KVM: x86: Return bool instead of int for CR4 and SREGS validity checks

Rework the common CR4 and SREGS checks to return a bool instead of an
int, i.e. true/false instead of 0/-EINVAL, and add "is" to the name to
clarify the polarity of the return value (which is effectively inverted
by this change).

No functional changed intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20201007014417.29276-6-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/svm/nested.c

@@ -254,7 +254,7 @@ static bool nested_vmcb_checks(struct vcpu_svm *svm, struct vmcb *vmcb12)
 		    (vmcb12->save.cr3 & MSR_CR3_LONG_MBZ_MASK))
 			return false;
 	}
-	if (kvm_valid_cr4(&svm->vcpu, vmcb12->save.cr4))
+	if (!kvm_is_valid_cr4(&svm->vcpu, vmcb12->save.cr4))
 		return false;
 
 	return nested_vmcb_check_controls(&vmcb12->control);

arch/x86/kvm/vmx/vmx.c

@@ -3100,7 +3100,7 @@ static bool vmx_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 	/*
 	 * We operate under the default treatment of SMM, so VMX cannot be
 	 * enabled under SMM.  Note, whether or not VMXE is allowed at all is
-	 * handled by kvm_valid_cr4().
+	 * handled by kvm_is_valid_cr4().
 	 */
 	if ((cr4 & X86_CR4_VMXE) && is_smm(vcpu))
 		return false;

arch/x86/kvm/x86.c

@@ -964,20 +964,17 @@ int kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
 }
 EXPORT_SYMBOL_GPL(kvm_set_xcr);
 
-int kvm_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
+bool kvm_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 {
 	if (cr4 & cr4_reserved_bits)
-		return -EINVAL;
+		return false;
 
 	if (cr4 & vcpu->arch.cr4_guest_rsvd_bits)
-		return -EINVAL;
-
-	if (!kvm_x86_ops.is_valid_cr4(vcpu, cr4))
-		return -EINVAL;
+		return false;
 
-	return 0;
+	return kvm_x86_ops.is_valid_cr4(vcpu, cr4);
 }
-EXPORT_SYMBOL_GPL(kvm_valid_cr4);
+EXPORT_SYMBOL_GPL(kvm_is_valid_cr4);
 
 int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 {
@@ -986,7 +983,7 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 				   X86_CR4_SMEP;
 	unsigned long mmu_role_bits = pdptr_bits | X86_CR4_SMAP | X86_CR4_PKE;
 
-	if (kvm_valid_cr4(vcpu, cr4))
+	if (!kvm_is_valid_cr4(vcpu, cr4))
 		return 1;
 
 	if (is_long_mode(vcpu)) {
@@ -9535,7 +9532,7 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int idt_index,
 }
 EXPORT_SYMBOL_GPL(kvm_task_switch);
 
-static int kvm_valid_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
+static bool kvm_is_valid_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
 {
 	if ((sregs->efer & EFER_LME) && (sregs->cr0 & X86_CR0_PG)) {
 		/*
@@ -9543,19 +9540,18 @@ static int kvm_valid_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
 		 * 64-bit mode (though maybe in a 32-bit code segment).
 		 * CR4.PAE and EFER.LMA must be set.
 		 */
-		if (!(sregs->cr4 & X86_CR4_PAE)
-		    || !(sregs->efer & EFER_LMA))
-			return -EINVAL;
+		if (!(sregs->cr4 & X86_CR4_PAE) || !(sregs->efer & EFER_LMA))
+			return false;
 	} else {
 		/*
 		 * Not in 64-bit mode: EFER.LMA is clear and the code
 		 * segment cannot be 64-bit.
 		 */
 		if (sregs->efer & EFER_LMA || sregs->cs.l)
-			return -EINVAL;
+			return false;
 	}
 
-	return kvm_valid_cr4(vcpu, sregs->cr4);
+	return kvm_is_valid_cr4(vcpu, sregs->cr4);
 }
 
 static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
@@ -9567,7 +9563,7 @@ static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
 	struct desc_ptr dt;
 	int ret = -EINVAL;
 
-	if (kvm_valid_sregs(vcpu, sregs))
+	if (!kvm_is_valid_sregs(vcpu, sregs))
 		goto out;
 
 	apic_base_msr.data = sregs->apic_base;

arch/x86/kvm/x86.h

@@ -369,7 +369,7 @@ static inline bool kvm_dr6_valid(u64 data)
 void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu);
 void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu);
 int kvm_spec_ctrl_test_value(u64 value);
-int kvm_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4);
+bool kvm_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4);
 bool kvm_vcpu_exit_request(struct kvm_vcpu *vcpu);
 int kvm_handle_memory_failure(struct kvm_vcpu *vcpu, int r,
 			      struct x86_exception *e);