KVM: arm64: Divorce the perf code from oprofile helpers

KVM/arm64 is the sole user of perf_num_counters(), and really
could do without it. Stop using the obsolete API by relying on
the existing probing code.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210414134409.1266357-2-maz@kernel.org

diff --git a/arch/arm64/kvm/perf.c b/arch/arm64/kvm/perf.c
index 7391643..b8b3986 100644 (file)
--- a/arch/arm64/kvm/perf.c
+++ b/arch/arm64/kvm/perf.c
@@ -50,12 +50,7 @@ static struct perf_guest_info_callbacks kvm_guest_cbs = {
 
 int kvm_perf_init(void)
 {
-       /*
-        * Check if HW_PERF_EVENTS are supported by checking the number of
-        * hardware performance counters. This could ensure the presence of
-        * a physical PMU and CONFIG_PERF_EVENT is selected.
-        */
-       if (IS_ENABLED(CONFIG_ARM_PMU) && perf_num_counters() > 0)
+       if (kvm_pmu_probe_pmuver() != 0xf)
                static_branch_enable(&kvm_arm_pmu_available);
 
        return perf_register_guest_info_callbacks(&kvm_guest_cbs);

diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index e32c6e1..fd167d4 100644 (file)
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -739,7 +739,7 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
        kvm_pmu_create_perf_event(vcpu, select_idx);
 }
 
-static int kvm_pmu_probe_pmuver(void)
+int kvm_pmu_probe_pmuver(void)
 {
        struct perf_event_attr attr = { };
        struct perf_event *event;

diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index 6fd3cda..864b999 100644 (file)
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -61,6 +61,7 @@ int kvm_arm_pmu_v3_get_attr(struct kvm_vcpu *vcpu,
 int kvm_arm_pmu_v3_has_attr(struct kvm_vcpu *vcpu,
                            struct kvm_device_attr *attr);
 int kvm_arm_pmu_v3_enable(struct kvm_vcpu *vcpu);
+int kvm_pmu_probe_pmuver(void);
 #else
 struct kvm_pmu {
 };
@@ -116,6 +117,9 @@ static inline u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
 {
        return 0;
 }
+
+static inline int kvm_pmu_probe_pmuver(void) { return 0xf; }
+
 #endif
 
 #endif