linux/drivers/ptp/ptp_kvm.c
Thomas Gleixner c942fddf87 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
Based on 3 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] this program is distributed in the hope that
  it will be useful but without any warranty without even the implied
  warranty of merchantability or fitness for a particular purpose see
  the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] this program is distributed in the hope
  that it will be useful but without any warranty without even the
  implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:37 -07:00

198 lines
4.3 KiB
C

// 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/module.h>
#include <uapi/linux/kvm_para.h>
#include <asm/kvm_para.h>
#include <asm/pvclock.h>
#include <asm/kvmclock.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;
};
DEFINE_SPINLOCK(kvm_ptp_lock);
static struct pvclock_vsyscall_time_info *hv_clock;
static struct kvm_clock_pairing clock_pair;
static phys_addr_t clock_pair_gpa;
static int ptp_kvm_get_time_fn(ktime_t *device_time,
struct system_counterval_t *system_counter,
void *ctx)
{
unsigned long ret;
struct timespec64 tspec;
unsigned version;
int cpu;
struct pvclock_vcpu_time_info *src;
spin_lock(&kvm_ptp_lock);
preempt_disable_notrace();
cpu = smp_processor_id();
src = &hv_clock[cpu].pvti;
do {
/*
* We are using a TSC value read in the hosts
* kvm_hc_clock_pairing handling.
* So any changes to tsc_to_system_mul
* and tsc_shift or any other pvclock
* data invalidate that measurement.
*/
version = pvclock_read_begin(src);
ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING,
clock_pair_gpa,
KVM_CLOCK_PAIRING_WALLCLOCK);
if (ret != 0) {
pr_err_ratelimited("clock pairing hypercall ret %lu\n", ret);
spin_unlock(&kvm_ptp_lock);
preempt_enable_notrace();
return -EOPNOTSUPP;
}
tspec.tv_sec = clock_pair.sec;
tspec.tv_nsec = clock_pair.nsec;
ret = __pvclock_read_cycles(src, clock_pair.tsc);
} while (pvclock_read_retry(src, version));
preempt_enable_notrace();
system_counter->cycles = ret;
system_counter->cs = &kvm_clock;
*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_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
{
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)
{
unsigned long ret;
struct timespec64 tspec;
spin_lock(&kvm_ptp_lock);
ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING,
clock_pair_gpa,
KVM_CLOCK_PAIRING_WALLCLOCK);
if (ret != 0) {
pr_err_ratelimited("clock offset hypercall ret %lu\n", ret);
spin_unlock(&kvm_ptp_lock);
return -EOPNOTSUPP;
}
tspec.tv_sec = clock_pair.sec;
tspec.tv_nsec = clock_pair.nsec;
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,
.adjfreq = ptp_kvm_adjfreq,
.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);
}
static int __init ptp_kvm_init(void)
{
long ret;
if (!kvm_para_available())
return -ENODEV;
clock_pair_gpa = slow_virt_to_phys(&clock_pair);
hv_clock = pvclock_get_pvti_cpu0_va();
if (!hv_clock)
return -ENODEV;
ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa,
KVM_CLOCK_PAIRING_WALLCLOCK);
if (ret == -KVM_ENOSYS || ret == -KVM_EOPNOTSUPP)
return -ENODEV;
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");