KVM: x86: expose cpuid_entry2_find for TDX

CPUID values are provided for TDX virtual machines as part of the
KVM_TDX_INIT_VM ioctl.  Unlike KVM_SET_CPUID2, TDX will need to
examine the leaves, either to validate against the CPUIDs listed
in the TDX modules configuration or to fill other controls with
matching values.

Since there is an existing function to look up a leaf/index pair
into a given list of CPUID entries, export it as kvm_find_cpuid_entry2().

Reviewed-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Author: bonzini

arch/x86/kvm/cpuid.c

@@ -82,17 +82,8 @@ u32 xstate_required_size(u64 xstate_bv, bool compacted)
 	return ret;
 }
 
-/*
- * Magic value used by KVM when querying userspace-provided CPUID entries and
- * doesn't care about the CPIUD index because the index of the function in
- * question is not significant.  Note, this magic value must have at least one
- * bit set in bits[63:32] and must be consumed as a u64 by cpuid_entry2_find()
- * to avoid false positives when processing guest CPUID input.
- */
-#define KVM_CPUID_INDEX_NOT_SIGNIFICANT -1ull
-
-static struct kvm_cpuid_entry2 *cpuid_entry2_find(struct kvm_vcpu *vcpu,
-						  u32 function, u64 index)
+struct kvm_cpuid_entry2 *kvm_find_cpuid_entry2(
+	struct kvm_cpuid_entry2 *entries, int nent, u32 function, u64 index)
 {
 	struct kvm_cpuid_entry2 *e;
 	int i;
@@ -109,8 +100,8 @@ static struct kvm_cpuid_entry2 *cpuid_entry2_find(struct kvm_vcpu *vcpu,
 	 */
 	lockdep_assert_irqs_enabled();
 
-	for (i = 0; i < vcpu->arch.cpuid_nent; i++) {
-		e = &vcpu->arch.cpuid_entries[i];
+	for (i = 0; i < nent; i++) {
+		e = &entries[i];
 
 		if (e->function != function)
 			continue;
@@ -141,26 +132,7 @@ static struct kvm_cpuid_entry2 *cpuid_entry2_find(struct kvm_vcpu *vcpu,
 
 	return NULL;
 }
-
-struct kvm_cpuid_entry2 *kvm_find_cpuid_entry_index(struct kvm_vcpu *vcpu,
-						    u32 function, u32 index)
-{
-	return cpuid_entry2_find(vcpu, function, index);
-}
-EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry_index);
-
-struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
-					      u32 function)
-{
-	return cpuid_entry2_find(vcpu, function, KVM_CPUID_INDEX_NOT_SIGNIFICANT);
-}
-EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
-
-/*
- * cpuid_entry2_find() and KVM_CPUID_INDEX_NOT_SIGNIFICANT should never be used
- * directly outside of kvm_find_cpuid_entry() and kvm_find_cpuid_entry_index().
- */
-#undef KVM_CPUID_INDEX_NOT_SIGNIFICANT
+EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry2);
 
 static int kvm_check_cpuid(struct kvm_vcpu *vcpu)
 {

arch/x86/kvm/cpuid.h

@@ -12,10 +12,34 @@ void kvm_set_cpu_caps(void);
 
 void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu);
 void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu);
-struct kvm_cpuid_entry2 *kvm_find_cpuid_entry_index(struct kvm_vcpu *vcpu,
-						    u32 function, u32 index);
-struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
-					      u32 function);
+struct kvm_cpuid_entry2 *kvm_find_cpuid_entry2(struct kvm_cpuid_entry2 *entries,
+					       int nent, u32 function, u64 index);
+/*
+ * Magic value used by KVM when querying userspace-provided CPUID entries and
+ * doesn't care about the CPIUD index because the index of the function in
+ * question is not significant.  Note, this magic value must have at least one
+ * bit set in bits[63:32] and must be consumed as a u64 by kvm_find_cpuid_entry2()
+ * to avoid false positives when processing guest CPUID input.
+ *
+ * KVM_CPUID_INDEX_NOT_SIGNIFICANT should never be used directly outside of
+ * kvm_find_cpuid_entry2() and kvm_find_cpuid_entry().
+ */
+#define KVM_CPUID_INDEX_NOT_SIGNIFICANT -1ull
+
+static inline struct kvm_cpuid_entry2 *kvm_find_cpuid_entry_index(struct kvm_vcpu *vcpu,
+								  u32 function, u32 index)
+{
+	return kvm_find_cpuid_entry2(vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent,
+				     function, index);
+}
+
+static inline struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
+							    u32 function)
+{
+	return kvm_find_cpuid_entry2(vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent,
+				     function, KVM_CPUID_INDEX_NOT_SIGNIFICANT);
+}
+
 int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
 			    struct kvm_cpuid_entry2 __user *entries,
 			    unsigned int type);