i386: "unavailable-features" QOM property

Add a "unavailable-features" QOM property to X86CPU objects that
have the same semantics of "unavailable-features" on
query-cpu-definitions.  The new property has the same goal of
"filtered-features", but is generic enough to let any kind of CPU
feature to be listed there without relying on low level details
like CPUID leaves or MSR numbers.

Message-Id: <20190422234742.15780-3-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 36589adb1f..7e5b545005 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -3692,6 +3692,17 @@ static void x86_cpu_list_feature_names(FeatureWordArray features,
     }
 }
 
+static void x86_cpu_get_unavailable_features(Object *obj, Visitor *v,
+                                             const char *name, void *opaque,
+                                             Error **errp)
+{
+    X86CPU *xc = X86_CPU(obj);
+    strList *result = NULL;
+
+    x86_cpu_list_feature_names(xc->filtered_features, &result);
+    visit_type_strList(v, "unavailable-features", &result, errp);
+}
+
 /* Check for missing features that may prevent the CPU class from
  * running using the current machine and accelerator.
  */
@@ -5632,6 +5643,15 @@ static void x86_cpu_initfn(Object *obj)
     object_property_add(obj, "filtered-features", "X86CPUFeatureWordInfo",
                         x86_cpu_get_feature_words,
                         NULL, NULL, (void *)cpu->filtered_features, NULL);
+    /*
+     * The "unavailable-features" property has the same semantics as
+     * CpuDefinitionInfo.unavailable-features on the "query-cpu-definitions"
+     * QMP command: they list the features that would have prevented the
+     * CPU from running if the "enforce" flag was set.
+     */
+    object_property_add(obj, "unavailable-features", "strList",
+                        x86_cpu_get_unavailable_features,
+                        NULL, NULL, NULL, &error_abort);
 
     object_property_add(obj, "crash-information", "GuestPanicInformation",
                         x86_cpu_get_crash_info_qom, NULL, NULL, NULL, NULL);