From bc88b0d69c0e81626e5c246cae83e499bfa3dccb Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Wed, 13 Dec 2017 15:47:37 -0200
Subject: [PATCH 2/3] target-i386: cpu: add new CPUID bits for indirect branch
 predictor restrictions

RH-Author: Eduardo Habkost <ehabkost@redhat.com>
Message-id: <20171213174738.20852-3-ehabkost@redhat.com>
Patchwork-id: n/a
O-Subject: [CONFIDENTIAL][RHEL-7.5 qemu-kvm-rhev PATCH v2 2/3] target-i386: add
 support for SPEC_CTRL MSR
Bugzilla: CVE-2017-5715
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 target/i386/cpu.c | 23 ++++++++++++++++++++---
 target/i386/cpu.h |  1 +
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index c2dee60..364e52e 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -456,8 +456,8 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
             NULL, NULL, NULL, NULL,
             NULL, NULL, NULL, NULL,
             NULL, NULL, NULL, NULL,
-            NULL, NULL, NULL, NULL,
-            NULL, NULL, NULL, NULL,
+            NULL, NULL, "spec-ctrl", "stibp",
+            NULL, "arch-facilities", NULL, NULL,
         },
         .cpuid_eax = 7,
         .cpuid_needs_ecx = true, .cpuid_ecx = 0,
@@ -480,6 +480,22 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         .tcg_features = TCG_APM_FEATURES,
         .unmigratable_flags = CPUID_APM_INVTSC,
     },
+    [FEAT_8000_0008_EBX] = {
+        .feat_names = {
+            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,
+        },
+        .cpuid_eax = 0x80000008,
+        .cpuid_reg = R_EBX,
+        .tcg_features = 0,
+        .unmigratable_flags = 0,
+    },
     [FEAT_XSAVE] = {
         .feat_names = {
             "xsaveopt", "xsavec", "xgetbv1", "xsaves",
@@ -3122,7 +3138,7 @@ 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) {
@@ -3578,6 +3594,7 @@ static void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
         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/target/i386/cpu.h b/target/i386/cpu.h
index 4dfb859..f2686d5 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -454,6 +454,7 @@ 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 */
-- 
1.8.3.1