[PULL 57/61] i386/kvm: Get X86MachineState in kvm_arch_init() without the cast check

[Paolo Bonzini <pbonzini@redhat.com>]

From: Xiaoyao Li <xiaoyao.li@intel.com>

Commit 8f54bbd0b4d9 ("x86: Check for machine state object class before
typecasting it") added back the object_dynamic_cast() check before
casting MachineState to X86MachineState. And commit 035d1ef26565 ("i386:
Add ratelimit for bus locks acquired in guest") followed it.

The reason to check object_dynamic_cast(OBJECT(ms), TYPE_PC_MACHINE)
before commit 8f54bbd0b4d9 was that smm was not supported for microvm
machine at that time. But after commit 8f54bbd0b4d9, smm is supported
for all x86 machines (both pc and microvm). And since it's the
target-specifc implementation of kvm_arch_init() in target/i386/kvm/kvm.c,
I don't see how it would be called for other machines than x86machine,
and why the check of object_dynamic_cast() is needed.

Drop the object_dynamic_cast() check and simplify the code.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Chenyi Qiang <chenyi.qiang@intel.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/r/20250729062014.1669578-2-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/kvm/kvm.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 28012d2b578..728ad401157 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -3235,6 +3235,7 @@ static int kvm_vm_enable_energy_msrs(KVMState *s)
 
 int kvm_arch_init(MachineState *ms, KVMState *s)
 {
+    X86MachineState *x86ms = X86_MACHINE(ms);
     int ret;
     struct utsname utsname;
     Error *local_err = NULL;
@@ -3316,8 +3317,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
     }
 
     if (kvm_check_extension(s, KVM_CAP_X86_SMM) &&
-        object_dynamic_cast(OBJECT(ms), TYPE_X86_MACHINE) &&
-        x86_machine_is_smm_enabled(X86_MACHINE(ms))) {
+        x86_machine_is_smm_enabled(x86ms)) {
         smram_machine_done.notify = register_smram_listener;
         qemu_add_machine_init_done_notifier(&smram_machine_done);
     }
@@ -3331,18 +3331,14 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
         }
     }
 
-    if (object_dynamic_cast(OBJECT(ms), TYPE_X86_MACHINE)) {
-        X86MachineState *x86ms = X86_MACHINE(ms);
-
-        if (x86ms->bus_lock_ratelimit > 0) {
-            ret = kvm_vm_enable_bus_lock_exit(s);
-            if (ret < 0) {
-                return ret;
-            }
-            ratelimit_init(&bus_lock_ratelimit_ctrl);
-            ratelimit_set_speed(&bus_lock_ratelimit_ctrl,
-                                x86ms->bus_lock_ratelimit, BUS_LOCK_SLICE_TIME);
+    if (x86ms->bus_lock_ratelimit > 0) {
+        ret = kvm_vm_enable_bus_lock_exit(s);
+        if (ret < 0) {
+            return ret;
         }
+        ratelimit_init(&bus_lock_ratelimit_ctrl);
+        ratelimit_set_speed(&bus_lock_ratelimit_ctrl,
+                            x86ms->bus_lock_ratelimit, BUS_LOCK_SLICE_TIME);
     }
 
     if (kvm_check_extension(s, KVM_CAP_X86_NOTIFY_VMEXIT)) {
-- 
2.51.0