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Date:   Fri, 11 Jun 2021 15:22:35 +0000
From:   Sean Christopherson <seanjc@google.com>
To:     Erdem Aktas <erdemaktas@google.com>
Cc:     "Yamahata, Isaku" <isaku.yamahata@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H . Peter Anvin" <hpa@zytor.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>, x86 <x86@kernel.org>,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        isaku.yamahata@gmail.com,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Xiaoyao Li <xiaoyao.li@intel.com>,
        Kai Huang <kai.huang@linux.intel.com>,
        Isaku Yamahata <isaku.yamahata@linux.intel.com>
Subject: Re: [RFC PATCH 64/67] KVM: TDX: Add "basic" support for building and
 running Trust Domains
Message-ID: <YMN/u3Xip2Do5dGR@google.com>
References: <cover.1605232743.git.isaku.yamahata@intel.com>
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 <CAAYXXYwHp-wiAsSjfsLngriGZpdQHUVY6o7zdGrN2fNm_RJZAQ@mail.gmail.com>
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On Thu, Jun 10, 2021, Erdem Aktas wrote:
> Hi Isaku,
> 
> I know you are going to submit a set of new patch series so here are
> few feedbacks thatI have encounter:
> 
> 
> KVM_TDX_INIT_VM has a parameter that user space VMM can provide the
> CPUID entries but it is not clear if any of those entries are
> mandatory.  If userspace VMM does not provide guest_supported_xcr0 and
> guest_supported_xss, TDX init will fail as their default values are
> set to 0.
> 
> It is expected but would be nice to document (or return an error
> message with more information) that KVM_CAP_X2APIC_API and
> KVM_IRQCHIP_SPLIT CAPS need to be enabled.
> 
> When CPUID entries are queried from KVM (using
> KVM_GET_SUPPORTED_CPUID) and provided back to the  KVM_TDX_INIT_VM,
> the default GPAW size requires 5 level SEPT but KVM still tries to
> create 4 level SEPT and fails to add private pages. Error messages are
> also not very helpful to figure out what was happening.

Please trim your replies and try to avoid top-posting.  Thanks for the input!

https://people.kernel.org/tglx/notes-about-netiquette