Re: [PATCH v4 09/25] KVM: VMX: nVMX: Support TSC scaling and PERF_GLOBAL_CTRL with enlightened VMCS

Paolo Bonzini
2022-07-25T17:09:22Z

On 7/21/22 23:58, Sean Christopherson wrote:
>
> diff --git a/arch/x86/kvm/vmx/evmcs.c b/arch/x86/kvm/vmx/evmcs.c
> index b5cfbf7d487b..7b348a03e096 100644
> --- a/arch/x86/kvm/vmx/evmcs.c
> +++ b/arch/x86/kvm/vmx/evmcs.c
> @@ -355,11 +355,6 @@ uint16_t nested_get_evmcs_version(struct kvm_vcpu *vcpu)
> return 0;
> }
>
> -enum evmcs_v1_revision {
> - EVMCSv1_2016,
> - EVMCSv1_2022,
> -};
> -
> enum evmcs_unsupported_ctrl_type {
> EVMCS_EXIT_CTLS,
> EVMCS_ENTRY_CTLS,
> @@ -372,29 +367,29 @@ static u32 evmcs_get_unsupported_ctls(struct kvm_vcpu *vcpu,
> enum evmcs_unsupported_ctrl_type ctrl_type)
> {
> struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
> - enum evmcs_v1_revision evmcs_rev = EVMCSv1_2016;
> + bool has_evmcs_2022_features;
>
> if (!hv_vcpu)
> return 0;
>
> - if (hv_vcpu->cpuid_cache.nested_ebx & HV_X64_NESTED_EVMCS1_2022_UPDATE)
> - evmcs_rev = EVMCSv1_2022;
> + has_evmcs_2022_features = hv_vcpu->cpuid_cache.nested_ebx &
> + HV_X64_NESTED_EVMCS1_2022_UPDATE;
>
> switch (ctrl_type) {
> case EVMCS_EXIT_CTLS:
> - if (evmcs_rev == EVMCSv1_2016)
> + if (!has_evmcs_2022_features)
> return EVMCS1_UNSUPPORTED_VMEXIT_CTRL |
> VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL;
> else
> return EVMCS1_UNSUPPORTED_VMEXIT_CTRL;
> case EVMCS_ENTRY_CTLS:
> - if (evmcs_rev == EVMCSv1_2016)
> + if (!has_evmcs_2022_features)
> return EVMCS1_UNSUPPORTED_VMENTRY_CTRL |
> VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL;
> else
> return EVMCS1_UNSUPPORTED_VMENTRY_CTRL;
> case EVMCS_2NDEXEC:
> - if (evmcs_rev == EVMCSv1_2016)
> + if (!has_evmcs_2022_features)
> return EVMCS1_UNSUPPORTED_2NDEXEC |
> SECONDARY_EXEC_TSC_SCALING;
> else
>

I kind of like the idea of having a two-dimensional array based on the
enums instead of switch statements, so for now I'll keep Vitaly's enums.

Paolo