Re: [PATCH] target/ppc: Implement gathering irq statistics

[BALATON Zoltan]

On Thu, 8 Jun 2023, Cédric Le Goater wrote:
> On 6/7/23 00:02, BALATON Zoltan wrote:
> > Count exceptions which can be queried with info irq monitor command.
>
> I don't think the TYPE_INTERRUPT_STATS_PROVIDER interface was designed
> for CPUs. It is more suitable for interrupt controllers.

True but:
- It works and provides useful statistics
- At least older PPC CPUs have embedded interrupt controller as the 
comment in cpu.h shows

so is this just a comment, question or you want something changed in this 
patch?

Regards,
BALATON Zoltan

> C.
>
> > Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
> > ---
> >   target/ppc/cpu.h         |  1 +
> >   target/ppc/cpu_init.c    | 18 ++++++++++++++++++
> >   target/ppc/excp_helper.c |  1 +
> >   3 files changed, 20 insertions(+)
> >
> > diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
> > index c7c2a5534c..d3a9197e02 100644
> > --- a/target/ppc/cpu.h
> > +++ b/target/ppc/cpu.h
> > @@ -1194,6 +1194,7 @@ struct CPUArchState {
> >       int error_code;
> >       uint32_t pending_interrupts;
> >   #if !defined(CONFIG_USER_ONLY)
> > +    uint64_t excp_stats[POWERPC_EXCP_NB];
> >       /*
> >        * This is the IRQ controller, which is implementation dependent and 
> > only
> >        * relevant when emulating a complete machine. Note that this isn't 
> > used
> > diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
> > index 05bf73296b..716f2b5d64 100644
> > --- a/target/ppc/cpu_init.c
> > +++ b/target/ppc/cpu_init.c
> > @@ -48,6 +48,7 @@
> >     #ifndef CONFIG_USER_ONLY
> >   #include "hw/boards.h"
> > +#include "hw/intc/intc.h"
> >   #endif
> >     /* #define PPC_DEBUG_SPR */
> > @@ -7123,6 +7124,16 @@ static bool ppc_cpu_is_big_endian(CPUState *cs)
> >       return !FIELD_EX64(env->msr, MSR, LE);
> >   }
> >   +static bool ppc_get_irq_stats(InterruptStatsProvider *obj,
> > +                              uint64_t **irq_counts, unsigned int 
> > *nb_irqs)
> > +{
> > +    CPUPPCState *env = &POWERPC_CPU(obj)->env;
> > +
> > +    *irq_counts = env->excp_stats;
> > +    *nb_irqs = ARRAY_SIZE(env->excp_stats);
> > +    return true;
> > +}
> > +
> >   #ifdef CONFIG_TCG
> >   static void ppc_cpu_exec_enter(CPUState *cs)
> >   {
> > @@ -7286,6 +7297,7 @@ static void ppc_cpu_class_init(ObjectClass *oc, void 
> > *data)
> >       cc->gdb_write_register = ppc_cpu_gdb_write_register;
> >   #ifndef CONFIG_USER_ONLY
> >       cc->sysemu_ops = &ppc_sysemu_ops;
> > +    INTERRUPT_STATS_PROVIDER_CLASS(oc)->get_statistics = 
> > ppc_get_irq_stats;
> >   #endif
> >         cc->gdb_num_core_regs = 71;
> > @@ -7323,6 +7335,12 @@ static const TypeInfo ppc_cpu_type_info = {
> >       .abstract = true,
> >       .class_size = sizeof(PowerPCCPUClass),
> >       .class_init = ppc_cpu_class_init,
> > +#ifndef CONFIG_USER_ONLY
> > +    .interfaces = (InterfaceInfo[]) {
> > +          { TYPE_INTERRUPT_STATS_PROVIDER },
> > +          { }
> > +    },
> > +#endif
> >   };
> >     #ifndef CONFIG_USER_ONLY
> > diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
> > index fea9221501..5480d9d2c7 100644
> > --- a/target/ppc/excp_helper.c
> > +++ b/target/ppc/excp_helper.c
> > @@ -1652,6 +1652,7 @@ static void powerpc_excp(PowerPCCPU *cpu, int excp)
> >       qemu_log_mask(CPU_LOG_INT, "Raise exception at " TARGET_FMT_lx
> >                     " => %s (%d) error=%02x\n", env->nip, 
> > powerpc_excp_name(excp),
> >                     excp, env->error_code);
> > +    env->excp_stats[excp]++;
> >         switch (env->excp_model) {
> >       case POWERPC_EXCP_40x: