summaryrefslogtreecommitdiffstats
path: root/arch/arm64/kvm/psci.c
blob: 7fbc4c1b9df049bd3a7535f22ff7bad5ae2e65ed (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012 - ARM Ltd
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 */

#include <linux/arm-smccc.h>
#include <linux/preempt.h>
#include <linux/kvm_host.h>
#include <linux/uaccess.h>
#include <linux/wait.h>

#include <asm/cputype.h>
#include <asm/kvm_emulate.h>

#include <kvm/arm_psci.h>
#include <kvm/arm_hypercalls.h>

/*
 * This is an implementation of the Power State Coordination Interface
 * as described in ARM document number ARM DEN 0022A.
 */

#define AFFINITY_MASK(level)	~((0x1UL << ((level) * MPIDR_LEVEL_BITS)) - 1)

static unsigned long psci_affinity_mask(unsigned long affinity_level)
{
	if (affinity_level <= 3)
		return MPIDR_HWID_BITMASK & AFFINITY_MASK(affinity_level);

	return 0;
}

static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
{
	/*
	 * NOTE: For simplicity, we make VCPU suspend emulation to be
	 * same-as WFI (Wait-for-interrupt) emulation.
	 *
	 * This means for KVM the wakeup events are interrupts and
	 * this is consistent with intended use of StateID as described
	 * in section 5.4.1 of PSCI v0.2 specification (ARM DEN 0022A).
	 *
	 * Further, we also treat power-down request to be same as
	 * stand-by request as-per section 5.4.2 clause 3 of PSCI v0.2
	 * specification (ARM DEN 0022A). This means all suspend states
	 * for KVM will preserve the register state.
	 */
	kvm_vcpu_wfi(vcpu);

	return PSCI_RET_SUCCESS;
}

static inline bool kvm_psci_valid_affinity(struct kvm_vcpu *vcpu,
					   unsigned long affinity)
{
	return !(affinity & ~MPIDR_HWID_BITMASK);
}

static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
{
	struct vcpu_reset_state *reset_state;
	struct kvm *kvm = source_vcpu->kvm;
	struct kvm_vcpu *vcpu = NULL;
	unsigned long cpu_id;

	cpu_id = smccc_get_arg1(source_vcpu);
	if (!kvm_psci_valid_affinity(source_vcpu, cpu_id))
		return PSCI_RET_INVALID_PARAMS;

	vcpu = kvm_mpidr_to_vcpu(kvm, cpu_id);

	/*
	 * Make sure the caller requested a valid CPU and that the CPU is
	 * turned off.
	 */
	if (!vcpu)
		return PSCI_RET_INVALID_PARAMS;
	if (!kvm_arm_vcpu_stopped(vcpu)) {
		if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1)
			return PSCI_RET_ALREADY_ON;
		else
			return PSCI_RET_INVALID_PARAMS;
	}

	reset_state = &vcpu->arch.reset_state;

	reset_state->pc = smccc_get_arg2(source_vcpu);

	/* Propagate caller endianness */
	reset_state->be = kvm_vcpu_is_be(source_vcpu);

	/*
	 * NOTE: We always update r0 (or x0) because for PSCI v0.1
	 * the general purpose registers are undefined upon CPU_ON.
	 */
	reset_state->r0 = smccc_get_arg3(source_vcpu);

	WRITE_ONCE(reset_state->reset, true);
	kvm_make_request(KVM_REQ_VCPU_RESET, vcpu);

	/*
	 * Make sure the reset request is observed if the RUNNABLE mp_state is
	 * observed.
	 */
	smp_wmb();

	vcpu->arch.mp_state.mp_state = KVM_MP_STATE_RUNNABLE;
	kvm_vcpu_wake_up(vcpu);

	return PSCI_RET_SUCCESS;
}

static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
{
	int matching_cpus = 0;
	unsigned long i, mpidr;
	unsigned long target_affinity;
	unsigned long target_affinity_mask;
	unsigned long lowest_affinity_level;
	struct kvm *kvm = vcpu->kvm;
	struct kvm_vcpu *tmp;

	target_affinity = smccc_get_arg1(vcpu);
	lowest_affinity_level = smccc_get_arg2(vcpu);

	if (!kvm_psci_valid_affinity(vcpu, target_affinity))
		return PSCI_RET_INVALID_PARAMS;

