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 07:54:25 -0800
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.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 Tue, Mar 03, 2020 at 04:47:46PM +0100, Paolo Bonzini wrote:
> 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.

That would be wonderful, thanks!