target-i386: get/put MSR_TSC_AUX across reset and migration

There's one report of migration breaking due to missing MSR_TSC_AUX
save/restore.  Fix this by adding a new subsection that saves the state
of this MSR.

https://bugzilla.redhat.com/show_bug.cgi?id=1261797

Reported-by: Xiaoqing Wei <xwei@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Juan Quintela <quintela@redhat.com>
CC: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
CC: Marcelo Tosatti <mtosatti@redhat.com>
CC: Richard Henderson <rth@twiddle.net>
CC: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

target-i386/kvm.c

@@ -67,6 +67,7 @@ const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
 
 static bool has_msr_star;
 static bool has_msr_hsave_pa;
+static bool has_msr_tsc_aux;
 static bool has_msr_tsc_adjust;
 static bool has_msr_tsc_deadline;
 static bool has_msr_feature_control;
@@ -825,6 +826,10 @@ static int kvm_get_supported_msrs(KVMState *s)
                     has_msr_hsave_pa = true;
                     continue;
                 }
+                if (kvm_msr_list->indices[i] == MSR_TSC_AUX) {
+                    has_msr_tsc_aux = true;
+                    continue;
+                }
                 if (kvm_msr_list->indices[i] == MSR_TSC_ADJUST) {
                     has_msr_tsc_adjust = true;
                     continue;
@@ -1299,6 +1304,9 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
     if (has_msr_hsave_pa) {
         kvm_msr_entry_set(&msrs[n++], MSR_VM_HSAVE_PA, env->vm_hsave);
     }
+    if (has_msr_tsc_aux) {
+        kvm_msr_entry_set(&msrs[n++], MSR_TSC_AUX, env->tsc_aux);
+    }
     if (has_msr_tsc_adjust) {
         kvm_msr_entry_set(&msrs[n++], MSR_TSC_ADJUST, env->tsc_adjust);
     }
@@ -1671,6 +1679,9 @@ static int kvm_get_msrs(X86CPU *cpu)
     if (has_msr_hsave_pa) {
         msrs[n++].index = MSR_VM_HSAVE_PA;
     }
+    if (has_msr_tsc_aux) {
+        msrs[n++].index = MSR_TSC_AUX;
+    }
     if (has_msr_tsc_adjust) {
         msrs[n++].index = MSR_TSC_ADJUST;
     }
@@ -1820,6 +1831,9 @@ static int kvm_get_msrs(X86CPU *cpu)
         case MSR_IA32_TSC:
             env->tsc = msrs[i].data;
             break;
+        case MSR_TSC_AUX:
+            env->tsc_aux = msrs[i].data;
+            break;
         case MSR_TSC_ADJUST:
             env->tsc_adjust = msrs[i].data;
             break;