// 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; }