xref: /linux/arch/arm64/kvm/hypercalls.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2019 Arm Ltd.
3 
4 #include <linux/arm-smccc.h>
5 #include <linux/kvm_host.h>
6 
7 #include <asm/kvm_emulate.h>
8 
9 #include <kvm/arm_hypercalls.h>
10 #include <kvm/arm_psci.h>
11 
12 #define KVM_ARM_SMCCC_STD_FEATURES				\
13 	GENMASK(KVM_REG_ARM_STD_BMAP_BIT_COUNT - 1, 0)
14 #define KVM_ARM_SMCCC_STD_HYP_FEATURES				\
15 	GENMASK(KVM_REG_ARM_STD_HYP_BMAP_BIT_COUNT - 1, 0)
16 #define KVM_ARM_SMCCC_VENDOR_HYP_FEATURES			\
17 	GENMASK(KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_COUNT - 1, 0)
18 
19 static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val)
20 {
21 	struct system_time_snapshot systime_snapshot;
22 	u64 cycles = ~0UL;
23 	u32 feature;
24 
25 	/*
26 	 * system time and counter value must captured at the same
27 	 * time to keep consistency and precision.
28 	 */
29 	ktime_get_snapshot(&systime_snapshot);
30 
31 	/*
32 	 * This is only valid if the current clocksource is the
33 	 * architected counter, as this is the only one the guest
34 	 * can see.
35 	 */
36 	if (systime_snapshot.cs_id != CSID_ARM_ARCH_COUNTER)
37 		return;
38 
39 	/*
40 	 * The guest selects one of the two reference counters
41 	 * (virtual or physical) with the first argument of the SMCCC
42 	 * call. In case the identifier is not supported, error out.
43 	 */
44 	feature = smccc_get_arg1(vcpu);
45 	switch (feature) {
46 	case KVM_PTP_VIRT_COUNTER:
47 		cycles = systime_snapshot.cycles - vcpu->kvm->arch.timer_data.voffset;
48 		break;
49 	case KVM_PTP_PHYS_COUNTER:
50 		cycles = systime_snapshot.cycles - vcpu->kvm->arch.timer_data.poffset;
51 		break;
52 	default:
53 		return;
54 	}
55 
56 	/*
57 	 * This relies on the top bit of val[0] never being set for
58 	 * valid values of system time, because that is *really* far
59 	 * in the future (about 292 years from 1970, and at that stage
60 	 * nobody will give a damn about it).
61 	 */
62 	val[0] = upper_32_bits(systime_snapshot.real);
63 	val[1] = lower_32_bits(systime_snapshot.real);
64 	val[2] = upper_32_bits(cycles);
65 	val[3] = lower_32_bits(cycles);
66 }
67 
68 static bool kvm_smccc_default_allowed(u32 func_id)
69 {
70 	switch (func_id) {
71 	/*
72 	 * List of function-ids that are not gated with the bitmapped
73 	 * feature firmware registers, and are to be allowed for
74 	 * servicing the call by default.
