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Subject: Re: [PATCH 05/54] Revert "KVM: x86/mmu: Drop
 kvm_mmu_extended_role.cr4_la57 hack"
To:     Yu Zhang <yu.c.zhang@linux.intel.com>,
        Sean Christopherson <seanjc@google.com>
Cc:     Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, Maxim Levitsky <mlevitsk@redhat.com>
References: <20210622175739.3610207-1-seanjc@google.com>
 <20210622175739.3610207-6-seanjc@google.com>
 <20210625084644.ort4oojvd27oy4ca@linux.intel.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <09a49caf-6ff5-295b-d1ab-023549f6a23b@redhat.com>
Date:   Fri, 25 Jun 2021 10:57:51 +0200
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On 25/06/21 10:47, Yu Zhang wrote:
>> But if L1 is crafty, it can load a new CR4 on VM-Exit and toggle LA57
>> without having to bounce through an unpaged section.  L1 can also load a
>
> May I ask how this is done by the guest? Thanks!

It can set HOST_CR3 and HOST_CR4 to a value that is different from the 
one on vmentry.

Paolo