Re: [PATCH v8 10/24] RISC-V: KVM: Fix the initial sample period value

[Anup Patel]

On Sat, Apr 20, 2024 at 5:18 AM Atish Patra <atishp@xxxxxxxxxxxx> wrote:
>
> The initial sample period value when counter value is not assigned
> should be set to maximum value supported by the counter width.
> Otherwise, it may result in spurious interrupts.
>
> Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
> Signed-off-by: Atish Patra <atishp@xxxxxxxxxxxx>

LGTM.

Reviewed-by: Anup Patel <anup@xxxxxxxxxxxxxx>

Regards,
Anup

> ---
>  arch/riscv/kvm/vcpu_pmu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c
> index 86391a5061dd..cee1b9ca4ec4 100644
> --- a/arch/riscv/kvm/vcpu_pmu.c
> +++ b/arch/riscv/kvm/vcpu_pmu.c
> @@ -39,7 +39,7 @@ static u64 kvm_pmu_get_sample_period(struct kvm_pmc *pmc)
>         u64 sample_period;
>
>         if (!pmc->counter_val)
> -               sample_period = counter_val_mask + 1;
> +               sample_period = counter_val_mask;
>         else
>                 sample_period = (-pmc->counter_val) & counter_val_mask;
>
> --
> 2.34.1
>