[PATCH] KVM: riscv: PMU: Bound counter mask scan to BITS_PER_LONG
Shengwen Cheng <[email protected]>
| Newsgroups | org.infradead.lists.kvm-riscv,org.infradead.lists.linux-riscv,org.kernel.vger.kvm,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
The PMU SBI handler passes the guest argument registers directly to the PMU start/stop helpers: kvm_riscv_vcpu_pmu_ctr_start(vcpu, cp->a0, cp->a1, cp->a2, ...) kvm_riscv_vcpu_pmu_ctr_stop(vcpu, cp->a0, cp->a1, cp->a2, ...) which map to: unsigned long ctr_base unsigned long ctr_mask unsigned long flags Thus cp->a1 is a single unsigned long ctr_mask, not a bitmap array sized for RISCV_MAX_COUNTERS. On RV32, RISCV_MAX_COUNTERS is 64 while BITS_PER_LONG is 32. Using for_each_set_bit() with RISCV_MAX_COUNTERS can therefore make find_next_bit() access bits beyond the storage of ctr_mask on RV32. Limit the scan to BITS_PER_LONG. The requested counter range is already validated by kvm_pmu_validate_counter_mask(), so this preserves RV64 behavior and avoids an out-of-bounds bitmap read on RV32. Signed-off-by: Shengwen Cheng <[email protected]> --- arch/riscv/kvm/vcpu_pmu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c index bb46dcbfb..2025b6649 100644 --- a/arch/riscv/kvm/vcpu_pmu.c +++ b/arch/riscv/kvm/vcpu_pmu.c @@ -586,7 +586,7 @@ int kvm_riscv_vcpu_pmu_ctr_start(struct kvm_vcpu *vcpu, unsigned long ctr_base, } } /* Start the counters that have been configured and requested by the guest */ - for_each_set_bit(i, &ctr_mask, RISCV_MAX_COUNTERS) { + for_each_set_bit(i, &ctr_mask, BITS_PER_LONG) { pmc_index = array_index_nospec(i + ctr_base, RISCV_KVM_MAX_COUNTERS); if (!test_bit(pmc_index, kvpmu->pmc_in_use)) @@ -658,7 +658,7 @@ int kvm_riscv_vcpu_pmu_ctr_stop(struct kvm_vcpu *vcpu, unsigned long ctr_base, } /* Stop the counters that have been configured and requested by the guest */ - for_each_set_bit(i, &ctr_mask, RISCV_MAX_COUNTERS) { + for_each_set_bit(i, &ctr_mask, BITS_PER_LONG) { pmc_index = array_index_nospec(i + ctr_base, RISCV_KVM_MAX_COUNTERS); if (!test_bit(pmc_index, kvpmu->pmc_in_use)) -- 2.43.0 -- kvm-riscv mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kvm-riscv