Re: [RFC PATCH v3 02/11] plugins: add API for registering discontinuity callbacks

[Pierrick Bouvier <pierrick.bouvier@linaro.org>]

On 12/2/24 11:26, Julian Ganz wrote:
> 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.
> ---
>   include/qemu/plugin-event.h |  3 +++
>   include/qemu/qemu-plugin.h  | 15 +++++++++++++++
>   plugins/core.c              | 15 +++++++++++++++
>   3 files changed, 33 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 9c67374b7e..f998a465e5 100644
> --- a/include/qemu/qemu-plugin.h
> +++ b/include/qemu/qemu-plugin.h
> @@ -273,6 +273,21 @@ 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
> + * @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 usually entails updating the PC 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 bb105e8e68..a89a4a0315 100644
> --- a/plugins/core.c
> +++ b/plugins/core.c
> @@ -559,6 +559,21 @@ 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)
>   {

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>