From f0fac2e6c70510f7a5c5c572831b1a851a29fc07 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Wed, 13 Dec 2017 15:47:36 -0200
Subject: [PATCH 1/3] target-i386: add support for SPEC_CTRL MSR

RH-Author: Eduardo Habkost <ehabkost@redhat.com>
Message-id: <20171213174738.20852-2-ehabkost@redhat.com>
Patchwork-id: n/a
O-Subject: [CONFIDENTIAL][RHEL-7.5 qemu-kvm-rhev PATCH v2 1/3] target-i386: cpu:
add new CPUID bits for indirect branch predictor restrictions
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.h     |  3 +++
 target/i386/kvm.c     | 14 ++++++++++++++
 target/i386/machine.c | 20 ++++++++++++++++++++
 3 files changed, 37 insertions(+)

diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index fd73888..4dfb859 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -335,6 +335,7 @@
 #define MSR_IA32_APICBASE_BASE          (0xfffffU<<12)
 #define MSR_IA32_FEATURE_CONTROL        0x0000003a
 #define MSR_TSC_ADJUST                  0x0000003b
+#define MSR_IA32_SPEC_CTRL              0x48
 #define MSR_IA32_TSCDEADLINE            0x6e0
 
 #define FEATURE_CONTROL_LOCKED                    (1<<0)
@@ -1082,6 +1083,8 @@ typedef struct CPUX86State {
 
     uint32_t pkru;
 
+    uint64_t spec_ctrl;
+
     /* End of state preserved by INIT (dummy marker).  */
     struct {} end_init_save;
 
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index ee4e91f..3f59629 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -91,6 +91,7 @@ static bool has_msr_hv_synic;
 static bool has_msr_hv_stimer;
 static bool has_msr_hv_frequencies;
 static bool has_msr_xss;
+static bool has_msr_spec_ctrl;
 
 static bool has_msr_architectural_pmu;
 static uint32_t num_architectural_pmu_counters;
@@ -1145,6 +1146,9 @@ static int kvm_get_supported_msrs(KVMState *s)
                 case HV_X64_MSR_TSC_FREQUENCY:
                     has_msr_hv_frequencies = true;
                     break;
+                case MSR_IA32_SPEC_CTRL:
+                    has_msr_spec_ctrl = true;
+                    break;
                 }
             }
         }
@@ -1627,6 +1631,9 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
     if (has_msr_xss) {
         kvm_msr_entry_add(cpu, MSR_IA32_XSS, env->xss);
     }
+    if (has_msr_spec_ctrl) {
+        kvm_msr_entry_add(cpu, MSR_IA32_SPEC_CTRL, env->spec_ctrl);
+    }
 #ifdef TARGET_X86_64
     if (lm_capable_kernel) {
         kvm_msr_entry_add(cpu, MSR_CSTAR, env->cstar);
@@ -1635,6 +1642,7 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
         kvm_msr_entry_add(cpu, MSR_LSTAR, env->lstar);
     }
 #endif
+
     /*
      * The following MSRs have side effects on the guest or are too heavy
      * for normal writeback. Limit them to reset or full state updates.
@@ -2000,6 +2008,9 @@ static int kvm_get_msrs(X86CPU *cpu)
     if (has_msr_xss) {
         kvm_msr_entry_add(cpu, MSR_IA32_XSS, 0);
     }
+    if (has_msr_spec_ctrl) {
+        kvm_msr_entry_add(cpu, MSR_IA32_SPEC_CTRL, 0);
+    }
 
 
     if (!env->tsc_valid) {
@@ -2349,6 +2360,9 @@ static int kvm_get_msrs(X86CPU *cpu)
                 env->mtrr_var[MSR_MTRRphysIndex(index)].base = msrs[i].data;
             }
             break;
+        case MSR_IA32_SPEC_CTRL:
+            env->spec_ctrl = msrs[i].data;
+            break;
         }
     }
 
diff --git a/target/i386/machine.c b/target/i386/machine.c
index 6156626..0212270 100644
--- a/target/i386/machine.c
+++ b/target/i386/machine.c
@@ -838,6 +838,25 @@ static const VMStateDescription vmstate_xsave ={
     }
 };
 
+static bool spec_ctrl_needed(void *opaque)
+{
+    X86CPU *cpu = opaque;
+    CPUX86State *env = &cpu->env;
+
+    return env->spec_ctrl != 0;
+}
+
+static const VMStateDescription vmstate_spec_ctrl = {
+    .name = "cpu/spec_ctrl",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = spec_ctrl_needed,
+    .fields = (VMStateField[]){
+        VMSTATE_UINT64(env.spec_ctrl, X86CPU),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 VMStateDescription vmstate_x86_cpu = {
     .name = "cpu",
     .version_id = 12,
@@ -956,6 +975,7 @@ VMStateDescription vmstate_x86_cpu = {
 #ifdef TARGET_X86_64
         &vmstate_pkru,
 #endif
+        &vmstate_spec_ctrl,
         &vmstate_mcg_ext_ctl,
         &vmstate_xsave,
         NULL
-- 
1.8.3.1