When emulating exit from long mode, EFER_LMA is cleared which lead to efer writing emulation, which will unset VM_ENTRY_IA32E_MODE control bit as requested by SDM. So no need to unset VM_ENTRY_IA32E_MODE again in exit_lmode() explicitly. In fact benefited from shadow controls mechanism, this change doesn't eliminate vmread or vmwrite. In case EFER isn't supported by hardware, long mode isn't supported, so this will no break. Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxx> --- arch/x86/kvm/vmx/vmx.c | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index cadb3769031c..70717f56a2a2 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2907,7 +2907,6 @@ static void enter_lmode(struct kvm_vcpu *vcpu) static void exit_lmode(struct kvm_vcpu *vcpu) { - vm_entry_controls_clearbit(to_vmx(vcpu), VM_ENTRY_IA32E_MODE); vmx_set_efer(vcpu, vcpu->arch.efer & ~EFER_LMA); } -- 2.25.1