target-i386: Disable cache info passthrough by default

The host cache information may not make sense for the guest if the VM
CPU topology doesn't match the host CPU topology. To make sure we won't
expose broken cache information to the guest, disable cache info
passthrough by default, and add a new "host-cache-info" property that
can be used to enable the old behavior for users that really need it.

Cc: Benoît Canet <benoit@irqsave.net>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index c5961d7c030e8154f89e8074bc7a8d0b6893f335..7037de044d70603c37fc2ada20d2be8c90cee7b0 100644 (file)
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -318,6 +318,11 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint64_t *);
             .driver   = "Broadwell-noTSX-" TYPE_X86_CPU,\
             .property = "abm",\
             .value    = "off",\
+        },\
+        {\
+            .driver   = "host" "-" TYPE_X86_CPU,\
+            .property = "host-cache-info",\
+            .value    = "on",\
         },
 
 #define PC_COMPAT_2_3 \

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 5f53af248f874aa41f524b5f252aa2438f23fe90..987253df3bbb13fc020e580b82ee9b80e2dc0b49 100644 (file)
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -656,7 +656,6 @@ struct X86CPUDefinition {
     int stepping;
     FeatureWordArray features;
     char model_id[48];
-    bool cache_info_passthrough;
 };
 
 static X86CPUDefinition builtin_x86_defs[] = {
@@ -1420,6 +1419,7 @@ static X86CPUDefinition host_cpudef;
 
 static Property host_x86_cpu_properties[] = {
     DEFINE_PROP_BOOL("migratable", X86CPU, migratable, true),
+    DEFINE_PROP_BOOL("host-cache-info", X86CPU, cache_info_passthrough, false),
     DEFINE_PROP_END_OF_LIST()
 };
 
@@ -1446,7 +1446,6 @@ static void host_x86_cpu_class_init(ObjectClass *oc, void *data)
     cpu_x86_fill_model_id(host_cpudef.model_id);
 
     xcc->cpu_def = &host_cpudef;
-    host_cpudef.cache_info_passthrough = true;
 
     /* level, xlevel, xlevel2, and the feature words are initialized on
      * instance_init, because they require KVM to be initialized.
@@ -2094,7 +2093,6 @@ static void x86_cpu_load_def(X86CPU *cpu, X86CPUDefinition *def, Error **errp)
     object_property_set_int(OBJECT(cpu), def->stepping, "stepping", errp);
     object_property_set_int(OBJECT(cpu), def->xlevel, "xlevel", errp);
     object_property_set_int(OBJECT(cpu), def->xlevel2, "xlevel2", errp);
-    cpu->cache_info_passthrough = def->cache_info_passthrough;
     object_property_set_str(OBJECT(cpu), def->model_id, "model-id", errp);
     for (w = 0; w < FEATURE_WORDS; w++) {
         env->features[w] = def->features[w];