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/*
* Copyright (C) 2015 Linaro Ltd.
* Author: Shannon Zhao <shannon.zhao@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/cpu.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/perf_event.h>
#include <asm/kvm_emulate.h>
#include <kvm/arm_pmu.h>
/**
* kvm_pmu_get_counter_value - get PMU counter value
* @vcpu: The vcpu pointer
* @select_idx: The counter index
*/
u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx)
{
u64 counter, reg, enabled, running;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc = &pmu->pmc[select_idx];
reg = (select_idx == ARMV8_PMU_CYCLE_IDX)
? PMCCNTR_EL0 : PMEVCNTR0_EL0 + select_idx;
counter = vcpu_sys_reg(vcpu, reg);
/* The real counter value is equal to the value of counter register plus
* the value perf event counts.
*/
if (pmc->perf_event)
counter += perf_event_read_value(pmc->perf_event, &enabled,
&running);
return counter & pmc->bitmask;
}
/**
* kvm_pmu_set_counter_value - set PMU counter value
* @vcpu: The vcpu pointer
* @select_idx: The counter index
* @val: The counter value
*/
void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val)
{
u64 reg;
reg = (select_idx == ARMV8_PMU_CYCLE_IDX)
? PMCCNTR_EL0 : PMEVCNTR0_EL0 + select_idx;
vcpu_sys_reg(vcpu, reg) += (s64)val - kvm_pmu_get_counter_value(vcpu, select_idx);
}
u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu)
{
u64 val = vcpu_sys_reg(vcpu, PMCR_EL0) >> ARMV8_PMU_PMCR_N_SHIFT;
val &= ARMV8_PMU_PMCR_N_MASK;
if (val == 0)
return BIT(ARMV8_PMU_CYCLE_IDX);
else
return GENMASK(val - 1, 0) | BIT(ARMV8_PMU_CYCLE_IDX);
}
/**
* kvm_pmu_enable_counter - enable selected PMU counter
* @vcpu: The vcpu pointer
* @val: the value guest writes to PMCNTENSET register
*
* Call perf_event_enable to start counting the perf event
*/
void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u64 val)
{
int i;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc;
if (!(vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E) || !val)
return;
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
if (!(val & BIT(i)))
continue;
pmc = &pmu->pmc[i];
if (pmc->perf_event) {
perf_event_enable(pmc->perf_event);
if (pmc->perf_event->state != PERF_EVENT_STATE_ACTIVE)
kvm_debug("fail to enable perf event\n");
}
}
}
/**
* kvm_pmu_disable_counter - disable selected PMU counter
* @vcpu: The vcpu pointer
* @val: the value guest writes to PMCNTENCLR register
*
* Call perf_event_disable to stop counting the perf event
*/
void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u64 val)
{
int i;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc;
if (!val)
return;
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
if (!(val & BIT(i)))
continue;
pmc = &pmu->pmc[i];
if (pmc->perf_event)
perf_event_disable(pmc->perf_event);
}
}
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