Re: [PATCH v5 08/22] RISC-V: KVM: Fix the initial sample period value

On Wed, Apr 03, 2024 at 01:04:37AM -0700, Atish Patra 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.

Signed-off-by: Atish Patra atishp@rivosinc.com

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

Reviewed-by: Andrew Jones ajones@ventanamicro.com