i386/cpu: Move x86_ext_save_areas[] initialization to .instance_init

In x86_cpu_post_initfn(), the initialization of x86_ext_save_areas[]
marks the unsupported xsave areas based on Host support.

This step must be done before accel_cpu_instance_init(), otherwise,
KVM's assertion on host xsave support would fail:

qemu-system-x86_64: ../target/i386/kvm/kvm-cpu.c:149:
kvm_cpu_xsave_init: Assertion `esa->size == eax' failed.

(on AMD EPYC 7302 16-Core Processor)

Move x86_ext_save_areas[] initialization to .instance_init and place it
before accel_cpu_instance_init().

Fixes: commit 5f158abef44c ("target/i386: move accel_cpu_instance_init to .instance_init")
Reported-by: Paolo Abeni <pabeni@redhat.com>
Tested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250717023933.2502109-1-zhao1.liu@intel.com
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 15 insertions, 7 deletions

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index da7d8dca63..251d5760a0 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -9620,6 +9620,16 @@ static void x86_cpu_register_feature_bit_props(X86CPUClass *xcc,
 
 static void x86_cpu_post_initfn(Object *obj)
 {
+#ifndef CONFIG_USER_ONLY
+    if (current_machine && current_machine->cgs) {
+        x86_confidential_guest_cpu_instance_init(
+            X86_CONFIDENTIAL_GUEST(current_machine->cgs), (CPU(obj)));
+    }
+#endif
+}
+
+static void x86_cpu_init_xsave(void)
+{
     static bool first = true;
     uint64_t supported_xcr0;
     int i;
@@ -9639,13 +9649,6 @@ static void x86_cpu_post_initfn(Object *obj)
             }
         }
     }
-
-#ifndef CONFIG_USER_ONLY
-    if (current_machine && current_machine->cgs) {
-        x86_confidential_guest_cpu_instance_init(
-            X86_CONFIDENTIAL_GUEST(current_machine->cgs), (CPU(obj)));
-    }
-#endif
 }
 
 static void x86_cpu_init_default_topo(X86CPU *cpu)
@@ -9715,6 +9718,11 @@ static void x86_cpu_initfn(Object *obj)
         x86_cpu_load_model(cpu, xcc->model);
     }
 
+    /*
+     * accel's cpu_instance_init may have the xsave check,
+     * so x86_ext_save_areas[] must be initialized before this.
+     */
+    x86_cpu_init_xsave();
     accel_cpu_instance_init(CPU(obj));
 }