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Subject: Re: [PATCH] KVM: X86: Expose KVM_HINTS_REALTIME in
 KVM_GET_SUPPORTED_CPUID
To:     Jim Mattson <jmattson@google.com>
Cc:     Wanpeng Li <kernellwp@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        kvm list <kvm@vger.kernel.org>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Joerg Roedel <joro@8bytes.org>
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 <CALMp9eQyJXko_CKPgg4xRDCsvOmA8zJvrg_kmU6weu=MwKBv0w@mail.gmail.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <823d5027-a1e5-4b91-2d35-693f3c2b9642@redhat.com>
Date:   Fri, 23 Oct 2020 11:07:16 +0200
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On 22/10/20 19:13, Jim Mattson wrote:
> We don't actually use KVM_GET_SUPPORTED_CPUID at all today. If it's
> commonly being misinterpreted as you say, perhaps we should add a
> KVM_GET_TRUE_SUPPORTED_CPUID ioctl. Or, perhaps we can just fix this
> in the documentation?

Yes, I think we should fix the documentation and document the best
practices around MSRs and CPUID bits.  Mostly documenting what QEMU
does, perhaps without all the quirks it has to support old kernels that
messed things up even more.

Paolo