[PATCH v5 10/22] RISC-V: KVM: No need to update the counter value during reset

Atish Patra
2024-04-03T08:05:33Z

The virtual counter value is updated during pmu_ctr_read. There is no need
to update it in reset case. Otherwise, it will be counted twice which is
incorrect.

Fixes: 0cb74b65d2e5 ("RISC-V: KVM: Implement perf support without sampling")
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
---
arch/riscv/kvm/vcpu_pmu.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c
index cee1b9ca4ec4..b5159ce4592d 100644
--- a/arch/riscv/kvm/vcpu_pmu.c
+++ b/arch/riscv/kvm/vcpu_pmu.c
@@ -397,7 +397,6 @@ int kvm_riscv_vcpu_pmu_ctr_stop(struct kvm_vcpu *vcpu, unsigned long ctr_base,
{
struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
int i, pmc_index, sbiret = 0;
- u64 enabled, running;
struct kvm_pmc *pmc;
int fevent_code;

@@ -432,12 +431,9 @@ int kvm_riscv_vcpu_pmu_ctr_stop(struct kvm_vcpu *vcpu, unsigned long ctr_base,
sbiret = SBI_ERR_ALREADY_STOPPED;
}

- if (flags & SBI_PMU_STOP_FLAG_RESET) {
- /* Relase the counter if this is a reset request */
- pmc->counter_val += perf_event_read_value(pmc->perf_event,
- &enabled, &running);
+ if (flags & SBI_PMU_STOP_FLAG_RESET)
+ /* Release the counter if this is a reset request */
kvm_pmu_release_perf_event(pmc);
- }
} else {
sbiret = SBI_ERR_INVALID_PARAM;
}
--
2.34.1