KVM: VMX: Move MSR_IA32_FEAT_CTL.LOCKED check into "is valid" helper

Move the check on IA32_FEATURE_CONTROL being locked, i.e. read-only from
the guest, into the helper to check the overall validity of the incoming
value.  Opportunistically rename the helper to make it clear that it
returns a bool.

No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20220607232353.3375324-3-seanjc@google.com

arch/x86/kvm/vmx/vmx.c

@@ -1850,7 +1850,7 @@ bool nested_vmx_allowed(struct kvm_vcpu *vcpu)
 					FEAT_CTL_SGX_ENABLED		 | \
 					FEAT_CTL_LMCE_ENABLED)
 
-static inline bool vmx_feature_control_msr_valid(struct vcpu_vmx *vmx,
+static inline bool is_vmx_feature_control_msr_valid(struct vcpu_vmx *vmx,
 						    struct msr_data *msr)
 {
 	uint64_t valid_bits;
@@ -1862,6 +1862,10 @@ static inline bool vmx_feature_control_msr_valid(struct vcpu_vmx *vmx,
 	WARN_ON_ONCE(vmx->msr_ia32_feature_control_valid_bits &
 		     ~KVM_SUPPORTED_FEATURE_CONTROL);
 
+	if (!msr->host_initiated &&
+	    (vmx->msr_ia32_feature_control & FEAT_CTL_LOCKED))
+		return false;
+
 	if (msr->host_initiated)
 		valid_bits = KVM_SUPPORTED_FEATURE_CONTROL;
 	else
@@ -2266,10 +2270,9 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		vcpu->arch.mcg_ext_ctl = data;
 		break;
 	case MSR_IA32_FEAT_CTL:
-		if (!vmx_feature_control_msr_valid(vmx, msr_info) ||
-		    (to_vmx(vcpu)->msr_ia32_feature_control &
-		     FEAT_CTL_LOCKED && !msr_info->host_initiated))
+		if (!is_vmx_feature_control_msr_valid(vmx, msr_info))
 			return 1;
+
 		vmx->msr_ia32_feature_control = data;
 		if (msr_info->host_initiated && data == 0)
 			vmx_leave_nested(vcpu);