linux-kernel - Re: [PATCH v3 2/3] drivers/perf: riscv: Reset the counter to hpmevent mapping while starting cpus

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Message-ID: <96ff4dd2-db66-4653-80e9-97d4f1381581@sifive.com>
Date: Wed, 26 Jun 2024 08:24:38 -0500
From: Samuel Holland <samuel.holland@...ive.com>
To: Atish Patra <atishp@...osinc.com>, linux-riscv@...ts.infradead.org,
 kvm-riscv@...ts.infradead.org
Cc: Atish Patra <atishp@...shpatra.org>, Anup Patel <anup@...infault.org>,
 Will Deacon <will@...nel.org>, Mark Rutland <mark.rutland@....com>,
 Paul Walmsley <paul.walmsley@...ive.com>, Palmer Dabbelt
 <palmer@...belt.com>, Andrew Jones <ajones@...tanamicro.com>,
 Conor Dooley <conor.dooley@...rochip.com>,
 Palmer Dabbelt <palmer@...osinc.com>,
 Alexandre Ghiti <alexghiti@...osinc.com>,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
 kvm@...r.kernel.org
Subject: Re: [PATCH v3 2/3] drivers/perf: riscv: Reset the counter to hpmevent
 mapping while starting cpus

On 2024-06-26 2:23 AM, Atish Patra wrote:
> From: Samuel Holland <samuel.holland@...ive.com>
> 
> Currently, we stop all the counters while a new cpu is brought online.
> However, the hpmevent to counter mappings are not reset. The firmware may
> have some stale encoding in their mapping structure which may lead to
> undesirable results. We have not encountered such scenario though.
> 

This needs:

Signed-off-by: Samuel Holland <samuel.holland@...ive.com>

otherwise your commit message looks fine to me.

> Signed-off-by: Atish Patra <atishp@...osinc.com>
> ---
>  drivers/perf/riscv_pmu_sbi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
> index a2e4005e1fd0..94bc369a3454 100644
> --- a/drivers/perf/riscv_pmu_sbi.c
> +++ b/drivers/perf/riscv_pmu_sbi.c
> @@ -762,7 +762,7 @@ static inline void pmu_sbi_stop_all(struct riscv_pmu *pmu)
>  	 * which may include counters that are not enabled yet.
>  	 */
>  	sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP,
> -		  0, pmu->cmask, 0, 0, 0, 0);
> +		  0, pmu->cmask, SBI_PMU_STOP_FLAG_RESET, 0, 0, 0);
>  }
>  
>  static inline void pmu_sbi_stop_hw_ctrs(struct riscv_pmu *pmu)
>