The plugin API allows registration of callbacks for a variety of VCPU
related events, such as VCPU reset, idle and resume. In addition to
those events, we recently defined discontinuity events, which include
traps.

This change introduces a function to register callbacks for these
events. We define one distinct plugin event type for each type of
discontinuity, granting fine control to plugins in term of which events
they receive.

Reviewed-by: Pierrick Bouvier <pierrick.bouv...@linaro.org>
Signed-off-by: Julian Ganz <neither@nut.email>
---
 include/qemu/plugin-event.h |  3 +++
 include/qemu/qemu-plugin.h  | 16 ++++++++++++++++
 plugins/core.c              | 15 +++++++++++++++
 3 files changed, 34 insertions(+)

diff --git a/include/qemu/plugin-event.h b/include/qemu/plugin-event.h
index 7056d8427b..1100dae212 100644
--- a/include/qemu/plugin-event.h
+++ b/include/qemu/plugin-event.h
@@ -20,6 +20,9 @@ enum qemu_plugin_event {
     QEMU_PLUGIN_EV_VCPU_SYSCALL_RET,
     QEMU_PLUGIN_EV_FLUSH,
     QEMU_PLUGIN_EV_ATEXIT,
+    QEMU_PLUGIN_EV_VCPU_INTERRUPT,
+    QEMU_PLUGIN_EV_VCPU_EXCEPTION,
+    QEMU_PLUGIN_EV_VCPU_HOSTCALL,
     QEMU_PLUGIN_EV_MAX, /* total number of plugin events we support */
 };
 
diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
index 2e849bff0b..6d46d15e27 100644
--- a/include/qemu/qemu-plugin.h
+++ b/include/qemu/qemu-plugin.h
@@ -274,6 +274,22 @@ QEMU_PLUGIN_API
 void qemu_plugin_register_vcpu_resume_cb(qemu_plugin_id_t id,
                                          qemu_plugin_vcpu_simple_cb_t cb);
 
+/**
+ * qemu_plugin_register_vcpu_discon_cb() - register a discontinuity callback
+ * @id: plugin ID
+ * @type: types of discontinuities for which to call the callback
+ * @cb: callback function
+ *
+ * The @cb function is called every time a vCPU receives a discontinuity event
+ * of the specified type(s), after the vCPU was prepared to handle the event.
+ * Preparation entails updating the PC, usually to some interrupt handler or
+ * trap vector entry.
+ */
+QEMU_PLUGIN_API
+void qemu_plugin_register_vcpu_discon_cb(qemu_plugin_id_t id,
+                                         enum qemu_plugin_discon_type type,
+                                         qemu_plugin_vcpu_discon_cb_t cb);
+
 /** struct qemu_plugin_tb - Opaque handle for a translation block */
 struct qemu_plugin_tb;
 /** struct qemu_plugin_insn - Opaque handle for a translated instruction */
diff --git a/plugins/core.c b/plugins/core.c
index eb9281fe54..dc1f5cb4d8 100644
--- a/plugins/core.c
+++ b/plugins/core.c
@@ -551,6 +551,21 @@ void qemu_plugin_register_vcpu_resume_cb(qemu_plugin_id_t 
id,
     plugin_register_cb(id, QEMU_PLUGIN_EV_VCPU_RESUME, cb);
 }
 
+void qemu_plugin_register_vcpu_discon_cb(qemu_plugin_id_t id,
+                                         enum qemu_plugin_discon_type type,
+                                         qemu_plugin_vcpu_discon_cb_t cb)
+{
+    if (type & QEMU_PLUGIN_DISCON_INTERRUPT) {
+        plugin_register_cb(id, QEMU_PLUGIN_EV_VCPU_INTERRUPT, cb);
+    }
+    if (type & QEMU_PLUGIN_DISCON_EXCEPTION) {
+        plugin_register_cb(id, QEMU_PLUGIN_EV_VCPU_EXCEPTION, cb);
+    }
+    if (type & QEMU_PLUGIN_DISCON_HOSTCALL) {
+        plugin_register_cb(id, QEMU_PLUGIN_EV_VCPU_HOSTCALL, cb);
+    }
+}
+
 void qemu_plugin_register_flush_cb(qemu_plugin_id_t id,
                                    qemu_plugin_simple_cb_t cb)
 {
-- 
2.49.0


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