On 6/4/24 02:18, Paolo Bonzini wrote:
PAUSE uses DISAS_NORETURN because the corresponding helper
calls cpu_loop_exit(). However, while HLT clear HF_INHIBIT_IRQ_MASK
to correctly handle "STI; HLT", the same is missing from PAUSE.
And also gen_eob() clears HF_RF_MASK and synthesizes a #DB exception
if single-step is active; none of this is done by HLT and PAUSE.
Start fixing PAUSE, HLT will follow.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
target/i386/tcg/misc_helper.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/target/i386/tcg/misc_helper.c b/target/i386/tcg/misc_helper.c
index 8316d42ffcd..ed4cda8001e 100644
--- a/target/i386/tcg/misc_helper.c
+++ b/target/i386/tcg/misc_helper.c
@@ -92,6 +92,10 @@ G_NORETURN void helper_pause(CPUX86State *env)
{
CPUState *cs = env_cpu(env);
+ /* Do gen_eob() tasks before going back to the main loop. */
+ do_end_instruction(env);
+ helper_rechecking_single_step(env);
+
/* Just let another CPU run. */
cs->exception_index = EXCP_INTERRUPT;
cpu_loop_exit(cs);
Perhaps it would be better to do
void helper_cpu_exit(CPUX86State *env)
{
cpu_exit(env_cpu(env));
}
static void gen_PAUSE(...)
{
helper_cpu_exit(tcg_env);
s->base.is_jmp = DISAS_EOB_NEXT;
}
to keep from replicating gen_eob?
Anyway, this is correct, so,
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>