If the user set disable smm by '-machine smm=off', we
should not register smram_listener so that we can
avoid waster memory in kvm since the added sencond
address space.

Meanwhile we should assign value of the global kvm_state
before invoking the kvm_arch_init(), because
pc_machine_is_smm_enabled() may use it by kvm_has_mm().

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
---
v2: 
 Do a a object_dynamic_cast before invoking PC_MACHINE(ms) [Paolo]

 kvm-all.c         | 4 ++--
 target/i386/kvm.c | 4 +++-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/kvm-all.c b/kvm-all.c
index 90b8573..92bdf2c 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1746,6 +1746,8 @@ static int kvm_init(MachineState *ms)
     kvm_ioeventfd_any_length_allowed =
         (kvm_check_extension(s, KVM_CAP_IOEVENTFD_ANY_LENGTH) > 0);
 
+    kvm_state = s;
+
     ret = kvm_arch_init(ms, s);
     if (ret < 0) {
         goto err;
@@ -1755,8 +1757,6 @@ static int kvm_init(MachineState *ms)
         kvm_irqchip_create(ms, s);
     }
 
-    kvm_state = s;
-
     if (kvm_eventfds_allowed) {
         s->memory_listener.listener.eventfd_add = kvm_mem_ioeventfd_add;
         s->memory_listener.listener.eventfd_del = kvm_mem_ioeventfd_del;
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 011d4a5..5106f5f 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -1254,7 +1254,9 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
         }
     }
 
-    if (kvm_check_extension(s, KVM_CAP_X86_SMM)) {
+    if (kvm_check_extension(s, KVM_CAP_X86_SMM) &&
+        object_dynamic_cast(OBJECT(ms), TYPE_PC_MACHINE) &&
+            pc_machine_is_smm_enabled(PC_MACHINE(ms))) {
         smram_machine_done.notify = register_smram_listener;
         qemu_add_machine_init_done_notifier(&smram_machine_done);
     }
-- 
1.8.3.1