[mirror_ubuntu-jammy-kernel.git] / drivers / ptp / ptp_kvm_x86.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/kernel.h>
#include <asm/pvclock.h>
#include <asm/kvmclock.h>
#include <linux/module.h>
#include <uapi/asm/kvm_para.h>
#include <uapi/linux/kvm_para.h>
#include <linux/ptp_clock_kernel.h>
#include <linux/ptp_kvm.h>

static phys_addr_t clock_pair_gpa;
static struct kvm_clock_pairing clock_pair;

int kvm_arch_ptp_init(void)
{
	long ret;

	if (!kvm_para_available())
		return -ENODEV;

	clock_pair_gpa = slow_virt_to_phys(&clock_pair);
	if (!pvclock_get_pvti_cpu0_va())
		return -ENODEV;

	ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa,
			     KVM_CLOCK_PAIRING_WALLCLOCK);
	if (ret == -KVM_ENOSYS)
		return -ENODEV;

	return ret;
}

int kvm_arch_ptp_get_clock(struct timespec64 *ts)
{
	long ret;

	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);
		return -EOPNOTSUPP;
	}

	ts->tv_sec = clock_pair.sec;
	ts->tv_nsec = clock_pair.nsec;

	return 0;
}

int kvm_arch_ptp_get_crosststamp(u64 *cycle, struct timespec64 *tspec,
			      struct clocksource **cs)
{
	struct pvclock_vcpu_time_info *src;
	unsigned int version;
	long ret;

	src = this_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);
			return -EOPNOTSUPP;
		}
		tspec->tv_sec = clock_pair.sec;
		tspec->tv_nsec = clock_pair.nsec;
		*cycle = __pvclock_read_cycles(src, clock_pair.tsc);
	} while (pvclock_read_retry(src, version));

	*cs = &kvm_clock;

	return 0;
}
Commit	Line	Data
a8cf291b JW	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
	8	#include <linux/device.h>
	9	#include <linux/kernel.h>
	10	#include <asm/pvclock.h>
	11	#include <asm/kvmclock.h>
	12	#include <linux/module.h>
	13	#include <uapi/asm/kvm_para.h>
	14	#include <uapi/linux/kvm_para.h>
	15	#include <linux/ptp_clock_kernel.h>
	16	#include <linux/ptp_kvm.h>
	17
a8cf291b JW	18	static phys_addr_t clock_pair_gpa;
	19	static struct kvm_clock_pairing clock_pair;
	20
	21	int kvm_arch_ptp_init(void)
	22	{
	23	long ret;
	24
	25	if (!kvm_para_available())
	26	return -ENODEV;
	27
	28	clock_pair_gpa = slow_virt_to_phys(&clock_pair);
773e89ab	29	if (!pvclock_get_pvti_cpu0_va())
a8cf291b JW	30	return -ENODEV;
	31
	32	ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa,
	33	KVM_CLOCK_PAIRING_WALLCLOCK);
c2402d43	34	if (ret == -KVM_ENOSYS)
a8cf291b JW	35	return -ENODEV;
a8cf291b JW	36
c2402d43	37	return ret;
a8cf291b JW	38	}
	39
	40	int kvm_arch_ptp_get_clock(struct timespec64 *ts)
	41	{
	42	long ret;
	43
	44	ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING,
	45	clock_pair_gpa,
	46	KVM_CLOCK_PAIRING_WALLCLOCK);
	47	if (ret != 0) {
	48	pr_err_ratelimited("clock offset hypercall ret %lu\n", ret);
	49	return -EOPNOTSUPP;
	50	}
	51
	52	ts->tv_sec = clock_pair.sec;
	53	ts->tv_nsec = clock_pair.nsec;
	54
	55	return 0;
	56	}
	57
	58	int kvm_arch_ptp_get_crosststamp(u64 cycle, struct timespec64 tspec,
	59	struct clocksource **cs)
	60	{
	61	struct pvclock_vcpu_time_info *src;
	62	unsigned int version;
	63	long ret;
a8cf291b	64
773e89ab	65	src = this_cpu_pvti();
a8cf291b JW	66
	67	do {
	68	/*
	69	* We are using a TSC value read in the hosts
	70	* kvm_hc_clock_pairing handling.
	71	* So any changes to tsc_to_system_mul
	72	* and tsc_shift or any other pvclock
	73	* data invalidate that measurement.
	74	*/
	75	version = pvclock_read_begin(src);
	76
	77	ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING,
	78	clock_pair_gpa,
	79	KVM_CLOCK_PAIRING_WALLCLOCK);
	80	if (ret != 0) {
	81	pr_err_ratelimited("clock pairing hypercall ret %lu\n", ret);
	82	return -EOPNOTSUPP;
	83	}
	84	tspec->tv_sec = clock_pair.sec;
	85	tspec->tv_nsec = clock_pair.nsec;
	86	*cycle = __pvclock_read_cycles(src, clock_pair.tsc);
	87	} while (pvclock_read_retry(src, version));
	88
	89	*cs = &kvm_clock;
	90
	91	return 0;
	92	}