summaryrefslogtreecommitdiff
path: root/arch/riscv/kvm/vcpu_timer.c
blob: ad34519c8a13dff001587abd739c018ac4038b6d (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
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2019 Western Digital Corporation or its affiliates.
 *
 * Authors:
 *     Atish Patra <atish.patra@wdc.com>
 */

#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
#include <linux/uaccess.h>
#include <clocksource/timer-riscv.h>
#include <asm/csr.h>
#include <asm/delay.h>
#include <asm/kvm_vcpu_timer.h>

static u64 kvm_riscv_current_cycles(struct kvm_guest_timer *gt)
{
	return get_cycles64() + gt->time_delta;
}

static u64 kvm_riscv_delta_cycles2ns(u64 cycles,
				     struct kvm_guest_timer *gt,
				     struct kvm_vcpu_timer *t)
{
	unsigned long flags;
	u64 cycles_now, cycles_delta, delta_ns;

	local_irq_save(flags);
	cycles_now = kvm_riscv_current_cycles(gt);
	if (cycles_now < cycles)
		cycles_delta = cycles - cycles_now;
	else
		cycles_delta = 0;
	delta_ns = (cycles_delta * gt->nsec_mult) >> gt->nsec_shift;
	local_irq_restore(flags);

	return delta_ns;
}

static enum hrtimer_restart kvm_riscv_vcpu_hrtimer_expired(struct hrtimer *h)
{
	u64 delta_ns;
	struct kvm_vcpu_timer *t = container_of(h, struct kvm_vcpu_timer, hrt);
	struct kvm_vcpu *vcpu = container_of(t, struct kvm_vcpu, arch.timer);
	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;

	if (kvm_riscv_current_cycles(gt) < t->next_cycles) {
		delta_ns = kvm_riscv_delta_cycles2ns(t->next_cycles, gt, t);
		hrtimer_forward_now(&t->hrt, ktime_set(0, delta_ns));
		return HRTIMER_RESTART;
	}

	t->next_set = false;
	kvm_riscv_vcpu_set_interrupt(vcpu, IRQ_VS_TIMER);

	return HRTIMER_NORESTART;
}

static int kvm_riscv_vcpu_timer_cancel(struct kvm_vcpu_timer *t)
{
	if (!t->init_done || !t->next_set)
		return -EINVAL;

	hrtimer_cancel(&t->hrt);
	t->next_set = false;

	return 0;
}

static int kvm_riscv_vcpu_update_vstimecmp(struct kvm_vcpu *vcpu, u64 ncycles)
{
#if defined(CONFIG_32BIT)
		csr_write(CSR_VSTIMECMP, ncycles & 0xFFFFFFFF);
		csr_write(CSR_VSTIMECMPH, ncycles >> 32);
#else
		csr_write(CSR_VSTIMECMP, ncycles);
#endif
		return 0;
}

static int kvm_riscv_vcpu_update_hrtimer(struct kvm_vcpu *vcpu, u64 ncycles)
{
	struct kvm_vcpu_timer *t = &vcpu->arch.timer;
	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
	u64 delta_ns;

	if (!t->init_done)
		return -EINVAL;

	kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_VS_TIMER);

	delta_ns = kvm_riscv_delta_cycles2ns(ncycles, gt, t);
	t->next_cycles = ncycles;
	hrtimer_start(&t->hrt, ktime_set(0, delta_ns), HRTIMER_MODE_REL);
	t->next_set = true;

	return 0;
}

int kvm_riscv_vcpu_timer_next_event(struct kvm_vcpu *vcpu, u64 ncycles)
{
	struct kvm_vcpu_timer *t = &vcpu->arch.timer;

	return t->timer_next_event(vcpu, ncycles);
}

static enum hrtimer_restart kvm_riscv_vcpu_vstimer_expired(struct hrtimer *h)
{
	u64 delta_ns;
	struct kvm_vcpu_timer *t = container_of(h, struct kvm_vcpu_timer, hrt);
	struct kvm_vcpu *vcpu = container_of(t, struct kvm_vcpu, arch.timer);
	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;

