projects / linux.git / blame
| 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; |
| 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 | } |