cpu-exec: unify icount_decr and tcg_exit_req
The icount interrupt flag and tcg_exit_req serve almost the same
purpose, let's make them completely the same.
The former TB_EXIT_REQUESTED and TB_EXIT_ICOUNT_EXPIRED cases are
unified, since we can distinguish them from the value of the
interrupt flag.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/cpu-exec.c b/cpu-exec.c
index 142a586..8f094c8 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -185,12 +185,6 @@
cc->set_pc(cpu, last_tb->pc);
}
}
- if (tb_exit == TB_EXIT_REQUESTED) {
- /* We were asked to stop executing TBs (probably a pending
- * interrupt. We've now stopped, so clear the flag.
- */
- atomic_set(&cpu->tcg_exit_req, 0);
- }
return ret;
}
@@ -537,6 +531,7 @@
SyncClocks *sc)
{
uintptr_t ret;
+ int32_t insns_left;
if (unlikely(atomic_read(&cpu->exit_request))) {
return;
@@ -546,8 +541,15 @@
ret = cpu_tb_exec(cpu, tb);
tb = (TranslationBlock *)(ret & ~TB_EXIT_MASK);
*tb_exit = ret & TB_EXIT_MASK;
- switch (*tb_exit) {
- case TB_EXIT_REQUESTED:
+ if (*tb_exit != TB_EXIT_REQUESTED) {
+ *last_tb = tb;
+ return;
+ }
+
+ *last_tb = NULL;
+ insns_left = atomic_read(&cpu->icount_decr.u32);
+ atomic_set(&cpu->icount_decr.u16.high, 0);
+ if (insns_left < 0) {
/* Something asked us to stop executing
* chained TBs; just continue round the main
* loop. Whatever requested the exit will also
@@ -559,38 +561,30 @@
* or cpu->interrupt_request.
*/
smp_mb();
- *last_tb = NULL;
- break;
- case TB_EXIT_ICOUNT_EXPIRED:
- {
- /* Instruction counter expired. */
-#ifdef CONFIG_USER_ONLY
- abort();
-#else
- int insns_left = cpu->icount_decr.u32;
- *last_tb = NULL;
- if (cpu->icount_extra && insns_left >= 0) {
- /* Refill decrementer and continue execution. */
- cpu->icount_extra += insns_left;
- insns_left = MIN(0xffff, cpu->icount_extra);
- cpu->icount_extra -= insns_left;
- cpu->icount_decr.u16.low = insns_left;
- } else {
- if (insns_left > 0) {
- /* Execute remaining instructions. */
- cpu_exec_nocache(cpu, insns_left, tb, false);
- align_clocks(sc, cpu);
- }
- cpu->exception_index = EXCP_INTERRUPT;
- cpu_loop_exit(cpu);
+ return;
+ }
+
+ /* Instruction counter expired. */
+ assert(use_icount);
+#ifndef CONFIG_USER_ONLY
+ if (cpu->icount_extra) {
+ /* Refill decrementer and continue execution. */
+ cpu->icount_extra += insns_left;
+ insns_left = MIN(0xffff, cpu->icount_extra);
+ cpu->icount_extra -= insns_left;
+ cpu->icount_decr.u16.low = insns_left;
+ } else {
+ /* Execute any remaining instructions, then let the main loop
+ * handle the next event.
+ */
+ if (insns_left > 0) {
+ cpu_exec_nocache(cpu, insns_left, tb, false);
+ align_clocks(sc, cpu);
}
- break;
+ cpu->exception_index = EXCP_INTERRUPT;
+ cpu_loop_exit(cpu);
+ }
#endif
- }
- default:
- *last_tb = tb;
- break;
- }
}
/* main execution loop */