Re: [PATCH v6 01/10] target/ppc: introduce PMUEventType and PMU overflow timers

[David Gibson]

On Mon, Nov 08, 2021 at 07:50:38PM -0300, Daniel Henrique Barboza wrote:
> This patch starts an IBM Power8+ compatible PMU implementation by adding
> the representation of PMU events that we are going to sample,
> PMUEventType. This enum represents a Perf event that is being sampled by
> a specific counter 'sprn'. Events that aren't available (i.e. no event
> was set in MMCR1) will be of type 'PMU_EVENT_INVALID'. Other types added
> in this patch are PMU_EVENT_CYCLES and PMU_EVENT_INSTRUCTIONS. More
> types will be added later on.
> 
> Let's also add the required PMU cycle overflow timers. They will be used
> to trigger cycle overflows when cycle events are being sampled. This
> timer will call cpu_ppc_pmu_timer_cb(), which in turn calls
> fire_PMC_interrupt().  Both functions are stubs that will be implemented
> later on when EBB support is added.
> 
> Two new helper files are created to host this new logic.
> cpu_ppc_pmu_init() will init all overflow timers during CPU init time.
> 
> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
> ---
>  hw/ppc/spapr_cpu_core.c |  6 +++++
>  target/ppc/cpu.h        | 15 +++++++++++
>  target/ppc/meson.build  |  1 +
>  target/ppc/power8-pmu.c | 57 +++++++++++++++++++++++++++++++++++++++++
>  target/ppc/power8-pmu.h | 25 ++++++++++++++++++
>  5 files changed, 104 insertions(+)
>  create mode 100644 target/ppc/power8-pmu.c
>  create mode 100644 target/ppc/power8-pmu.h
> 
> diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> index 58e7341cb7..45abffd891 100644
> --- a/hw/ppc/spapr_cpu_core.c
> +++ b/hw/ppc/spapr_cpu_core.c
> @@ -20,6 +20,7 @@
>  #include "target/ppc/kvm_ppc.h"
>  #include "hw/ppc/ppc.h"
>  #include "target/ppc/mmu-hash64.h"
> +#include "target/ppc/power8-pmu.h"
>  #include "sysemu/numa.h"
>  #include "sysemu/reset.h"
>  #include "sysemu/hw_accel.h"
> @@ -266,6 +267,11 @@ static bool spapr_realize_vcpu(PowerPCCPU *cpu, 
> SpaprMachineState *spapr,
>          return false;
>      }
>  
> +    /* Init PMU interrupt timer (TCG only) */
> +    if (!kvm_enabled()) {
> +        cpu_ppc_pmu_init(env);

AFAIK, the PMU should be universal in the cpu model, not tied to spapr
specifically, so this looks like the wrong place to trigger the
initialization.

