ranges /= sizeof(reg->constituents[0]);
	ret = ffa_host_share_ranges(reg->constituents, nr_ranges);
	if (ret)
		goto out_unlock;

	ffa_mem_xfer(res, func_id, len, fraglen);
	if (fraglen != len) {
		if (res->a0 != FFA_MEM_FRAG_RX)
			goto err_unshare;

		if (res->a3 != fraglen)
			goto err_unshare;
	} else if (res->a0 != FFA_SUCCESS) {
		goto err_unshare;
	}

out_unlock:
	hyp_spin_unlock(&host_buffers.lock);
out:
	if (ret)
		ffa_to_smccc_res(res, ret);
	return;

err_unshare:
	WARN_ON(ffa_host_unshare_ranges(reg->constituents, nr_ranges));
	goto out_unlock;
}

static void do_ffa_mem_reclaim(struct arm_smccc_res *res,
			       struct kvm_cpu_context *ctxt)
{
	DECLARE_REG(u32, handle_lo, ctxt, 1);
	DECLARE_REG(u32, handle_hi, ctxt, 2);
	DECLARE_REG(u32, flags, ctxt, 3);
	struct ffa_mem_region_attributes *ep_mem_access;
	struct ffa_composite_mem_region *reg;
	u32 offset, len, fraglen, fragoff;
	struct ffa_mem_region *buf;
	int ret = 0;
	u64 handle;

	handle = PACK_HANDLE(handle_lo, handle_hi);

	hyp_spin_lock(&host_buffers.lock);

	buf = hyp_buffers.tx;
	*buf = (struct ffa_mem_region) {
		.sender_id	= HOST_FFA_ID,
		.handle		= handle,
	};

	ffa_retrieve_req(res, sizeof(*buf));
	buf = hyp_buffers.rx;
	if (res->a0 != FFA_MEM_RETRIEVE_RESP)
		goto out_unlock;

	len = res->a1;
	fraglen = res->a2;

	ep_mem_access = (void *)buf +
			ffa_mem_desc_offset(buf, 0, FFA_VERSION_1_0);
	offset = ep_mem_access->composite_off;
	/*
	 * We can trust the SPMD to get this right, but let's at least
	 * check that we end up with something that doesn't look _completely_
	 * bogus.
	 */
	if (WARN_ON(offset > len ||
		    fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE)) {
		ret = FFA_RET_ABORTED;
		goto out_unlock;
	}

	if (len > ffa_desc_buf.len) {
		ret = FFA_RET_NO_MEMORY;
		goto out_unlock;
	}

	buf = ffa_desc_buf.buf;
	memcpy(buf, hyp_buffers.rx, fraglen);

	for (fragoff = fraglen; fragoff < len; fragoff += fraglen) {
		ffa_mem_frag_rx(res, handle_lo, handle_hi, fragoff);
		if (res->a0 != FFA_MEM_FRAG_TX) {
			ret = FFA_RET_INVALID_PARAMETERS;
			goto out_unlock;
		}

		fraglen = res->a3;
		memcpy((void *)buf + fragoff, hyp_buffers.rx, fraglen);
	}

	ffa_mem_reclaim(res, handle_lo, handle_hi, flags);
	if (res->a0 != FFA_SUCCESS)
		goto out_unlock;

	reg = (void *)buf + offset;
	/* If the SPMD was happy, then we should be too. */
	WARN_ON(ffa_host_unshare_ranges(reg->constituents,
					reg->addr_range_cnt));
out_unlock:
	hyp_spin_unlock(&host_buffers.lock);

	if (ret)
		ffa_to_smccc_res(res, ret);
}

/*
 * Is a given FFA function supported, either by forwarding on directly
 * or by handling at EL2?
 */
static bool ffa_call_supported(u64 func_id)
{
	switch (func_id) {
	/* Unsupported memory management calls */
	case FFA_FN64_MEM_RETRIEVE_REQ:
	case FFA_MEM_RETRIEVE_RESP:
	case FFA_MEM_RELINQUISH:
	case FFA_MEM_OP_PAUSE:
	case FFA_MEM_OP_RESUME:
	case FFA_MEM_FRAG_RX:
	case FFA_FN64_MEM_DONATE:
	/* Indirect message passing via RX/TX buffers */
	case FFA_MSG_SEND:
	case FFA_MSG_POLL:
	case FFA_MSG_WAIT:
	/* 32-bit variants of 64-bit calls */
	case FFA_MSG_SEND_DIRECT_RESP:
	case FFA_RXTX_MAP:
	case FFA_MEM_DONATE:
	case FFA_MEM_RETRIEVE_REQ:
		return false;
	}

	return true;
}

static bool do_ffa_features(struct arm_smccc_res *res,
			    struct kvm_cpu_context *ctxt)
{
	DECLARE_REG(u32, id, ctxt, 1);
	u64 prop = 0;
	int ret = 0;

	if (!ffa_call_supported(id)) {
		ret = FFA_RET_NOT_SUPPORTED;
		goto out_handled;
	}

	switch (id) {
	case FFA_MEM_SHARE:
	case FFA_FN64_MEM_SHARE:
	case FFA_MEM_LEND:
	case FFA_FN64_MEM_LEND:
		ret = FFA_RET_SUCCESS;
		prop = 0; /* No support for dynamic buffers */
		goto out_handled;
	default:
		return false;
	}

out_handled:
	ffa_to_smccc_res_prop(res, ret, prop);
	return true;
}

bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt, u32 func_id)
{
	struct arm_smccc_res res;

