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 <seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210921000303.400537-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 629442e..69d6561 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10611,8 +10611,6 @@ 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)