numa: move source of default CPUs to NUMA node mapping into boards

Originally CPU threads were by default assigned in
round-robin fashion. However it was causing issues in
guest since CPU threads from the same socket/core could
be placed on different NUMA nodes.
Commit fb43b73b (pc: fix default VCPU to NUMA node mapping)
fixed it by grouping threads within a socket on the same node
introducing cpu_index_to_socket_id() callback and commit
20bb648d (spapr: Fix default NUMA node allocation for threads)
reused callback to fix similar issues for SPAPR machine
even though socket doesn't make much sense there.

As result QEMU ended up having 3 default distribution rules
used by 3 targets /virt-arm, spapr, pc/.

In effort of moving NUMA mapping for CPUs into possible_cpus,
generalize default mapping in numa.c by making boards decide
on default mapping and let them explicitly tell generic
numa code to which node a CPU thread belongs to by replacing
cpu_index_to_socket_id() with @cpu_index_to_instance_props()
which provides default node_id assigned by board to specified
cpu_index.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <1494415802-227633-2-git-send-email-imammedo@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/include/hw/boards.h b/include/hw/boards.h
index 99458eb859..3ffa255fb8 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -74,7 +74,10 @@ typedef struct {
  *    of HotplugHandler object, which handles hotplug operation
  *    for a given @dev. It may return NULL if @dev doesn't require
  *    any actions to be performed by hotplug handler.
- * @cpu_index_to_socket_id:
+ * @cpu_index_to_instance_props:
+ *    used to provide @cpu_index to socket/core/thread number mapping, allowing
+ *    legacy code to perform maping from cpu_index to topology properties
+ *    Returns: tuple of socket/core/thread ids given cpu_index belongs to.
  *    used to provide @cpu_index to socket number mapping, allowing
  *    a machine to group CPU threads belonging to the same socket/package
  *    Returns: socket number given cpu_index belongs to.
@@ -141,7 +144,8 @@ struct MachineClass {
 
     HotplugHandler *(*get_hotplug_handler)(MachineState *machine,
                                            DeviceState *dev);
-    unsigned (*cpu_index_to_socket_id)(unsigned cpu_index);
+    CpuInstanceProperties (*cpu_index_to_instance_props)(MachineState *machine,
+                                                         unsigned cpu_index);
     const CPUArchIdList *(*possible_cpu_arch_ids)(MachineState *machine);
 };