	if (kvm_riscv_current_cycles(gt) < t->next_cycles) {
		delta_ns = kvm_riscv_delta_cycles2ns(t->next_cycles, gt, t);
		hrtimer_forward_now(&t->hrt, ktime_set(0, delta_ns));
		return HRTIMER_RESTART;
	}

	t->next_set = false;
	kvm_vcpu_kick(vcpu);

	return HRTIMER_NORESTART;
}

bool kvm_riscv_vcpu_timer_pending(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_timer *t = &vcpu->arch.timer;
	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;

	if (!kvm_riscv_delta_cycles2ns(t->next_cycles, gt, t) ||
	    kvm_riscv_vcpu_has_interrupts(vcpu, 1UL << IRQ_VS_TIMER))
		return true;
	else
		return false;
}

static void kvm_riscv_vcpu_timer_blocking(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_timer *t = &vcpu->arch.timer;
	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
	u64 delta_ns;

	if (!t->init_done)
		return;

	delta_ns = kvm_riscv_delta_cycles2ns(t->next_cycles, gt, t);
	if (delta_ns) {
		hrtimer_start(&t->hrt, ktime_set(0, delta_ns), HRTIMER_MODE_REL);
		t->next_set = true;
	}
}

static void kvm_riscv_vcpu_timer_unblocking(struct kvm_vcpu *vcpu)
{
	kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer);
}

int kvm_riscv_vcpu_get_reg_timer(struct kvm_vcpu *vcpu,
				 const struct kvm_one_reg *reg)
{
	struct kvm_vcpu_timer *t = &vcpu->arch.timer;
	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
	u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr;
	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
					    KVM_REG_SIZE_MASK |
					    KVM_REG_RISCV_TIMER);
	u64 reg_val;

	if (KVM_REG_SIZE(reg->id) != sizeof(u64))
		return -EINVAL;
	if (reg_num >= sizeof(struct kvm_riscv_timer) / sizeof(u64))
		return -EINVAL;

	switch (reg_num) {
	case KVM_REG_RISCV_TIMER_REG(frequency):
		reg_val = riscv_timebase;
		break;
	case KVM_REG_RISCV_TIMER_REG(time):
		reg_val = kvm_riscv_current_cycles(gt);
		break;
	case KVM_REG_RISCV_TIMER_REG(compare):
		reg_val = t->next_cycles;
		break;
	case KVM_REG_RISCV_TIMER_REG(state):
		reg_val = (t->next_set) ? KVM_RISCV_TIMER_STATE_ON :
					  KVM_RISCV_TIMER_STATE_OFF;
		break;
	default:
		return -EINVAL;
	}

	if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
		return -EFAULT;

	return 0;
}

int kvm_riscv_vcpu_set_reg_timer(struct kvm_vcpu *vcpu,
				 const struct kvm_one_reg *reg)
{
	struct kvm_vcpu_timer *t = &vcpu->arch.timer;
	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
	u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr;
	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
					    KVM_REG_SIZE_MASK |
					    KVM_REG_RISCV_TIMER);
	u64 reg_val;
	int ret = 0;

	if (KVM_REG_SIZE(reg->id) != sizeof(u64))
		return -EINVAL;
	if (reg_num >= sizeof(struct kvm_riscv_timer) / sizeof(u64))
		return -EINVAL;

	if (copy_from_user(&reg_val, uaddr, KVM_REG_SIZE(reg->id)))
		return -EFAULT;

	switch (reg_num) {
	case KVM_REG_RISCV_TIMER_REG(frequency):
		ret = -EOPNOTSUPP;
		break;
	case KVM_REG_RISCV_TIMER_REG(time):
		gt->time_delta = reg_val - get_cycles64();
		break;
	case KVM_REG_RISCV_TIMER_REG(compare):
		t->next_cycles = reg_val;
		break;
	case KVM_REG_RISCV_TIMER_REG(state):
		if (reg_val == KVM_RISCV_TIMER_STATE_ON)
			ret = kvm_riscv_vcpu_timer_next_event(vcpu, reg_val);
		else
			ret = kvm_riscv_vcpu_timer_cancel(t);
		break;
	default:
		ret = -EINVAL;
		break;
	}

