1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2012 - ARM Ltd
4 * Author: Marc Zyngier <marc.zyngier@arm.com>
5 */
6
7 #include <linux/arm-smccc.h>
8 #include <linux/preempt.h>
9 #include <linux/kvm_host.h>
10 #include <linux/uaccess.h>
11 #include <linux/wait.h>
12
13 #include <asm/cputype.h>
14 #include <asm/kvm_emulate.h>
15
16 #include <kvm/arm_psci.h>
17 #include <kvm/arm_hypercalls.h>
18
19 /*
20 * This is an implementation of the Power State Coordination Interface
21 * as described in ARM document number ARM DEN 0022A.
22 */
23
kvm_psci_vcpu_suspend(struct kvm_vcpu * vcpu)24 static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
25 {
26 /*
27 * NOTE: For simplicity, we make VCPU suspend emulation to be
28 * same-as WFI (Wait-for-interrupt) emulation.
29 *
30 * This means for KVM the wakeup events are interrupts and
31 * this is consistent with intended use of StateID as described
32 * in section 5.4.1 of PSCI v0.2 specification (ARM DEN 0022A).
33 *
34 * Further, we also treat power-down request to be same as
35 * stand-by request as-per section 5.4.2 clause 3 of PSCI v0.2
36 * specification (ARM DEN 0022A). This means all suspend states
37 * for KVM will preserve the register state.
38 */
39 kvm_vcpu_block(vcpu);
40 kvm_clear_request(KVM_REQ_UNHALT, vcpu);
41
42 return PSCI_RET_SUCCESS;
43 }
44
kvm_psci_vcpu_off(struct kvm_vcpu * vcpu)45 static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
46 {
47 vcpu->arch.power_off = true;
48 kvm_make_request(KVM_REQ_SLEEP, vcpu);
49 kvm_vcpu_kick(vcpu);
50 }
51
kvm_psci_vcpu_on(struct kvm_vcpu * source_vcpu)52 static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
53 {
54 struct vcpu_reset_state *reset_state;
55 struct kvm *kvm = source_vcpu->kvm;
56 struct kvm_vcpu *vcpu = NULL;
57 unsigned long cpu_id;
58
59 cpu_id = smccc_get_arg1(source_vcpu);
60 if (!kvm_psci_valid_affinity(source_vcpu, cpu_id))
61 return PSCI_RET_INVALID_PARAMS;
62
63 vcpu = kvm_mpidr_to_vcpu(kvm, cpu_id);
64
65 /*
66 * Make sure the caller requested a valid CPU and that the CPU is
67 * turned off.
68 */
69 if (!vcpu)
70 return PSCI_RET_INVALID_PARAMS;
71 if (!vcpu->arch.power_off) {
72 if (kvm_psci_version(source_vcpu, kvm) != KVM_ARM_PSCI_0_1)
73 return PSCI_RET_ALREADY_ON;
74 else
75 return PSCI_RET_INVALID_PARAMS;
76 }
77
78 reset_state = &vcpu->arch.reset_state;
79
80 reset_state->pc = smccc_get_arg2(source_vcpu);
81
82 /* Propagate caller endianness */
83 reset_state->be = kvm_vcpu_is_be(source_vcpu);
84
85 /*
86 * NOTE: We always update r0 (or x0) because for PSCI v0.1
87 * the general purpose registers are undefined upon CPU_ON.
88 */
89 reset_state->r0 = smccc_get_arg3(source_vcpu);
90
91 WRITE_ONCE(reset_state->reset, true);
92 kvm_make_request(KVM_REQ_VCPU_RESET, vcpu);
93
94 /*
95 * Make sure the reset request is observed if the change to
96 * power_off is observed.
