1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2019 Western Digital Corporation or its affiliates.
4 *
5 * Authors:
6 * Atish Patra <atish.patra@wdc.com>
7 */
8
9 #include <linux/errno.h>
10 #include <linux/err.h>
11 #include <linux/kvm_host.h>
12 #include <linux/uaccess.h>
13 #include <clocksource/timer-riscv.h>
14 #include <asm/csr.h>
15 #include <asm/delay.h>
16 #include <asm/kvm_vcpu_timer.h>
17
18 static u64 kvm_riscv_current_cycles(struct kvm_guest_timer *gt)
19 {
20 return get_cycles64() + gt->time_delta;
21 }
22
23 static u64 kvm_riscv_delta_cycles2ns(u64 cycles,
24 struct kvm_guest_timer *gt,
25 struct kvm_vcpu_timer *t)
26 {
27 unsigned long flags;
28 u64 cycles_now, cycles_delta, delta_ns;
29
30 local_irq_save(flags);
31 cycles_now = kvm_riscv_current_cycles(gt);
32 if (cycles_now < cycles)
33 cycles_delta = cycles - cycles_now;
34 else
35 cycles_delta = 0;
36 delta_ns = (cycles_delta * gt->nsec_mult) >> gt->nsec_shift;
37 local_irq_restore(flags);
38
39 return delta_ns;
40 }
41
42 static enum hrtimer_restart kvm_riscv_vcpu_hrtimer_expired(struct hrtimer *h)
43 {
44 u64 delta_ns;
45 struct kvm_vcpu_timer *t = container_of(h, struct kvm_vcpu_timer, hrt);
46 struct kvm_vcpu *vcpu = container_of(t, struct kvm_vcpu, arch.timer);
47 struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
48
49 if (kvm_riscv_current_cycles(gt) < t->next_cycles) {
50 delta_ns = kvm_riscv_delta_cycles2ns(t->next_cycles, gt, t);
51 hrtimer_forward_now(&t->hrt, ktime_set(0, delta_ns));
52 return HRTIMER_RESTART;
53 }
54
55 t->next_set = false;
56 kvm_riscv_vcpu_set_interrupt(vcpu, IRQ_VS_TIMER);
57
58 return HRTIMER_NORESTART;
59 }
60
61 static int kvm_riscv_vcpu_timer_cancel(struct kvm_vcpu_timer *t)
62 {
63 if (!t->init_done || !t->next_set)
64 return -EINVAL;
65
66 hrtimer_cancel(&t->hrt);
67 t->next_set = false;
68
69 return 0;
70 }
71
72 static int kvm_riscv_vcpu_update_vstimecmp(struct kvm_vcpu *vcpu, u64 ncycles)
73 {
74 #if defined(CONFIG_32BIT)
75 csr_write(CSR_VSTIMECMP, ncycles & 0xFFFFFFFF);
76 csr_write(CSR_VSTIMECMPH, ncycles >> 32);
77 #else
78 csr_write(CSR_VSTIMECMP, ncycles);
79 #endif
80 return 0;
81 }
82
83 static int kvm_riscv_vcpu_update_hrtimer(struct kvm_vcpu *vcpu, u64 ncycles)
84 {
85 struct kvm_vcpu_timer *t = &vcpu->arch.timer;
86 struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
87 u64 delta_ns;
88
89 if (!t->init_done)
90 return -EINVAL;
91
92 kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_VS_TIMER);
93
94 delta_ns = kvm_riscv_delta_cycles2ns(ncycles, gt, t);
95 t->next_cycles = ncycles;
96 hrtimer_start(&t->hrt, ktime_set(0, delta_ns), HRTIMER_MODE_REL);
97 t->next_set = true;
98
99 return 0;
100 }
101
102 int kvm_riscv_vcpu_timer_next_event(struct kvm_vcpu *vcpu, u64 ncycles)
103 {
104 struct kvm_vcpu_timer *t = &vcpu->arch.timer;
105
106 return t->timer_next_event(vcpu, ncycles);
107 }
108
109 static enum hrtimer_restart kvm_riscv_vcpu_vstimer_expired(struct hrtimer *h)
110 {
111 u64 delta_ns;
112 struct kvm_vcpu_timer *t = container_of(h, struct kvm_vcpu_timer, hrt);
113 struct kvm_vcpu *vcpu = container_of(t, struct kvm_vcpu, arch.timer);
114 struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
115
116 if (kvm_riscv_current_cycles(gt) < t->next_cycles) {
117 delta_ns = kvm_riscv_delta_cycles2ns(t->next_cycles, gt, t);
118 hrtimer_forward_now(&t->hrt, ktime_set(0, delta_ns));
