target-i386: Add a marker to end of the region zeroed on reset

Instead of using cpuid_level, use an empty struct as a marker
(like we already did with {start,end}_init_save). This will avoid
accidentaly resetting the wrong fields if we change the field
ordering on CPUX86State.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

2 files changed, 2 insertions, 1 deletions

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 920b78fb30..26f0e59ab9 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -2714,7 +2714,7 @@ static void x86_cpu_reset(CPUState *s)
 
     xcc->parent_reset(s);
 
-    memset(env, 0, offsetof(CPUX86State, cpuid_level));
+    memset(env, 0, offsetof(CPUX86State, end_reset_fields));
 
     tlb_flush(s, 1);
 
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 27af9c3f9a..604d591829 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -1108,6 +1108,7 @@ typedef struct CPUX86State {
     CPU_COMMON
 
     /* Fields from here on are preserved across CPU reset. */
+    struct {} end_reset_fields;
 
     /* processor features (e.g. for CPUID insn) */
     uint32_t cpuid_level;