Re: [PATCH v2 24/54] KVM: x86/pmu: Create a function prototype to disable MSR interception

Chen, Zide
2024-05-08T22:03:40Z

On 5/5/2024 10:29 PM, Mingwei Zhang wrote:
> Add one extra pmu function prototype in kvm_pmu_ops to disable PMU MSR
> interception.
>
> Signed-off-by: Mingwei Zhang <mizhang@google.com>
> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
> ---
> arch/x86/include/asm/kvm-x86-pmu-ops.h | 1 +
> arch/x86/kvm/cpuid.c | 4 ++++
> arch/x86/kvm/pmu.c | 5 +++++
> arch/x86/kvm/pmu.h | 2 ++
> 4 files changed, 12 insertions(+)
>
> diff --git a/arch/x86/include/asm/kvm-x86-pmu-ops.h b/arch/x86/include/asm/kvm-x86-pmu-ops.h
> index fd986d5146e4..1b7876dcb3c3 100644
> --- a/arch/x86/include/asm/kvm-x86-pmu-ops.h
> +++ b/arch/x86/include/asm/kvm-x86-pmu-ops.h
> @@ -24,6 +24,7 @@ KVM_X86_PMU_OP(is_rdpmc_passthru_allowed)
> KVM_X86_PMU_OP_OPTIONAL(reset)
> KVM_X86_PMU_OP_OPTIONAL(deliver_pmi)
> KVM_X86_PMU_OP_OPTIONAL(cleanup)
> +KVM_X86_PMU_OP_OPTIONAL(passthrough_pmu_msrs)
>
> #undef KVM_X86_PMU_OP
> #undef KVM_X86_PMU_OP_OPTIONAL
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 77352a4abd87..b577ba649feb 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -381,6 +381,10 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
> vcpu->arch.reserved_gpa_bits = kvm_vcpu_reserved_gpa_bits_raw(vcpu);
>
> kvm_pmu_refresh(vcpu);
> +
> + if (is_passthrough_pmu_enabled(vcpu))
> + kvm_pmu_passthrough_pmu_msrs(vcpu);
> +
> vcpu->arch.cr4_guest_rsvd_bits =
> __cr4_reserved_bits(guest_cpuid_has, vcpu);
>
> diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
> index 3afefe4cf6e2..bd94f2d67f5c 100644
> --- a/arch/x86/kvm/pmu.c
> +++ b/arch/x86/kvm/pmu.c
> @@ -1059,3 +1059,8 @@ int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp)
> kfree(filter);
> return r;
> }
> +
> +void kvm_pmu_passthrough_pmu_msrs(struct kvm_vcpu *vcpu)
> +{
> + static_call_cond(kvm_x86_pmu_passthrough_pmu_msrs)(vcpu);
> +}

Don't quite understand why a separate callback is needed. It seems it's
not messier if put this logic in the kvm_x86_vcpu_after_set_cpuid()
callback.