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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Virtual PTP 1588 clock for use with KVM guests
*
* Copyright (C) 2017 Red Hat Inc.
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/ptp_kvm.h>
#include <uapi/linux/kvm_para.h>
#include <asm/kvm_para.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;
};
static DEFINE_SPINLOCK(kvm_ptp_lock);
static int ptp_kvm_get_time_fn(ktime_t *device_time,
struct system_counterval_t *system_counter,
void *ctx)
{
enum clocksource_ids cs_id;
struct timespec64 tspec;
u64 cycle;
int ret;
spin_lock(&kvm_ptp_lock);
preempt_disable_notrace();
ret = kvm_arch_ptp_get_crosststamp(&cycle, &tspec, &cs_id);
if (ret) {
spin_unlock(&kvm_ptp_lock);
preempt_enable_notrace();
return ret;
}
preempt_enable_notrace();
system_counter->cycles = cycle;
system_counter->cs_id = cs_id;
*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_adjfine(struct ptp_clock_info *ptp, long delta)
{
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)
{
long ret;
struct timespec64 tspec;
spin_lock(&kvm_ptp_lock);
ret = kvm_arch_ptp_get_clock(&tspec);
if (ret) {
spin_unlock(&kvm_ptp_lock);
return ret;
}
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 const 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,
.adjfine = ptp_kvm_adjfine,
.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);
kvm_arch_ptp_exit();
}
static int __init ptp_kvm_init(void)
{
long ret;
ret = kvm_arch_ptp_init();
if (ret) {
if (ret != -EOPNOTSUPP)
pr_err("fail to initialize ptp_kvm");
return ret;
}
kvm_ptp_clock.caps = ptp_kvm_caps;
kvm_ptp_clock.ptp_clock = ptp_clock_register(&kvm_ptp_clock.caps, NULL);
return PTR_ERR_OR_ZERO(kvm_ptp_clock.ptp_clock);
}
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");
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