	/* Determine target affinity mask */
	target_affinity_mask = psci_affinity_mask(lowest_affinity_level);
	if (!target_affinity_mask)
		return PSCI_RET_INVALID_PARAMS;

	/* Ignore other bits of target affinity */
	target_affinity &= target_affinity_mask;

	/*
	 * If one or more VCPU matching target affinity are running
	 * then ON else OFF
	 */
	kvm_for_each_vcpu(i, tmp, kvm) {
		mpidr = kvm_vcpu_get_mpidr_aff(tmp);
		if ((mpidr & target_affinity_mask) == target_affinity) {
			matching_cpus++;
			if (!kvm_arm_vcpu_stopped(tmp))
				return PSCI_0_2_AFFINITY_LEVEL_ON;
		}
	}

	if (!matching_cpus)
		return PSCI_RET_INVALID_PARAMS;

	return PSCI_0_2_AFFINITY_LEVEL_OFF;
}

static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type, u64 flags)
{
	unsigned long i;
	struct kvm_vcpu *tmp;

	/*
	 * The KVM ABI specifies that a system event exit may call KVM_RUN
	 * again and may perform shutdown/reboot at a later time that when the
	 * actual request is made.  Since we are implementing PSCI and a
	 * caller of PSCI reboot and shutdown expects that the system shuts
	 * down or reboots immediately, let's make sure that VCPUs are not run
	 * after this call is handled and before the VCPUs have been
	 * re-initialized.
	 */
	kvm_for_each_vcpu(i, tmp, vcpu->kvm)
		tmp->arch.mp_state.mp_state = KVM_MP_STATE_STOPPED;
	kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);

	memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
	vcpu->run->system_event.type = type;
	vcpu->run->system_event.ndata = 1;
	vcpu->run->system_event.data[0] = flags;
	vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
}

static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
{
	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN, 0);
}

static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
{
	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET, 0);
}

static void kvm_psci_system_reset2(struct kvm_vcpu *vcpu)
{
	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET,
				 KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2);
}

static void kvm_psci_system_suspend(struct kvm_vcpu *vcpu)
{
	struct kvm_run *run = vcpu->run;

	memset(&run->system_event, 0, sizeof(vcpu->run->system_event));
	run->system_event.type = KVM_SYSTEM_EVENT_SUSPEND;
	run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
}

static void kvm_psci_narrow_to_32bit(struct kvm_vcpu *vcpu)
{
	int i;

	/*
	 * Zero the input registers' upper 32 bits. They will be fully
	 * zeroed on exit, so we're fine changing them in place.
	 */
	for (i = 1; i < 4; i++)
		vcpu_set_reg(vcpu, i, lower_32_bits(vcpu_get_reg(vcpu, i)));
}

static unsigned long kvm_psci_check_allowed_function(struct kvm_vcpu *vcpu, u32 fn)
{
	/*
	 * Prevent 32 bit guests from calling 64 bit PSCI functions.
	 */
	if ((fn & PSCI_0_2_64BIT) && vcpu_mode_is_32bit(vcpu))
		return PSCI_RET_NOT_SUPPORTED;

	return 0;
}

static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
{
	struct kvm *kvm = vcpu->kvm;
	u32 psci_fn = smccc_get_function(vcpu);
	unsigned long val;
	int ret = 1;

