diff --git a/arch/riscv/kvm/vcpu_sbi_system.c b/arch/riscv/kvm/vcpu_sbi_system.c
index c6f7e609ac794b..6f64a59e5d3c4e 100644
--- a/arch/riscv/kvm/vcpu_sbi_system.c
+++ b/arch/riscv/kvm/vcpu_sbi_system.c
@@ -35,6 +35,20 @@ static int kvm_sbi_ext_susp_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
 			return 0;
 		}
 
+		/*
+		 * Check that all other vCPUs are stopped before entering
+		 * system suspend.
+		 *
+		 * There is a known TOCTOU race here: a concurrent HSM
+		 * HART_START on another vCPU can start a vCPU after it
+		 * has already passed this check, violating the invariant.
+		 *
+		 * We do not fix this because:
+		 * 1. Triggering the race requires a pathological guest.
+		 * 2. Only guest state is at risk, not host integrity.
+		 * 3. Userspace can double-check vCPU states before
+		 *    proceeding with suspend.
+		 */
 		kvm_for_each_vcpu(i, tmp, vcpu->kvm) {
 			if (tmp == vcpu)
 				continue;