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 | |
27 | static 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 | |
58 | static 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 | |
69 | static int ptp_kvm_adjfine(struct ptp_clock_info *ptp, long delta) |
70 | { |
71 | return -EOPNOTSUPP; |
72 | } |
73 | |
74 | static int ptp_kvm_adjtime(struct ptp_clock_info *ptp, s64 delta) |
75 | { |
76 | return -EOPNOTSUPP; |
77 | } |
78 | |
79 | static int ptp_kvm_settime(struct ptp_clock_info *ptp, |
80 | const struct timespec64 *ts) |
81 | { |
82 | return -EOPNOTSUPP; |
83 | } |
84 | |
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(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(ts, &tspec, sizeof(struct timespec64)); |
101 | |
102 | return 0; |
103 | } |
104 | |
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 | .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 | |
128 | static struct kvm_ptp_clock kvm_ptp_clock; |
129 | |
130 | static void __exit ptp_kvm_exit(void) |
131 | { |
132 | ptp_clock_unregister(ptp: kvm_ptp_clock.ptp_clock); |
133 | kvm_arch_ptp_exit(); |
134 | } |
135 | |
136 | static 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 | |
154 | module_init(ptp_kvm_init); |
155 | module_exit(ptp_kvm_exit); |
156 | |
157 | MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>" ); |
158 | MODULE_DESCRIPTION("PTP clock using KVMCLOCK" ); |
159 | MODULE_LICENSE("GPL" ); |
160 | |