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Date:   Mon, 20 Sep 2021 17:02:57 -0700
From:   Sean Christopherson <>
To:     Paolo Bonzini <>
Cc:     Sean Christopherson <>,
        Vitaly Kuznetsov <>,
        Wanpeng Li <>,
        Jim Mattson <>,
        Joerg Roedel <>,,, Reiji Watanabe <>
Subject: [PATCH v2 04/10] KVM: x86: Remove defunct setting of CR0.ET for
 guests during vCPU create

Drop code to set CR0.ET for the guest during initialization of the guest
FPU.  The code was added as a misguided bug fix by commit 380102c8e431
("KVM Set the ET flag in CR0 after initializing FX") to resolve an issue
where vcpu->cr0 (now vcpu->arch.cr0) was not correctly initialized on SVM
systems.  While init_vmcb() did set CR0.ET, it only did so in the VMCB,
and subtly did not update vcpu->cr0.  Stuffing CR0.ET worked around the
immediate problem, but did not fix the real bug of vcpu->cr0 and the VMCB
being out of sync.  That underlying bug was eventually remedied by commit
18fa000ae453 ("KVM: SVM: Reset cr0 properly on vcpu reset").

No functional change intended.

Signed-off-by: Sean Christopherson <>
 arch/x86/kvm/x86.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ab907a0b9eeb..e0bff5473813 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10628,8 +10628,6 @@ static void fx_init(struct kvm_vcpu *vcpu)
 	 * Ensure guest xcr0 is valid for loading
 	vcpu->arch.xcr0 = XFEATURE_MASK_FP;
-	vcpu->arch.cr0 |= X86_CR0_ET;
 void kvm_free_guest_fpu(struct kvm_vcpu *vcpu)

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