STI will trigger a singlestep exception even if it has inhibit-IRQ
behavior. Do not suppress single-step for all IRQ-inhibiting
instructions, instead special case MOV SS and POP SS.
Cc: qemu-sta...@nongnu.org
Fixes: f0f0136abba ("target/i386: no single-step exception after MOV or POP
SS", 2024-05-25)
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
target/i386/tcg/translate.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index a4e935b043b..ed43c95c1d9 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -2047,11 +2047,15 @@ static void gen_movl_seg(DisasContext *s, X86Seg
seg_reg, TCGv src, bool inhibit
* stop as a special handling must be done to disable hardware
* interrupts for the next instruction.
*
+ * This is the last instruction, so it's okay to overwrite
+ * HF_TF_MASK; the next TB will start with the flag set.
+ *
* DISAS_EOB_INHIBIT_IRQ is a superset of DISAS_EOB_NEXT which
* might have been set above.
*/
if (inhibit_irq) {
s->base.is_jmp = DISAS_EOB_INHIBIT_IRQ;
+ s->flags &= ~HF_TF_MASK;
}
}
@@ -2302,7 +2306,7 @@ gen_eob(DisasContext *s, int mode)
if (mode == DISAS_EOB_RECHECK_TF) {
gen_helper_rechecking_single_step(tcg_env);
tcg_gen_exit_tb(NULL, 0);
- } else if ((s->flags & HF_TF_MASK) && mode != DISAS_EOB_INHIBIT_IRQ) {
+ } else if (s->flags & HF_TF_MASK) {
gen_helper_single_step(tcg_env);
} else if (mode == DISAS_JUMP &&
/* give irqs a chance to happen */
--
2.49.0
