[PATCH] RISC-V: KVM: Validate PMU counter info using available counters

[Qingwei Hu]

COUNTER_GET_INFO validates the counter index using the pmc[] storage
capacity rather than the number of counters advertised by NUM_COUNTERS.
When fewer counters are available, a guest can query an index outside
the advertised range and receive success.

Validate the index using kvm_pmu_num_counters(), matching the counter
initialization and read paths.

Fixes: 8f0153ecd3bf ("RISC-V: KVM: Add skeleton support for perf")
Signed-off-by: Qingwei Hu <qingwei.hu@xxxxxxxxxxxxx>
---
 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 e095d1ff439f..ea788619091a 100644
--- a/arch/riscv/kvm/vcpu_pmu.c
+++ b/arch/riscv/kvm/vcpu_pmu.c
@@ -560,7 +560,7 @@ int kvm_riscv_vcpu_pmu_ctr_info(struct kvm_vcpu *vcpu, unsigned long cidx,
 {
 	struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
 
-	if (cidx >= RISCV_KVM_MAX_COUNTERS || cidx == 1) {
+	if (cidx >= kvm_pmu_num_counters(kvpmu) || cidx == 1) {
 		retdata->err_val = SBI_ERR_INVALID_PARAM;
 		return 0;
 	}
-- 
2.39.5