130 lines
2.7 KiB
C
130 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Virtual PTP 1588 clock for use with KVM guests
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*
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* Copyright (C) 2017 Red Hat Inc.
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*/
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <asm/pvclock.h>
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#include <asm/kvmclock.h>
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#include <linux/module.h>
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#include <uapi/asm/kvm_para.h>
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#include <uapi/linux/kvm_para.h>
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#include <linux/ptp_clock_kernel.h>
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#include <linux/ptp_kvm.h>
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#include <linux/set_memory.h>
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static phys_addr_t clock_pair_gpa;
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static struct kvm_clock_pairing clock_pair_glbl;
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static struct kvm_clock_pairing *clock_pair;
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int kvm_arch_ptp_init(void)
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{
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struct page *p;
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long ret;
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if (!kvm_para_available())
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return -ENODEV;
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if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
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p = alloc_page(GFP_KERNEL | __GFP_ZERO);
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if (!p)
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return -ENOMEM;
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clock_pair = page_address(p);
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ret = set_memory_decrypted((unsigned long)clock_pair, 1);
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if (ret) {
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__free_page(p);
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clock_pair = NULL;
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goto nofree;
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}
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} else {
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clock_pair = &clock_pair_glbl;
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}
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clock_pair_gpa = slow_virt_to_phys(clock_pair);
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if (!pvclock_get_pvti_cpu0_va()) {
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ret = -ENODEV;
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goto err;
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}
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ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa,
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KVM_CLOCK_PAIRING_WALLCLOCK);
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if (ret == -KVM_ENOSYS) {
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ret = -ENODEV;
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goto err;
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}
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return ret;
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err:
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kvm_arch_ptp_exit();
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nofree:
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return ret;
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}
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void kvm_arch_ptp_exit(void)
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{
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if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
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WARN_ON(set_memory_encrypted((unsigned long)clock_pair, 1));
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free_page((unsigned long)clock_pair);
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clock_pair = NULL;
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}
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}
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int kvm_arch_ptp_get_clock(struct timespec64 *ts)
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{
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long ret;
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ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING,
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clock_pair_gpa,
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KVM_CLOCK_PAIRING_WALLCLOCK);
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if (ret != 0) {
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pr_err_ratelimited("clock offset hypercall ret %lu\n", ret);
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return -EOPNOTSUPP;
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}
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ts->tv_sec = clock_pair->sec;
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ts->tv_nsec = clock_pair->nsec;
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return 0;
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}
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int kvm_arch_ptp_get_crosststamp(u64 *cycle, struct timespec64 *tspec,
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struct clocksource **cs)
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{
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struct pvclock_vcpu_time_info *src;
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unsigned int version;
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long ret;
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src = this_cpu_pvti();
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do {
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/*
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* We are using a TSC value read in the hosts
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* kvm_hc_clock_pairing handling.
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* So any changes to tsc_to_system_mul
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* and tsc_shift or any other pvclock
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* data invalidate that measurement.
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*/
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version = pvclock_read_begin(src);
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ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING,
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clock_pair_gpa,
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KVM_CLOCK_PAIRING_WALLCLOCK);
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if (ret != 0) {
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pr_err_ratelimited("clock pairing hypercall ret %lu\n", ret);
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return -EOPNOTSUPP;
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}
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tspec->tv_sec = clock_pair->sec;
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tspec->tv_nsec = clock_pair->nsec;
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*cycle = __pvclock_read_cycles(src, clock_pair->tsc);
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} while (pvclock_read_retry(src, version));
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*cs = &kvm_clock;
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return 0;
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}
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