From: Corey Minyard <cminyard@mvista.com>

Migration capability is being added for pm_smbus and SMBus devices.
This change will allow backwards compatibility to be kept when
migrating back to an old qemu version.  Add a bool to the machine
class tho keep smbus migration from happening.  Future changes
will use this.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 hw/i386/pc_piix.c   | 1 +
 hw/i386/pc_q35.c    | 1 +
 include/hw/boards.h | 1 +
 3 files changed, 3 insertions(+)

diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 6ba163ccbb..3bead1143f 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -442,6 +442,7 @@ static void pc_i440fx_3_1_machine_options(MachineClass *m)
 {
     pc_i440fx_4_0_machine_options(m);
     m->is_default = 0;
+    m->smbus_no_migration_support = true;
     m->alias = NULL;
     compat_props_add(m->compat_props, hw_compat_3_1, hw_compat_3_1_len);
     compat_props_add(m->compat_props, pc_compat_3_1, pc_compat_3_1_len);
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 1689885cac..f24ee74cc5 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -378,6 +378,7 @@ static void pc_q35_3_1_machine_options(MachineClass *m)
 {
     pc_q35_4_0_machine_options(m);
     m->default_kernel_irqchip_split = false;
+    m->smbus_no_migration_support = true;
     m->alias = NULL;
     compat_props_add(m->compat_props, hw_compat_3_1, hw_compat_3_1_len);
     compat_props_add(m->compat_props, pc_compat_3_1, pc_compat_3_1_len);
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 02f114085f..e7f7b85008 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -207,6 +207,7 @@ struct MachineClass {
     void (*numa_auto_assign_ram)(MachineClass *mc, NodeInfo *nodes,
                                  int nb_nodes, ram_addr_t size);
     bool ignore_boot_device_suffixes;
+    bool smbus_no_migration_support;
 
     HotplugHandler *(*get_hotplug_handler)(MachineState *machine,
                                            DeviceState *dev);
-- 
2.17.1