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@xxxxxxx>
---
include/kvm/arm_pmu.h | 1 -
virt/kvm/arm/pmu.c | 19 +++++++++----------
2 files changed, 9 insertions(+), 11 deletions(-)
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index b73f31baca52..2f0e28dc5a9e 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -28,7 +28,6 @@
struct kvm_pmc {
u8 idx; /* index into the pmu->pmc array */
struct perf_event *perf_event;
- u64 bitmask;
};
struct kvm_pmu {
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index ae1e886d4a1a..88ce24ae0b45 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -47,7 +47,10 @@ 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 (select_idx != ARMV8_PMU_CYCLE_IDX)
+ counter = lower_32_bits(counter);
+
+ return counter;
}
/**
@@ -113,7 +116,6 @@ 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;
}
}
@@ -348,8 +350,6 @@ 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;
@@ -368,11 +368,6 @@ 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)
@@ -420,7 +415,11 @@ 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 (pmc->idx == ARMV8_PMU_CYCLE_IDX &&
+ __vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_LC)
+ 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);
--
2.21.0
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