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From:   Anup Patel <anup@brainfault.org>
Date:   Thu, 14 Dec 2023 18:02:19 +0530
Message-ID: <CAAhSdy1L6smTUtjO1XJp2L=EfK-jYN9CS70h9nNa639ownKJBg@mail.gmail.com>
Subject: Re: [RFC 5/9] RISC-V: Add SBI PMU snapshot definitions
To:     Atish Patra <atishp@rivosinc.com>
Cc:     linux-kernel@vger.kernel.org,
        Alexandre Ghiti <alexghiti@rivosinc.com>,
        Andrew Jones <ajones@ventanamicro.com>,
        Atish Patra <atishp@atishpatra.org>,
        Conor Dooley <conor.dooley@microchip.com>,
        Guo Ren <guoren@kernel.org>, Icenowy Zheng <uwu@icenowy.me>,
        kvm-riscv@lists.infradead.org, kvm@vger.kernel.org,
        linux-riscv@lists.infradead.org,
        Mark Rutland <mark.rutland@arm.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Will Deacon <will@kernel.org>
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On Tue, Dec 5, 2023 at 8:13=E2=80=AFAM Atish Patra <atishp@rivosinc.com> wr=
ote:
>
> SBI PMU Snapshot function optimizes the number of traps to
> higher privilege mode by leveraging a shared memory between the S/VS-mode
> and the M/HS mode. Add the definitions for that extension
>
> Signed-off-by: Atish Patra <atishp@rivosinc.com>

LGTM.

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

Regards,
Anup

> ---
>  arch/riscv/include/asm/sbi.h | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
> index f3eeca79a02d..29821addb9b7 100644
> --- a/arch/riscv/include/asm/sbi.h
> +++ b/arch/riscv/include/asm/sbi.h
> @@ -122,6 +122,7 @@ enum sbi_ext_pmu_fid {
>         SBI_EXT_PMU_COUNTER_STOP,
>         SBI_EXT_PMU_COUNTER_FW_READ,
>         SBI_EXT_PMU_COUNTER_FW_READ_HI,
> +       SBI_EXT_PMU_SNAPSHOT_SET_SHMEM,
>  };
>
>  union sbi_pmu_ctr_info {
> @@ -138,6 +139,13 @@ union sbi_pmu_ctr_info {
>         };
>  };
>
> +/* Data structure to contain the pmu snapshot data */
> +struct riscv_pmu_snapshot_data {
> +       uint64_t ctr_overflow_mask;
> +       uint64_t ctr_values[64];
> +       uint64_t reserved[447];
> +};
> +
>  #define RISCV_PMU_RAW_EVENT_MASK GENMASK_ULL(47, 0)
>  #define RISCV_PMU_RAW_EVENT_IDX 0x20000
>
> @@ -234,9 +242,11 @@ enum sbi_pmu_ctr_type {
>
>  /* Flags defined for counter start function */
>  #define SBI_PMU_START_FLAG_SET_INIT_VALUE (1 << 0)
> +#define SBI_PMU_START_FLAG_INIT_FROM_SNAPSHOT (1 << 1)
>
>  /* Flags defined for counter stop function */
>  #define SBI_PMU_STOP_FLAG_RESET (1 << 0)
> +#define SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT (1 << 1)
>
>  enum sbi_ext_dbcn_fid {
>         SBI_EXT_DBCN_CONSOLE_WRITE =3D 0,
> --
> 2.34.1
>