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Re: [PATCH v10 04/12] target/riscv: pmu: Make number of counters configu


From: Atish Patra
Subject: Re: [PATCH v10 04/12] target/riscv: pmu: Make number of counters configurable
Date: Tue, 26 Jul 2022 15:19:51 -0700

On Tue, Jul 5, 2022 at 1:20 AM Weiwei Li <liweiwei@iscas.ac.cn> wrote:
>
>
> 在 2022/7/5 下午3:51, Atish Kumar Patra 写道:
> > On Mon, Jul 4, 2022 at 5:38 PM Weiwei Li <liweiwei@iscas.ac.cn> wrote:
> >>
> >> 在 2022/7/4 下午11:26, Weiwei Li 写道:
> >>> 在 2022/6/21 上午7:15, Atish Patra 写道:
> >>>> The RISC-V privilege specification provides flexibility to implement
> >>>> any number of counters from 29 programmable counters. However, the QEMU
> >>>> implements all the counters.
> >>>>
> >>>> Make it configurable through pmu config parameter which now will
> >>>> indicate
> >>>> how many programmable counters should be implemented by the cpu.
> >>>>
> >>>> 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.c |  3 +-
> >>>>    target/riscv/cpu.h |  2 +-
> >>>>    target/riscv/csr.c | 94 ++++++++++++++++++++++++++++++----------------
> >>>>    3 files changed, 63 insertions(+), 36 deletions(-)
> >>>>
> >>>> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> >>>> index 1b57b3c43980..d12c6dc630ca 100644
> >>>> --- a/target/riscv/cpu.c
> >>>> +++ b/target/riscv/cpu.c
> >>>> @@ -851,7 +851,6 @@ static void riscv_cpu_init(Object *obj)
> >>>>    {
> >>>>        RISCVCPU *cpu = RISCV_CPU(obj);
> >>>>    -    cpu->cfg.ext_pmu = true;
> >>>>        cpu->cfg.ext_ifencei = true;
> >>>>        cpu->cfg.ext_icsr = true;
> >>>>        cpu->cfg.mmu = true;
> >>>> @@ -879,7 +878,7 @@ static Property riscv_cpu_extensions[] = {
> >>>>        DEFINE_PROP_BOOL("u", RISCVCPU, cfg.ext_u, true),
> >>>>        DEFINE_PROP_BOOL("v", RISCVCPU, cfg.ext_v, false),
> >>>>        DEFINE_PROP_BOOL("h", RISCVCPU, cfg.ext_h, true),
> >>>> -    DEFINE_PROP_BOOL("pmu", RISCVCPU, cfg.ext_pmu, true),
> >>>> +    DEFINE_PROP_UINT8("pmu-num", RISCVCPU, cfg.pmu_num, 16),
> >>> I think It's better to add  a check on cfg.pmu_num to  <= 29.
> >>>
> >> OK, I find this check in the following patch.
> >>>>        DEFINE_PROP_BOOL("Zifencei", RISCVCPU, cfg.ext_ifencei, true),
> >>>>        DEFINE_PROP_BOOL("Zicsr", RISCVCPU, cfg.ext_icsr, true),
> >>>>        DEFINE_PROP_BOOL("Zfh", RISCVCPU, cfg.ext_zfh, false),
> >>>> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> >>>> index 252c30a55d78..ffee54ea5c27 100644
> >>>> --- a/target/riscv/cpu.h
> >>>> +++ b/target/riscv/cpu.h
> >>>> @@ -397,7 +397,6 @@ struct RISCVCPUConfig {
> >>>>        bool ext_zksed;
> >>>>        bool ext_zksh;
> >>>>        bool ext_zkt;
> >>>> -    bool ext_pmu;
> >>>>        bool ext_ifencei;
> >>>>        bool ext_icsr;
> >>>>        bool ext_svinval;
> >>>> @@ -421,6 +420,7 @@ struct RISCVCPUConfig {
> >>>>        /* Vendor-specific custom extensions */
> >>>>        bool ext_XVentanaCondOps;
> >>>>    +    uint8_t pmu_num;
> >>>>        char *priv_spec;
> >>>>        char *user_spec;
> >>>>        char *bext_spec;
> >>>> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> >>>> index 0ca05c77883c..b4a8e15f498f 100644
> >>>> --- a/target/riscv/csr.c
> >>>> +++ b/target/riscv/csr.c
> >>>> @@ -73,9 +73,17 @@ static RISCVException ctr(CPURISCVState *env, int
> >>>> csrno)
> >>>>        CPUState *cs = env_cpu(env);
> >>>>        RISCVCPU *cpu = RISCV_CPU(cs);
> >>>>        int ctr_index;
> >>>> +    int base_csrno = CSR_HPMCOUNTER3;
> >>>> +    bool rv32 = riscv_cpu_mxl(env) == MXL_RV32 ? true : false;
> >>>>    -    if (!cpu->cfg.ext_pmu) {
> >>>> -        /* The PMU extension is not enabled */
> >>>> +    if (rv32 && csrno >= CSR_CYCLEH) {
> >>>> +        /* Offset for RV32 hpmcounternh counters */
> >>>> +        base_csrno += 0x80;
> >>>> +    }
> >>>> +    ctr_index = csrno - base_csrno;
> >>>> +
> >>>> +    if (!cpu->cfg.pmu_num || ctr_index >= (cpu->cfg.pmu_num)) {
> >>>> +        /* No counter is enabled in PMU or the counter is out of
> >>>> range */
> >>> I seems unnecessary to add '!cpu->cfg.pmu_num ' here, 'ctr_index >=
> >>> (cpu->cfg.pmu_num)' is true
> > The check is improved in the following patches as well.
> >
> Do you mean 'if ((!cpu->cfg.pmu_num || !(cpu->pmu_avail_ctrs &
> ctr_mask)))'  in patch 9 ?
>
> In this condition, '!cpu->cfg.pmu_num' seems unnecessary too.
>