	/*
	 * There's no way we can tell what a non-standard SMC call might
	 * be up to. Ideally, we would terminate these here and return
	 * an error to the host, but sadly devices make use of custom
	 * firmware calls for things like power management, debugging,
	 * RNG access and crash reporting.
	 *
	 * Given that the architecture requires us to trust EL3 anyway,
	 * we forward unrecognised calls on under the assumption that
	 * the firmware doesn't expose a mechanism to access arbitrary
	 * non-secure memory. Short of a per-device table of SMCs, this
	 * is the best we can do.
	 */
	if (!is_ffa_call(func_id))
		return false;

	switch (func_id) {
	case FFA_FEATURES:
		if (!do_ffa_features(&res, host_ctxt))
			return false;
		goto out_handled;
	/* Memory management */
	case FFA_FN64_RXTX_MAP:
		do_ffa_rxtx_map(&res, host_ctxt);
		goto out_handled;
	case FFA_RXTX_UNMAP:
		do_ffa_rxtx_unmap(&res, host_ctxt);
		goto out_handled;
	case FFA_MEM_SHARE:
	case FFA_FN64_MEM_SHARE:
		do_ffa_mem_xfer(FFA_FN64_MEM_SHARE, &res, host_ctxt);
		goto out_handled;
	case FFA_MEM_RECLAIM:
		do_ffa_mem_reclaim(&res, host_ctxt);
		goto out_handled;
	case FFA_MEM_LEND:
	case FFA_FN64_MEM_LEND:
		do_ffa_mem_xfer(FFA_FN64_MEM_LEND, &res, host_ctxt);
		goto out_handled;
	case FFA_MEM_FRAG_TX:
		do_ffa_mem_frag_tx(&res, host_ctxt);
		goto out_handled;
	}

	if (ffa_call_supported(func_id))
		return false; /* Pass through */

	ffa_to_smccc_error(&res, FFA_RET_NOT_SUPPORTED);
out_handled:
	ffa_set_retval(host_ctxt, &res);
	return true;
}

int hyp_ffa_init(void *pages)
{
	struct arm_smccc_res res;
	size_t min_rxtx_sz;
	void *tx, *rx;

	if (kvm_host_psci_config.smccc_version < ARM_SMCCC_VERSION_1_2)
		return 0;

	arm_smccc_1_1_smc(FFA_VERSION, FFA_VERSION_1_0, 0, 0, 0, 0, 0, 0, &res);
	if (res.a0 == FFA_RET_NOT_SUPPORTED)
		return 0;

	/*
	 * Firmware returns the maximum supported version of the FF-A
	 * implementation. Check that the returned version is
	 * backwards-compatible with the hyp according to the rules in DEN0077A
	 * v1.1 REL0 13.2.1.
	 *
	 * Of course, things are never simple when dealing with firmware. v1.1
	 * broke ABI with v1.0 on several structures, which is itself
	 * incompatible with the aforementioned versioning scheme. The
	 * expectation is that v1.x implementations that do not support the v1.0
	 * ABI return NOT_SUPPORTED rather than a version number, according to
	 * DEN0077A v1.1 REL0 18.6.4.
	 */
	if (FFA_MAJOR_VERSION(res.a0) != 1)
		return -EOPNOTSUPP;

	arm_smccc_1_1_smc(FFA_ID_GET, 0, 0, 0, 0, 0, 0, 0, &res);
	if (res.a0 != FFA_SUCCESS)
		return -EOPNOTSUPP;

	if (res.a2 != HOST_FFA_ID)
		return -EINVAL;

	arm_smccc_1_1_smc(FFA_FEATURES, FFA_FN64_RXTX_MAP,
			  0, 0, 0, 0, 0, 0, &res);
	if (res.a0 != FFA_SUCCESS)
		return -EOPNOTSUPP;

	switch (res.a2) {
	case FFA_FEAT_RXTX_MIN_SZ_4K:
		min_rxtx_sz = SZ_4K;
		break;
	case FFA_FEAT_RXTX_MIN_SZ_16K:
		min_rxtx_sz = SZ_16K;
		break;
	case FFA_FEAT_RXTX_MIN_SZ_64K:
		min_rxtx_sz = SZ_64K;
		break;
	default:
		return -EINVAL;
	}

	if (min_rxtx_sz > PAGE_SIZE)
		return -EOPNOTSUPP;

	tx = pages;
	pages += KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE;
	rx = pages;
	pages += KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE;

	ffa_desc_buf = (struct kvm_ffa_descriptor_buffer) {
		.buf	= pages,
		.len	= PAGE_SIZE *
			  (hyp_ffa_proxy_pages() - (2 * KVM_FFA_MBOX_NR_PAGES)),
	};

	hyp_buffers = (struct kvm_ffa_buffers) {
		.lock	= __HYP_SPIN_LOCK_UNLOCKED,
		.tx	= tx,
		.rx	= rx,
	};

	host_buffers = (struct kvm_ffa_buffers) {
		.lock	= __HYP_SPIN_LOCK_UNLOCKED,
	};

	return 0;
}