Re: [PATCH v10 05/12] target/riscv: Implement mcountinhibit CSR

[Weiwei Li <liweiwei@iscas.ac.cn>]

在 2022/6/21 上午7:15, Atish Patra 写道:
> From: Atish Patra <atish.patra@wdc.com>
>
> As per the privilege specification v1.11, mcountinhibit allows to start/stop
> a pmu counter selectively.
>
> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
> Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Signed-off-by: Atish Patra <atishp@rivosinc.com>
> ---
>   target/riscv/cpu.h      |  2 ++
>   target/riscv/cpu_bits.h |  4 ++++
>   target/riscv/csr.c      | 25 +++++++++++++++++++++++++
>   target/riscv/machine.c  |  1 +
>   4 files changed, 32 insertions(+)
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index ffee54ea5c27..0a916db9f614 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -275,6 +275,8 @@ struct CPUArchState {
>       target_ulong scounteren;
>       target_ulong mcounteren;
>   
> +    target_ulong mcountinhibit;
> +
>       target_ulong sscratch;
>       target_ulong mscratch;
>   
> diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> index 4d04b20d064e..b3f7fa713000 100644
> --- a/target/riscv/cpu_bits.h
> +++ b/target/riscv/cpu_bits.h
> @@ -367,6 +367,10 @@
>   #define CSR_MHPMCOUNTER29   0xb1d
>   #define CSR_MHPMCOUNTER30   0xb1e
>   #define CSR_MHPMCOUNTER31   0xb1f
> +
> +/* Machine counter-inhibit register */
> +#define CSR_MCOUNTINHIBIT   0x320
> +
>   #define CSR_MHPMEVENT3      0x323
>   #define CSR_MHPMEVENT4      0x324
>   #define CSR_MHPMEVENT5      0x325
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index b4a8e15f498f..94d39a4ce1c5 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -1475,6 +1475,28 @@ static RISCVException write_mtvec(CPURISCVState *env, int csrno,
>       return RISCV_EXCP_NONE;
>   }
>   
> +static RISCVException read_mcountinhibit(CPURISCVState *env, int csrno,
> +                                         target_ulong *val)
> +{
> +    if (env->priv_ver < PRIV_VERSION_1_11_0) {
> +        return RISCV_EXCP_ILLEGAL_INST;
> +    }
> +

This seems can be done by add  .min_priv_ver=PRIV_VERSION_1_11_0 in 
csr_ops table.

Regards,

Weiwei Li

> +    *val = env->mcountinhibit;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException write_mcountinhibit(CPURISCVState *env, int csrno,
> +                                          target_ulong val)
> +{
> +    if (env->priv_ver < PRIV_VERSION_1_11_0) {
> +        return RISCV_EXCP_ILLEGAL_INST;
> +    }
> +
> +    env->mcountinhibit = val;
> +    return RISCV_EXCP_NONE;
> +}
> +
>   static RISCVException read_mcounteren(CPURISCVState *env, int csrno,
>                                         target_ulong *val)
>   {
> @@ -3745,6 +3767,9 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
>       [CSR_MHPMCOUNTER30]  = { "mhpmcounter30",  mctr,   read_zero },
>       [CSR_MHPMCOUNTER31]  = { "mhpmcounter31",  mctr,   read_zero },
>   
> +    [CSR_MCOUNTINHIBIT]  = { "mcountinhibit",   any,    read_mcountinhibit,
> +                                                       write_mcountinhibit },
> +
>       [CSR_MHPMEVENT3]     = { "mhpmevent3",     any,    read_zero },
>       [CSR_MHPMEVENT4]     = { "mhpmevent4",     any,    read_zero },
>       [CSR_MHPMEVENT5]     = { "mhpmevent5",     any,    read_zero },
> diff --git a/target/riscv/machine.c b/target/riscv/machine.c
> index 2a437b29a1ce..87cd55bfd3a7 100644
> --- a/target/riscv/machine.c
> +++ b/target/riscv/machine.c
> @@ -330,6 +330,7 @@ const VMStateDescription vmstate_riscv_cpu = {
>           VMSTATE_UINTTL(env.siselect, RISCVCPU),
>           VMSTATE_UINTTL(env.scounteren, RISCVCPU),
>           VMSTATE_UINTTL(env.mcounteren, RISCVCPU),
> +        VMSTATE_UINTTL(env.mcountinhibit, RISCVCPU),
>           VMSTATE_UINTTL(env.sscratch, RISCVCPU),
>           VMSTATE_UINTTL(env.mscratch, RISCVCPU),
>           VMSTATE_UINT64(env.mfromhost, RISCVCPU),