	switch (psci_fn) {
	case PSCI_0_2_FN_PSCI_VERSION:
		/*
		 * Bits[31:16] = Major Version = 0
		 * Bits[15:0] = Minor Version = 2
		 */
		val = KVM_ARM_PSCI_0_2;
		break;
	case PSCI_0_2_FN_CPU_SUSPEND:
	case PSCI_0_2_FN64_CPU_SUSPEND:
		val = kvm_psci_vcpu_suspend(vcpu);
		break;
	case PSCI_0_2_FN_CPU_OFF:
		kvm_arm_vcpu_power_off(vcpu);
		val = PSCI_RET_SUCCESS;
		break;
	case PSCI_0_2_FN_CPU_ON:
		kvm_psci_narrow_to_32bit(vcpu);
		fallthrough;
	case PSCI_0_2_FN64_CPU_ON:
		mutex_lock(&kvm->lock);
		val = kvm_psci_vcpu_on(vcpu);
		mutex_unlock(&kvm->lock);
		break;
	case PSCI_0_2_FN_AFFINITY_INFO:
		kvm_psci_narrow_to_32bit(vcpu);
		fallthrough;
	case PSCI_0_2_FN64_AFFINITY_INFO:
		val = kvm_psci_vcpu_affinity_info(vcpu);
		break;
	case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
		/*
		 * Trusted OS is MP hence does not require migration
	         * or
		 * Trusted OS is not present
		 */
		val = PSCI_0_2_TOS_MP;
		break;
	case PSCI_0_2_FN_SYSTEM_OFF:
		kvm_psci_system_off(vcpu);
		/*
		 * We shouldn't be going back to guest VCPU after
		 * receiving SYSTEM_OFF request.
		 *
		 * If user space accidentally/deliberately resumes
		 * guest VCPU after SYSTEM_OFF request then guest
		 * VCPU should see internal failure from PSCI return
		 * value. To achieve this, we preload r0 (or x0) with
		 * PSCI return value INTERNAL_FAILURE.
		 */
		val = PSCI_RET_INTERNAL_FAILURE;
		ret = 0;
		break;
	case PSCI_0_2_FN_SYSTEM_RESET:
		kvm_psci_system_reset(vcpu);
		/*
		 * Same reason as SYSTEM_OFF for preloading r0 (or x0)
		 * with PSCI return value INTERNAL_FAILURE.
		 */
		val = PSCI_RET_INTERNAL_FAILURE;
		ret = 0;
		break;
	default:
		val = PSCI_RET_NOT_SUPPORTED;
		break;
	}

	smccc_set_retval(vcpu, val, 0, 0, 0);
	return ret;
}

static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor)
{
	unsigned long val = PSCI_RET_NOT_SUPPORTED;
	u32 psci_fn = smccc_get_function(vcpu);
	struct kvm *kvm = vcpu->kvm;
	u32 arg;
	int ret = 1;

	switch(psci_fn) {
	case PSCI_0_2_FN_PSCI_VERSION:
		val = minor == 0 ? KVM_ARM_PSCI_1_0 : KVM_ARM_PSCI_1_1;
		break;
	case PSCI_1_0_FN_PSCI_FEATURES:
		arg = smccc_get_arg1(vcpu);
		val = kvm_psci_check_allowed_function(vcpu, arg);
		if (val)
			break;

		val = PSCI_RET_NOT_SUPPORTED;

