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
20struct kvm_ptp_clock {
21 struct ptp_clock *ptp_clock;
22 struct ptp_clock_info caps;
23};
24
25static DEFINE_SPINLOCK(kvm_ptp_lock);
26
27static int ptp_kvm_get_time_fn(ktime_t *device_time,
28 struct system_counterval_t *system_counter,
29 void *ctx)
30{
31 enum clocksource_ids cs_id;
32 struct timespec64 tspec;
33 u64 cycle;
34 int ret;
35
36 spin_lock(lock: &kvm_ptp_lock);
37
38 preempt_disable_notrace();
39 ret = kvm_arch_ptp_get_crosststamp(cycle: &cycle, tspec: &tspec, cs_id: &cs_id);
40 if (ret) {
41 spin_unlock(lock: &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_id = cs_id;
50
51 *device_time = timespec64_to_ktime(ts: tspec);
52
53 spin_unlock(lock: &kvm_ptp_lock);
54
55 return 0;
56}
57
58static int ptp_kvm_getcrosststamp(struct ptp_clock_info *ptp,
59 struct system_device_crosststamp *xtstamp)
60{
61 return get_device_system_crosststamp(get_time_fn: ptp_kvm_get_time_fn, NULL,
62 NULL, xtstamp);
63}
64
65/*
66 * PTP clock operations
67 */
68
69static int ptp_kvm_adjfine(struct ptp_clock_info *ptp, long delta)
70{
71 return -EOPNOTSUPP;
72}
73
74static int ptp_kvm_adjtime(struct ptp_clock_info *ptp, s64 delta)
75{
76 return -EOPNOTSUPP;
77}
78
79static int ptp_kvm_settime(struct ptp_clock_info *ptp,
80 const struct timespec64 *ts)
81{
82 return -EOPNOTSUPP;
83}
84
85static int ptp_kvm_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
86{
87 long ret;
88 struct timespec64 tspec;
89
90 spin_lock(lock: &kvm_ptp_lock);
91
92 ret = kvm_arch_ptp_get_clock(ts: &tspec);
93 if (ret) {
94 spin_unlock(lock: &kvm_ptp_lock);
95 return ret;
96 }
97
98 spin_unlock(lock: &kvm_ptp_lock);
99
100 memcpy(to: ts, from: &tspec, len: sizeof(struct timespec64));
101
102 return 0;
103}
104
105static int ptp_kvm_enable(struct ptp_clock_info *ptp,
106 struct ptp_clock_request *rq, int on)
107{
108 return -EOPNOTSUPP;
109}
110
111static 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 .adjfine = ptp_kvm_adjfine,
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
128static struct kvm_ptp_clock kvm_ptp_clock;
129
130static void __exit ptp_kvm_exit(void)
131{
132 ptp_clock_unregister(ptp: kvm_ptp_clock.ptp_clock);
133 kvm_arch_ptp_exit();
134}
135
136static int __init ptp_kvm_init(void)
137{
138 long ret;
139
140 ret = kvm_arch_ptp_init();
141 if (ret) {
142 if (ret != -EOPNOTSUPP)
143 pr_err("fail to initialize ptp_kvm");
144 return ret;
145 }
146
147 kvm_ptp_clock.caps = ptp_kvm_caps;
148
149 kvm_ptp_clock.ptp_clock = ptp_clock_register(info: &kvm_ptp_clock.caps, NULL);
150
151 return PTR_ERR_OR_ZERO(ptr: kvm_ptp_clock.ptp_clock);
152}
153
154module_init(ptp_kvm_init);
155module_exit(ptp_kvm_exit);
156
157MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>");
158MODULE_DESCRIPTION("PTP clock using KVMCLOCK");
159MODULE_LICENSE("GPL");
160