plugins/api: split out time control helpers

These are only usable in system mode where we control the timer. For
user-mode make them NOPs.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20250304222439.2035603-29-alex.bennee@linaro.org>

plugins/api-system.c

@@ -95,3 +95,37 @@ const char *qemu_plugin_hwaddr_device_name(const struct qemu_plugin_hwaddr *h)
         return g_intern_static_string("RAM");
     }
 }
+
+/*
+ * Time control
+ */
+static bool has_control;
+static Error *migration_blocker;
+
+const void *qemu_plugin_request_time_control(void)
+{
+    if (!has_control) {
+        has_control = true;
+        error_setg(&migration_blocker,
+                   "TCG plugin time control does not support migration");
+        migrate_add_blocker(&migration_blocker, NULL);
+        return &has_control;
+    }
+    return NULL;
+}
+
+static void advance_virtual_time__async(CPUState *cpu, run_on_cpu_data data)
+{
+    int64_t new_time = data.host_ulong;
+    qemu_clock_advance_virtual_time(new_time);
+}
+
+void qemu_plugin_update_ns(const void *handle, int64_t new_time)
+{
+    if (handle == &has_control) {
+        /* Need to execute out of cpu_exec, so bql can be locked. */
+        async_run_on_cpu(current_cpu,
+                         advance_virtual_time__async,
+                         RUN_ON_CPU_HOST_ULONG(new_time));
+    }
+}

plugins/api-user.c

@@ -12,6 +12,7 @@
 
 #include "qemu/osdep.h"
 #include "qemu/plugin.h"
+#include "exec/log.h"
 
 /*
  * Virtual Memory queries - these are all NOPs for user-mode which
@@ -38,3 +39,19 @@ const char *qemu_plugin_hwaddr_device_name(const struct qemu_plugin_hwaddr *h)
 {
     return g_intern_static_string("Invalid");
 }
+
+/*
+ * Time control - for user mode the only real time is wall clock time
+ * so realistically all you can do in user mode is slow down execution
+ * which doesn't require the ability to mess with the clock.
+ */
+
+const void *qemu_plugin_request_time_control(void)
+{
+    return NULL;
+}
+
+void qemu_plugin_update_ns(const void *handle, int64_t new_time)
+{
+    qemu_log_mask(LOG_UNIMP, "user-mode can't control time");
+}

plugins/api.c

@@ -526,44 +526,3 @@ uint64_t qemu_plugin_u64_sum(qemu_plugin_u64 entry)
     return total;
 }
 
-/*
- * Time control
- */
-static bool has_control;
-#ifdef CONFIG_SOFTMMU
-static Error *migration_blocker;
-#endif
-
-const void *qemu_plugin_request_time_control(void)
-{
-    if (!has_control) {
-        has_control = true;
-#ifdef CONFIG_SOFTMMU
-        error_setg(&migration_blocker,
-                   "TCG plugin time control does not support migration");
-        migrate_add_blocker(&migration_blocker, NULL);
-#endif
-        return &has_control;
-    }
-    return NULL;
-}
-
-#ifdef CONFIG_SOFTMMU
-static void advance_virtual_time__async(CPUState *cpu, run_on_cpu_data data)
-{
-    int64_t new_time = data.host_ulong;
-    qemu_clock_advance_virtual_time(new_time);
-}
-#endif
-
-void qemu_plugin_update_ns(const void *handle, int64_t new_time)
-{
-#ifdef CONFIG_SOFTMMU
-    if (handle == &has_control) {
-        /* Need to execute out of cpu_exec, so bql can be locked. */
-        async_run_on_cpu(current_cpu,
-                         advance_virtual_time__async,
-                         RUN_ON_CPU_HOST_ULONG(new_time));
-    }
-#endif
-}