75 	 */
76 	case ARM_SMCCC_VERSION_FUNC_ID:
77 	case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
78 		return true;
79 	default:
80 		/* PSCI 0.2 and up is in the 0:0x1f range */
81 		if (ARM_SMCCC_OWNER_NUM(func_id) == ARM_SMCCC_OWNER_STANDARD &&
82 		    ARM_SMCCC_FUNC_NUM(func_id) <= 0x1f)
83 			return true;
84 
85 		/*
86 		 * KVM's PSCI 0.1 doesn't comply with SMCCC, and has
87 		 * its own function-id base and range
88 		 */
89 		if (func_id >= KVM_PSCI_FN(0) && func_id <= KVM_PSCI_FN(3))
90 			return true;
91 
92 		return false;
93 	}
94 }
95 
96 static bool kvm_smccc_test_fw_bmap(struct kvm_vcpu *vcpu, u32 func_id)
97 {
98 	struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;
99 
100 	switch (func_id) {
101 	case ARM_SMCCC_TRNG_VERSION:
102 	case ARM_SMCCC_TRNG_FEATURES:
103 	case ARM_SMCCC_TRNG_GET_UUID:
104 	case ARM_SMCCC_TRNG_RND32:
105 	case ARM_SMCCC_TRNG_RND64:
106 		return test_bit(KVM_REG_ARM_STD_BIT_TRNG_V1_0,
107 				&smccc_feat->std_bmap);
108 	case ARM_SMCCC_HV_PV_TIME_FEATURES:
109 	case ARM_SMCCC_HV_PV_TIME_ST:
110 		return test_bit(KVM_REG_ARM_STD_HYP_BIT_PV_TIME,
111 				&smccc_feat->std_hyp_bmap);
112 	case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
113 	case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID:
114 		return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT,
115 				&smccc_feat->vendor_hyp_bmap);
116 	case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
117 		return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_PTP,
118 				&smccc_feat->vendor_hyp_bmap);
119 	default:
120 		return false;
121 	}
122 }
123 
124 #define SMC32_ARCH_RANGE_BEGIN	ARM_SMCCC_VERSION_FUNC_ID
125 #define SMC32_ARCH_RANGE_END	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,		\
126 						   ARM_SMCCC_SMC_32,		\
127 						   0, ARM_SMCCC_FUNC_MASK)
128 
129 #define SMC64_ARCH_RANGE_BEGIN	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,		\
130 						   ARM_SMCCC_SMC_64,		\
131 						   0, 0)
132 #define SMC64_ARCH_RANGE_END	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,		\
133 						   ARM_SMCCC_SMC_64,		\
134 						   0, ARM_SMCCC_FUNC_MASK)
135 
136 static int kvm_smccc_filter_insert_reserved(struct kvm *kvm)
137 {
138 	int r;
139 
140 	/*
141 	 * Prevent userspace from handling any SMCCC calls in the architecture
142 	 * range, avoiding the risk of misrepresenting Spectre mitigation status
143 	 * to the guest.
144 	 */
145 	r = mtree_insert_range(&kvm->arch.smccc_filter,
146 			       SMC32_ARCH_RANGE_BEGIN, SMC32_ARCH_RANGE_END,
147 			       xa_mk_value(KVM_SMCCC_FILTER_HANDLE),
148 			       GFP_KERNEL_ACCOUNT);
149 	if (r)
150 		goto out_destroy;
151 
152 	r = mtree_insert_range(&kvm->arch.smccc_filter,
153 			       SMC64_ARCH_RANGE_BEGIN, SMC64_ARCH_RANGE_END,
154 			       xa_mk_value(KVM_SMCCC_FILTER_HANDLE),
155 			       GFP_KERNEL_ACCOUNT);
156 	if (r)
157 		goto out_destroy;
158 
159 	return 0;
160 out_destroy:
161 	mtree_destroy(&kvm->arch.smccc_filter);
162 	return r;
163 }
164 
165 static bool kvm_smccc_filter_configured(struct kvm *kvm)
166 {
167 	return !mtree_empty(&kvm->arch.smccc_filter);
168 }
169 
170 static int kvm_smccc_set_filter(struct kvm *kvm, struct kvm_smccc_filter __user *uaddr)
171 {
172 	const void *zero_page = page_to_virt(ZERO_PAGE(0));
173 	struct kvm_smccc_filter filter;
174 	u32 start, end;
175 	int r;
176 
177 	if (copy_from_user(&filter, uaddr, sizeof(filter)))
178 		return -EFAULT;
179 
180 	if (memcmp(filter.pad, zero_page, sizeof(filter.pad)))
181 		return -EINVAL;
182 
183 	start = filter.base;
184 	end = start + filter.nr_functions - 1;
185 
186 	if (end < start || filter.action >= NR_SMCCC_FILTER_ACTIONS)
187 		return -EINVAL;
188 
189 	mutex_lock(&kvm->arch.config_lock);
190 
191 	if (kvm_vm_has_ran_once(kvm)) {
192 		r = -EBUSY;
193 		goto out_unlock;
194 	}
195 
196 	if (!kvm_smccc_filter_configured(kvm)) {
197 		r = kvm_smccc_filter_insert_reserved(kvm);
198 		if (WARN_ON_ONCE(r))
199 			goto out_unlock;
200 	}
201 
202 	r = mtree_insert_range(&kvm->arch.smccc_filter, start, end,
203 			       xa_mk_value(filter.action), GFP_KERNEL_ACCOUNT);
204 out_unlock:
205 	mutex_unlock(&kvm->arch.config_lock);
206 	return r;
207 }
208 
209 static u8 kvm_smccc_filter_get_action(struct kvm *kvm, u32 func_id)
210 {
211 	unsigned long idx = func_id;
212 	void *val;
213 
214 	if (!kvm_smccc_filter_configured(kvm))
215 		return KVM_SMCCC_FILTER_HANDLE;
216 
217 	/*
218 	 * But where's the error handling, you say?
