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Commit | Line | Data |
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790c73f6 GOC |
1 | /* KVM paravirtual clock driver. A clocksource implementation |
2 | Copyright (C) 2008 Glauber de Oliveira Costa, Red Hat Inc. | |
3 | ||
4 | This program is free software; you can redistribute it and/or modify | |
5 | it under the terms of the GNU General Public License as published by | |
6 | the Free Software Foundation; either version 2 of the License, or | |
7 | (at your option) any later version. | |
8 | ||
9 | This program is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | GNU General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU General Public License | |
15 | along with this program; if not, write to the Free Software | |
16 | Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
17 | */ | |
18 | ||
19 | #include <linux/clocksource.h> | |
20 | #include <linux/kvm_para.h> | |
f6e16d5a | 21 | #include <asm/pvclock.h> |
790c73f6 GOC |
22 | #include <asm/msr.h> |
23 | #include <asm/apic.h> | |
24 | #include <linux/percpu.h> | |
3b5d56b9 | 25 | #include <linux/hardirq.h> |
7069ed67 | 26 | #include <linux/memblock.h> |
0ad83caa | 27 | #include <linux/sched.h> |
736decac TG |
28 | |
29 | #include <asm/x86_init.h> | |
1e977aa1 | 30 | #include <asm/reboot.h> |
790c73f6 | 31 | |
790c73f6 | 32 | static int kvmclock = 1; |
838815a7 GC |
33 | static int msr_kvm_system_time = MSR_KVM_SYSTEM_TIME; |
34 | static int msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK; | |
790c73f6 GOC |
35 | |
36 | static int parse_no_kvmclock(char *arg) | |
37 | { | |
38 | kvmclock = 0; | |
39 | return 0; | |
40 | } | |
41 | early_param("no-kvmclock", parse_no_kvmclock); | |
42 | ||
43 | /* The hypervisor will put information about time periodically here */ | |
3dc4f7cf | 44 | static struct pvclock_vsyscall_time_info *hv_clock; |
f6e16d5a | 45 | static struct pvclock_wall_clock wall_clock; |
790c73f6 | 46 | |
790c73f6 GOC |
47 | /* |
48 | * The wallclock is the time of day when we booted. Since then, some time may | |
49 | * have elapsed since the hypervisor wrote the data. So we try to account for | |
50 | * that with system time | |
51 | */ | |
3565184e | 52 | static void kvm_get_wallclock(struct timespec *now) |
790c73f6 | 53 | { |
f6e16d5a | 54 | struct pvclock_vcpu_time_info *vcpu_time; |
790c73f6 | 55 | int low, high; |
7069ed67 | 56 | int cpu; |
790c73f6 | 57 | |
a20316d2 GC |
58 | low = (int)__pa_symbol(&wall_clock); |
59 | high = ((u64)__pa_symbol(&wall_clock) >> 32); | |
838815a7 GC |
60 | |
61 | native_write_msr(msr_kvm_wall_clock, low, high); | |
790c73f6 | 62 | |
c6338ce4 | 63 | cpu = get_cpu(); |
7069ed67 | 64 | |
3dc4f7cf | 65 | vcpu_time = &hv_clock[cpu].pvti; |
3565184e | 66 | pvclock_read_wallclock(&wall_clock, vcpu_time, now); |
7069ed67 | 67 | |
c6338ce4 | 68 | put_cpu(); |
790c73f6 GOC |
69 | } |
70 | ||
3565184e | 71 | static int kvm_set_wallclock(const struct timespec *now) |