97 */
98 smp_wmb();
99
100 vcpu->arch.power_off = false;
101 kvm_vcpu_wake_up(vcpu);
102
103 return PSCI_RET_SUCCESS;
104 }
105
kvm_psci_vcpu_affinity_info(struct kvm_vcpu * vcpu)106 static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
107 {
108 int i, matching_cpus = 0;
109 unsigned long mpidr;
110 unsigned long target_affinity;
111 unsigned long target_affinity_mask;
112 unsigned long lowest_affinity_level;
113 struct kvm *kvm = vcpu->kvm;
114 struct kvm_vcpu *tmp;
115
116 target_affinity = smccc_get_arg1(vcpu);
117 lowest_affinity_level = smccc_get_arg2(vcpu);
118
119 if (!kvm_psci_valid_affinity(vcpu, target_affinity))
120 return PSCI_RET_INVALID_PARAMS;
121
122 /* Determine target affinity mask */
123 target_affinity_mask = psci_affinity_mask(lowest_affinity_level);
124 if (!target_affinity_mask)
125 return PSCI_RET_INVALID_PARAMS;
126
127 /* Ignore other bits of target affinity */
128 target_affinity &= target_affinity_mask;
129
130 /*
131 * If one or more VCPU matching target affinity are running
132 * then ON else OFF
133 */
134 kvm_for_each_vcpu(i, tmp, kvm) {
135 mpidr = kvm_vcpu_get_mpidr_aff(tmp);
136 if ((mpidr & target_affinity_mask) == target_affinity) {
137 matching_cpus++;
138 if (!tmp->arch.power_off)
139 return PSCI_0_2_AFFINITY_LEVEL_ON;
140 }
141 }
142
143 if (!matching_cpus)
144 return PSCI_RET_INVALID_PARAMS;
145
146 return PSCI_0_2_AFFINITY_LEVEL_OFF;
147 }
148
kvm_prepare_system_event(struct kvm_vcpu * vcpu,u32 type,u64 flags)149 static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type, u64 flags)
150 {
151 int i;
152 struct kvm_vcpu *tmp;
153
154 /*
155 * The KVM ABI specifies that a system event exit may call KVM_RUN
156 * again and may perform shutdown/reboot at a later time that when the
157 * actual request is made. Since we are implementing PSCI and a
158 * caller of PSCI reboot and shutdown expects that the system shuts
159 * down or reboots immediately, let's make sure that VCPUs are not run
160 * after this call is handled and before the VCPUs have been
161 * re-initialized.
162 */
163 kvm_for_each_vcpu(i, tmp, vcpu->kvm)
164 tmp->arch.power_off = true;
165 kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
166
167 memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
168 vcpu->run->system_event.type = type;
169 vcpu->run->system_event.flags = flags;
170 vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
171 }
172
kvm_psci_system_off(struct kvm_vcpu * vcpu)173 static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
174 {
175 kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN, 0);
176 }
177
kvm_psci_system_reset(struct kvm_vcpu * vcpu)178 static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
179 {
180 kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET, 0);
181 }
182
kvm_psci_system_reset2(struct kvm_vcpu * vcpu)183 static void kvm_psci_system_reset2(struct kvm_vcpu *vcpu)
184 {
185 kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET,
186 KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2);
187 }
188
kvm_psci_check_allowed_function(struct kvm_vcpu * vcpu,u32 fn)189 static unsigned long kvm_psci_check_allowed_function(struct kvm_vcpu *vcpu, u32 fn)
190 {
191 /*
192 * Prevent 32 bit guests from calling 64 bit PSCI functions.
193 */
194 if ((fn & PSCI_0_2_64BIT) && vcpu_mode_is_32bit(vcpu))
195 return PSCI_RET_NOT_SUPPORTED;
196
197 return 0;
198 }
199
kvm_psci_0_2_call(struct kvm_vcpu * vcpu)200 static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
201 {
202 struct kvm *kvm = vcpu->kvm;
203 u32 psci_fn = smccc_get_function(vcpu);
204 unsigned long val;
205 int ret = 1;
206
207 switch (psci_fn) {
208 case PSCI_0_2_FN_PSCI_VERSION:
209 /*
210 * Bits[31:16] = Major Version = 0
211 * Bits[15:0] = Minor Version = 2
212 */
213 val = KVM_ARM_PSCI_0_2;
214 break;
215 case PSCI_0_2_FN_CPU_SUSPEND:
216 case PSCI_0_2_FN64_CPU_SUSPEND:
217 val = kvm_psci_vcpu_suspend(vcpu);
218 break;
219 case PSCI_0_2_FN_CPU_OFF:
220 kvm_psci_vcpu_off(vcpu);
221 val = PSCI_RET_SUCCESS;
222 break;
223 case PSCI_0_2_FN_CPU_ON:
224 kvm_psci_narrow_to_32bit(vcpu);
225 fallthrough;
226 case PSCI_0_2_FN64_CPU_ON:
227 mutex_lock(&kvm->lock);
228 val = kvm_psci_vcpu_on(vcpu);
229 mutex_unlock(&kvm->lock);
230 break;
231 case PSCI_0_2_FN_AFFINITY_INFO:
232 kvm_psci_narrow_to_32bit(vcpu);
233 fallthrough;
234 case PSCI_0_2_FN64_AFFINITY_INFO:
235 val = kvm_psci_vcpu_affinity_info(vcpu);
236 break;
237 case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
238 /*
239 * Trusted OS is MP hence does not require migration
240 * or
241 * Trusted OS is not present
242 */
243 val = PSCI_0_2_TOS_MP;
244 break;
245 case PSCI_0_2_FN_SYSTEM_OFF:
246 kvm_psci_system_off(vcpu);
247 /*
248 * We shouldn't be going back to guest VCPU after
249 * receiving SYSTEM_OFF request.