119 return HRTIMER_RESTART;
120 }
121
122 t->next_set = false;
123 kvm_vcpu_kick(vcpu);
124
125 return HRTIMER_NORESTART;
126 }
127
128 bool kvm_riscv_vcpu_timer_pending(struct kvm_vcpu *vcpu)
129 {
130 struct kvm_vcpu_timer *t = &vcpu->arch.timer;
131 struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
132
133 if (!kvm_riscv_delta_cycles2ns(t->next_cycles, gt, t) ||
134 kvm_riscv_vcpu_has_interrupts(vcpu, 1UL << IRQ_VS_TIMER))
135 return true;
136 else
137 return false;
138 }
139
140 static void kvm_riscv_vcpu_timer_blocking(struct kvm_vcpu *vcpu)
141 {
142 struct kvm_vcpu_timer *t = &vcpu->arch.timer;
143 struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
144 u64 delta_ns;
145
146 if (!t->init_done)
147 return;
148
149 delta_ns = kvm_riscv_delta_cycles2ns(t->next_cycles, gt, t);
150 hrtimer_start(&t->hrt, ktime_set(0, delta_ns), HRTIMER_MODE_REL);
151 t->next_set = true;
152 }
153
154 static void kvm_riscv_vcpu_timer_unblocking(struct kvm_vcpu *vcpu)
155 {
156 kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer);
157 }
158
159 int kvm_riscv_vcpu_get_reg_timer(struct kvm_vcpu *vcpu,
160 const struct kvm_one_reg *reg)
161 {
162 struct kvm_vcpu_timer *t = &vcpu->arch.timer;
163 struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
164 u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr;
165 unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
166 KVM_REG_SIZE_MASK |
167 KVM_REG_RISCV_TIMER);
168 u64 reg_val;
169
170 if (KVM_REG_SIZE(reg->id) != sizeof(u64))
171 return -EINVAL;
172 if (reg_num >= sizeof(struct kvm_riscv_timer) / sizeof(u64))
173 return -ENOENT;
174
175 switch (reg_num) {
176 case KVM_REG_RISCV_TIMER_REG(frequency):
177 reg_val = riscv_timebase;
178 break;
179 case KVM_REG_RISCV_TIMER_REG(time):
180 reg_val = kvm_riscv_current_cycles(gt);
181 break;
182 case KVM_REG_RISCV_TIMER_REG(compare):
183 reg_val = t->next_cycles;
184 break;
185 case KVM_REG_RISCV_TIMER_REG(state):
186 reg_val = (t->next_set) ? KVM_RISCV_TIMER_STATE_ON :
187 KVM_RISCV_TIMER_STATE_OFF;
188 break;
189 default:
190 return -ENOENT;
191 }
192
193 if (copy_to_user(uaddr, ®_val, KVM_REG_SIZE(reg->id)))
194 return -EFAULT;
195
196 return 0;
197 }
198
199 int kvm_riscv_vcpu_set_reg_timer(struct kvm_vcpu *vcpu,
200 const struct kvm_one_reg *reg)
201 {
202 struct kvm_vcpu_timer *t = &vcpu->arch.timer;
203 struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
204 u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr;
205 unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
206 KVM_REG_SIZE_MASK |
207 KVM_REG_RISCV_TIMER);
208 u64 reg_val;
209 int ret = 0;
210
211 if (KVM_REG_SIZE(reg->id) != sizeof(u64))
212 return -EINVAL;
213 if (reg_num >= sizeof(struct kvm_riscv_timer) / sizeof(u64))
214 return -ENOENT;
215
216 if (copy_from_user(®_val, uaddr, KVM_REG_SIZE(reg->id)))
217 return -EFAULT;
218
219 switch (reg_num) {
220 case KVM_REG_RISCV_TIMER_REG(frequency):
221 if (reg_val != riscv_timebase)
222 return -EINVAL;
223 break;
224 case KVM_REG_RISCV_TIMER_REG(time):
225 gt->time_delta = reg_val - get_cycles64();
226 break;
227 case KVM_REG_RISCV_TIMER_REG(compare):
228 t->next_cycles = reg_val;
229 break;
230 case KVM_REG_RISCV_TIMER_REG(state):
231 if (reg_val == KVM_RISCV_TIMER_STATE_ON)
232 ret = kvm_riscv_vcpu_timer_next_event(vcpu, reg_val);
233 else
234 ret = kvm_riscv_vcpu_timer_cancel(t);