790c73f6 | 72 | { |
f6e16d5a | 73 | return -1; |
790c73f6 GOC |
74 | } |
75 | ||
790c73f6 GOC |
76 | static cycle_t kvm_clock_read(void) |
77 | { | |
f6e16d5a GH |
78 | struct pvclock_vcpu_time_info *src; |
79 | cycle_t ret; | |
7069ed67 | 80 | int cpu; |
790c73f6 | 81 | |
95ef1e52 | 82 | preempt_disable_notrace(); |
7069ed67 | 83 | cpu = smp_processor_id(); |
3dc4f7cf | 84 | src = &hv_clock[cpu].pvti; |
f6e16d5a | 85 | ret = pvclock_clocksource_read(src); |
95ef1e52 | 86 | preempt_enable_notrace(); |
f6e16d5a | 87 | return ret; |
790c73f6 | 88 | } |
f6e16d5a | 89 | |
8e19608e MD |
90 | static cycle_t kvm_clock_get_cycles(struct clocksource *cs) |
91 | { | |
92 | return kvm_clock_read(); | |
93 | } | |
94 | ||
0293615f GC |
95 | /* |
96 | * If we don't do that, there is the possibility that the guest | |
97 | * will calibrate under heavy load - thus, getting a lower lpj - | |
98 | * and execute the delays themselves without load. This is wrong, | |
99 | * because no delay loop can finish beforehand. | |
100 | * Any heuristics is subject to fail, because ultimately, a large | |
101 | * poll of guests can be running and trouble each other. So we preset | |
102 | * lpj here | |
103 | */ | |
104 | static unsigned long kvm_get_tsc_khz(void) | |
105 | { | |
e93353c9 | 106 | struct pvclock_vcpu_time_info *src; |
7069ed67 MT |
107 | int cpu; |
108 | unsigned long tsc_khz; | |
109 | ||
c6338ce4 | 110 | cpu = get_cpu(); |
3dc4f7cf | 111 | src = &hv_clock[cpu].pvti; |
7069ed67 | 112 | tsc_khz = pvclock_tsc_khz(src); |
c6338ce4 | 113 | put_cpu(); |
7069ed67 | 114 | return tsc_khz; |
0293615f GC |
115 | } |
116 | ||
117 | static void kvm_get_preset_lpj(void) | |
118 | { | |
0293615f GC |
119 | unsigned long khz; |
120 | u64 lpj; | |
121 | ||
e93353c9 | 122 | khz = kvm_get_tsc_khz(); |
0293615f GC |
123 | |
124 | lpj = ((u64)khz * 1000); | |
125 | do_div(lpj, HZ); | |
126 | preset_lpj = lpj; | |
127 | } | |
128 | ||
3b5d56b9 EM |
129 | bool kvm_check_and_clear_guest_paused(void) |
130 | { | |
131 | bool ret = false; | |
132 | struct pvclock_vcpu_time_info *src; | |
7069ed67 MT |
133 | int cpu = smp_processor_id(); |
134 | ||
135 | if (!hv_clock) | |
136 | return ret; | |
3b5d56b9 | 137 | |
3dc4f7cf | 138 | src = &hv_clock[cpu].pvti; |
3b5d56b9 | 139 | if ((src->flags & PVCLOCK_GUEST_STOPPED) != 0) { |
7069ed67 | 140 | src->flags &= ~PVCLOCK_GUEST_STOPPED; |
d63285e9 | 141 | pvclock_touch_watchdogs(); |
3b5d56b9 EM |
142 | ret = true; |
143 | } | |
144 | ||
145 | return ret; | |
146 | } | |
3b5d56b9 | 147 | |
790c73f6 GOC |
148 | static struct clocksource kvm_clock = { |
149 | .name = "kvm-clock", | |
8e19608e | 150 | .read = kvm_clock_get_cycles, |
790c73f6 GOC |
151 | .rating = 400, |
152 | .mask = CLOCKSOURCE_MASK(64), | |
790c73f6 GOC |
153 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
154 | }; | |
155 | ||
ca3f1017 | 156 | int kvm_register_clock(char *txt) |
790c73f6 GOC |
157 | { |
158 | int cpu = smp_processor_id(); | |
