On 7/31/2024 9:58 PM, Mingwei Zhang wrote:
> Introduce PMU operator for setting counter overflow. When emulating counter
> increment, multiple counters could overflow at the same time, i.e., during
> the execution of the same instruction. In passthrough PMU, having an PMU
> operator provides convenience to update the PMU global status in one shot
> with details hidden behind the vendor specific implementation.
Since neither Intel nor AMD does implement this API, this patch should
be dropped.
>
> Signed-off-by: Mingwei Zhang <mizhang@xxxxxxxxxx>
> Signed-off-by: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx>
> ---
> arch/x86/include/asm/kvm-x86-pmu-ops.h | 1 +
> arch/x86/kvm/pmu.h | 1 +
> arch/x86/kvm/vmx/pmu_intel.c | 5 +++++
> 3 files changed, 7 insertions(+)
>
> diff --git a/arch/x86/include/asm/kvm-x86-pmu-ops.h b/arch/x86/include/asm/kvm-x86-pmu-ops.h
> index 72ca78df8d2b..bd5b118a5ce5 100644
> --- a/arch/x86/include/asm/kvm-x86-pmu-ops.h
> +++ b/arch/x86/include/asm/kvm-x86-pmu-ops.h
> @@ -28,6 +28,7 @@ KVM_X86_PMU_OP_OPTIONAL(passthrough_pmu_msrs)
> KVM_X86_PMU_OP_OPTIONAL(save_pmu_context)
> KVM_X86_PMU_OP_OPTIONAL(restore_pmu_context)
> KVM_X86_PMU_OP_OPTIONAL(incr_counter)
> +KVM_X86_PMU_OP_OPTIONAL(set_overflow)
>
> #undef KVM_X86_PMU_OP
> #undef KVM_X86_PMU_OP_OPTIONAL
> diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
> index 325f17673a00..78a7f0c5f3ba 100644
> --- a/arch/x86/kvm/pmu.h
> +++ b/arch/x86/kvm/pmu.h
> @@ -45,6 +45,7 @@ struct kvm_pmu_ops {
> void (*save_pmu_context)(struct kvm_vcpu *vcpu);
> void (*restore_pmu_context)(struct kvm_vcpu *vcpu);
> bool (*incr_counter)(struct kvm_pmc *pmc);
> + void (*set_overflow)(struct kvm_vcpu *vcpu);
>
> const u64 EVENTSEL_EVENT;
> const int MAX_NR_GP_COUNTERS;
> diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
> index 42af2404bdb9..2d46c911f0b7 100644
> --- a/arch/x86/kvm/vmx/pmu_intel.c
> +++ b/arch/x86/kvm/vmx/pmu_intel.c
> @@ -881,6 +881,10 @@ static void intel_restore_guest_pmu_context(struct kvm_vcpu *vcpu)
> wrmsrl(MSR_CORE_PERF_FIXED_CTR_CTRL, pmu->fixed_ctr_ctrl_hw);
> }
>
> +static void intel_set_overflow(struct kvm_vcpu *vcpu)
> +{
> +}
> +
> struct kvm_pmu_ops intel_pmu_ops __initdata = {
> .rdpmc_ecx_to_pmc = intel_rdpmc_ecx_to_pmc,
> .msr_idx_to_pmc = intel_msr_idx_to_pmc,
> @@ -897,6 +901,7 @@ struct kvm_pmu_ops intel_pmu_ops __initdata = {
> .save_pmu_context = intel_save_guest_pmu_context,
> .restore_pmu_context = intel_restore_guest_pmu_context,
> .incr_counter = intel_incr_counter,
> + .set_overflow = intel_set_overflow,
> .EVENTSEL_EVENT = ARCH_PERFMON_EVENTSEL_EVENT,
> .MAX_NR_GP_COUNTERS = KVM_INTEL_PMC_MAX_GENERIC,
> .MIN_NR_GP_COUNTERS = 1,
