From: Oliver Upton <[email protected]> KVM allows userspace to configure the number of event counters by writing to PMCR_EL0.N. While this makes a bit of sense prior to NV, the value of the field is context-dependent whether or not the vCPU is at EL2 or EL1. As such, the vCPU attribute was added afterwards and made mandatory for NV.
As we're in the process of papering over old mistakes, force userspace to use the vCPU attribute if KVM_ARM_VCPU_PMU_V3_STRICT is set. Signed-off-by: Oliver Upton <[email protected]> Reviewed-by: Geoff Blake <[email protected]> Reviewed-by: Haris Okanovic <[email protected]> Signed-off-by: Congkai Tan <[email protected]> --- arch/arm64/kvm/sys_regs.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 4c6f608c4fe5..e93f11b90813 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1502,6 +1502,7 @@ static int set_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r, */ if (!kvm_vm_has_ran_once(kvm) && !vcpu_has_nv(vcpu) && + !kvm_vcpu_has_pmuv3_strict(vcpu) && new_n <= kvm_arm_pmu_get_max_counters(kvm)) kvm->arch.nr_pmu_counters = new_n; -- 2.50.1