250 *
251 * If user space accidentally/deliberately resumes
252 * guest VCPU after SYSTEM_OFF request then guest
253 * VCPU should see internal failure from PSCI return
254 * value. To achieve this, we preload r0 (or x0) with
255 * PSCI return value INTERNAL_FAILURE.
256 */
257 val = PSCI_RET_INTERNAL_FAILURE;
258 ret = 0;
259 break;
260 case PSCI_0_2_FN_SYSTEM_RESET:
261 kvm_psci_system_reset(vcpu);
262 /*
263 * Same reason as SYSTEM_OFF for preloading r0 (or x0)
264 * with PSCI return value INTERNAL_FAILURE.
265 */
266 val = PSCI_RET_INTERNAL_FAILURE;
267 ret = 0;
268 break;
269 default:
270 val = PSCI_RET_NOT_SUPPORTED;
271 break;
272 }
273
274 smccc_set_retval(vcpu, val, 0, 0, 0);
275 return ret;
276 }
277
kvm_psci_1_x_call(struct kvm_vcpu * vcpu,u32 minor)278 static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor)
279 {
280 u32 psci_fn = smccc_get_function(vcpu);
281 u32 arg;
282 unsigned long val;
283 int ret = 1;
284
285 if (minor > 1)
286 return -EINVAL;
287
288 switch(psci_fn) {
289 case PSCI_0_2_FN_PSCI_VERSION:
290 val = minor == 0 ? KVM_ARM_PSCI_1_0 : KVM_ARM_PSCI_1_1;
291 break;
292 case PSCI_1_0_FN_PSCI_FEATURES:
293 arg = smccc_get_arg1(vcpu);
294 val = kvm_psci_check_allowed_function(vcpu, arg);
295 if (val)
296 break;
297
298 switch(arg) {
299 case PSCI_0_2_FN_PSCI_VERSION:
300 case PSCI_0_2_FN_CPU_SUSPEND:
301 case PSCI_0_2_FN64_CPU_SUSPEND:
302 case PSCI_0_2_FN_CPU_OFF:
303 case PSCI_0_2_FN_CPU_ON:
304 case PSCI_0_2_FN64_CPU_ON:
305 case PSCI_0_2_FN_AFFINITY_INFO:
306 case PSCI_0_2_FN64_AFFINITY_INFO:
307 case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
308 case PSCI_0_2_FN_SYSTEM_OFF:
309 case PSCI_0_2_FN_SYSTEM_RESET:
310 case PSCI_1_0_FN_PSCI_FEATURES:
311 case ARM_SMCCC_VERSION_FUNC_ID:
312 val = 0;
313 break;
314 case PSCI_1_1_FN_SYSTEM_RESET2:
315 case PSCI_1_1_FN64_SYSTEM_RESET2:
316 if (minor >= 1) {
317 val = 0;
318 break;
319 }
320 fallthrough;
321 default:
322 val = PSCI_RET_NOT_SUPPORTED;
323 break;
324 }
325 break;
326 case PSCI_1_1_FN_SYSTEM_RESET2:
327 kvm_psci_narrow_to_32bit(vcpu);
328 fallthrough;
329 case PSCI_1_1_FN64_SYSTEM_RESET2:
330 if (minor >= 1) {
331 arg = smccc_get_arg1(vcpu);
332
333 if (arg <= PSCI_1_1_RESET_TYPE_SYSTEM_WARM_RESET ||
334 arg >= PSCI_1_1_RESET_TYPE_VENDOR_START) {
335 kvm_psci_system_reset2(vcpu);
336 vcpu_set_reg(vcpu, 0, PSCI_RET_INTERNAL_FAILURE);
337 return 0;
338 }
339
340 val = PSCI_RET_INVALID_PARAMS;
341 break;
342 };
343 fallthrough;
344 default:
345 return kvm_psci_0_2_call(vcpu);
346 }
347
348 smccc_set_retval(vcpu, val, 0, 0, 0);
349 return ret;
350 }
351
kvm_psci_0_1_call(struct kvm_vcpu * vcpu)352 static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
