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| author | Marc Zyngier <maz@kernel.org> | 2021-03-05 18:52:50 +0000 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-03-06 04:18:40 -0500 |
| commit | 6b5b368fccd7109b052e45af8ba1464c8d140a49 (patch) | |
| tree | 25ee8f56e285fc586d63e53f0b78396f8c0ddd0b /arch/arm64 | |
| parent | c4b000c3928d4f20acef79dccf3a65ae3795e0b0 (diff) | |
| download | linux-6b5b368fccd7109b052e45af8ba1464c8d140a49.tar.bz2 | |
KVM: arm64: Turn kvm_arm_support_pmu_v3() into a static key
We currently find out about the presence of a HW PMU (or the handling
of that PMU by perf, which amounts to the same thing) in a fairly
roundabout way, by checking the number of counters available to perf.
That's good enough for now, but we will soon need to find about about
that on paths where perf is out of reach (in the world switch).
Instead, let's turn kvm_arm_support_pmu_v3() into a static key.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Link: https://lore.kernel.org/r/20210209114844.3278746-2-maz@kernel.org
Message-Id: <20210305185254.3730990-5-maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/kvm/perf.c | 10 | ||||
| -rw-r--r-- | arch/arm64/kvm/pmu-emul.c | 10 |
2 files changed, 10 insertions, 10 deletions
diff --git a/arch/arm64/kvm/perf.c b/arch/arm64/kvm/perf.c index d45b8b9a4415..739164324afe 100644 --- a/arch/arm64/kvm/perf.c +++ b/arch/arm64/kvm/perf.c @@ -11,6 +11,8 @@ #include <asm/kvm_emulate.h> +DEFINE_STATIC_KEY_FALSE(kvm_arm_pmu_available); + static int kvm_is_in_guest(void) { return kvm_get_running_vcpu() != NULL; @@ -48,6 +50,14 @@ 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) + 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 e9ec08b0b070..e32c6e139a09 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -823,16 +823,6 @@ u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1) return val & mask; } -bool kvm_arm_support_pmu_v3(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. - */ - return (perf_num_counters() > 0); -} - int kvm_arm_pmu_v3_enable(struct kvm_vcpu *vcpu) { if (!kvm_vcpu_has_pmu(vcpu)) |