Re: [PATCH v3 7/9] KVM: x86: Implement Intel Processor Trace MSRs read/write

[Paolo Bonzini]

On 27/11/2017 21:24, Luwei Kang wrote:
> +             case MSR_IA32_RTIT_ADDR0_A ... MSR_IA32_RTIT_ADDR3_B: {
> +                     u32 eax, ebx, ecx, edx;
> +
> +                     cpuid_count(0x14, 1, &eax, &ebx, &ecx, &edx);

Please cache the cpuid_count result, or do the cpuid_count after testing
vmx_pt_supported() (which you can use instead of going through kvm_x86_ops).

Thanks,

Paolo

> +                     if (!kvm_x86_ops->pt_supported() || msrs_to_save[i] -
> +                                     MSR_IA32_RTIT_ADDR0_A >= (eax & 0x7))
> +                             continue;
> +                     break;