Add CPUID leaf 0x29 sub-leaf 0 to expose these APX sub-features, if the
APX foundation is available:

  * New Conditional Instructions (NCI)
  * New Data Destination (NDD)
  * Flags Suppression (NF)

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
---
 arch/x86/include/asm/kvm_host.h | 1 +
 arch/x86/kvm/cpuid.c            | 7 ++++++-
 arch/x86/kvm/reverse_cpuid.h    | 4 ++++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 48547842d9fa..7df964f32ba0 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -868,6 +868,7 @@ enum kvm_only_cpuid_leafs {
 	CPUID_7_1_ECX,
 	CPUID_1E_1_EAX,
 	CPUID_24_1_ECX,
+	CPUID_29_0_EBX,
 	NR_KVM_CPU_CAPS,
 
 	NKVMCAPINTS = NR_KVM_CPU_CAPS - NCAPINTS,
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index db95f6b578d0..0339700e885d 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -1112,6 +1112,10 @@ void kvm_initialize_cpu_caps(void)
 		F(AVX10_VNNI_INT),
 	);
 
+	kvm_cpu_cap_init(CPUID_29_0_EBX,
+		F(APX_NCI_NDD_NF),
+	);
+
 	kvm_cpu_cap_init(CPUID_8000_0001_ECX,
 		F(LAHF_LM),
 		F(CMP_LEGACY),
@@ -1719,7 +1723,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 	}
 	/* APX sub-features */
 	case 0x29:
-		entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
+		if (!kvm_cpu_cap_has(X86_FEATURE_APX))
+			entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
 		break;
 	case KVM_CPUID_SIGNATURE: {
 		const u32 *sigptr = (const u32 *)KVM_SIGNATURE;
diff --git a/arch/x86/kvm/reverse_cpuid.h b/arch/x86/kvm/reverse_cpuid.h
index de90697c4e5a..cff071ccf926 100644
--- a/arch/x86/kvm/reverse_cpuid.h
+++ b/arch/x86/kvm/reverse_cpuid.h
@@ -67,6 +67,9 @@
 /* Intel-defined sub-features, CPUID level 0x00000024:1 (ECX) */
 #define X86_FEATURE_AVX10_VNNI_INT	KVM_X86_FEATURE(CPUID_24_1_ECX, 2)
 
+/* Intel-defined sub-features, CPUID level 0x00000029:0 (EBX) */
+#define X86_FEATURE_APX_NCI_NDD_NF	KVM_X86_FEATURE(CPUID_29_0_EBX, 0)
+
 /* CPUID level 0x80000007 (EDX). */
 #define KVM_X86_FEATURE_CONSTANT_TSC	KVM_X86_FEATURE(CPUID_8000_0007_EDX, 8)
 
@@ -110,6 +113,7 @@ static const struct cpuid_reg reverse_cpuid[] = {
 	[CPUID_7_1_ECX]       = {         7, 1, CPUID_ECX},
 	[CPUID_1E_1_EAX]      = {      0x1e, 1, CPUID_EAX},
 	[CPUID_24_1_ECX]      = {      0x24, 1, CPUID_ECX},
+	[CPUID_29_0_EBX]      = {      0x29, 0, CPUID_EBX},
 };
 
 /*
-- 
2.53.0