diff --git a/lib/sbi/sbi_pmu.c b/lib/sbi/sbi_pmu.c
index 5983a784..6ca4efdb 100644
--- a/lib/sbi/sbi_pmu.c
+++ b/lib/sbi/sbi_pmu.c
@@ -206,6 +206,12 @@ static int pmu_ctr_validate(struct sbi_pmu_hart_state *phs,
 	return event_idx_type;
 }
 
+static bool pmu_ctr_idx_validate(unsigned long cbase, unsigned long cmask)
+{
+	/* Do a basic sanity check of counter base & mask */
+	return cmask && cbase + sbi_fls(cmask) < total_ctrs;
+}
+
 int sbi_pmu_ctr_fw_read(uint32_t cidx, uint64_t *cval)
 {
 	int event_idx_type;
@@ -472,7 +478,7 @@ int sbi_pmu_ctr_start(unsigned long cbase, unsigned long cmask,
 	int i, cidx;
 	uint64_t edata;
 
-	if ((cbase + sbi_fls(cmask)) >= total_ctrs)
+	if (!pmu_ctr_idx_validate(cbase, cmask))
 		return ret;
 
 	if (flags & SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT)
@@ -577,8 +583,8 @@ int sbi_pmu_ctr_stop(unsigned long cbase, unsigned long cmask,
 	uint32_t event_code;
 	int i, cidx;
 
-	if ((cbase + sbi_fls(cmask)) >= total_ctrs)
-		return SBI_EINVAL;
+	if (!pmu_ctr_idx_validate(cbase, cmask))
+		return ret;
 
 	if (flag & SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT)
 		return SBI_ENO_SHMEM;
@@ -839,8 +845,7 @@ int sbi_pmu_ctr_cfg_match(unsigned long cidx_base, unsigned long cidx_mask,
 	int ret, event_type, ctr_idx = SBI_ENOTSUPP;
 	u32 event_code;
 
-	/* Do a basic sanity check of counter base & mask */
-	if ((cidx_base + sbi_fls(cidx_mask)) >= total_ctrs)
+	if (!pmu_ctr_idx_validate(cidx_base, cidx_mask))
 		return SBI_EINVAL;
 
 	event_type = pmu_event_validate(phs, event_idx, event_data);