Yes. I will remove it.

> Regards,
>
> Weiwei Li
>
> >> Typo.  I -> It
> >>> when cpu->cfg.pmu_num is zero if the problem for base_csrno is fixed.
> >>>
> >>> Ragards,
> >>>
> >>> Weiwei Li
> >>>
> >>>>            return RISCV_EXCP_ILLEGAL_INST;
> >>>>        }
> >>>>    @@ -103,7 +111,7 @@ static RISCVException ctr(CPURISCVState *env,
> >>>> int csrno)
> >>>>                }
> >>>>                break;
> >>>>            }
> >>>> -        if (riscv_cpu_mxl(env) == MXL_RV32) {
> >>>> +        if (rv32) {
> >>>>                switch (csrno) {
> >>>>                case CSR_CYCLEH:
> >>>>                    if (!get_field(env->mcounteren, COUNTEREN_CY)) {
> >>>> @@ -158,7 +166,7 @@ static RISCVException ctr(CPURISCVState *env, int
> >>>> csrno)
> >>>>                }
> >>>>                break;
> >>>>            }
> >>>> -        if (riscv_cpu_mxl(env) == MXL_RV32) {
> >>>> +        if (rv32) {
> >>>>                switch (csrno) {
> >>>>                case CSR_CYCLEH:
> >>>>                    if (!get_field(env->hcounteren, COUNTEREN_CY) &&
> >>>> @@ -202,6 +210,26 @@ static RISCVException ctr32(CPURISCVState *env,
> >>>> int csrno)
> >>>>    }
> >>>>      #if !defined(CONFIG_USER_ONLY)
> >>>> +static RISCVException mctr(CPURISCVState *env, int csrno)
> >>>> +{
> >>>> +    CPUState *cs = env_cpu(env);
> >>>> +    RISCVCPU *cpu = RISCV_CPU(cs);
> >>>> +    int ctr_index;
> >>>> +    int base_csrno = CSR_MHPMCOUNTER3;
> >>>> +
> >>>> +    if ((riscv_cpu_mxl(env) == MXL_RV32) && csrno >= CSR_MCYCLEH) {
> >>>> +        /* Offset for RV32 mhpmcounternh counters */
> >>>> +        base_csrno += 0x80;
> >>>> +    }
> >>>> +    ctr_index = csrno - base_csrno;
> >>>> +    if (!cpu->cfg.pmu_num || ctr_index >= cpu->cfg.pmu_num) {
> >>>> +        /* The PMU is not enabled or counter is out of range*/
> >>>> +        return RISCV_EXCP_ILLEGAL_INST;
> >>>> +    }
> >>>> +
> >>>> +    return RISCV_EXCP_NONE;
> >>>> +}
> >>>> +
> >>>>    static RISCVException any(CPURISCVState *env, int csrno)
> >>>>    {
> >>>>        return RISCV_EXCP_NONE;
> >>>> @@ -3687,35 +3715,35 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
> >>>>        [CSR_HPMCOUNTER30]   = { "hpmcounter30",   ctr, read_zero },
> >>>>        [CSR_HPMCOUNTER31]   = { "hpmcounter31",   ctr, read_zero },
> >>>>    -    [CSR_MHPMCOUNTER3]   = { "mhpmcounter3",   any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER4]   = { "mhpmcounter4",   any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER5]   = { "mhpmcounter5",   any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER6]   = { "mhpmcounter6",   any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER7]   = { "mhpmcounter7",   any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER8]   = { "mhpmcounter8",   any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER9]   = { "mhpmcounter9",   any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER10]  = { "mhpmcounter10",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER11]  = { "mhpmcounter11",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER12]  = { "mhpmcounter12",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER13]  = { "mhpmcounter13",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER14]  = { "mhpmcounter14",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER15]  = { "mhpmcounter15",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER16]  = { "mhpmcounter16",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER17]  = { "mhpmcounter17",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER18]  = { "mhpmcounter18",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER19]  = { "mhpmcounter19",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER20]  = { "mhpmcounter20",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER21]  = { "mhpmcounter21",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER22]  = { "mhpmcounter22",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER23]  = { "mhpmcounter23",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER24]  = { "mhpmcounter24",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER25]  = { "mhpmcounter25",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER26]  = { "mhpmcounter26",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER27]  = { "mhpmcounter27",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER28]  = { "mhpmcounter28",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER29]  = { "mhpmcounter29",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER30]  = { "mhpmcounter30",  any, read_zero },
> >>>> -    [CSR_MHPMCOUNTER31]  = { "mhpmcounter31",  any, read_zero },
> >>>> +    [CSR_MHPMCOUNTER3]   = { "mhpmcounter3",   mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER4]   = { "mhpmcounter4",   mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER5]   = { "mhpmcounter5",   mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER6]   = { "mhpmcounter6",   mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER7]   = { "mhpmcounter7",   mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER8]   = { "mhpmcounter8",   mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER9]   = { "mhpmcounter9",   mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER10]  = { "mhpmcounter10",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER11]  = { "mhpmcounter11",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER12]  = { "mhpmcounter12",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER13]  = { "mhpmcounter13",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER14]  = { "mhpmcounter14",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER15]  = { "mhpmcounter15",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER16]  = { "mhpmcounter16",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER17]  = { "mhpmcounter17",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER18]  = { "mhpmcounter18",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER19]  = { "mhpmcounter19",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER20]  = { "mhpmcounter20",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER21]  = { "mhpmcounter21",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER22]  = { "mhpmcounter22",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER23]  = { "mhpmcounter23",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER24]  = { "mhpmcounter24",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER25]  = { "mhpmcounter25",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER26]  = { "mhpmcounter26",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER27]  = { "mhpmcounter27",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER28]  = { "mhpmcounter28",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER29]  = { "mhpmcounter29",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER30]  = { "mhpmcounter30",  mctr, read_zero },
> >>>> +    [CSR_MHPMCOUNTER31]  = { "mhpmcounter31",  mctr, read_zero },
> >>>>          [CSR_MHPMEVENT3]     = { "mhpmevent3",     any, read_zero },
> >>>>        [CSR_MHPMEVENT4]     = { "mhpmevent4",     any, read_zero },
>
>


-- 
Regards,
Atish



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