KVM: x86: cleanup enter_rmode()

vmx_set_efer() sets uret->data but, in fact if the value of uret->data
will be used vmx_setup_uret_msrs() will have rewritten it with the value
returned by update_transition_efer().  uret->data is consumed if and only
if uret->load_into_hardware is true, and vmx_setup_uret_msrs() takes care
of (a) updating uret->data before setting uret->load_into_hardware to true
(b) setting uret->load_into_hardware to false if uret->data isn't updated.

Opportunistically use "vmx" directly instead of redoing to_vmx().
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Message-Id: <20220311102643.807507-2-zhenzhong.duan@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/vmx.c

@@ -2866,21 +2866,17 @@ static void enter_rmode(struct kvm_vcpu *vcpu)
 int vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
-	struct vmx_uret_msr *msr = vmx_find_uret_msr(vmx, MSR_EFER);
 
 	/* Nothing to do if hardware doesn't support EFER. */
-	if (!msr)
+	if (!vmx_find_uret_msr(vmx, MSR_EFER))
 		return 0;
 
 	vcpu->arch.efer = efer;
-	if (efer & EFER_LMA) {
-		vm_entry_controls_setbit(to_vmx(vcpu), VM_ENTRY_IA32E_MODE);
-		msr->data = efer;
-	} else {
-		vm_entry_controls_clearbit(to_vmx(vcpu), VM_ENTRY_IA32E_MODE);
+	if (efer & EFER_LMA)
+		vm_entry_controls_setbit(vmx, VM_ENTRY_IA32E_MODE);
+	else
+		vm_entry_controls_clearbit(vmx, VM_ENTRY_IA32E_MODE);
 
-		msr->data = efer & ~EFER_LME;
-	}
 	vmx_setup_uret_msrs(vmx);
 	return 0;
 }