19b6a85b | 159 | int low, high, ret; |
fe1140cc JK |
160 | struct pvclock_vcpu_time_info *src; |
161 | ||
162 | if (!hv_clock) | |
163 | return 0; | |
19b6a85b | 164 | |
fe1140cc | 165 | src = &hv_clock[cpu].pvti; |
5dfd486c DH |
166 | low = (int)slow_virt_to_phys(src) | 1; |
167 | high = ((u64)slow_virt_to_phys(src) >> 32); | |
19b6a85b | 168 | ret = native_write_msr_safe(msr_kvm_system_time, low, high); |
f6e16d5a GH |
169 | printk(KERN_INFO "kvm-clock: cpu %d, msr %x:%x, %s\n", |
170 | cpu, high, low, txt); | |
838815a7 | 171 | |
19b6a85b | 172 | return ret; |
790c73f6 GOC |
173 | } |
174 | ||
b74f05d6 MT |
175 | static void kvm_save_sched_clock_state(void) |
176 | { | |
177 | } | |
178 | ||
179 | static void kvm_restore_sched_clock_state(void) | |
180 | { | |
181 | kvm_register_clock("primary cpu clock, resume"); | |
182 | } | |
183 | ||
b8ba5f10 | 184 | #ifdef CONFIG_X86_LOCAL_APIC |
148f9bb8 | 185 | static void kvm_setup_secondary_clock(void) |
790c73f6 GOC |
186 | { |
187 | /* | |
188 | * Now that the first cpu already had this clocksource initialized, | |
189 | * we shouldn't fail. | |
190 | */ | |
f6e16d5a | 191 | WARN_ON(kvm_register_clock("secondary cpu clock")); |
790c73f6 | 192 | } |
b8ba5f10 | 193 | #endif |
790c73f6 | 194 | |
1e977aa1 GC |
195 | /* |
196 | * After the clock is registered, the host will keep writing to the | |
197 | * registered memory location. If the guest happens to shutdown, this memory | |
198 | * won't be valid. In cases like kexec, in which you install a new kernel, this | |
199 | * means a random memory location will be kept being written. So before any | |
200 | * kind of shutdown from our side, we unregister the clock by writting anything | |
201 | * that does not have the 'enable' bit set in the msr | |
202 | */ | |
2965faa5 | 203 | #ifdef CONFIG_KEXEC_CORE |
1e977aa1 GC |
204 | static void kvm_crash_shutdown(struct pt_regs *regs) |
205 | { | |
838815a7 | 206 | native_write_msr(msr_kvm_system_time, 0, 0); |
d910f5c1 | 207 | kvm_disable_steal_time(); |
1e977aa1 GC |
208 | native_machine_crash_shutdown(regs); |
209 | } | |
210 | #endif | |
211 | ||
212 | static void kvm_shutdown(void) | |
213 | { | |
838815a7 | 214 | native_write_msr(msr_kvm_system_time, 0, 0); |
d910f5c1 | 215 | kvm_disable_steal_time(); |
1e977aa1 GC |
216 | native_machine_shutdown(); |
217 | } | |
218 | ||
790c73f6 GOC |
219 | void __init kvmclock_init(void) |
220 | { | |
0ad83caa | 221 | struct pvclock_vcpu_time_info *vcpu_time; |
7069ed67 | 222 | unsigned long mem; |
0ad83caa LC |
223 | int size, cpu; |
224 | u8 flags; | |
ed55705d MT |
225 | |
226 | size = PAGE_ALIGN(sizeof(struct pvclock_vsyscall_time_info)*NR_CPUS); | |
7069ed67 | 227 | |
790c73f6 GOC |
228 | if (!kvm_para_available()) |
229 | return; | |
230 | ||
838815a7 GC |
231 | if (kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) { |
232 | msr_kvm_system_time = MSR_KVM_SYSTEM_TIME_NEW; | |
233 | msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK_NEW; | |
