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Subject: Re: [PATCH] KVM: nVMX: Fix CR4 after VMLAUNCH/VMRESUME failure
To: Jim Mattson <jmattson@google.com>, Wanpeng Li <kernellwp@gmail.com>
Cc: kvm list <kvm@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        Radim Krcmar <rkrcmar@redhat.com>
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From: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <ad78ef46-7471-c095-0dd9-a5d5fbe85698@redhat.com>
Date: Thu, 8 Feb 2018 17:40:37 +0100
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On 08/02/2018 16:54, Jim Mattson wrote:
> On Thu, Feb 8, 2018 at 7:29 AM, Jim Mattson <jmattson@google.com> wrote:
>> Similarly, the correct L1 CR4 value should be in vmcs01's CR4
>> read shadow field.
> Sorry; that's wrong. L1's CR4 value has to be reconstructed from the
> vmcs01 guest CR4 field and CR4 shadow field using the cr4 guest/host
> mask. But there is no way to get it from any field(s) in vmcs12.

Now that we have the prepare_vmcs02_full/prepare_vmcs02 split, we
probably should do more checks in there, and not rely on the processor
anymore.

Paolo