linux-kernel - Re: [PATCH v2 36/66] KVM: x86: Handle GBPAGE CPUID adjustment for EPT in VMX code

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Date:   Tue, 3 Mar 2020 16:47:46 +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, Xiaoyao Li <xiaoyao.li@...el.com>
Subject: Re: [PATCH v2 36/66] KVM: x86: Handle GBPAGE CPUID adjustment for EPT
 in VMX code

On 03/03/20 16:44, Sean Christopherson wrote:
>>> Oof, that took me a long time to process.  You're saying that KVM can
>>> allow the guest to use GBPAGES when shadow paging is enabled because KVM
>>> can effectively emulate GBPAGES.  And IIUC, you're also saying that
>>> cpuid.GBPAGES should never be influenced by EPT restrictions.
>>>
>>> That all makes sense.
>> Yes, exactly.
> I'll tack that on to the front of the series.  Should it be tagged Fixes?
> Feels like a fix, but is also more than a bit scary.

If you don't mind, I prefer to do the changes myself and also fix the
conflicts, in order to get my feet wet in the new cpu_caps world.  I'll
push it to a temporary branch for you to take a look, possibly tomorrow.

Paolo