> +    }
> +
>      if (!sc->pre_3_0_migration) {
>          vmstate_register(NULL, cs->cpu_index, &vmstate_spapr_cpu_state,
>                           cpu->machine_data);
> diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
> index e946da5f3a..04ef9300af 100644
> --- a/target/ppc/cpu.h
> +++ b/target/ppc/cpu.h
> @@ -296,6 +296,15 @@ typedef struct ppc_v3_pate_t {
>      uint64_t dw1;
>  } ppc_v3_pate_t;
>  
> +/* PMU related structs and defines */
> +#define PMU_COUNTERS_NUM 6
> +#define PMU_TIMERS_NUM   (PMU_COUNTERS_NUM - 1) /* PMC5 doesn't count cycles 
> */
> +typedef enum {
> +    PMU_EVENT_INVALID = 0,
> +    PMU_EVENT_CYCLES,
> +    PMU_EVENT_INSTRUCTIONS,
> +} PMUEventType;
> +
>  
> /*****************************************************************************/
>  /* Machine state register bits definition                                    
> */
>  #define MSR_SF   63 /* Sixty-four-bit mode                            hflags 
> */
> @@ -1191,6 +1200,12 @@ struct CPUPPCState {
>      uint32_t tm_vscr;
>      uint64_t tm_dscr;
>      uint64_t tm_tar;
> +
> +    /*
> +     * Timers used to fire performance monitor alerts
> +     * when counting cycles.
> +     */
> +    QEMUTimer *pmu_cyc_overflow_timers[PMU_TIMERS_NUM];
>  };
>  
>  #define SET_FIT_PERIOD(a_, b_, c_, d_)          \
> diff --git a/target/ppc/meson.build b/target/ppc/meson.build
> index b85f295703..a49a8911e0 100644
> --- a/target/ppc/meson.build
> +++ b/target/ppc/meson.build
> @@ -51,6 +51,7 @@ ppc_softmmu_ss.add(when: 'TARGET_PPC64', if_true: files(
>    'mmu-book3s-v3.c',
>    'mmu-hash64.c',
>    'mmu-radix64.c',
> +  'power8-pmu.c',
>  ))
>  
>  target_arch += {'ppc': ppc_ss}
> diff --git a/target/ppc/power8-pmu.c b/target/ppc/power8-pmu.c
> new file mode 100644
> index 0000000000..3c2f73896f
> --- /dev/null
> +++ b/target/ppc/power8-pmu.c
> @@ -0,0 +1,57 @@
> +/*
> + * PMU emulation helpers for TCG IBM POWER chips
> + *
> + *  Copyright IBM Corp. 2021
> + *
> + * Authors:
> + *  Daniel Henrique Barboza      <danielhb413@gmail.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + */
> +
> +#include "qemu/osdep.h"
> +
> +#include "power8-pmu.h"
> +#include "cpu.h"
> +#include "helper_regs.h"
> +#include "exec/exec-all.h"
> +#include "exec/helper-proto.h"
> +#include "qemu/error-report.h"
> +#include "qemu/main-loop.h"
> +#include "hw/ppc/ppc.h"
> +
> +#if defined(TARGET_PPC64) && !defined(CONFIG_USER_ONLY)
> +
> +static void fire_PMC_interrupt(PowerPCCPU *cpu)
> +{
> +    CPUPPCState *env = &cpu->env;
> +
> +    if (!(env->spr[SPR_POWER_MMCR0] & MMCR0_EBE)) {
> +        return;
> +    }
> +
> +    /* PMC interrupt not implemented yet */
> +    return;
> +}
> +
> +static void cpu_ppc_pmu_timer_cb(void *opaque)
> +{
> +    PowerPCCPU *cpu = opaque;
> +
> +    fire_PMC_interrupt(cpu);
> +}
> +
> +void cpu_ppc_pmu_init(CPUPPCState *env)
> +{
> +    PowerPCCPU *cpu = env_archcpu(env);
> +    int i;
> +
> +    for (i = 0; i < PMU_TIMERS_NUM; i++) {
> +        env->pmu_cyc_overflow_timers[i] = timer_new_ns(QEMU_CLOCK_VIRTUAL,
> +                                                       &cpu_ppc_pmu_timer_cb,
> +                                                       cpu);
> +    }
> +}
> +
> +#endif /* defined(TARGET_PPC64) && !defined(CONFIG_USER_ONLY) */
> diff --git a/target/ppc/power8-pmu.h b/target/ppc/power8-pmu.h
> new file mode 100644
> index 0000000000..49a813a443
> --- /dev/null
> +++ b/target/ppc/power8-pmu.h
> @@ -0,0 +1,25 @@
> +/*
> + * PMU emulation helpers for TCG IBM POWER chips
> + *
> + *  Copyright IBM Corp. 2021
> + *
> + * Authors:
> + *  Daniel Henrique Barboza      <danielhb413@gmail.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + */
> +
> +#ifndef POWER8_PMU
> +#define POWER8_PMU
> +
> +#include "qemu/osdep.h"
> +#include "cpu.h"
> +#include "exec/exec-all.h"
> +#include "exec/helper-proto.h"
> +#include "qemu/error-report.h"
> +#include "qemu/main-loop.h"
> +
> +void cpu_ppc_pmu_init(CPUPPCState *env);
> +
> +#endif

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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