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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vcpu_timer.c (5508B)


      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Copyright (C) 2019 Western Digital Corporation or its affiliates.
      4 *
      5 * Authors:
      6 *     Atish Patra <atish.patra@wdc.com>
      7 */
      8
      9#include <linux/errno.h>
     10#include <linux/err.h>
     11#include <linux/kvm_host.h>
     12#include <linux/uaccess.h>
     13#include <clocksource/timer-riscv.h>
     14#include <asm/csr.h>
     15#include <asm/delay.h>
     16#include <asm/kvm_vcpu_timer.h>
     17
     18static u64 kvm_riscv_current_cycles(struct kvm_guest_timer *gt)
     19{
     20	return get_cycles64() + gt->time_delta;
     21}
     22
     23static u64 kvm_riscv_delta_cycles2ns(u64 cycles,
     24				     struct kvm_guest_timer *gt,
     25				     struct kvm_vcpu_timer *t)
     26{
     27	unsigned long flags;
     28	u64 cycles_now, cycles_delta, delta_ns;
     29
     30	local_irq_save(flags);
     31	cycles_now = kvm_riscv_current_cycles(gt);
     32	if (cycles_now < cycles)
     33		cycles_delta = cycles - cycles_now;
     34	else
     35		cycles_delta = 0;
     36	delta_ns = (cycles_delta * gt->nsec_mult) >> gt->nsec_shift;
     37	local_irq_restore(flags);
     38
     39	return delta_ns;
     40}
     41
     42static enum hrtimer_restart kvm_riscv_vcpu_hrtimer_expired(struct hrtimer *h)
     43{
     44	u64 delta_ns;
     45	struct kvm_vcpu_timer *t = container_of(h, struct kvm_vcpu_timer, hrt);
     46	struct kvm_vcpu *vcpu = container_of(t, struct kvm_vcpu, arch.timer);
     47	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
     48
     49	if (kvm_riscv_current_cycles(gt) < t->next_cycles) {
     50		delta_ns = kvm_riscv_delta_cycles2ns(t->next_cycles, gt, t);
     51		hrtimer_forward_now(&t->hrt, ktime_set(0, delta_ns));
     52		return HRTIMER_RESTART;
     53	}
     54
     55	t->next_set = false;
     56	kvm_riscv_vcpu_set_interrupt(vcpu, IRQ_VS_TIMER);
     57
     58	return HRTIMER_NORESTART;
     59}
     60
     61static int kvm_riscv_vcpu_timer_cancel(struct kvm_vcpu_timer *t)
     62{
     63	if (!t->init_done || !t->next_set)
     64		return -EINVAL;
     65
     66	hrtimer_cancel(&t->hrt);
     67	t->next_set = false;
     68
     69	return 0;
     70}
     71
     72int kvm_riscv_vcpu_timer_next_event(struct kvm_vcpu *vcpu, u64 ncycles)
     73{
     74	struct kvm_vcpu_timer *t = &vcpu->arch.timer;
     75	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
     76	u64 delta_ns;
     77
     78	if (!t->init_done)
     79		return -EINVAL;
     80
     81	kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_VS_TIMER);
     82
     83	delta_ns = kvm_riscv_delta_cycles2ns(ncycles, gt, t);
     84	t->next_cycles = ncycles;
     85	hrtimer_start(&t->hrt, ktime_set(0, delta_ns), HRTIMER_MODE_REL);
     86	t->next_set = true;
     87
     88	return 0;
     89}
     90
     91int kvm_riscv_vcpu_get_reg_timer(struct kvm_vcpu *vcpu,
     92				 const struct kvm_one_reg *reg)
     93{
     94	struct kvm_vcpu_timer *t = &vcpu->arch.timer;
     95	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
     96	u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr;
     97	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
     98					    KVM_REG_SIZE_MASK |
     99					    KVM_REG_RISCV_TIMER);
    100	u64 reg_val;
    101
    102	if (KVM_REG_SIZE(reg->id) != sizeof(u64))
    103		return -EINVAL;
    104	if (reg_num >= sizeof(struct kvm_riscv_timer) / sizeof(u64))
    105		return -EINVAL;
    106
