linux-kernel - Re: [PATCH 47/61] KVM: x86: Squash CPUID 0x2.0 insanity for modern CPUs

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Message-ID: <21b4346e-def0-9343-3368-e81b89ffb152@redhat.com>
Date:   Tue, 25 Feb 2020 16:17:24 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Sean Christopherson <sean.j.christopherson@...el.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 47/61] KVM: x86: Squash CPUID 0x2.0 insanity for modern
 CPUs

On 01/02/20 19:52, Sean Christopherson wrote:
> Although it's _extremely_ tempting to yank KVM's stateful code, leave it
> in for now but annotate all its code paths as "unlikely".  The code is
> relatively contained, and if by some miracle there is someone running KVM
> on a CPU with a stateful CPUID 0x2, more power to 'em.

I suppose the only way that could happen is with nested virtualization.
 I would just drop it.

Paolo