cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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ptp_kvm_x86.c (2067B)

      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
     18static phys_addr_t clock_pair_gpa;
     19static struct kvm_clock_pairing clock_pair;
     20
     21int 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);
     29	if (!pvclock_get_pvti_cpu0_va())
     30		return -ENODEV;
     31
     32	ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa,
     33			     KVM_CLOCK_PAIRING_WALLCLOCK);
     34	if (ret == -KVM_ENOSYS)
     35		return -ENODEV;
     36
     37	return ret;
     38}
     39
     40int 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
     58int 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;
     64
     65	src = this_cpu_pvti();
     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}