Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Reply-To: Sean Christopherson <seanjc@google.com>
Date:   Fri, 23 Apr 2021 17:46:32 -0700
In-Reply-To: <20210424004645.3950558-1-seanjc@google.com>
Message-Id: <20210424004645.3950558-31-seanjc@google.com>
Mime-Version: 1.0
References: <20210424004645.3950558-1-seanjc@google.com>
Subject: [PATCH 30/43] KVM: SVM: Drop redundant writes to vmcb->save.cr4 at RESET/INIT
From:   Sean Christopherson <seanjc@google.com>
To:     Paolo Bonzini <pbonzini@redhat.com>
Cc:     Sean Christopherson <seanjc@google.com>,
        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
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

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@google.com>
---
 arch/x86/kvm/svm/svm.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 88d34fa93d8b..558329f53709 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1211,8 +1211,6 @@ static void init_vmcb(struct kvm_vcpu *vcpu)
 	kvm_set_rflags(vcpu, X86_EFLAGS_FIXED);
 	vcpu->arch.regs[VCPU_REGS_RIP] = 0x0000fff0;
 
-	save->cr4 = X86_CR4_PAE;
-
 	if (npt_enabled) {
 		/* Setup VMCB for Nested Paging */
 		control->nested_ctl |= SVM_NESTED_CTL_NP_ENABLE;
@@ -1222,7 +1220,6 @@ static void init_vmcb(struct kvm_vcpu *vcpu)
 		svm_clr_intercept(svm, INTERCEPT_CR3_WRITE);
 		save->g_pat = vcpu->arch.pat;
 		save->cr3 = 0;
-		save->cr4 = 0;
 	}
 	svm->current_vmcb->asid_generation = 0;
 	svm->asid = 0;
-- 
2.31.1.498.g6c1eba8ee3d-goog