gen_helper_rsm cannot generate an exception, and reloads the flags.
So there's no need to spill cc_op and update cpu_eip, but on the
other hand cc_op must be reset to CC_OP_EFLAGS before returning.

It all works by chance, because by spilling cc_op before the call
to the helper, it becomes non-dirty and gen_eob will not overwrite
the CC_OP_EFLAGS value that is placed there by the helper.  But
let's clean it up.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/tcg/translate.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index f44edb3c29c..3c7d8d72144 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -4488,9 +4488,8 @@ static void disas_insn_old(DisasContext *s, CPUState *cpu, int b)
         /* we should not be in SMM mode */
         g_assert_not_reached();
 #else
-        gen_update_cc_op(s);
-        gen_update_eip_next(s);
         gen_helper_rsm(tcg_env);
+        set_cc_op(s, CC_OP_EFLAGS);
 #endif /* CONFIG_USER_ONLY */
         s->base.is_jmp = DISAS_EOB_ONLY;
         break;
-- 
2.45.1

On 5/24/24 01:10, Paolo Bonzini wrote:
> gen_helper_rsm cannot generate an exception, and reloads the flags.
> So there's no need to spill cc_op and update cpu_eip, but on the
> other hand cc_op must be reset to CC_OP_EFLAGS before returning.
> 
> It all works by chance, because by spilling cc_op before the call
> to the helper, it becomes non-dirty and gen_eob will not overwrite
> the CC_OP_EFLAGS value that is placed there by the helper.  But
> let's clean it up.
> 
> Signed-off-by: Paolo Bonzini<pbonzini@redhat.com>
> ---
>   target/i386/tcg/translate.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~