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Message-ID: <36df723c-4794-69a8-8d12-ea371a7865df@intel.com>
Date:   Wed, 6 Apr 2022 10:06:16 +0800
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Subject: Re: [RFC PATCH v5 027/104] KVM: TDX: initialize VM with TDX specific
 parameters
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To:     Paolo Bonzini <pbonzini@redhat.com>,
        Kai Huang <kai.huang@intel.com>, isaku.yamahata@intel.com,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     isaku.yamahata@gmail.com, Jim Mattson <jmattson@google.com>,
        erdemaktas@google.com, Connor Kuehl <ckuehl@redhat.com>,
        Sean Christopherson <seanjc@google.com>
References: <cover.1646422845.git.isaku.yamahata@intel.com>
 <c3b37cf5c83f92be0e153075d81a80729bf1031e.1646422845.git.isaku.yamahata@intel.com>
 <509fb6fb5c581e6bf14149dff17d7426a6b061f2.camel@intel.com>
 <6e370d39-fcb6-c158-e5fb-690cd3802150@redhat.com>
From:   Xiaoyao Li <xiaoyao.li@intel.com>
In-Reply-To: <6e370d39-fcb6-c158-e5fb-690cd3802150@redhat.com>
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On 4/5/2022 9:01 PM, Paolo Bonzini wrote:
> On 3/31/22 06:55, Kai Huang wrote:
>>> +struct kvm_tdx_init_vm {
>>> +    __u32 max_vcpus;
>>> +    __u32 tsc_khz;
>>> +    __u64 attributes;
>>> +    __u64 cpuid;
>> Is it better to append all CPUIDs directly into this structure, 
>> perhaps at end
>> of this structure, to make it more consistent with TD_PARAMS?
>>
>> Also, I think somewhere in commit message or comments we should 
>> explain why
>> CPUIDs are passed here (why existing KVM_SET_CUPID2 is not sufficient).
>>
> 
> Indeed, it would be easier to use the existing cpuid data in struct 
> kvm_vcpu, because right now there is no way to ensure that they are 
> consistent.
> 
> Why is KVM_SET_CPUID2 not enough?  Are there any modifications done by 
> KVM that affect the measurement?

Then we get the situation that KVM_TDX_INIT_VM must be called after 1 
vcpu is created. It seems illogical that it has chance to fail the VM 
scope initialization after 1 vcpu is successfully created.

> Thanks,
> 
> Paolo
>