219 	 *
220 	 * mt_find() returns NULL if no entry was found, which just so happens
221 	 * to match KVM_SMCCC_FILTER_HANDLE.
222 	 */
223 	val = mt_find(&kvm->arch.smccc_filter, &idx, idx);
224 	return xa_to_value(val);
225 }
226 
227 static u8 kvm_smccc_get_action(struct kvm_vcpu *vcpu, u32 func_id)
228 {
229 	/*
230 	 * Intervening actions in the SMCCC filter take precedence over the
231 	 * pseudo-firmware register bitmaps.
232 	 */
233 	u8 action = kvm_smccc_filter_get_action(vcpu->kvm, func_id);
234 	if (action != KVM_SMCCC_FILTER_HANDLE)
235 		return action;
236 
237 	if (kvm_smccc_test_fw_bmap(vcpu, func_id) ||
238 	    kvm_smccc_default_allowed(func_id))
239 		return KVM_SMCCC_FILTER_HANDLE;
240 
241 	return KVM_SMCCC_FILTER_DENY;
242 }
243 
244 static void kvm_prepare_hypercall_exit(struct kvm_vcpu *vcpu, u32 func_id)
245 {
246 	u8 ec = ESR_ELx_EC(kvm_vcpu_get_esr(vcpu));
247 	struct kvm_run *run = vcpu->run;
248 	u64 flags = 0;
249 
250 	if (ec == ESR_ELx_EC_SMC32 || ec == ESR_ELx_EC_SMC64)
251 		flags |= KVM_HYPERCALL_EXIT_SMC;
252 
253 	if (!kvm_vcpu_trap_il_is32bit(vcpu))
254 		flags |= KVM_HYPERCALL_EXIT_16BIT;
255 
256 	run->exit_reason = KVM_EXIT_HYPERCALL;
257 	run->hypercall = (typeof(run->hypercall)) {
258 		.nr	= func_id,
259 		.flags	= flags,
260 	};
261 }
262 
263 int kvm_smccc_call_handler(struct kvm_vcpu *vcpu)
264 {
265 	struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;
266 	u32 func_id = smccc_get_function(vcpu);
267 	u64 val[4] = {SMCCC_RET_NOT_SUPPORTED};
268 	u32 feature;
269 	u8 action;
270 	gpa_t gpa;
271 
272 	action = kvm_smccc_get_action(vcpu, func_id);
273 	switch (action) {
274 	case KVM_SMCCC_FILTER_HANDLE:
275 		break;
276 	case KVM_SMCCC_FILTER_DENY:
277 		goto out;
278 	case KVM_SMCCC_FILTER_FWD_TO_USER:
279 		kvm_prepare_hypercall_exit(vcpu, func_id);
280 		return 0;
281 	default:
282 		WARN_RATELIMIT(1, "Unhandled SMCCC filter action: %d\n", action);
283 		goto out;
284 	}
285 
286 	switch (func_id) {
287 	case ARM_SMCCC_VERSION_FUNC_ID:
288 		val[0] = ARM_SMCCC_VERSION_1_1;
289 		break;
290 	case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
291 		feature = smccc_get_arg1(vcpu);
292 		switch (feature) {
293 		case ARM_SMCCC_ARCH_WORKAROUND_1:
294 			switch (arm64_get_spectre_v2_state()) {
295 			case SPECTRE_VULNERABLE:
296 				break;
297 			case SPECTRE_MITIGATED:
298 				val[0] = SMCCC_RET_SUCCESS;
299 				break;
300 			case SPECTRE_UNAFFECTED:
301 				val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
302 				break;
303 			}
304 			break;
305 		case ARM_SMCCC_ARCH_WORKAROUND_2:
306 			switch (arm64_get_spectre_v4_state()) {
307 			case SPECTRE_VULNERABLE:
308 				break;
309 			case SPECTRE_MITIGATED:
310 				/*
311 				 * SSBS everywhere: Indicate no firmware
312 				 * support, as the SSBS support will be
313 				 * indicated to the guest and the default is
314 				 * safe.
