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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
24#define AFFINITY_MASK(level) ~((0x1UL << ((level) * MPIDR_LEVEL_BITS)) - 1)
25
26static unsigned long psci_affinity_mask(unsigned long affinity_level)
27{
28 if (affinity_level <= 3)
29 return MPIDR_HWID_BITMASK & AFFINITY_MASK(affinity_level);
30
31 return 0;
32}
33
34static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
35{
36 /*
37 * NOTE: For simplicity, we make VCPU suspend emulation to be
38 * same-as WFI (Wait-for-interrupt) emulation.
39 *
40 * This means for KVM the wakeup events are interrupts and
41 * this is consistent with intended use of StateID as described
42 * in section 5.4.1 of PSCI v0.2 specification (ARM DEN 0022A).
43 *
44 * Further, we also treat power-down request to be same as
45 * stand-by request as-per section 5.4.2 clause 3 of PSCI v0.2
46 * specification (ARM DEN 0022A). This means all suspend states
47 * for KVM will preserve the register state.
48 */
49 kvm_vcpu_wfi(vcpu);
50
51 return PSCI_RET_SUCCESS;
52}
53
54static inline bool kvm_psci_valid_affinity(struct kvm_vcpu *vcpu,
55 unsigned long affinity)
56{
57 return !(affinity & ~MPIDR_HWID_BITMASK);
58}
59
60static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
61{
62 struct vcpu_reset_state *reset_state;
63 struct kvm *kvm = source_vcpu->kvm;
64 struct kvm_vcpu *vcpu = NULL;
65 unsigned long cpu_id;
66
67 cpu_id = smccc_get_arg1(source_vcpu);
68 if (!kvm_psci_valid_affinity(source_vcpu, cpu_id))
69 return PSCI_RET_INVALID_PARAMS;
70
71 vcpu = kvm_mpidr_to_vcpu(kvm, cpu_id);
72
73 /*
74 * Make sure the caller requested a valid CPU and that the CPU is
75 * turned off.
76 */
77 if (!vcpu)
78 return PSCI_RET_INVALID_PARAMS;
79 if (!kvm_arm_vcpu_stopped(vcpu)) {
80 if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1)
81 return PSCI_RET_ALREADY_ON;
82 else
83 return PSCI_RET_INVALID_PARAMS;
84 }
85
86 reset_state = &vcpu->arch.reset_state;
87
88 reset_state->pc = smccc_get_arg2(source_vcpu);
89
90 /* Propagate caller endianness */
91 reset_state->be = kvm_vcpu_is_be(source_vcpu);
92
93 /*
94 * NOTE: We always update r0 (or x0) because for PSCI v0.1
95 * the general purpose registers are undefined upon CPU_ON.
96 */
97 reset_state->r0 = smccc_get_arg3(source_vcpu);
98
99 WRITE_ONCE(reset_state->reset, true);
100 kvm_make_request(KVM_REQ_VCPU_RESET, vcpu);
101
102 /*
103 * Make sure the reset request is observed if the RUNNABLE mp_state is
104 * observed.
