RISCV_IOMMU_CQT
q->tail_off = (uint32_t)base - RISCV_IOMMU_CQB + RISCV_IOMMU_CQT;
#define QUEUE_TAIL(q) ((q)->csr + RISCV_IOMMU_CQT - RISCV_IOMMU_CQB)