315 				 *
316 				 * Otherwise, expose a permanent mitigation
317 				 * to the guest, and hide SSBS so that the
318 				 * guest stays protected.
319 				 */
320 				if (kvm_has_feat(vcpu->kvm, ID_AA64PFR1_EL1, SSBS, IMP))
321 					break;
322 				fallthrough;
323 			case SPECTRE_UNAFFECTED:
324 				val[0] = SMCCC_RET_NOT_REQUIRED;
325 				break;
326 			}
327 			break;
328 		case ARM_SMCCC_ARCH_WORKAROUND_3:
329 			switch (arm64_get_spectre_bhb_state()) {
330 			case SPECTRE_VULNERABLE:
331 				break;
332 			case SPECTRE_MITIGATED:
333 				val[0] = SMCCC_RET_SUCCESS;
334 				break;
335 			case SPECTRE_UNAFFECTED:
336 				val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
337 				break;
338 			}
339 			break;
340 		case ARM_SMCCC_HV_PV_TIME_FEATURES:
341 			if (test_bit(KVM_REG_ARM_STD_HYP_BIT_PV_TIME,
342 				     &smccc_feat->std_hyp_bmap))
343 				val[0] = SMCCC_RET_SUCCESS;
344 			break;
345 		}
346 		break;
347 	case ARM_SMCCC_HV_PV_TIME_FEATURES:
348 		val[0] = kvm_hypercall_pv_features(vcpu);
349 		break;
350 	case ARM_SMCCC_HV_PV_TIME_ST:
351 		gpa = kvm_init_stolen_time(vcpu);
352 		if (gpa != INVALID_GPA)
353 			val[0] = gpa;
354 		break;
355 	case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID:
356 		val[0] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0;
357 		val[1] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1;
358 		val[2] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2;
359 		val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3;
360 		break;
361 	case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
362 		val[0] = smccc_feat->vendor_hyp_bmap;
363 		break;
364 	case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
365 		kvm_ptp_get_time(vcpu, val);
366 		break;
367 	case ARM_SMCCC_TRNG_VERSION:
368 	case ARM_SMCCC_TRNG_FEATURES:
369 	case ARM_SMCCC_TRNG_GET_UUID:
370 	case ARM_SMCCC_TRNG_RND32:
371 	case ARM_SMCCC_TRNG_RND64:
372 		return kvm_trng_call(vcpu);
373 	default:
374 		return kvm_psci_call(vcpu);
375 	}
376 
377 out:
378 	smccc_set_retval(vcpu, val[0], val[1], val[2], val[3]);
379 	return 1;
380 }
381 
382 static const u64 kvm_arm_fw_reg_ids[] = {
383 	KVM_REG_ARM_PSCI_VERSION,
384 	KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1,
385 	KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2,
386 	KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3,
387 	KVM_REG_ARM_STD_BMAP,
388 	KVM_REG_ARM_STD_HYP_BMAP,
389 	KVM_REG_ARM_VENDOR_HYP_BMAP,
390 };
391 
392 void kvm_arm_init_hypercalls(struct kvm *kvm)
393 {
394 	struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat;
395 
396 	smccc_feat->std_bmap = KVM_ARM_SMCCC_STD_FEATURES;
397 	smccc_feat->std_hyp_bmap = KVM_ARM_SMCCC_STD_HYP_FEATURES;
398 	smccc_feat->vendor_hyp_bmap = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES;
399 
400 	mt_init(&kvm->arch.smccc_filter);
401 }
402 
403 void kvm_arm_teardown_hypercalls(struct kvm *kvm)
404 {
405 	mtree_destroy(&kvm->arch.smccc_filter);
406 }
407 
408 int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
409 {
410 	return ARRAY_SIZE(kvm_arm_fw_reg_ids);
411 }
412 
413 int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
414 {
415 	int i;
416 
417 	for (i = 0; i < ARRAY_SIZE(kvm_arm_fw_reg_ids); i++) {
418 		if (put_user(kvm_arm_fw_reg_ids[i], uindices++))
419 			return -EFAULT;
420 	}
421 
422 	return 0;
423 }
424 
425 #define KVM_REG_FEATURE_LEVEL_MASK	GENMASK(3, 0)
426 
427 /*
428  * Convert the workaround level into an easy-to-compare number, where higher
429  * values mean better protection.
