From 6fbabb4bce8e111e98eaa6fe2b5a3efdf442cd54 Mon Sep 17 00:00:00 2001
From: Eduardo Habkost <ehabkost@redhat.com>
Date: Mon, 5 Mar 2018 12:40:31 -0500
Subject: [PATCH] i386: Add FEAT_8000_0008_EBX CPUID feature word

Add the new feature word and the "ibpb" feature flag.

Based on a patch by Paolo Bonzini.

Backports commit 1ade973f5202404e772aae7b1acd331270d246dc from qemu
---
 qemu/target/i386/cpu.c | 43 +++++++++++++++++++++++++++++++++++++++++-
 qemu/target/i386/cpu.h |  3 +++
 2 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/qemu/target/i386/cpu.c b/qemu/target/i386/cpu.c
index fd247c44..52785e1b 100644
--- a/qemu/target/i386/cpu.c
+++ b/qemu/target/i386/cpu.c
@@ -399,6 +399,24 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         TCG_APM_FEATURES,
         CPUID_APM_INVTSC,
     },
+    // FEAT_8000_0008_EBX
+    {
+        {
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            "ibpb", NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+        },
+        0x80000008,
+        false,0,
+        R_EBX,
+        0,
+        0,
+    },
     // FEAT_C000_0001_EDX
     {
         {
@@ -946,6 +964,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT3_ABM | CPUID_EXT3_SSE4A,
         // FEAT_8000_0007_EDX
             0,
+        // FEAT_8000_0008_EBX
+            0,
         // FEAT_C000_0001_EDX
             0,
         // FEAT_KVM
@@ -1292,6 +1312,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT3_LAHF_LM,
         // FEAT_8000_0007_EDX
             0,
+        // FEAT_8000_0008_EBX
+            0,
         // FEAT_C000_0001_EDX
             0,
         // FEAT_KVM
@@ -1342,6 +1364,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT3_LAHF_LM,
         // FEAT_8000_0007_EDX
             0,
+        // FEAT_8000_0008_EBX
+            0,
         // FEAT_C000_0001_EDX
             0,
         // FEAT_KVM
@@ -1393,6 +1417,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT3_LAHF_LM,
         // FEAT_8000_0007_EDX
             0,
+        // FEAT_8000_0008_EBX
+            0,
         // FEAT_C000_0001_EDX
             0,
         // FEAT_KVM
@@ -1446,6 +1472,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT3_ABM | CPUID_EXT3_LAHF_LM,
         // FEAT_8000_0007_EDX
             0,
+        // FEAT_8000_0008_EBX
+            0,
         // FEAT_C000_0001_EDX
             0,
         // FEAT_KVM
@@ -1500,6 +1528,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT3_ABM | CPUID_EXT3_LAHF_LM,
         // FEAT_8000_0007_EDX
             0,
+        // FEAT_8000_0008_EBX
+            0,
         // FEAT_C000_0001_EDX
             0,
         // FEAT_KVM
@@ -1555,6 +1585,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT3_ABM | CPUID_EXT3_LAHF_LM | CPUID_EXT3_3DNOWPREFETCH,
         // FEAT_8000_0007_EDX
             0,
+        // FEAT_8000_0008_EBX
+            0,
         // FEAT_C000_0001_EDX
             0,
         // FEAT_KVM
@@ -1610,6 +1642,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT3_ABM | CPUID_EXT3_LAHF_LM | CPUID_EXT3_3DNOWPREFETCH,
         // FEAT_8000_0007_EDX
             0,
+        // FEAT_8000_0008_EBX
+            0,
         // FEAT_C000_0001_EDX
             0,
         // FEAT_KVM
@@ -1665,6 +1699,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT3_ABM | CPUID_EXT3_LAHF_LM | CPUID_EXT3_3DNOWPREFETCH,
         // FEAT_8000_0007_EDX
             0,
+        // FEAT_8000_0008_EBX
+            0,
         // FEAT_C000_0001_EDX
             0,
         // FEAT_KVM
@@ -1732,6 +1768,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT3_ABM | CPUID_EXT3_LAHF_LM | CPUID_EXT3_3DNOWPREFETCH,
         // FEAT_8000_0007_EDX
             0,
+        // FEAT_8000_0008_EBX
+            0,
         // FEAT_C000_0001_EDX
             0,
         // FEAT_KVM
@@ -1944,6 +1982,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT3_CR8LEG | CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM,
         // FEAT_8000_0007_EDX
             0,
+        // FEAT_8000_0008_EBX
+            0,
         // FEAT_C000_0001_EDX
             0,
         // FEAT_KVM
@@ -2905,7 +2945,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
         } else {
             *eax = cpu->phys_bits;
         }
-        *ebx = 0;
+        *ebx = env->features[FEAT_8000_0008_EBX];
         *ecx = 0;
         *edx = 0;
         if (cs->nr_cores * cs->nr_threads > 1) {
@@ -3306,6 +3346,7 @@ static void x86_cpu_expand_features(struct uc_struct *uc, X86CPU *cpu, Error **e
         x86_cpu_adjust_feat_level(cpu, FEAT_8000_0001_EDX);
         x86_cpu_adjust_feat_level(cpu, FEAT_8000_0001_ECX);
         x86_cpu_adjust_feat_level(cpu, FEAT_8000_0007_EDX);
+        x86_cpu_adjust_feat_level(cpu, FEAT_8000_0008_EBX);
         x86_cpu_adjust_feat_level(cpu, FEAT_C000_0001_EDX);
         x86_cpu_adjust_feat_level(cpu, FEAT_SVM);
         x86_cpu_adjust_feat_level(cpu, FEAT_XSAVE);
diff --git a/qemu/target/i386/cpu.h b/qemu/target/i386/cpu.h
index 880678fe..3dbf1cf7 100644
--- a/qemu/target/i386/cpu.h
+++ b/qemu/target/i386/cpu.h
@@ -452,6 +452,7 @@ typedef enum FeatureWord {
     FEAT_8000_0001_EDX, /* CPUID[8000_0001].EDX */
     FEAT_8000_0001_ECX, /* CPUID[8000_0001].ECX */
     FEAT_8000_0007_EDX, /* CPUID[8000_0007].EDX */
+    FEAT_8000_0008_EBX, /* CPUID[8000_0008].EBX */
     FEAT_C000_0001_EDX, /* CPUID[C000_0001].EDX */
     FEAT_KVM,           /* CPUID[4000_0001].EAX (KVM_CPUID_FEATURES) */
     FEAT_HYPERV_EAX,    /* CPUID[4000_0003].EAX */
@@ -642,6 +643,8 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
 #define CPUID_7_0_EDX_AVX512_4FMAPS (1U << 3) /* AVX512 Multiply Accumulation Single Precision */
 #define CPUID_7_0_EDX_SPEC_CTRL     (1U << 26) /* Speculation Control */
 
+#define CPUID_8000_0008_EBX_IBPB    (1U << 12) /* Indirect Branch Prediction Barrier */
+
 #define CPUID_XSAVE_XSAVEOPT   (1U << 0)
 #define CPUID_XSAVE_XSAVEC     (1U << 1)
 #define CPUID_XSAVE_XGETBV1    (1U << 2)