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KVM: arm64: Add helpers to determine if PMC counts at a given EL

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Checking the exception level filters for a PMC is a minor annoyance to
open code. Add helpers to check if an event counts at EL0 and EL1, which
will prove useful in a subsequent change.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241025182354.3364124-15-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Oliver Upton 2024-10-25 18:23:49 +00:00
parent 9a1c58cfef
commit 9d15f8290a
1 changed files with 28 additions and 12 deletions
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40
arch/arm64/kvm/pmu-emul.c
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@ -111,6 +111,11 @@ static u32 counter_index_to_evtreg(u64 idx)
return (idx == ARMV8_PMU_CYCLE_IDX) ? PMCCFILTR_EL0 : PMEVTYPER0_EL0 + idx;
}
static u64 kvm_pmc_read_evtreg(const struct kvm_pmc *pmc)
{
return __vcpu_sys_reg(kvm_pmc_to_vcpu(pmc), counter_index_to_evtreg(pmc->idx));
}
static u64 kvm_pmu_get_pmc_value(struct kvm_pmc *pmc)
{
struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
@ -619,6 +624,24 @@ static bool kvm_pmu_counter_is_enabled(struct kvm_pmc *pmc)
(__vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & BIT(pmc->idx));
}
static bool kvm_pmc_counts_at_el0(struct kvm_pmc *pmc)
{
u64 evtreg = kvm_pmc_read_evtreg(pmc);
bool nsu = evtreg & ARMV8_PMU_EXCLUDE_NS_EL0;
bool u = evtreg & ARMV8_PMU_EXCLUDE_EL0;
return u == nsu;
}
static bool kvm_pmc_counts_at_el1(struct kvm_pmc *pmc)
{
u64 evtreg = kvm_pmc_read_evtreg(pmc);
bool nsk = evtreg & ARMV8_PMU_EXCLUDE_NS_EL1;
bool p = evtreg & ARMV8_PMU_EXCLUDE_EL1;
return p == nsk;
}
/**
* kvm_pmu_create_perf_event - create a perf event for a counter
* @pmc: Counter context
@ -629,17 +652,15 @@ static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc)
struct arm_pmu *arm_pmu = vcpu->kvm->arch.arm_pmu;
struct perf_event *event;
struct perf_event_attr attr;
u64 eventsel, reg, data;
bool p, u, nsk, nsu;
u64 eventsel, evtreg;
reg = counter_index_to_evtreg(pmc->idx);
data = __vcpu_sys_reg(vcpu, reg);
evtreg = kvm_pmc_read_evtreg(pmc);
kvm_pmu_stop_counter(pmc);
if (pmc->idx == ARMV8_PMU_CYCLE_IDX)
eventsel = ARMV8_PMUV3_PERFCTR_CPU_CYCLES;
else
eventsel = data & kvm_pmu_event_mask(vcpu->kvm);
eventsel = evtreg & kvm_pmu_event_mask(vcpu->kvm);
/*
* Neither SW increment nor chained events need to be backed
@ -657,18 +678,13 @@ static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc)
!test_bit(eventsel, vcpu->kvm->arch.pmu_filter))
return;
p = data & ARMV8_PMU_EXCLUDE_EL1;
u = data & ARMV8_PMU_EXCLUDE_EL0;
nsk = data & ARMV8_PMU_EXCLUDE_NS_EL1;
nsu = data & ARMV8_PMU_EXCLUDE_NS_EL0;
memset(&attr, 0, sizeof(struct perf_event_attr));
attr.type = arm_pmu->pmu.type;
attr.size = sizeof(attr);
attr.pinned = 1;
attr.disabled = !kvm_pmu_counter_is_enabled(pmc);
attr.exclude_user = (u != nsu);
attr.exclude_kernel = (p != nsk);
attr.exclude_user = !kvm_pmc_counts_at_el0(pmc);
attr.exclude_kernel = !kvm_pmc_counts_at_el1(pmc);
attr.exclude_hv = 1; /* Don't count EL2 events */
attr.exclude_host = 1; /* Don't count host events */
attr.config = eventsel;