430  */
431 static int get_kernel_wa_level(struct kvm_vcpu *vcpu, u64 regid)
432 {
433 	switch (regid) {
434 	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
435 		switch (arm64_get_spectre_v2_state()) {
436 		case SPECTRE_VULNERABLE:
437 			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
438 		case SPECTRE_MITIGATED:
439 			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_AVAIL;
440 		case SPECTRE_UNAFFECTED:
441 			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_REQUIRED;
442 		}
443 		return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
444 	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
445 		switch (arm64_get_spectre_v4_state()) {
446 		case SPECTRE_MITIGATED:
447 			/*
448 			 * As for the hypercall discovery, we pretend we
449 			 * don't have any FW mitigation if SSBS is there at
450 			 * all times.
451 			 */
452 			if (kvm_has_feat(vcpu->kvm, ID_AA64PFR1_EL1, SSBS, IMP))
453 				return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
454 			fallthrough;
455 		case SPECTRE_UNAFFECTED:
456 			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
457 		case SPECTRE_VULNERABLE:
458 			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
459 		}
460 		break;
461 	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
462 		switch (arm64_get_spectre_bhb_state()) {
463 		case SPECTRE_VULNERABLE:
464 			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL;
465 		case SPECTRE_MITIGATED:
466 			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_AVAIL;
467 		case SPECTRE_UNAFFECTED:
468 			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_REQUIRED;
469 		}
470 		return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL;
471 	}
472 
473 	return -EINVAL;
474 }
475 
476 int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
477 {
478 	struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;
479 	void __user *uaddr = (void __user *)(long)reg->addr;
480 	u64 val;
481 
482 	switch (reg->id) {
483 	case KVM_REG_ARM_PSCI_VERSION:
484 		val = kvm_psci_version(vcpu);
485 		break;
486 	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
487 	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
488 	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
489 		val = get_kernel_wa_level(vcpu, reg->id) & KVM_REG_FEATURE_LEVEL_MASK;
490 		break;
491 	case KVM_REG_ARM_STD_BMAP:
492 		val = READ_ONCE(smccc_feat->std_bmap);
493 		break;
494 	case KVM_REG_ARM_STD_HYP_BMAP:
495 		val = READ_ONCE(smccc_feat->std_hyp_bmap);
496 		break;
497 	case KVM_REG_ARM_VENDOR_HYP_BMAP:
498 		val = READ_ONCE(smccc_feat->vendor_hyp_bmap);
499 		break;
500 	default:
501 		return -ENOENT;
502 	}
503 
504 	if (copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)))
505 		return -EFAULT;
506 
507 	return 0;
508 }
509 
510 static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val)
511 {
512 	int ret = 0;
513 	struct kvm *kvm = vcpu->kvm;
514 	struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat;
515 	unsigned long *fw_reg_bmap, fw_reg_features;
516 
517 	switch (reg_id) {
518 	case KVM_REG_ARM_STD_BMAP:
519 		fw_reg_bmap = &smccc_feat->std_bmap;
520 		fw_reg_features = KVM_ARM_SMCCC_STD_FEATURES;
521 		break;
522 	case KVM_REG_ARM_STD_HYP_BMAP:
523 		fw_reg_bmap = &smccc_feat->std_hyp_bmap;
524 		fw_reg_features = KVM_ARM_SMCCC_STD_HYP_FEATURES;
525 		break;
526 	case KVM_REG_ARM_VENDOR_HYP_BMAP:
527 		fw_reg_bmap = &smccc_feat->vendor_hyp_bmap;
528 		fw_reg_features = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES;
529 		break;
530 	default:
531 		return -ENOENT;
532 	}
533 
534 	/* Check for unsupported bit */
