Re: [BUG] crypto: hisilicon: accessing the data mapped to streaming DMA

[Jia-Ju Bai]

On 2020/8/3 9:12, Zhou Wang wrote:
> On 2020/8/2 22:52, Jia-Ju Bai wrote:
> > In qm_qp_ctx_cfg(), "sqc" and "aeqc" are mapped to streaming DMA:
> >    eqc_dma = dma_map_single(..., eqc, ...);
> >    ......
> >    aeqc_dma = dma_map_single(..., aeqc, ...);
> Only sqc, cqc will be configured in qm_qp_ctx_cfg.
>
> > Then "sqc" and "aeqc" are accessed at many places, such as:
> >    eqc->base_l = cpu_to_le32(lower_32_bits(qm->eqe_dma));
> >    eqc->base_h = cpu_to_le32(upper_32_bits(qm->eqe_dma));
> >    ......
> >    aeqc->base_l = cpu_to_le32(lower_32_bits(qm->aeqe_dma));
> >    aeqc->base_h = cpu_to_le32(upper_32_bits(qm->aeqe_dma));
> There are sqc, cqc, eqc, aeqc, you seems misunderstand them.
>
> > These accesses may cause data inconsistency between CPU cache and hardware.
> >
> > I am not sure how to properly fix this problem, and thus I only report it.
> In qm_qp_ctx_cfg, sqc/cqc memory will be allocated and related mailbox will be sent
> to hardware. In qm_eq_ctx_cfg, eqc/aeqc related operations will be done.
>
> So there is no problem here :)

Ah, sorry, I misunderstood qm_eq_ctx_cfg() and qm_qp_ctx_cfg(), because their names are quite similar.
Now, I re-organize this report as follows:

In qm_eq_ctx_cfg(), "eqc" and "aeqc" are mapped to streaming DMA:
  eqc_dma = dma_map_single(..., eqc, ...);
  ......
  aeqc_dma = dma_map_single(..., aeqc, ...);

Then "sqc" and "aeqc" are accessed at some places in qm_eq_ctx_cfg(), such as:
  eqc->base_l = cpu_to_le32(lower_32_bits(qm->eqe_dma));
  eqc->base_h = cpu_to_le32(upper_32_bits(qm->eqe_dma));
  ......
  aeqc->base_l = cpu_to_le32(lower_32_bits(qm->aeqe_dma));
  aeqc->base_h = cpu_to_le32(upper_32_bits(qm->aeqe_dma));

These accesses may cause data inconsistency between CPU cache and hardware.

Besides, in qm_qp_ctx_cfg(), "sqc" and "cqc" are mapped to streaming DMA:
  sqc_dma = dma_map_single(..., sqc, ...);
  ......
  cqc_dma = dma_map_single(..., cqc, ...);


Then "sqc" and "cqc" are at some places in qm_qp_ctx_cfg(), such as:
  sqc->cq_num = cpu_to_le16(qp_id);
  sqc->w13 = cpu_to_le16(QM_MK_SQC_W13(0, 1, qp->alg_type));
  ......
  cqc->dw3 = cpu_to_le32(QM_MK_CQC_DW3_V2(4));
  cqc->w8 = 0;

These accesses may cause data inconsistency between CPU cache and hardware.

I think such problems (if they are real) can be fixed by finishing data assignment before DMA mapping.
 

Best wishes,
Jia-Ju Bai