Re: [PATCH 4/4] cpu-exec: assert that plugin_mem_cbs is NULL after execution

[Emilio Cota]

On Mon, Jan 09, 2023 at 13:52:36 +0000, Alex Bennée wrote:
> Emilio Cota <cota@braap.org> writes:
> > --- a/accel/tcg/cpu-exec.c
> > +++ b/accel/tcg/cpu-exec.c
> > @@ -504,6 +504,7 @@ static void cpu_exec_exit(CPUState *cpu)
> >      if (cc->tcg_ops->cpu_exec_exit) {
> >          cc->tcg_ops->cpu_exec_exit(cpu);
> >      }
> > +    g_assert(cpu->plugin_mem_cbs == NULL);
(snip)
> > +            g_assert(cpu->plugin_mem_cbs == NULL);
> 
> Can we assert this anywhere else? This fails with non-plugin enabled
> builds:
> 
>   https://gitlab.com/stsquad/qemu/-/pipelines/741478109/failures

Ouch. Fixed in v2 with:

diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index de4ba6e23c..0010b2d31e 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -504,7 +504,7 @@ static void cpu_exec_exit(CPUState *cpu)
     if (cc->tcg_ops->cpu_exec_exit) {
         cc->tcg_ops->cpu_exec_exit(cpu);
     }
-    g_assert(cpu->plugin_mem_cbs == NULL);
+    QEMU_PLUGIN_ASSERT(cpu->plugin_mem_cbs == NULL);
 }
 
 void cpu_exec_step_atomic(CPUState *cpu)
@@ -1032,7 +1032,7 @@ int cpu_exec(CPUState *cpu)
 
             cpu_loop_exec_tb(cpu, tb, pc, &last_tb, &tb_exit);
 
-            g_assert(cpu->plugin_mem_cbs == NULL);
+            QEMU_PLUGIN_ASSERT(cpu->plugin_mem_cbs == NULL);
             /* Try to align the host and virtual clocks
                if the guest is in advance */
             align_clocks(&sc, cpu);
diff --git a/include/qemu/plugin.h b/include/qemu/plugin.h
index e0ebedef84..fb338ba576 100644
--- a/include/qemu/plugin.h
+++ b/include/qemu/plugin.h
@@ -59,6 +59,8 @@ get_plugin_meminfo_rw(qemu_plugin_meminfo_t i)
 #ifdef CONFIG_PLUGIN
 extern QemuOptsList qemu_plugin_opts;
 
+#define QEMU_PLUGIN_ASSERT(cond) g_assert(cond)
+
 static inline void qemu_plugin_add_opts(void)
 {
     qemu_add_opts(&qemu_plugin_opts);
@@ -250,6 +252,8 @@ void qemu_plugin_user_postfork(bool is_child);
 
 #else /* !CONFIG_PLUGIN */
 
+#define QEMU_PLUGIN_ASSERT(cond)
+
 static inline void qemu_plugin_add_opts(void)
 { }

Thanks,
                Emilio