	return ret;
}

int kvm_riscv_vcpu_timer_init(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_timer *t = &vcpu->arch.timer;

	if (t->init_done)
		return -EINVAL;

	hrtimer_init(&t->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	t->init_done = true;
	t->next_set = false;

	/* Enable sstc for every vcpu if available in hardware */
	if (riscv_isa_extension_available(NULL, SSTC)) {
		t->sstc_enabled = true;
		t->hrt.function = kvm_riscv_vcpu_vstimer_expired;
		t->timer_next_event = kvm_riscv_vcpu_update_vstimecmp;
	} else {
		t->sstc_enabled = false;
		t->hrt.function = kvm_riscv_vcpu_hrtimer_expired;
		t->timer_next_event = kvm_riscv_vcpu_update_hrtimer;
	}

	return 0;
}

int kvm_riscv_vcpu_timer_deinit(struct kvm_vcpu *vcpu)
{
	int ret;

	ret = kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer);
	vcpu->arch.timer.init_done = false;

	return ret;
}

int kvm_riscv_vcpu_timer_reset(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_timer *t = &vcpu->arch.timer;

	t->next_cycles = -1ULL;
	return kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer);
}

static void kvm_riscv_vcpu_update_timedelta(struct kvm_vcpu *vcpu)
{
	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;

#if defined(CONFIG_32BIT)
	csr_write(CSR_HTIMEDELTA, (u32)(gt->time_delta));
	csr_write(CSR_HTIMEDELTAH, (u32)(gt->time_delta >> 32));
#else
	csr_write(CSR_HTIMEDELTA, gt->time_delta);
#endif
}

void kvm_riscv_vcpu_timer_restore(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_timer *t = &vcpu->arch.timer;

	kvm_riscv_vcpu_update_timedelta(vcpu);

	if (!t->sstc_enabled)
		return;

#if defined(CONFIG_32BIT)
	csr_write(CSR_VSTIMECMP, (u32)t->next_cycles);
	csr_write(CSR_VSTIMECMPH, (u32)(t->next_cycles >> 32));
#else
	csr_write(CSR_VSTIMECMP, t->next_cycles);
#endif

	/* timer should be enabled for the remaining operations */
	if (unlikely(!t->init_done))
		return;

	kvm_riscv_vcpu_timer_unblocking(vcpu);
}

void kvm_riscv_vcpu_timer_sync(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_timer *t = &vcpu->arch.timer;

	if (!t->sstc_enabled)
		return;

#if defined(CONFIG_32BIT)
	t->next_cycles = csr_read(CSR_VSTIMECMP);
	t->next_cycles |= (u64)csr_read(CSR_VSTIMECMPH) << 32;
#else
	t->next_cycles = csr_read(CSR_VSTIMECMP);
#endif
}

void kvm_riscv_vcpu_timer_save(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_timer *t = &vcpu->arch.timer;

	if (!t->sstc_enabled)
		return;

	/*
	 * The vstimecmp CSRs are saved by kvm_riscv_vcpu_timer_sync()
	 * upon every VM exit so no need to save here.
	 */

	/* timer should be enabled for the remaining operations */
	if (unlikely(!t->init_done))
		return;

	if (kvm_vcpu_is_blocking(vcpu))
		kvm_riscv_vcpu_timer_blocking(vcpu);
}

void kvm_riscv_guest_timer_init(struct kvm *kvm)
{
	struct kvm_guest_timer *gt = &kvm->arch.timer;

	riscv_cs_get_mult_shift(&gt->nsec_mult, &gt->nsec_shift);
	gt->time_delta = -get_cycles64();
}