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
|
/* KVM paravirtual clock driver. A clocksource implementation
Copyright (C) 2008 Glauber de Oliveira Costa, Red Hat Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <linux/clocksource.h>
#include <linux/kvm_para.h>
#include <asm/pvclock.h>
#include <asm/msr.h>
#include <asm/apic.h>
#include <linux/percpu.h>
#include <asm/reboot.h>
#define KVM_SCALE 22
static int kvmclock = 1;
static int parse_no_kvmclock(char *arg)
{
kvmclock = 0;
return 0;
}
early_param("no-kvmclock", parse_no_kvmclock);
/* The hypervisor will put information about time periodically here */
static DEFINE_PER_CPU_SHARED_ALIGNED(struct pvclock_vcpu_time_info, hv_clock);
static struct pvclock_wall_clock wall_clock;
/*
* The wallclock is the time of day when we booted. Since then, some time may
* have elapsed since the hypervisor wrote the data. So we try to account for
* that with system time
*/
static unsigned long kvm_get_wallclock(void)
{
struct pvclock_vcpu_time_info *vcpu_time;
struct timespec ts;
int low, high;
low = (int)__pa_symbol(&wall_clock);
high = ((u64)__pa_symbol(&wall_clock) >> 32);
native_write_msr(MSR_KVM_WALL_CLOCK, low, high);
vcpu_time = &get_cpu_var(hv_clock);
pvclock_read_wallclock(&wall_clock, vcpu_time, &ts);
put_cpu_var(hv_clock);
return ts.tv_sec;
}
static int kvm_set_wallclock(unsigned long now)
{
return -1;
}
static cycle_t kvm_clock_read(void)
{
struct pvclock_vcpu_time_info *src;
cycle_t ret;
src = &get_cpu_var(hv_clock);
ret = pvclock_clocksource_read(src);
put_cpu_var(hv_clock);
return ret;
}
static cycle_t kvm_clock_get_cycles(struct clocksource *cs)
{
return kvm_clock_read();
}
/*
* If we don't do that, there is the possibility that the guest
* will calibrate under heavy load - thus, getting a lower lpj -
* and execute the delays themselves without load. This is wrong,
* because no delay loop can finish beforehand.
* Any heuristics is subject to fail, because ultimately, a large
* poll of guests can be running and trouble each other. So we preset
* lpj here
*/
static unsigned long kvm_get_tsc_khz(void)
{
struct pvclock_vcpu_time_info *src;
src = &per_cpu(hv_clock, 0);
return pvclock_tsc_khz(src);
}
static void kvm_get_preset_lpj(void)
{
unsigned long khz;
u64 lpj;
khz = kvm_get_tsc_khz();
lpj = ((u64)khz * 1000);
do_div(lpj, HZ);
preset_lpj = lpj;
}
static struct clocksource kvm_clock = {
.name = "kvm-clock",
.read = kvm_clock_get_cycles,
.rating = 400,
.mask = CLOCKSOURCE_MASK(64),
.mult = 1 << KVM_SCALE,
.shift = KVM_SCALE,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static int kvm_register_clock(char *txt)
{
int cpu = smp_processor_id();
int low, high;
low = (int)__pa(&per_cpu(hv_clock, cpu)) | 1;
high = ((u64)__pa(&per_cpu(hv_clock, cpu)) >> 32);
printk(KERN_INFO "kvm-clock: cpu %d, msr %x:%x, %s\n",
cpu, high, low, txt);
return native_write_msr_safe(MSR_KVM_SYSTEM_TIME, low, high);
}
#ifdef CONFIG_X86_LOCAL_APIC
static void __cpuinit kvm_setup_secondary_clock(void)
{
/*
* Now that the first cpu already had this clocksource initialized,
* we shouldn't fail.
*/
WARN_ON(kvm_register_clock("secondary cpu clock"));
/* ok, done with our trickery, call native */
setup_secondary_APIC_clock();
}
#endif
#ifdef CONFIG_SMP
static void __init kvm_smp_prepare_boot_cpu(void)
{
WARN_ON(kvm_register_clock("primary cpu clock"));
native_smp_prepare_boot_cpu();
}
#endif
/*
* After the clock is registered, the host will keep writing to the
* registered memory location. If the guest happens to shutdown, this memory
* won't be valid. In cases like kexec, in which you install a new kernel, this
* means a random memory location will be kept being written. So before any
* kind of shutdown from our side, we unregister the clock by writting anything
* that does not have the 'enable' bit set in the msr
*/
#ifdef CONFIG_KEXEC
static void kvm_crash_shutdown(struct pt_regs *regs)
{
native_write_msr_safe(MSR_KVM_SYSTEM_TIME, 0, 0);
native_machine_crash_shutdown(regs);
}
#endif
static void kvm_shutdown(void)
{
native_write_msr_safe(MSR_KVM_SYSTEM_TIME, 0, 0);
native_machine_shutdown();
}
void __init kvmclock_init(void)
{
if (!kvm_para_available())
return;
if (kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE)) {
if (kvm_register_clock("boot clock"))
return;
pv_time_ops.get_wallclock = kvm_get_wallclock;
pv_time_ops.set_wallclock = kvm_set_wallclock;
pv_time_ops.sched_clock = kvm_clock_read;
pv_time_ops.get_tsc_khz = kvm_get_tsc_khz;
#ifdef CONFIG_X86_LOCAL_APIC
pv_apic_ops.setup_secondary_clock = kvm_setup_secondary_clock;
#endif
#ifdef CONFIG_SMP
smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
#endif
machine_ops.shutdown = kvm_shutdown;
#ifdef CONFIG_KEXEC
machine_ops.crash_shutdown = kvm_crash_shutdown;
#endif
kvm_get_preset_lpj();
clocksource_register(&kvm_clock);
pv_info.paravirt_enabled = 1;
pv_info.name = "KVM";
}
}
|
