diff --git a/hw/cpu/core.c b/hw/cpu/core.c
index 92d3b2fbad..9876075155 100644
--- a/hw/cpu/core.c
+++ b/hw/cpu/core.c
@@ -66,10 +66,16 @@ static void core_prop_set_nr_threads(Object *obj, Visitor *v, const char *name,
 
 static void cpu_core_instance_init(Object *obj)
 {
-    MachineState *ms = MACHINE(qdev_get_machine());
     CPUCore *core = CPU_CORE(obj);
 
-    core->nr_threads = ms->smp.threads;
+    /*
+     * Only '-device something-cpu-core,help' can get us there before
+     * the machine has been created. We don't care to set nr_threads
+     * in this case since it isn't used afterwards.
+     */
+    if (current_machine) {
+        core->nr_threads = current_machine->smp.threads;
+    }
 }
 
 static void cpu_core_class_init(ObjectClass *oc, void *data)
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 6b3e9467f1..ad99cad0e7 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -4179,6 +4179,18 @@ static X86CPUDefinition builtin_x86_defs[] = {
         .xlevel = 0x8000001E,
         .model_id = "AMD EPYC-Rome Processor",
         .cache_info = &epyc_rome_cache_info,
+        .versions = (X86CPUVersionDefinition[]) {
+            { .version = 1 },
+            {
+                .version = 2,
+                .props = (PropValue[]) {
+                    { "ibrs", "on" },
+                    { "amd-ssbd", "on" },
+                    { /* end of list */ }
+                }
+            },
+            { /* end of list */ }
+        }
     },
     {
         .name = "EPYC-Milan",