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
|
/*
* Virtual PTP 1588 clock for use with KVM guests
*
* Copyright (C) 2017 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.
*
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <uapi/linux/kvm_para.h>
#include <asm/kvm_para.h>
#include <asm/pvclock.h>
#include <asm/kvmclock.h>
#include <uapi/asm/kvm_para.h>
#include <linux/ptp_clock_kernel.h>
struct kvm_ptp_clock {
struct ptp_clock *ptp_clock;
struct ptp_clock_info caps;
};
DEFINE_SPINLOCK(kvm_ptp_lock);
static struct pvclock_vsyscall_time_info *hv_clock;
static struct kvm_clock_pairing clock_pair;
static phys_addr_t clock_pair_gpa;
static int ptp_kvm_get_time_fn(ktime_t *device_time,
struct system_counterval_t *system_counter,
void *ctx)
{
unsigned long ret;
struct timespec64 tspec;
unsigned version;
int cpu;
struct pvclock_vcpu_time_info *src;
spin_lock(&kvm_ptp_lock);
preempt_disable_notrace();
cpu = smp_processor_id();
src = &hv_clock[cpu].pvti;
do {
/*
* We are using a TSC value read in the hosts
* kvm_hc_clock_pairing handling.
* So any changes to tsc_to_system_mul
* and tsc_shift or any other pvclock
* data invalidate that measurement.
*/
version = pvclock_read_begin(src);
ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING,
clock_pair_gpa,
KVM_CLOCK_PAIRING_WALLCLOCK);
if (ret != 0) {
pr_err_ratelimited("clock pairing hypercall ret %lu\n", ret);
spin_unlock(&kvm_ptp_lock);
preempt_enable_notrace();
return -EOPNOTSUPP;
}
tspec.tv_sec = clock_pair.sec;
tspec.tv_nsec = clock_pair.nsec;
ret = __pvclock_read_cycles(src, clock_pair.tsc);
} while (pvclock_read_retry(src, version));
preempt_enable_notrace();
system_counter->cycles = ret;
system_counter->cs = &kvm_clock;
*device_time = timespec64_to_ktime(tspec);
spin_unlock(&kvm_ptp_lock);
return 0;
}
static int ptp_kvm_getcrosststamp(struct ptp_clock_info *ptp,
struct system_device_crosststamp *xtstamp)
{
return get_device_system_crosststamp(ptp_kvm_get_time_fn, NULL,
NULL, xtstamp);
}
/*
* PTP clock operations
*/
static int ptp_kvm_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
{
return -EOPNOTSUPP;
}
static int ptp_kvm_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
return -EOPNOTSUPP;
}
static int ptp_kvm_settime(struct ptp_clock_info *ptp,
const struct timespec64 *ts)
{
return -EOPNOTSUPP;
}
static int ptp_kvm_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
{
unsigned long ret;
struct timespec64 tspec;
spin_lock(&kvm_ptp_lock);
ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING,
clock_pair_gpa,
KVM_CLOCK_PAIRING_WALLCLOCK);
if (ret != 0) {
pr_err_ratelimited("clock offset hypercall ret %lu\n", ret);
spin_unlock(&kvm_ptp_lock);
return -EOPNOTSUPP;
}
tspec.tv_sec = clock_pair.sec;
tspec.tv_nsec = clock_pair.nsec;
spin_unlock(&kvm_ptp_lock);
memcpy(ts, &tspec, sizeof(struct timespec64));
return 0;
}
static int ptp_kvm_enable(struct ptp_clock_info *ptp,
struct ptp_clock_request *rq, int on)
{
return -EOPNOTSUPP;
}
static struct ptp_clock_info ptp_kvm_caps = {
.owner = THIS_MODULE,
.name = "KVM virtual PTP",
.max_adj = 0,
.n_ext_ts = 0,
.n_pins = 0,
.pps = 0,
.adjfreq = ptp_kvm_adjfreq,
.adjtime = ptp_kvm_adjtime,
.gettime64 = ptp_kvm_gettime,
.settime64 = ptp_kvm_settime,
.enable = ptp_kvm_enable,
.getcrosststamp = ptp_kvm_getcrosststamp,
};
/* module operations */
static struct kvm_ptp_clock kvm_ptp_clock;
static void __exit ptp_kvm_exit(void)
{
ptp_clock_unregister(kvm_ptp_clock.ptp_clock);
}
static int __init ptp_kvm_init(void)
{
clock_pair_gpa = slow_virt_to_phys(&clock_pair);
hv_clock = pvclock_pvti_cpu0_va();
if (!hv_clock)
return -ENODEV;
kvm_ptp_clock.caps = ptp_kvm_caps;
kvm_ptp_clock.ptp_clock = ptp_clock_register(&kvm_ptp_clock.caps, NULL);
if (IS_ERR(kvm_ptp_clock.ptp_clock))
return PTR_ERR(kvm_ptp_clock.ptp_clock);
return 0;
}
module_init(ptp_kvm_init);
module_exit(ptp_kvm_exit);
MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>");
MODULE_DESCRIPTION("PTP clock using KVMCLOCK");
MODULE_LICENSE("GPL");
|
