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From 151cbf5d444ab746d05dc0757ec972df8880d0ec Mon Sep 17 00:00:00 2001
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From: Paolo Bonzini <pbonzini@redhat.com>
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Date: Wed, 13 Dec 2017 15:43:39 -0200
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Subject: [PATCH 1/3] target-i386: cpu: add new CPUID bits for indirect branch
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 predictor restrictions
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RH-Author: Eduardo Habkost <ehabkost@redhat.com>
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Message-id: <20171213174341.20684-2-ehabkost@redhat.com>
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Patchwork-id: n/a
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O-Subject: [CONFIDENTIAL][RHEL-7.5 qemu-kvm PATCH v2 1/3] target-i386: cpu:
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    add new CPUID bits for indirect branch predictor restrictions
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Bugzilla: CVE-2017-5715
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 target-i386/cpu.c | 19 ++++++++++++++++++-
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 target-i386/cpu.h |  1 +
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 2 files changed, 19 insertions(+), 1 deletion(-)
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diff --git a/target-i386/cpu.c b/target-i386/cpu.c
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index 539d659..335689b 100644
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--- a/target-i386/cpu.c
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+++ b/target-i386/cpu.c
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@@ -172,6 +172,17 @@ static const char *cpuid_7_0_edx_feature_name[] = {
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     NULL, NULL, NULL, NULL,
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     NULL, NULL, NULL, NULL,
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     NULL, NULL, NULL, NULL,
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+    NULL, NULL, "spec-ctrl", "stibp",
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+    NULL, "arch-facilities", NULL, NULL,
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+};
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+
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+static const char *cpuid_80000008_ebx_feature_name[] = {
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+    NULL, NULL, NULL, NULL,
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+    NULL, NULL, NULL, NULL,
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+    NULL, NULL, NULL, NULL,
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+    "ibpb", NULL, NULL, NULL,
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+    NULL, NULL, NULL, NULL,
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+    NULL, NULL, NULL, NULL,
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     NULL, NULL, NULL, NULL,
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     NULL, NULL, NULL, NULL,
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 };
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@@ -314,6 +325,12 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
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         .cpuid_reg = R_EDX,
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         .tcg_features = TCG_7_0_EDX_FEATURES,
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     },
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+    [FEAT_8000_0008_EBX] = {
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+        .feat_names = cpuid_80000008_ebx_feature_name,
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+        .cpuid_eax = 0x80000008,
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+        .cpuid_needs_ecx = false, .cpuid_ecx = 0,
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+        .cpuid_reg = R_EBX,
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+    },
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     [FEAT_XSAVE] = {
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         .feat_names = cpuid_xsave_feature_name,
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         .cpuid_eax = 0xd,
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@@ -2470,7 +2487,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
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                 *eax = 0x00000020; /* 32 bits physical */
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             }
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         }
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-        *ebx = 0;
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+        *ebx = env->features[FEAT_8000_0008_EBX];
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         *ecx = 0;
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         *edx = 0;
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         if (cs->nr_cores * cs->nr_threads > 1) {
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diff --git a/target-i386/cpu.h b/target-i386/cpu.h
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index 78b8072..1e5c980 100644
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--- a/target-i386/cpu.h
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+++ b/target-i386/cpu.h
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@@ -406,6 +406,7 @@ typedef enum FeatureWord {
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     FEAT_7_0_EDX,       /* CPUID[EAX=7,ECX=0].EDX */
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     FEAT_8000_0001_EDX, /* CPUID[8000_0001].EDX */
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     FEAT_8000_0001_ECX, /* CPUID[8000_0001].ECX */
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+    FEAT_8000_0008_EBX, /* CPUID[8000_0008].EBX */
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     FEAT_C000_0001_EDX, /* CPUID[C000_0001].EDX */
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     FEAT_KVM,           /* CPUID[4000_0001].EAX (KVM_CPUID_FEATURES) */
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     FEAT_SVM,           /* CPUID[8000_000A].EDX */
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-- 
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1.8.3.1
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