LXR linux/drivers/ptp/ptp_kvm

   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        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
  58static 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
  69static int ptp_kvm_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
  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(&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
 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        .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
 128static struct kvm_ptp_clock kvm_ptp_clock;
 129
 130static void __exit ptp_kvm_exit(void)
 131{
 132        ptp_clock_unregister(kvm_ptp_clock.ptp_clock);
 133}
 134
 135static 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
 153module_init(ptp_kvm_init);
 154module_exit(ptp_kvm_exit);
 155
 156MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>");
 157MODULE_DESCRIPTION("PTP clock using KVMCLOCK");
 158MODULE_LICENSE("GPL");
 159