Re: [RFC PATCH v3 03/11] plugins: add hooks for new discontinuity related 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, 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.
> ---
>   include/qemu/plugin.h | 12 ++++++++++
>   plugins/core.c        | 52 +++++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 64 insertions(+)
> 
> diff --git a/include/qemu/plugin.h b/include/qemu/plugin.h
> index 27a176b631..3de9cb3fe4 100644
> --- a/include/qemu/plugin.h
> +++ b/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, uint64_t to);
> +void qemu_plugin_vcpu_exception_cb(CPUState *cpu, uint64_t from, uint64_t to);
> +void qemu_plugin_vcpu_hostcall_cb(CPUState *cpu, uint64_t from, uint64_t to);
>   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,
> @@ -243,6 +246,15 @@ static inline void qemu_plugin_vcpu_idle_cb(CPUState *cpu)
>   static inline void qemu_plugin_vcpu_resume_cb(CPUState *cpu)
>   { }
>   
> +void qemu_plugin_vcpu_interrupt_cb(CPUState *cpu, uint64_t from, uint64_t to)
> +{ }
> +
> +void qemu_plugin_vcpu_exception_cb(CPUState *cpu, uint64_t from, uint64_t to)
> +{ }
> +
> +void qemu_plugin_vcpu_hostcall_cb(CPUState *cpu, uint64_t from, uint64_t to)
> +{ }
> +
>   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,
> diff --git a/plugins/core.c b/plugins/core.c
> index a89a4a0315..2c9637334f 100644
> --- a/plugins/core.c
> +++ b/plugins/core.c
> @@ -112,6 +112,43 @@ 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_discon_type type,
> +                                   uint64_t from, uint64_t to)
> +{
> +    struct qemu_plugin_cb *cb, *next;
> +    enum qemu_plugin_event ev;
> +
> +    if (cpu->cpu_index < plugin.num_vcpus) {
> +        switch (type) {
> +        case QEMU_PLUGIN_DISCON_INTERRUPT:
> +            ev = QEMU_PLUGIN_EV_VCPU_INTERRUPT;
> +            break;
> +        case QEMU_PLUGIN_DISCON_EXCEPTION:
> +            ev = QEMU_PLUGIN_EV_VCPU_EXCEPTION;
> +            break;
> +        case QEMU_PLUGIN_DISCON_HOSTCALL:
> +            ev = QEMU_PLUGIN_EV_VCPU_HOSTCALL;
> +            break;
> +        default:
> +            g_assert_not_reached();
> +        }
> +
> +        /* 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
> @@ -547,6 +584,21 @@ void qemu_plugin_vcpu_resume_cb(CPUState *cpu)
>       }
>   }
>   
> +void qemu_plugin_vcpu_interrupt_cb(CPUState *cpu, uint64_t from, uint64_t to)
> +{
> +    plugin_vcpu_cb__discon(cpu, QEMU_PLUGIN_DISCON_INTERRUPT, from, to);
> +}
> +
> +void qemu_plugin_vcpu_exception_cb(CPUState *cpu, uint64_t from, uint64_t to)
> +{
> +    plugin_vcpu_cb__discon(cpu, QEMU_PLUGIN_DISCON_EXCEPTION, from, to);
> +}
> +
> +void qemu_plugin_vcpu_hostcall_cb(CPUState *cpu, uint64_t from, uint64_t to)
> +{
> +    plugin_vcpu_cb__discon(cpu, QEMU_PLUGIN_DISCON_HOSTCALL, from, to);
> +}
> +
>   void qemu_plugin_register_vcpu_idle_cb(qemu_plugin_id_t id,
>                                          qemu_plugin_vcpu_simple_cb_t cb)
>   {

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