105 */
106 smp_wmb();
107
108 vcpu->arch.mp_state.mp_state = KVM_MP_STATE_RUNNABLE;
109 kvm_vcpu_wake_up(vcpu);
110
111 return PSCI_RET_SUCCESS;
112}
113
114static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
115{
116 int matching_cpus = 0;
117 unsigned long i, mpidr;
118 unsigned long target_affinity;
119 unsigned long target_affinity_mask;
120 unsigned long lowest_affinity_level;
121 struct kvm *kvm = vcpu->kvm;
122 struct kvm_vcpu *tmp;
123
124 target_affinity = smccc_get_arg1(vcpu);
125 lowest_affinity_level = smccc_get_arg2(vcpu);
126
127 if (!kvm_psci_valid_affinity(vcpu, target_affinity))
128 return PSCI_RET_INVALID_PARAMS;
129
130 /* Determine target affinity mask */
131 target_affinity_mask = psci_affinity_mask(lowest_affinity_level);
132 if (!target_affinity_mask)
133 return PSCI_RET_INVALID_PARAMS;
134
135 /* Ignore other bits of target affinity */
136 target_affinity &= target_affinity_mask;
137
138 /*
139 * If one or more VCPU matching target affinity are running
140 * then ON else OFF
141 */
142 kvm_for_each_vcpu(i, tmp, kvm) {
143 mpidr = kvm_vcpu_get_mpidr_aff(tmp);
144 if ((mpidr & target_affinity_mask) == target_affinity) {
145 matching_cpus++;
146 if (!kvm_arm_vcpu_stopped(tmp))
147 return PSCI_0_2_AFFINITY_LEVEL_ON;
148 }
149 }
150
151 if (!matching_cpus)
152 return PSCI_RET_INVALID_PARAMS;
153
154 return PSCI_0_2_AFFINITY_LEVEL_OFF;
155}
156
157static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type, u64 flags)
158{
159 unsigned long i;
160 struct kvm_vcpu *tmp;
161
162 /*
163 * The KVM ABI specifies that a system event exit may call KVM_RUN
164 * again and may perform shutdown/reboot at a later time that when the
165 * actual request is made. Since we are implementing PSCI and a
166 * caller of PSCI reboot and shutdown expects that the system shuts
167 * down or reboots immediately, let's make sure that VCPUs are not run
168 * after this call is handled and before the VCPUs have been
169 * re-initialized.
170 */
171 kvm_for_each_vcpu(i, tmp, vcpu->kvm)
172 tmp->arch.mp_state.mp_state = KVM_MP_STATE_STOPPED;
173 kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
174
175 memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
176 vcpu->run->system_event.type = type;
177 vcpu->run->system_event.ndata = 1;
178 vcpu->run->system_event.data[0] = flags;
179 vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
180}
181
182static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
183{
184 kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN, 0);
185}
186
187static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
188{
189 kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET, 0);
190}
191
192static void kvm_psci_system_reset2(struct kvm_vcpu *vcpu)
193{
194 kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET,
195 KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2);
196}
197
198static void kvm_psci_system_suspend(struct kvm_vcpu *vcpu)
199{
200 struct kvm_run *run = vcpu->run;
201
202 memset(&run->system_event, 0, sizeof(vcpu->run->system_event));
203 run->system_event.type = KVM_SYSTEM_EVENT_SUSPEND;
204 run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
205}
206
207static void kvm_psci_narrow_to_32bit(struct kvm_vcpu *vcpu)
208{
209 int i;
210
211 /*
212 * Zero the input registers' upper 32 bits. They will be fully
213 * zeroed on exit, so we're fine changing them in place.
214 */
215 for (i = 1; i < 4; i++)
216 vcpu_set_reg(vcpu, i, lower_32_bits(vcpu_get_reg(vcpu, i)));
217}
218
219static unsigned long kvm_psci_check_allowed_function(struct kvm_vcpu *vcpu, u32 fn)
220{
221 /*
222 * Prevent 32 bit guests from calling 64 bit PSCI functions.
