linux-kernel - Re: [PATCH 30/43] KVM: SVM: Drop redundant writes to vmcb->save.cr4 at RESET/INIT

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Message-ID: <CAAeT=FwW0xuJ54a1ut8bKtd4R9NWajqmJYcxwOS7nKGtEQW9iw@mail.gmail.com>
Date:   Tue, 18 May 2021 22:35:35 -0700
From:   Reiji Watanabe <reijiw@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        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 30/43] KVM: SVM: Drop redundant writes to vmcb->save.cr4
 at RESET/INIT

On Fri, Apr 23, 2021 at 5:54 PM Sean Christopherson <seanjc@...gle.com> wrote:
>
> Drop direct writes to vmcb->save.cr4 during vCPU RESET/INIT, as the
> values being written are fully redundant with respect to
> svm_set_cr4(vcpu, 0) a few lines earlier.  Note, svm_set_cr4() also
> correctly forces X86_CR4_PAE when NPT is disabled.
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>

Reviewed-by: Reiji Watanabe <reijiw@...gle.com>