[RFC v2 12/15] hw/i386: Allow i386 to create new CPUs in topology tree

[Zhao Liu <zhao1.liu@xxxxxxxxx>]

For x86, CPU's apic ID represent its topology path and is the
combination of topology sub IDs in each leavl.

When x86 machine creates CPUs, to insert the CPU into topology tree, use
apic ID to get topology sub IDs.

Then search the topology tree for the corresponding parent topology
device and insert the CPU into the CPU bus of the parent device.

Signed-off-by: Zhao Liu <zhao1.liu@xxxxxxxxx>
---
 hw/i386/x86-common.c | 101 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 97 insertions(+), 4 deletions(-)

diff --git a/hw/i386/x86-common.c b/hw/i386/x86-common.c
index b21d2ab97349..a7f082b0a90b 100644
--- a/hw/i386/x86-common.c
+++ b/hw/i386/x86-common.c
@@ -53,14 +53,107 @@
 /* Physical Address of PVH entry point read from kernel ELF NOTE */
 static size_t pvh_start_addr;
 
-static void x86_cpu_new(X86MachineState *x86ms, int64_t apic_id, Error **errp)
+static int x86_cpu_get_topo_id(const X86CPUTopoIDs *topo_ids,
+                               CpuTopologyLevel level)
 {
-    Object *cpu = object_new(MACHINE(x86ms)->cpu_type);
+    switch (level) {
+    case CPU_TOPOLOGY_LEVEL_THREAD:
+        return topo_ids->smt_id;
+    case CPU_TOPOLOGY_LEVEL_CORE:
+        return topo_ids->core_id;
+    case CPU_TOPOLOGY_LEVEL_MODULE:
+        return topo_ids->module_id;
+    case CPU_TOPOLOGY_LEVEL_DIE:
+        return topo_ids->die_id;
+    case CPU_TOPOLOGY_LEVEL_SOCKET:
+        return topo_ids->pkg_id;
+    default:
+        g_assert_not_reached();
+    }
+
+    return -1;
+}
+
+typedef struct SearchCoreCb {
+    const X86CPUTopoIDs *topo_ids;
+    const CPUTopoState *parent;
+} SearchCoreCb;
+
+static int x86_search_topo_parent(DeviceState *dev, void *opaque)
+{
+    CPUTopoState *topo = CPU_TOPO(dev);
+    CpuTopologyLevel level = GET_CPU_TOPO_LEVEL(topo);
+    SearchCoreCb *cb = opaque;
+    int topo_id, index;
+
+    topo_id = x86_cpu_get_topo_id(cb->topo_ids, level);
+    index = cpu_topo_get_index(topo);
+
+    if (topo_id < 0) {
+        error_report("Invalid %s-id: %d",
+                     CpuTopologyLevel_str(level), topo_id);
+        error_printf("Try to set the %s-id in [0-%d].\n",
+                     CpuTopologyLevel_str(level),
+                     cpu_topo_get_instances_num(topo) - 1);
+        return TOPO_FOREACH_ERR;
+    }
+
+    if (topo_id == index) {
+        if (level == CPU_TOPOLOGY_LEVEL_CORE) {
+            cb->parent = topo;
+            /* The error result could exit directly. */
+            return TOPO_FOREACH_ERR;
+        }
+        return TOPO_FOREACH_CONTINUE;
+    }
+    return TOPO_FOREACH_END;
+}
+
+static BusState *x86_find_topo_bus(MachineState *ms, X86CPUTopoIDs *topo_ids)
+{
+    SearchCoreCb cb;
+
+    cb.topo_ids = topo_ids;
+    cb.parent = NULL;
+    qbus_walk_children(BUS(&ms->topo->bus), x86_search_topo_parent,
+                       NULL, NULL, NULL, &cb);
+
+    if (!cb.parent) {
+        return NULL;
+    }
+
+    return BUS(cb.parent->bus);
+}
+
+static void x86_cpu_new(X86MachineState *x86ms, int index,
+                        int64_t apic_id, Error **errp)
+{
+    MachineState *ms = MACHINE(x86ms);
+    MachineClass *mc = MACHINE_GET_CLASS(ms);
+    Object *cpu = object_new(ms->cpu_type);
+    DeviceState *dev = DEVICE(cpu);
+    BusState *bus = NULL;
+
+    /*
+     * Once x86 machine supports topo_tree_supported, x86 CPU would
+     * also have bus_type.
+     */
+    if (mc->smp_props.topo_tree_supported) {
+        X86CPUTopoIDs topo_ids;
+        X86CPUTopoInfo topo_info;
+
+        init_topo_info(&topo_info, x86ms);
+        x86_topo_ids_from_apicid(apic_id, &topo_info, &topo_ids);
+        bus = x86_find_topo_bus(ms, &topo_ids);
+
+        /* Only with dev->id, CPU can be inserted into topology tree. */
+        dev->id = g_strdup_printf("%s[%d]", ms->cpu_type, index);
+    }
 
     if (!object_property_set_uint(cpu, "apic-id", apic_id, errp)) {
         goto out;
     }
-    qdev_realize(DEVICE(cpu), NULL, errp);
+    qdev_realize(dev, bus, errp);
 
 out:
     object_unref(cpu);
@@ -111,7 +204,7 @@ void x86_cpus_init(X86MachineState *x86ms, int default_cpu_version)
 
     possible_cpus = mc->possible_cpu_arch_ids(ms);
     for (i = 0; i < ms->smp.cpus; i++) {
-        x86_cpu_new(x86ms, possible_cpus->cpus[i].arch_id, &error_fatal);
+        x86_cpu_new(x86ms, i, possible_cpus->cpus[i].arch_id, &error_fatal);
     }
 }
 
-- 
2.34.1