When running under a nesting hypervisor, it isn't guaranteed that the virtual HW will include a PMU. In which case, let's not try to access the PMU registers in the world switch, as that'd be deadly.
Reported-by: Andre Przywara <andre.przyw...@arm.com> Signed-off-by: Marc Zyngier <m...@kernel.org> Reviewed-by: Alexandru Elisei <alexandru.eli...@arm.com> Link: https://lore.kernel.org/r/20210209114844.3278746-3-...@kernel.org --- arch/arm64/kernel/image-vars.h | 3 +++ arch/arm64/kvm/hyp/include/hyp/switch.h | 9 ++++++--- 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index 23f1a557bd9f..5aa9ed1e9ec6 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -101,6 +101,9 @@ KVM_NVHE_ALIAS(__stop___kvm_ex_table); /* Array containing bases of nVHE per-CPU memory regions. */ KVM_NVHE_ALIAS(kvm_arm_hyp_percpu_base); +/* PMU available static key */ +KVM_NVHE_ALIAS(kvm_arm_pmu_available); + #endif /* CONFIG_KVM */ #endif /* __ARM64_KERNEL_IMAGE_VARS_H */ diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 54f4860cd87c..6c1f51f25eb3 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -90,15 +90,18 @@ static inline void __activate_traps_common(struct kvm_vcpu *vcpu) * counter, which could make a PMXEVCNTR_EL0 access UNDEF at * EL1 instead of being trapped to EL2. */ - write_sysreg(0, pmselr_el0); - write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0); + if (kvm_arm_support_pmu_v3()) { + write_sysreg(0, pmselr_el0); + write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0); + } write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2); } static inline void __deactivate_traps_common(void) { write_sysreg(0, hstr_el2); - write_sysreg(0, pmuserenr_el0); + if (kvm_arm_support_pmu_v3()) + write_sysreg(0, pmuserenr_el0); } static inline void ___activate_traps(struct kvm_vcpu *vcpu) -- 2.29.2 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