353 {
354 struct kvm *kvm = vcpu->kvm;
355 u32 psci_fn = smccc_get_function(vcpu);
356 unsigned long val;
357
358 switch (psci_fn) {
359 case KVM_PSCI_FN_CPU_OFF:
360 kvm_psci_vcpu_off(vcpu);
361 val = PSCI_RET_SUCCESS;
362 break;
363 case KVM_PSCI_FN_CPU_ON:
364 mutex_lock(&kvm->lock);
365 val = kvm_psci_vcpu_on(vcpu);
366 mutex_unlock(&kvm->lock);
367 break;
368 default:
369 val = PSCI_RET_NOT_SUPPORTED;
370 break;
371 }
372
373 smccc_set_retval(vcpu, val, 0, 0, 0);
374 return 1;
375 }
376
377 /**
378 * kvm_psci_call - handle PSCI call if r0 value is in range
379 * @vcpu: Pointer to the VCPU struct
380 *
381 * Handle PSCI calls from guests through traps from HVC instructions.
382 * The calling convention is similar to SMC calls to the secure world
383 * where the function number is placed in r0.
384 *
385 * This function returns: > 0 (success), 0 (success but exit to user
386 * space), and < 0 (errors)
387 *
388 * Errors:
389 * -EINVAL: Unrecognized PSCI function
390 */
kvm_psci_call(struct kvm_vcpu * vcpu)391 int kvm_psci_call(struct kvm_vcpu *vcpu)
392 {
393 u32 psci_fn = smccc_get_function(vcpu);
394 unsigned long val;
395
396 val = kvm_psci_check_allowed_function(vcpu, psci_fn);
397 if (val) {
398 smccc_set_retval(vcpu, val, 0, 0, 0);
399 return 1;
400 }
401
402 switch (kvm_psci_version(vcpu, vcpu->kvm)) {
403 case KVM_ARM_PSCI_1_1:
404 return kvm_psci_1_x_call(vcpu, 1);
405 case KVM_ARM_PSCI_1_0:
406 return kvm_psci_1_x_call(vcpu, 0);
407 case KVM_ARM_PSCI_0_2:
408 return kvm_psci_0_2_call(vcpu);
409 case KVM_ARM_PSCI_0_1:
410 return kvm_psci_0_1_call(vcpu);
411 default:
412 return -EINVAL;
413 };
414 }
415
kvm_arm_get_fw_num_regs(struct kvm_vcpu * vcpu)416 int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
417 {
418 return 4; /* PSCI version and three workaround registers */
419 }
420
kvm_arm_copy_fw_reg_indices(struct kvm_vcpu * vcpu,u64 __user * uindices)421 int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
422 {
423 if (put_user(KVM_REG_ARM_PSCI_VERSION, uindices++))
424 return -EFAULT;
425
426 if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1, uindices++))
427 return -EFAULT;
428
429 if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2, uindices++))
430 return -EFAULT;
431
432 if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3, uindices++))
433 return -EFAULT;
434
435 return 0;
436 }
437
438 #define KVM_REG_FEATURE_LEVEL_WIDTH 4
439 #define KVM_REG_FEATURE_LEVEL_MASK (BIT(KVM_REG_FEATURE_LEVEL_WIDTH) - 1)
440
441 /*
442 * Convert the workaround level into an easy-to-compare number, where higher
443 * values mean better protection.
