plugins: add hooks for new discontinuity related callbacks

The plugin API allows registration of callbacks for a variety of VCPU
related events, such as VCPU reset, idle and resume. In addition, we
recently introduced API for registering callbacks for discontinuity
events, specifically for interrupts, exceptions and host calls.

This change introduces the corresponding hooks called from target
specific code inside qemu.

Signed-off-by: Julian Ganz <neither@nut.email>
Message-ID: <20251027110344.2289945-10-alex.bennee@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

include/qemu/plugin.h

@@ -161,6 +161,9 @@ void qemu_plugin_vcpu_exit_hook(CPUState *cpu);
 void qemu_plugin_tb_trans_cb(CPUState *cpu, struct qemu_plugin_tb *tb);
 void qemu_plugin_vcpu_idle_cb(CPUState *cpu);
 void qemu_plugin_vcpu_resume_cb(CPUState *cpu);
+void qemu_plugin_vcpu_interrupt_cb(CPUState *cpu, uint64_t from);
+void qemu_plugin_vcpu_exception_cb(CPUState *cpu, uint64_t from);
+void qemu_plugin_vcpu_hostcall_cb(CPUState *cpu, uint64_t from);
 void
 qemu_plugin_vcpu_syscall(CPUState *cpu, int64_t num, uint64_t a1,
                          uint64_t a2, uint64_t a3, uint64_t a4, uint64_t a5,
@@ -258,6 +261,15 @@ static inline void qemu_plugin_vcpu_idle_cb(CPUState *cpu)
 static inline void qemu_plugin_vcpu_resume_cb(CPUState *cpu)
 { }
 
+static inline void qemu_plugin_vcpu_interrupt_cb(CPUState *cpu, uint64_t from)
+{ }
+
+static inline void qemu_plugin_vcpu_exception_cb(CPUState *cpu, uint64_t from)
+{ }
+
+static inline void qemu_plugin_vcpu_hostcall_cb(CPUState *cpu, uint64_t from)
+{ }
+
 static inline void
 qemu_plugin_vcpu_syscall(CPUState *cpu, int64_t num, uint64_t a1, uint64_t a2,
                          uint64_t a3, uint64_t a4, uint64_t a5, uint64_t a6,

plugins/core.c

@@ -105,6 +105,30 @@ static void plugin_vcpu_cb__simple(CPUState *cpu, enum qemu_plugin_event ev)
     }
 }
 
+/*
+ * Disable CFI checks.
+ * The callback function has been loaded from an external library so we do not
+ * have type information
+ */
+QEMU_DISABLE_CFI
+static void plugin_vcpu_cb__discon(CPUState *cpu,
+                                   enum qemu_plugin_event ev,
+                                   enum qemu_plugin_discon_type type,
+                                   uint64_t from)
+{
+    struct qemu_plugin_cb *cb, *next;
+    uint64_t to = cpu->cc->get_pc(cpu);
+
+    if (cpu->cpu_index < plugin.num_vcpus) {
+        /* iterate safely; plugins might uninstall themselves at any time */
+        QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
+            qemu_plugin_vcpu_discon_cb_t func = cb->f.vcpu_discon;
+
+            func(cb->ctx->id, cpu->cpu_index, type, from, to);
+        }
+    }
+}
+
 /*
  * Disable CFI checks.
  * The callback function has been loaded from an external library so we do not
@@ -557,6 +581,24 @@ void qemu_plugin_vcpu_resume_cb(CPUState *cpu)
     }
 }
 
+void qemu_plugin_vcpu_interrupt_cb(CPUState *cpu, uint64_t from)
+{
+    plugin_vcpu_cb__discon(cpu, QEMU_PLUGIN_EV_VCPU_INTERRUPT,
+                           QEMU_PLUGIN_DISCON_INTERRUPT, from);
+}
+
+void qemu_plugin_vcpu_exception_cb(CPUState *cpu, uint64_t from)
+{
+    plugin_vcpu_cb__discon(cpu, QEMU_PLUGIN_EV_VCPU_EXCEPTION,
+                           QEMU_PLUGIN_DISCON_EXCEPTION, from);
+}
+
+void qemu_plugin_vcpu_hostcall_cb(CPUState *cpu, uint64_t from)
+{
+    plugin_vcpu_cb__discon(cpu, QEMU_PLUGIN_EV_VCPU_HOSTCALL,
+                           QEMU_PLUGIN_DISCON_HOSTCALL, from);
+}
+
 void qemu_plugin_register_vcpu_idle_cb(qemu_plugin_id_t id,
                                        qemu_plugin_vcpu_simple_cb_t cb)
 {