Commit 9d15f829 authored by Oliver Upton's avatar Oliver Upton
Browse files

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



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: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241025182354.3364124-15-oliver.upton@linux.dev


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent 9a1c58cf

arch/arm64/kvm/pmu-emul.c

+28 −12
Original line number Diff line number Diff line
@@ -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;