444 */
get_kernel_wa_level(u64 regid)445 static int get_kernel_wa_level(u64 regid)
446 {
447 switch (regid) {
448 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
449 switch (arm64_get_spectre_v2_state()) {
450 case SPECTRE_VULNERABLE:
451 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
452 case SPECTRE_MITIGATED:
453 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_AVAIL;
454 case SPECTRE_UNAFFECTED:
455 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_REQUIRED;
456 }
457 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
458 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
459 switch (arm64_get_spectre_v4_state()) {
460 case SPECTRE_MITIGATED:
461 /*
462 * As for the hypercall discovery, we pretend we
463 * don't have any FW mitigation if SSBS is there at
464 * all times.
465 */
466 if (cpus_have_final_cap(ARM64_SSBS))
467 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
468 fallthrough;
469 case SPECTRE_UNAFFECTED:
470 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
471 case SPECTRE_VULNERABLE:
472 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
473 }
474 break;
475 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
476 switch (arm64_get_spectre_bhb_state()) {
477 case SPECTRE_VULNERABLE:
478 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL;
479 case SPECTRE_MITIGATED:
480 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_AVAIL;
481 case SPECTRE_UNAFFECTED:
482 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_REQUIRED;
483 }
484 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL;
485 }
486
487 return -EINVAL;
488 }
489
kvm_arm_get_fw_reg(struct kvm_vcpu * vcpu,const struct kvm_one_reg * reg)490 int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
491 {
492 void __user *uaddr = (void __user *)(long)reg->addr;
493 u64 val;
494
495 switch (reg->id) {
496 case KVM_REG_ARM_PSCI_VERSION:
497 val = kvm_psci_version(vcpu, vcpu->kvm);
498 break;
499 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
500 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
501 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
502 val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK;
503 break;
504 default:
505 return -ENOENT;
506 }
507
508 if (copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)))
509 return -EFAULT;
510
511 return 0;
512 }
513
kvm_arm_set_fw_reg(struct kvm_vcpu * vcpu,const struct kvm_one_reg * reg)514 int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
515 {
516 void __user *uaddr = (void __user *)(long)reg->addr;
517 u64 val;
518 int wa_level;
519
520 if (KVM_REG_SIZE(reg->id) != sizeof(val))
521 return -ENOENT;
522 if (copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id)))
523 return -EFAULT;
524
525 switch (reg->id) {
526 case KVM_REG_ARM_PSCI_VERSION:
527 {
528 bool wants_02;
529
530 wants_02 = test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features);
531
532 switch (val) {
533 case KVM_ARM_PSCI_0_1:
534 if (wants_02)
535 return -EINVAL;
536 vcpu->kvm->arch.psci_version = val;
537 return 0;
538 case KVM_ARM_PSCI_0_2:
539 case KVM_ARM_PSCI_1_0:
540 case KVM_ARM_PSCI_1_1:
541 if (!wants_02)
542 return -EINVAL;
543 vcpu->kvm->arch.psci_version = val;
544 return 0;
545 }
546 break;
547 }
548
549 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
550 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
551 if (val & ~KVM_REG_FEATURE_LEVEL_MASK)
552 return -EINVAL;
553
554 if (get_kernel_wa_level(reg->id) < val)
555 return -EINVAL;
556
557 return 0;
558
559 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
560 if (val & ~(KVM_REG_FEATURE_LEVEL_MASK |
561 KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED))
562 return -EINVAL;
563
564 /* The enabled bit must not be set unless the level is AVAIL. */
565 if ((val & KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED) &&
566 (val & KVM_REG_FEATURE_LEVEL_MASK) != KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL)
567 return -EINVAL;
568
569 /*
570 * Map all the possible incoming states to the only two we
571 * really want to deal with.
572 */
573 switch (val & KVM_REG_FEATURE_LEVEL_MASK) {
574 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL:
575 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN:
576 wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
577 break;
578 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL:
579 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED:
580 wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
581 break;
582 default:
583 return -EINVAL;
584 }
585
586 /*
587 * We can deal with NOT_AVAIL on NOT_REQUIRED, but not the
588 * other way around.
589 */
590 if (get_kernel_wa_level(reg->id) < wa_level)
591 return -EINVAL;
592
593 return 0;
594 default:
595 return -ENOENT;
596 }
597
598 return -EINVAL;
599 }
600