    107	switch (reg_num) {
    108	case KVM_REG_RISCV_TIMER_REG(frequency):
    109		reg_val = riscv_timebase;
    110		break;
    111	case KVM_REG_RISCV_TIMER_REG(time):
    112		reg_val = kvm_riscv_current_cycles(gt);
    113		break;
    114	case KVM_REG_RISCV_TIMER_REG(compare):
    115		reg_val = t->next_cycles;
    116		break;
    117	case KVM_REG_RISCV_TIMER_REG(state):
    118		reg_val = (t->next_set) ? KVM_RISCV_TIMER_STATE_ON :
    119					  KVM_RISCV_TIMER_STATE_OFF;
    120		break;
    121	default:
    122		return -EINVAL;
    123	}
    124
    125	if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
    126		return -EFAULT;
    127
    128	return 0;
    129}
    130
    131int kvm_riscv_vcpu_set_reg_timer(struct kvm_vcpu *vcpu,
    132				 const struct kvm_one_reg *reg)
    133{
    134	struct kvm_vcpu_timer *t = &vcpu->arch.timer;
    135	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
    136	u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr;
    137	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
    138					    KVM_REG_SIZE_MASK |
    139					    KVM_REG_RISCV_TIMER);
    140	u64 reg_val;
    141	int ret = 0;
    142
    143	if (KVM_REG_SIZE(reg->id) != sizeof(u64))
    144		return -EINVAL;
    145	if (reg_num >= sizeof(struct kvm_riscv_timer) / sizeof(u64))
    146		return -EINVAL;
    147
    148	if (copy_from_user(&reg_val, uaddr, KVM_REG_SIZE(reg->id)))
    149		return -EFAULT;
    150
    151	switch (reg_num) {
    152	case KVM_REG_RISCV_TIMER_REG(frequency):
    153		ret = -EOPNOTSUPP;
    154		break;
    155	case KVM_REG_RISCV_TIMER_REG(time):
    156		gt->time_delta = reg_val - get_cycles64();
    157		break;
    158	case KVM_REG_RISCV_TIMER_REG(compare):
    159		t->next_cycles = reg_val;
    160		break;
    161	case KVM_REG_RISCV_TIMER_REG(state):
    162		if (reg_val == KVM_RISCV_TIMER_STATE_ON)
    163			ret = kvm_riscv_vcpu_timer_next_event(vcpu, reg_val);
    164		else
    165			ret = kvm_riscv_vcpu_timer_cancel(t);
    166		break;
    167	default:
    168		ret = -EINVAL;
    169		break;
    170	}
    171
    172	return ret;
    173}
    174
    175int kvm_riscv_vcpu_timer_init(struct kvm_vcpu *vcpu)
    176{
    177	struct kvm_vcpu_timer *t = &vcpu->arch.timer;
    178
    179	if (t->init_done)
    180		return -EINVAL;
    181
    182	hrtimer_init(&t->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
    183	t->hrt.function = kvm_riscv_vcpu_hrtimer_expired;
    184	t->init_done = true;
    185	t->next_set = false;
    186
    187	return 0;
    188}
    189
    190int kvm_riscv_vcpu_timer_deinit(struct kvm_vcpu *vcpu)
    191{
    192	int ret;
    193
    194	ret = kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer);
    195	vcpu->arch.timer.init_done = false;
    196
    197	return ret;
    198}
    199
    200int kvm_riscv_vcpu_timer_reset(struct kvm_vcpu *vcpu)
    201{
    202	return kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer);
    203}
    204
    205void kvm_riscv_vcpu_timer_restore(struct kvm_vcpu *vcpu)
    206{
    207	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
    208
    209#ifdef CONFIG_64BIT
    210	csr_write(CSR_HTIMEDELTA, gt->time_delta);
    211#else
    212	csr_write(CSR_HTIMEDELTA, (u32)(gt->time_delta));
    213	csr_write(CSR_HTIMEDELTAH, (u32)(gt->time_delta >> 32));
    214#endif
    215}
    216
    217int kvm_riscv_guest_timer_init(struct kvm *kvm)
    218{
    219	struct kvm_guest_timer *gt = &kvm->arch.timer;
    220
    221	riscv_cs_get_mult_shift(&gt->nsec_mult, &gt->nsec_shift);
    222	gt->time_delta = -get_cycles64();
    223
    224	return 0;
    225}