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References: <20240415031131.23443-1-liangshenlin@eswincomputing.com> <20240415031131.23443-2-liangshenlin@eswincomputing.com>
In-Reply-To: <20240415031131.23443-2-liangshenlin@eswincomputing.com>
From: Anup Patel <anup@brainfault.org>
Date: Tue, 16 Apr 2024 09:14:51 +0530
Message-ID: <CAAhSdy1D9x4GJVrXJMzzqU-2iYLxduSHeRvxezmeBTQhgcruJQ@mail.gmail.com>
Subject: Re: [PATCH v2 1/2] RISCV: KVM: add tracepoints for entry and exit events
To: Shenlin Liang <liangshenlin@eswincomputing.com>
Cc: atishp@atishpatra.org, paul.walmsley@sifive.com, palmer@dabbelt.com, 
	aou@eecs.berkeley.edu, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, 
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, 
	peterz@infradead.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org, 
	mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, 
	irogers@google.com, adrian.hunter@intel.com, linux-perf-users@vger.kernel.org
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On Mon, Apr 15, 2024 at 8:45=E2=80=AFAM Shenlin Liang
<liangshenlin@eswincomputing.com> wrote:
>
> Like other architectures, RISCV KVM also needs to add these event
> tracepoints to count the number of times kvm guest entry/exit.
>
> Signed-off-by: Shenlin Liang <liangshenlin@eswincomputing.com>

LGTM.

Reviewed-by: Anup Patel <anup@brainfault.org>

Regards,
Anup

> ---
>  arch/riscv/kvm/trace.h | 67 ++++++++++++++++++++++++++++++++++++++++++
>  arch/riscv/kvm/vcpu.c  |  7 +++++
>  2 files changed, 74 insertions(+)
>  create mode 100644 arch/riscv/kvm/trace.h
>
> diff --git a/arch/riscv/kvm/trace.h b/arch/riscv/kvm/trace.h
> new file mode 100644
> index 000000000000..3d54175d805c
> --- /dev/null
> +++ b/arch/riscv/kvm/trace.h
> @@ -0,0 +1,67 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Tracepoints for RISC-V KVM
> + *
> + * Copyright 2024 Beijing ESWIN Computing Technology Co., Ltd.
> + *
> + */
> +#if !defined(_TRACE_KVM_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_KVM_H
> +
> +#include <linux/tracepoint.h>
> +
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM kvm
> +
> +TRACE_EVENT(kvm_entry,
> +       TP_PROTO(struct kvm_vcpu *vcpu),
> +       TP_ARGS(vcpu),
> +
> +       TP_STRUCT__entry(
> +               __field(unsigned long, pc)
> +       ),
> +
> +       TP_fast_assign(
> +               __entry->pc     =3D vcpu->arch.guest_context.sepc;
> +       ),
> +
> +       TP_printk("PC: 0x016%lx", __entry->pc)
> +);
> +
> +TRACE_EVENT(kvm_exit,
> +       TP_PROTO(struct kvm_cpu_trap *trap),
> +       TP_ARGS(trap),
> +
> +       TP_STRUCT__entry(
> +               __field(unsigned long, sepc)
> +               __field(unsigned long, scause)
> +               __field(unsigned long, stval)
> +               __field(unsigned long, htval)
> +               __field(unsigned long, htinst)
> +       ),
> +
> +       TP_fast_assign(
> +               __entry->sepc           =3D trap->sepc;
> +               __entry->scause         =3D trap->scause;
> +               __entry->stval          =3D trap->stval;
> +               __entry->htval          =3D trap->htval;
> +               __entry->htinst         =3D trap->htinst;
> +       ),
> +
> +       TP_printk("SEPC:0x%lx, SCAUSE:0x%lx, STVAL:0x%lx, HTVAL:0x%lx, HT=
INST:0x%lx",
> +               __entry->sepc,
> +               __entry->scause,
> +               __entry->stval,
> +               __entry->htval,
> +               __entry->htinst)
> +);
> +
> +#endif /* _TRACE_RSICV_KVM_H */
> +
> +#undef TRACE_INCLUDE_PATH
> +#define TRACE_INCLUDE_PATH .
> +#undef TRACE_INCLUDE_FILE
> +#define TRACE_INCLUDE_FILE trace
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index b5ca9f2e98ac..f4e27004ceb8 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -21,6 +21,9 @@
>  #include <asm/cacheflush.h>
>  #include <asm/kvm_vcpu_vector.h>
>
> +#define CREATE_TRACE_POINTS
> +#include "trace.h"
> +
>  const struct _kvm_stats_desc kvm_vcpu_stats_desc[] =3D {
>         KVM_GENERIC_VCPU_STATS(),
>         STATS_DESC_COUNTER(VCPU, ecall_exit_stat),
> @@ -782,6 +785,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>                  */
>                 kvm_riscv_local_tlb_sanitize(vcpu);
>
> +               trace_kvm_entry(vcpu);
> +
>                 guest_timing_enter_irqoff();
>
>                 kvm_riscv_vcpu_enter_exit(vcpu);
> @@ -820,6 +825,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>
>                 local_irq_enable();
>
> +               trace_kvm_exit(&trap);
> +
>                 preempt_enable();
>
>                 kvm_vcpu_srcu_read_lock(vcpu);
> --
> 2.37.2
>