cpu-exec: remove outermost infinite loop

Reorganize the sigsetjmp so that the restart case falls through
to cpu_handle_exception and the execution loop.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

cpu-exec.c

@@ -624,25 +624,8 @@ int cpu_exec(CPUState *cpu)
      */
     init_delay_params(&sc, cpu);
 
-    for(;;) {
     /* prepare setjmp context for exception handling */
-        if (sigsetjmp(cpu->jmp_env, 0) == 0) {
-            /* if an exception is pending, we execute it here */
-            while (!cpu_handle_exception(cpu, &ret)) {
-                TranslationBlock *last_tb = NULL;
-                int tb_exit = 0;
-
-                while (!cpu_handle_interrupt(cpu, &last_tb)) {
-                    TranslationBlock *tb = tb_find(cpu, last_tb, tb_exit);
-                    cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit, &sc);
-                    /* Try to align the host and virtual clocks
-                       if the guest is in advance */
-                    align_clocks(&sc, cpu);
-                }
-            }
-            break;
-
-        } else {
+    if (sigsetjmp(cpu->jmp_env, 0) != 0) {
 #if defined(__clang__) || !QEMU_GNUC_PREREQ(4, 6)
         /* Some compilers wrongly smash all local variables after
          * siglongjmp. There were bug reports for gcc 4.5.0 and clang.
@@ -658,7 +641,20 @@ int cpu_exec(CPUState *cpu)
         cpu->can_do_io = 1;
         tb_lock_reset();
     }
-    } /* for(;;) */
+
+    /* if an exception is pending, we execute it here */
+    while (!cpu_handle_exception(cpu, &ret)) {
+        TranslationBlock *last_tb = NULL;
+        int tb_exit = 0;
+
+        while (!cpu_handle_interrupt(cpu, &last_tb)) {
+            TranslationBlock *tb = tb_find(cpu, last_tb, tb_exit);
+            cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit, &sc);
+            /* Try to align the host and virtual clocks
+               if the guest is in advance */
+            align_clocks(&sc, cpu);
+        }
+    }
 
     cc->cpu_exec_exit(cpu);
     rcu_read_unlock();