535 	if (val & ~fw_reg_features)
536 		return -EINVAL;
537 
538 	mutex_lock(&kvm->arch.config_lock);
539 
540 	if (kvm_vm_has_ran_once(kvm) && val != *fw_reg_bmap) {
541 		ret = -EBUSY;
542 		goto out;
543 	}
544 
545 	WRITE_ONCE(*fw_reg_bmap, val);
546 out:
547 	mutex_unlock(&kvm->arch.config_lock);
548 	return ret;
549 }
550 
551 int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
552 {
553 	void __user *uaddr = (void __user *)(long)reg->addr;
554 	u64 val;
555 	int wa_level;
556 
557 	if (KVM_REG_SIZE(reg->id) != sizeof(val))
558 		return -ENOENT;
559 	if (copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id)))
560 		return -EFAULT;
561 
562 	switch (reg->id) {
563 	case KVM_REG_ARM_PSCI_VERSION:
564 	{
565 		bool wants_02;
566 
567 		wants_02 = vcpu_has_feature(vcpu, KVM_ARM_VCPU_PSCI_0_2);
568 
569 		switch (val) {
570 		case KVM_ARM_PSCI_0_1:
571 			if (wants_02)
572 				return -EINVAL;
573 			vcpu->kvm->arch.psci_version = val;
574 			return 0;
575 		case KVM_ARM_PSCI_0_2:
576 		case KVM_ARM_PSCI_1_0:
577 		case KVM_ARM_PSCI_1_1:
578 			if (!wants_02)
579 				return -EINVAL;
580 			vcpu->kvm->arch.psci_version = val;
581 			return 0;
582 		}
583 		break;
584 	}
585 
586 	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
587 	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
588 		if (val & ~KVM_REG_FEATURE_LEVEL_MASK)
589 			return -EINVAL;
590 
591 		if (get_kernel_wa_level(vcpu, reg->id) < val)
592 			return -EINVAL;
593 
594 		return 0;
595 
596 	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
597 		if (val & ~(KVM_REG_FEATURE_LEVEL_MASK |
598 			    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED))
599 			return -EINVAL;
600 
601 		/* The enabled bit must not be set unless the level is AVAIL. */
602 		if ((val & KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED) &&
603 		    (val & KVM_REG_FEATURE_LEVEL_MASK) != KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL)
604 			return -EINVAL;
605 
606 		/*
607 		 * Map all the possible incoming states to the only two we
608 		 * really want to deal with.
609 		 */
610 		switch (val & KVM_REG_FEATURE_LEVEL_MASK) {
611 		case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL:
612 		case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN:
613 			wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
614 			break;
615 		case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL:
616 		case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED:
617 			wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
618 			break;
619 		default:
620 			return -EINVAL;
621 		}
622 
623 		/*
624 		 * We can deal with NOT_AVAIL on NOT_REQUIRED, but not the
625 		 * other way around.
626 		 */
627 		if (get_kernel_wa_level(vcpu, reg->id) < wa_level)
628 			return -EINVAL;
629 
630 		return 0;
631 	case KVM_REG_ARM_STD_BMAP:
632 	case KVM_REG_ARM_STD_HYP_BMAP:
633 	case KVM_REG_ARM_VENDOR_HYP_BMAP:
634 		return kvm_arm_set_fw_reg_bmap(vcpu, reg->id, val);
635 	default:
636 		return -ENOENT;
637 	}
638 
639 	return -EINVAL;
640 }
641 
642 int kvm_vm_smccc_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
643 {
644 	switch (attr->attr) {
645 	case KVM_ARM_VM_SMCCC_FILTER:
646 		return 0;
647 	default:
648 		return -ENXIO;
649 	}
650 }
651 
652 int kvm_vm_smccc_set_attr(struct kvm *kvm, struct kvm_device_attr *attr)
653 {
654 	void __user *uaddr = (void __user *)attr->addr;
655 
656 	switch (attr->attr) {
657 	case KVM_ARM_VM_SMCCC_FILTER:
658 		return kvm_smccc_set_filter(kvm, uaddr);
659 	default:
660 		return -ENXIO;
661 	}
662 }
663