234 | } else if (!(kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE))) | |
235 | return; | |
236 | ||
237 | printk(KERN_INFO "kvm-clock: Using msrs %x and %x", | |
238 | msr_kvm_system_time, msr_kvm_wall_clock); | |
239 | ||
ed55705d | 240 | mem = memblock_alloc(size, PAGE_SIZE); |
7069ed67 MT |
241 | if (!mem) |
242 | return; | |
243 | hv_clock = __va(mem); | |
07868fc6 | 244 | memset(hv_clock, 0, size); |
7069ed67 | 245 | |
0d75de4a | 246 | if (kvm_register_clock("primary cpu clock")) { |
7069ed67 | 247 | hv_clock = NULL; |
ed55705d | 248 | memblock_free(mem, size); |
838815a7 | 249 | return; |
7069ed67 | 250 | } |
838815a7 GC |
251 | pv_time_ops.sched_clock = kvm_clock_read; |
252 | x86_platform.calibrate_tsc = kvm_get_tsc_khz; | |
253 | x86_platform.get_wallclock = kvm_get_wallclock; | |
254 | x86_platform.set_wallclock = kvm_set_wallclock; | |
b8ba5f10 | 255 | #ifdef CONFIG_X86_LOCAL_APIC |
df156f90 | 256 | x86_cpuinit.early_percpu_clock_init = |
838815a7 | 257 | kvm_setup_secondary_clock; |
b8ba5f10 | 258 | #endif |
b74f05d6 MT |
259 | x86_platform.save_sched_clock_state = kvm_save_sched_clock_state; |
260 | x86_platform.restore_sched_clock_state = kvm_restore_sched_clock_state; | |
838815a7 | 261 | machine_ops.shutdown = kvm_shutdown; |
2965faa5 | 262 | #ifdef CONFIG_KEXEC_CORE |
838815a7 | 263 | machine_ops.crash_shutdown = kvm_crash_shutdown; |
1e977aa1 | 264 | #endif |
838815a7 | 265 | kvm_get_preset_lpj(); |
b01cc1b0 | 266 | clocksource_register_hz(&kvm_clock, NSEC_PER_SEC); |
838815a7 | 267 | pv_info.name = "KVM"; |
3a0d7256 GC |
268 | |
269 | if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STABLE_BIT)) | |
0ad83caa LC |
270 | pvclock_set_flags(~0); |
271 | ||
272 | cpu = get_cpu(); | |
273 | vcpu_time = &hv_clock[cpu].pvti; | |
274 | flags = pvclock_read_flags(vcpu_time); | |
275 | if (flags & PVCLOCK_COUNTS_FROM_ZERO) | |
276 | set_sched_clock_stable(); | |
277 | put_cpu(); | |
790c73f6 | 278 | } |
3dc4f7cf MT |
279 | |
280 | int __init kvm_setup_vsyscall_timeinfo(void) | |
281 | { | |
282 | #ifdef CONFIG_X86_64 | |
283 | int cpu; | |
284 | int ret; | |
285 | u8 flags; | |
286 | struct pvclock_vcpu_time_info *vcpu_time; | |
287 | unsigned int size; | |
288 | ||
fe1140cc JK |
289 | if (!hv_clock) |
290 | return 0; | |
291 | ||
ed55705d | 292 | size = PAGE_ALIGN(sizeof(struct pvclock_vsyscall_time_info)*NR_CPUS); |
3dc4f7cf | 293 | |
c6338ce4 | 294 | cpu = get_cpu(); |
3dc4f7cf MT |
295 | |
296 | vcpu_time = &hv_clock[cpu].pvti; | |
297 | flags = pvclock_read_flags(vcpu_time); | |
298 | ||
299 | if (!(flags & PVCLOCK_TSC_STABLE_BIT)) { | |
c6338ce4 | 300 | put_cpu(); |
3dc4f7cf MT |
301 | return 1; |
302 | } | |
303 | ||
304 | if ((ret = pvclock_init_vsyscall(hv_clock, size))) { | |
c6338ce4 | 305 | put_cpu(); |
3dc4f7cf MT |
306 | return ret; |
307 | } | |
308 | ||
c6338ce4 | 309 | put_cpu(); |
3dc4f7cf MT |
310 | |
311 | kvm_clock.archdata.vclock_mode = VCLOCK_PVCLOCK; | |
312 | #endif | |
313 | return 0; | |
314 | } |