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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/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;
- }
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