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Subject: Re: [PATCH v6 2/3] KVM: vmx: Emulate MSR IA32_UMWAIT_CONTROL
To:     Paolo Bonzini <pbonzini@redhat.com>
Cc:     rkrcmar@redhat.com, corbet@lwn.net, tglx@linutronix.de,
        mingo@redhat.com, bp@alien8.de, hpa@zytor.com,
        sean.j.christopherson@intel.com, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, fenghua.yu@intel.com,
        xiaoyao.li@linux.intel.com, jingqi.liu@intel.com
References: <20190621055747.17060-1-tao3.xu@intel.com>
 <20190621055747.17060-3-tao3.xu@intel.com>
 <43814a5e-12bf-ceb5-e4fb-12bbb32cd4cb@redhat.com>
From:   Tao Xu <tao3.xu@intel.com>
Message-ID: <fcae19b2-e37e-1a39-1569-f514631913b1@intel.com>
Date:   Fri, 12 Jul 2019 08:42:44 +0800
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On 7/11/2019 9:25 PM, Paolo Bonzini wrote:
> On 21/06/19 07:57, Tao Xu wrote:
>> +	if (guest_cpuid_has(vcpu, X86_FEATURE_WAITPKG))
>> +		atomic_switch_umwait_control_msr(vmx);
>> +
> 
> guest_cpuid_has is slow.  Please replace it with a test on
> secondary_exec_controls_get(vmx).

Thank you paolo, I will improve it.

> 
> Are you going to look into nested virtualization support?  This should
> include only 1) allowing setting the enable bit in secondary execution
> controls, and passing it through in prepare_vmcs02_early; 2) reflecting
> the vmexit in nested_vmx_exit_reflected.
> 

I will add nested support in next version.

> Thanks,
> 
> Paolo
>