235 break;
236 default:
237 ret = -ENOENT;
238 break;
239 }
240
241 return ret;
242 }
243
244 int kvm_riscv_vcpu_timer_init(struct kvm_vcpu *vcpu)
245 {
246 struct kvm_vcpu_timer *t = &vcpu->arch.timer;
247
248 if (t->init_done)
249 return -EINVAL;
250
251 hrtimer_init(&t->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
252 t->init_done = true;
253 t->next_set = false;
254
255 /* Enable sstc for every vcpu if available in hardware */
256 if (riscv_isa_extension_available(NULL, SSTC)) {
257 t->sstc_enabled = true;
258 t->hrt.function = kvm_riscv_vcpu_vstimer_expired;
259 t->timer_next_event = kvm_riscv_vcpu_update_vstimecmp;
260 } else {
261 t->sstc_enabled = false;
262 t->hrt.function = kvm_riscv_vcpu_hrtimer_expired;
263 t->timer_next_event = kvm_riscv_vcpu_update_hrtimer;
264 }
265
266 return 0;
267 }
268
269 int kvm_riscv_vcpu_timer_deinit(struct kvm_vcpu *vcpu)
270 {
271 int ret;
272
273 ret = kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer);
274 vcpu->arch.timer.init_done = false;
275
276 return ret;
277 }
278
279 int kvm_riscv_vcpu_timer_reset(struct kvm_vcpu *vcpu)
280 {
281 struct kvm_vcpu_timer *t = &vcpu->arch.timer;
282
283 t->next_cycles = -1ULL;
284 return kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer);
285 }
286
287 static void kvm_riscv_vcpu_update_timedelta(struct kvm_vcpu *vcpu)
288 {
289 struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
290
291 #if defined(CONFIG_32BIT)
292 csr_write(CSR_HTIMEDELTA, (u32)(gt->time_delta));
293 csr_write(CSR_HTIMEDELTAH, (u32)(gt->time_delta >> 32));
294 #else
295 csr_write(CSR_HTIMEDELTA, gt->time_delta);
296 #endif
297 }
298
299 void kvm_riscv_vcpu_timer_restore(struct kvm_vcpu *vcpu)
300 {
301 struct kvm_vcpu_timer *t = &vcpu->arch.timer;
302
303 kvm_riscv_vcpu_update_timedelta(vcpu);
304
305 if (!t->sstc_enabled)
306 return;
307
308 #if defined(CONFIG_32BIT)
309 csr_write(CSR_VSTIMECMP, (u32)t->next_cycles);
310 csr_write(CSR_VSTIMECMPH, (u32)(t->next_cycles >> 32));
311 #else
312 csr_write(CSR_VSTIMECMP, t->next_cycles);
313 #endif
314
315 /* timer should be enabled for the remaining operations */
316 if (unlikely(!t->init_done))
317 return;
318
319 kvm_riscv_vcpu_timer_unblocking(vcpu);
320 }
321
322 void kvm_riscv_vcpu_timer_sync(struct kvm_vcpu *vcpu)
323 {
324 struct kvm_vcpu_timer *t = &vcpu->arch.timer;
325
326 if (!t->sstc_enabled)
327 return;
328
329 #if defined(CONFIG_32BIT)
330 t->next_cycles = csr_read(CSR_VSTIMECMP);
331 t->next_cycles |= (u64)csr_read(CSR_VSTIMECMPH) << 32;
332 #else
333 t->next_cycles = csr_read(CSR_VSTIMECMP);
334 #endif
335 }
336
337 void kvm_riscv_vcpu_timer_save(struct kvm_vcpu *vcpu)
338 {
339 struct kvm_vcpu_timer *t = &vcpu->arch.timer;
340
341 if (!t->sstc_enabled)
342 return;
343
344 /*
345 * The vstimecmp CSRs are saved by kvm_riscv_vcpu_timer_sync()
346 * upon every VM exit so no need to save here.
347 */
348
349 /* timer should be enabled for the remaining operations */
350 if (unlikely(!t->init_done))
351 return;
352
353 if (kvm_vcpu_is_blocking(vcpu))
354 kvm_riscv_vcpu_timer_blocking(vcpu);
355 }
356
357 void kvm_riscv_guest_timer_init(struct kvm *kvm)
358 {
359 struct kvm_guest_timer *gt = &kvm->arch.timer;
360
361 riscv_cs_get_mult_shift(>->nsec_mult, >->nsec_shift);
362 gt->time_delta = -get_cycles64();
363 }
364
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