223 */
224 if ((fn & PSCI_0_2_64BIT) && vcpu_mode_is_32bit(vcpu))
225 return PSCI_RET_NOT_SUPPORTED;
226
227 return 0;
228}
229
230static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
231{
232 struct kvm *kvm = vcpu->kvm;
233 u32 psci_fn = smccc_get_function(vcpu);
234 unsigned long val;
235 int ret = 1;
236
237 switch (psci_fn) {
238 case PSCI_0_2_FN_PSCI_VERSION:
239 /*
240 * Bits[31:16] = Major Version = 0
241 * Bits[15:0] = Minor Version = 2
242 */
243 val = KVM_ARM_PSCI_0_2;
244 break;
245 case PSCI_0_2_FN_CPU_SUSPEND:
246 case PSCI_0_2_FN64_CPU_SUSPEND:
247 val = kvm_psci_vcpu_suspend(vcpu);
248 break;
249 case PSCI_0_2_FN_CPU_OFF:
250 kvm_arm_vcpu_power_off(vcpu);
251 val = PSCI_RET_SUCCESS;
252 break;
253 case PSCI_0_2_FN_CPU_ON:
254 kvm_psci_narrow_to_32bit(vcpu);
255 fallthrough;
256 case PSCI_0_2_FN64_CPU_ON:
257 mutex_lock(&kvm->lock);
258 val = kvm_psci_vcpu_on(vcpu);
259 mutex_unlock(&kvm->lock);
260 break;
261 case PSCI_0_2_FN_AFFINITY_INFO:
262 kvm_psci_narrow_to_32bit(vcpu);
263 fallthrough;
264 case PSCI_0_2_FN64_AFFINITY_INFO:
265 val = kvm_psci_vcpu_affinity_info(vcpu);
266 break;
267 case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
268 /*
269 * Trusted OS is MP hence does not require migration
270 * or
271 * Trusted OS is not present
272 */
273 val = PSCI_0_2_TOS_MP;
274 break;
275 case PSCI_0_2_FN_SYSTEM_OFF:
276 kvm_psci_system_off(vcpu);
277 /*
278 * We shouldn't be going back to guest VCPU after
279 * receiving SYSTEM_OFF request.
280 *
281 * If user space accidentally/deliberately resumes
282 * guest VCPU after SYSTEM_OFF request then guest
283 * VCPU should see internal failure from PSCI return
284 * value. To achieve this, we preload r0 (or x0) with
285 * PSCI return value INTERNAL_FAILURE.
286 */
287 val = PSCI_RET_INTERNAL_FAILURE;
288 ret = 0;
289 break;
290 case PSCI_0_2_FN_SYSTEM_RESET:
291 kvm_psci_system_reset(vcpu);
292 /*
293 * Same reason as SYSTEM_OFF for preloading r0 (or x0)
294 * with PSCI return value INTERNAL_FAILURE.
295 */
296 val = PSCI_RET_INTERNAL_FAILURE;
297 ret = 0;
298 break;
299 default:
300 val = PSCI_RET_NOT_SUPPORTED;
301 break;
302 }
303
304 smccc_set_retval(vcpu, val, 0, 0, 0);
305 return ret;
306}
307
308static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor)
309{
310 unsigned long val = PSCI_RET_NOT_SUPPORTED;
311 u32 psci_fn = smccc_get_function(vcpu);
312 struct kvm *kvm = vcpu->kvm;
313 u32 arg;
314 int ret = 1;
315
316 switch(psci_fn) {
317 case PSCI_0_2_FN_PSCI_VERSION:
318 val = minor == 0 ? KVM_ARM_PSCI_1_0 : KVM_ARM_PSCI_1_1;
319 break;
320 case PSCI_1_0_FN_PSCI_FEATURES:
321 arg = smccc_get_arg1(vcpu);
322 val = kvm_psci_check_allowed_function(vcpu, arg);
323 if (val)
324 break;
325
326 val = PSCI_RET_NOT_SUPPORTED;
327
328 switch(arg) {
329 case PSCI_0_2_FN_PSCI_VERSION:
330 case PSCI_0_2_FN_CPU_SUSPEND:
331 case PSCI_0_2_FN64_CPU_SUSPEND:
332 case PSCI_0_2_FN_CPU_OFF:
333 case PSCI_0_2_FN_CPU_ON:
334 case PSCI_0_2_FN64_CPU_ON:
335 case PSCI_0_2_FN_AFFINITY_INFO:
336 case PSCI_0_2_FN64_AFFINITY_INFO:
337 case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
338 case PSCI_0_2_FN_SYSTEM_OFF:
339 case PSCI_0_2_FN_SYSTEM_RESET:
340 case PSCI_1_0_FN_PSCI_FEATURES:
341 case ARM_SMCCC_VERSION_FUNC_ID:
342 val = 0;
343 break;
344 case PSCI_1_0_FN_SYSTEM_SUSPEND:
345 case PSCI_1_0_FN64_SYSTEM_SUSPEND:
346 if (test_bit(KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED, &kvm->arch.flags))
347 val = 0;
348 break;
349 case PSCI_1_1_FN_SYSTEM_RESET2:
350 case PSCI_1_1_FN64_SYSTEM_RESET2:
351 if (minor >= 1)
352 val = 0;
353 break;
354 }
355 break;
356 case PSCI_1_0_FN_SYSTEM_SUSPEND:
357 kvm_psci_narrow_to_32bit(vcpu);
358 fallthrough;
359 case PSCI_1_0_FN64_SYSTEM_SUSPEND:
360 /*
361 * Return directly to userspace without changing the vCPU's
362 * registers. Userspace depends on reading the SMCCC parameters
363 * to implement SYSTEM_SUSPEND.