		switch(arg) {
		case PSCI_0_2_FN_PSCI_VERSION:
		case PSCI_0_2_FN_CPU_SUSPEND:
		case PSCI_0_2_FN64_CPU_SUSPEND:
		case PSCI_0_2_FN_CPU_OFF:
		case PSCI_0_2_FN_CPU_ON:
		case PSCI_0_2_FN64_CPU_ON:
		case PSCI_0_2_FN_AFFINITY_INFO:
		case PSCI_0_2_FN64_AFFINITY_INFO:
		case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
		case PSCI_0_2_FN_SYSTEM_OFF:
		case PSCI_0_2_FN_SYSTEM_RESET:
		case PSCI_1_0_FN_PSCI_FEATURES:
		case ARM_SMCCC_VERSION_FUNC_ID:
			val = 0;
			break;
		case PSCI_1_0_FN_SYSTEM_SUSPEND:
		case PSCI_1_0_FN64_SYSTEM_SUSPEND:
			if (test_bit(KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED, &kvm->arch.flags))
				val = 0;
			break;
		case PSCI_1_1_FN_SYSTEM_RESET2:
		case PSCI_1_1_FN64_SYSTEM_RESET2:
			if (minor >= 1)
				val = 0;
			break;
		}
		break;
	case PSCI_1_0_FN_SYSTEM_SUSPEND:
		kvm_psci_narrow_to_32bit(vcpu);
		fallthrough;
	case PSCI_1_0_FN64_SYSTEM_SUSPEND:
		/*
		 * Return directly to userspace without changing the vCPU's
		 * registers. Userspace depends on reading the SMCCC parameters
		 * to implement SYSTEM_SUSPEND.
		 */
		if (test_bit(KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED, &kvm->arch.flags)) {
			kvm_psci_system_suspend(vcpu);
			return 0;
		}
		break;
	case PSCI_1_1_FN_SYSTEM_RESET2:
		kvm_psci_narrow_to_32bit(vcpu);
		fallthrough;
	case PSCI_1_1_FN64_SYSTEM_RESET2:
		if (minor >= 1) {
			arg = smccc_get_arg1(vcpu);

			if (arg <= PSCI_1_1_RESET_TYPE_SYSTEM_WARM_RESET ||
			    arg >= PSCI_1_1_RESET_TYPE_VENDOR_START) {
				kvm_psci_system_reset2(vcpu);
				vcpu_set_reg(vcpu, 0, PSCI_RET_INTERNAL_FAILURE);
				return 0;
			}

			val = PSCI_RET_INVALID_PARAMS;
			break;
		}
		break;
	default:
		return kvm_psci_0_2_call(vcpu);
	}

	smccc_set_retval(vcpu, val, 0, 0, 0);
	return ret;
}

static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
{
	struct kvm *kvm = vcpu->kvm;
	u32 psci_fn = smccc_get_function(vcpu);
	unsigned long val;

	switch (psci_fn) {
	case KVM_PSCI_FN_CPU_OFF:
		kvm_arm_vcpu_power_off(vcpu);
		val = PSCI_RET_SUCCESS;
		break;
	case KVM_PSCI_FN_CPU_ON:
		mutex_lock(&kvm->lock);
		val = kvm_psci_vcpu_on(vcpu);
		mutex_unlock(&kvm->lock);
		break;
	default:
		val = PSCI_RET_NOT_SUPPORTED;
		break;
	}

	smccc_set_retval(vcpu, val, 0, 0, 0);
	return 1;
}

/**
 * kvm_psci_call - handle PSCI call if r0 value is in range
 * @vcpu: Pointer to the VCPU struct
 *
 * Handle PSCI calls from guests through traps from HVC instructions.
 * The calling convention is similar to SMC calls to the secure world
 * where the function number is placed in r0.
 *
 * This function returns: > 0 (success), 0 (success but exit to user
 * space), and < 0 (errors)
 *
 * Errors:
 * -EINVAL: Unrecognized PSCI function
 */
int kvm_psci_call(struct kvm_vcpu *vcpu)
{
	u32 psci_fn = smccc_get_function(vcpu);
	unsigned long val;

	val = kvm_psci_check_allowed_function(vcpu, psci_fn);
	if (val) {
		smccc_set_retval(vcpu, val, 0, 0, 0);
		return 1;
	}

	switch (kvm_psci_version(vcpu)) {
	case KVM_ARM_PSCI_1_1:
		return kvm_psci_1_x_call(vcpu, 1);
	case KVM_ARM_PSCI_1_0:
		return kvm_psci_1_x_call(vcpu, 0);
	case KVM_ARM_PSCI_0_2:
		return kvm_psci_0_2_call(vcpu);
	case KVM_ARM_PSCI_0_1:
		return kvm_psci_0_1_call(vcpu);
	default:
		return -EINVAL;
	}
}