RISCV_PREEMPT_V_IN_SCHEDULE
prev->thread.riscv_v_flags |= RISCV_PREEMPT_V_IN_SCHEDULE;
if (next->thread.riscv_v_flags & RISCV_PREEMPT_V_IN_SCHEDULE) {
next->thread.riscv_v_flags &= ~RISCV_PREEMPT_V_IN_SCHEDULE;