364 */
365 if (test_bit(KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED, &kvm->arch.flags)) {
366 kvm_psci_system_suspend(vcpu);
367 return 0;
368 }
369 break;
370 case PSCI_1_1_FN_SYSTEM_RESET2:
371 kvm_psci_narrow_to_32bit(vcpu);
372 fallthrough;
373 case PSCI_1_1_FN64_SYSTEM_RESET2:
374 if (minor >= 1) {
375 arg = smccc_get_arg1(vcpu);
376
377 if (arg <= PSCI_1_1_RESET_TYPE_SYSTEM_WARM_RESET ||
378 arg >= PSCI_1_1_RESET_TYPE_VENDOR_START) {
379 kvm_psci_system_reset2(vcpu);
380 vcpu_set_reg(vcpu, 0, PSCI_RET_INTERNAL_FAILURE);
381 return 0;
382 }
383
384 val = PSCI_RET_INVALID_PARAMS;
385 break;
386 }
387 break;
388 default:
389 return kvm_psci_0_2_call(vcpu);
390 }
391
392 smccc_set_retval(vcpu, val, 0, 0, 0);
393 return ret;
394}
395
396static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
397{
398 struct kvm *kvm = vcpu->kvm;
399 u32 psci_fn = smccc_get_function(vcpu);
400 unsigned long val;
401
402 switch (psci_fn) {
403 case KVM_PSCI_FN_CPU_OFF:
404 kvm_arm_vcpu_power_off(vcpu);
405 val = PSCI_RET_SUCCESS;
406 break;
407 case KVM_PSCI_FN_CPU_ON:
408 mutex_lock(&kvm->lock);
409 val = kvm_psci_vcpu_on(vcpu);
410 mutex_unlock(&kvm->lock);
411 break;
412 default:
413 val = PSCI_RET_NOT_SUPPORTED;
414 break;
415 }
416
417 smccc_set_retval(vcpu, val, 0, 0, 0);
418 return 1;
419}
420
421/**
422 * kvm_psci_call - handle PSCI call if r0 value is in range
423 * @vcpu: Pointer to the VCPU struct
424 *
425 * Handle PSCI calls from guests through traps from HVC instructions.
426 * The calling convention is similar to SMC calls to the secure world
427 * where the function number is placed in r0.
428 *
429 * This function returns: > 0 (success), 0 (success but exit to user
430 * space), and < 0 (errors)
431 *
432 * Errors:
433 * -EINVAL: Unrecognized PSCI function
434 */
435int kvm_psci_call(struct kvm_vcpu *vcpu)
436{
437 u32 psci_fn = smccc_get_function(vcpu);
438 unsigned long val;
439
440 val = kvm_psci_check_allowed_function(vcpu, psci_fn);
441 if (val) {
442 smccc_set_retval(vcpu, val, 0, 0, 0);
443 return 1;
444 }
445
446 switch (kvm_psci_version(vcpu)) {
447 case KVM_ARM_PSCI_1_1:
448 return kvm_psci_1_x_call(vcpu, 1);
449 case KVM_ARM_PSCI_1_0:
450 return kvm_psci_1_x_call(vcpu, 0);
451 case KVM_ARM_PSCI_0_2:
452 return kvm_psci_0_2_call(vcpu);
453 case KVM_ARM_PSCI_0_1:
454 return kvm_psci_0_1_call(vcpu);
455 default:
456 return -EINVAL;
457 }
458}