1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Virtual PTP 1588 clock for use with KVM guests
4 *
5 * Copyright (C) 2017 Red Hat Inc.
6 */
7 #include <linux/device.h>
8 #include <linux/err.h>
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12 #include <linux/module.h>
13 #include <linux/ptp_kvm.h>
14 #include <uapi/linux/kvm_para.h>
15 #include <asm/kvm_para.h>
16 #include <uapi/asm/kvm_para.h>
17
18 #include <linux/ptp_clock_kernel.h>
19
20 struct kvm_ptp_clock {
21 struct ptp_clock *ptp_clock;
22 struct ptp_clock_info caps;
23 };
24
25 static DEFINE_SPINLOCK(kvm_ptp_lock);
26
ptp_kvm_get_time_fn(ktime_t * device_time,struct system_counterval_t * system_counter,void * ctx)27 static int ptp_kvm_get_time_fn(ktime_t *device_time,
28 struct system_counterval_t *system_counter,
29 void *ctx)
30 {
31 long ret;
32 u64 cycle;
33 struct timespec64 tspec;
34 struct clocksource *cs;
35
36 spin_lock(&kvm_ptp_lock);
37
38 preempt_disable_notrace();
39 ret = kvm_arch_ptp_get_crosststamp(&cycle, &tspec, &cs);
40 if (ret) {
41 spin_unlock(&kvm_ptp_lock);
42 preempt_enable_notrace();
43 return ret;
44 }
45
46 preempt_enable_notrace();
47
48 system_counter->cycles = cycle;
49 system_counter->cs = cs;
50
51 *device_time = timespec64_to_ktime(tspec);
52
53 spin_unlock(&kvm_ptp_lock);
54
55 return 0;
56 }
57
ptp_kvm_getcrosststamp(struct ptp_clock_info * ptp,struct system_device_crosststamp * xtstamp)58 static int ptp_kvm_getcrosststamp(struct ptp_clock_info *ptp,
59 struct system_device_crosststamp *xtstamp)
60 {
61 return get_device_system_crosststamp(ptp_kvm_get_time_fn, NULL,
62 NULL, xtstamp);
63 }
64
65 /*
66 * PTP clock operations
67 */
68
ptp_kvm_adjfreq(struct ptp_clock_info * ptp,s32 ppb)69 static int ptp_kvm_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
70 {
71 return -EOPNOTSUPP;
72 }
73
ptp_kvm_adjtime(struct ptp_clock_info * ptp,s64 delta)74 static int ptp_kvm_adjtime(struct ptp_clock_info *ptp, s64 delta)
75 {
76 return -EOPNOTSUPP;
77 }
78
ptp_kvm_settime(struct ptp_clock_info * ptp,const struct timespec64 * ts)79 static int ptp_kvm_settime(struct ptp_clock_info *ptp,
80 const struct timespec64 *ts)
81 {
82 return -EOPNOTSUPP;
83 }
84
ptp_kvm_gettime(struct ptp_clock_info * ptp,struct timespec64 * ts)85 static int ptp_kvm_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
86 {
87 long ret;
88 struct timespec64 tspec;
89
90 spin_lock(&kvm_ptp_lock);
91
92 ret = kvm_arch_ptp_get_clock(&tspec);
93 if (ret) {
94 spin_unlock(&kvm_ptp_lock);
95 return ret;
96 }
97
98 spin_unlock(&kvm_ptp_lock);
99
100 memcpy(ts, &tspec, sizeof(struct timespec64));
101
102 return 0;
103 }
104
ptp_kvm_enable(struct ptp_clock_info * ptp,struct ptp_clock_request * rq,int on)105 static int ptp_kvm_enable(struct ptp_clock_info *ptp,
106 struct ptp_clock_request *rq, int on)
107 {
108 return -EOPNOTSUPP;
109 }
110
111 static const struct ptp_clock_info ptp_kvm_caps = {
112 .owner = THIS_MODULE,
113 .name = "KVM virtual PTP",
114 .max_adj = 0,
115 .n_ext_ts = 0,
116 .n_pins = 0,
117 .pps = 0,
118 .adjfreq = ptp_kvm_adjfreq,
119 .adjtime = ptp_kvm_adjtime,
120 .gettime64 = ptp_kvm_gettime,
121 .settime64 = ptp_kvm_settime,
122 .enable = ptp_kvm_enable,
123 .getcrosststamp = ptp_kvm_getcrosststamp,
124 };
125
126 /* module operations */
127
128 static struct kvm_ptp_clock kvm_ptp_clock;
129
ptp_kvm_exit(void)130 static void __exit ptp_kvm_exit(void)
131 {
132 ptp_clock_unregister(kvm_ptp_clock.ptp_clock);
133 }
134
ptp_kvm_init(void)135 static int __init ptp_kvm_init(void)
136 {
137 long ret;
138
139 ret = kvm_arch_ptp_init();
140 if (ret) {
141 if (ret != -EOPNOTSUPP)
142 pr_err("fail to initialize ptp_kvm");
143 return ret;
144 }
145
146 kvm_ptp_clock.caps = ptp_kvm_caps;
147
148 kvm_ptp_clock.ptp_clock = ptp_clock_register(&kvm_ptp_clock.caps, NULL);
149
150 return PTR_ERR_OR_ZERO(kvm_ptp_clock.ptp_clock);
151 }
152
153 module_init(ptp_kvm_init);
154 module_exit(ptp_kvm_exit);
155
156 MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>");
157 MODULE_DESCRIPTION("PTP clock using KVMCLOCK");
158 MODULE_LICENSE("GPL");
159