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KVM: arm/arm64: Remove pmc->bitmask 

We currently use pmc->bitmask to determine the width of the pmc - however
it's superfluous as the pmc index already describes if the pmc is a cycle
counter or event counter. The architecture clearly describes the widths of
these counters.

Let's remove the bitmask to simplify the code.

Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Andrew Murray 2019-06-17 20:01:04 +01:00 committed by Marc Zyngier
parent 30d97754b2
commit 218907cbc2
2 changed files with 20 additions and 11 deletions
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1
include/kvm/arm_pmu.h
View File

@ -17,7 +17,6 @@
struct kvm_pmc {
u8 idx; /* index into the pmu->pmc array */
struct perf_event *perf_event;
u64 bitmask;
};
struct kvm_pmu {

30
virt/kvm/arm/pmu.c
View File

@ -14,6 +14,18 @@
#include <kvm/arm_vgic.h>
static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx);
/**
* kvm_pmu_idx_is_64bit - determine if select_idx is a 64bit counter
* @vcpu: The vcpu pointer
* @select_idx: The counter index
*/
static bool kvm_pmu_idx_is_64bit(struct kvm_vcpu *vcpu, u64 select_idx)
{
return (select_idx == ARMV8_PMU_CYCLE_IDX &&
__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_LC);
}
/**
* kvm_pmu_get_counter_value - get PMU counter value
* @vcpu: The vcpu pointer
@ -36,7 +48,10 @@ u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx)
counter += perf_event_read_value(pmc->perf_event, &enabled,
&running);
return counter & pmc->bitmask;
if (!kvm_pmu_idx_is_64bit(vcpu, select_idx))
counter = lower_32_bits(counter);
return counter;
}
/**
@ -102,7 +117,6 @@ void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu)
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
kvm_pmu_stop_counter(vcpu, &pmu->pmc[i]);
pmu->pmc[i].idx = i;
pmu->pmc[i].bitmask = 0xffffffffUL;
}
}
@ -337,8 +351,6 @@ void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val)
*/
void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
{
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc;
u64 mask;
int i;
@ -357,11 +369,6 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
for (i = 0; i < ARMV8_PMU_CYCLE_IDX; i++)
kvm_pmu_set_counter_value(vcpu, i, 0);
}
if (val & ARMV8_PMU_PMCR_LC) {
pmc = &pmu->pmc[ARMV8_PMU_CYCLE_IDX];
pmc->bitmask = 0xffffffffffffffffUL;
}
}
static bool kvm_pmu_counter_is_enabled(struct kvm_vcpu *vcpu, u64 select_idx)
@ -409,7 +416,10 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx)
counter = kvm_pmu_get_counter_value(vcpu, select_idx);
/* The initial sample period (overflow count) of an event. */
attr.sample_period = (-counter) & pmc->bitmask;
if (kvm_pmu_idx_is_64bit(vcpu, pmc->idx))
attr.sample_period = (-counter) & GENMASK(63, 0);
else
attr.sample_period = (-counter) & GENMASK(31, 0);
event = perf_event_create_kernel_counter(&attr, -1, current,
kvm_pmu_perf_overflow, pmc);