From 4d20debf9ca160720a0b01ba4f2dc3d62296c4d1 Mon Sep 17 00:00:00 2001 From: Raghavendra Rao Ananta Date: Fri, 20 Oct 2023 21:40:44 +0000 Subject: KVM: arm64: PMU: Set PMCR_EL0.N for vCPU based on the associated PMU The number of PMU event counters is indicated in PMCR_EL0.N. For a vCPU with PMUv3 configured, the value is set to the same value as the current PE on every vCPU reset. Unless the vCPU is pinned to PEs that has the PMU associated to the guest from the initial vCPU reset, the value might be different from the PMU's PMCR_EL0.N on heterogeneous PMU systems. Fix this by setting the vCPU's PMCR_EL0.N to the PMU's PMCR_EL0.N value. Track the PMCR_EL0.N per guest, as only one PMU can be set for the guest (PMCR_EL0.N must be the same for all vCPUs of the guest), and it is convenient for updating the value. To achieve this, the patch introduces a helper, kvm_arm_pmu_get_max_counters(), that reads the maximum number of counters from the arm_pmu associated to the VM. Make the function global as upcoming patches will be interested to know the value while setting the PMCR.N of the guest from userspace. KVM does not yet support userspace modifying PMCR_EL0.N. The following patch will add support for that. Reviewed-by: Sebastian Ott Co-developed-by: Marc Zyngier Signed-off-by: Marc Zyngier Signed-off-by: Reiji Watanabe Signed-off-by: Raghavendra Rao Ananta Link: https://lore.kernel.org/r/20231020214053.2144305-5-rananta@google.com Signed-off-by: Oliver Upton --- include/kvm/arm_pmu.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/kvm') diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h index c6a5e49b850a..96e15f4bb18c 100644 --- a/include/kvm/arm_pmu.h +++ b/include/kvm/arm_pmu.h @@ -102,6 +102,7 @@ void kvm_vcpu_pmu_resync_el0(void); u8 kvm_arm_pmu_get_pmuver_limit(void); int kvm_arm_set_default_pmu(struct kvm *kvm); +u8 kvm_arm_pmu_get_max_counters(struct kvm *kvm); u64 kvm_vcpu_read_pmcr(struct kvm_vcpu *vcpu); #else @@ -181,6 +182,11 @@ static inline int kvm_arm_set_default_pmu(struct kvm *kvm) return -ENODEV; } +static inline u8 kvm_arm_pmu_get_max_counters(struct kvm *kvm) +{ + return 0; +} + static inline u64 kvm_vcpu_read_pmcr(struct kvm_vcpu *vcpu) { return 0; -- cgit v1.2.3