Re: [PATCH v4 2/4] hisi_acc_vfio_pci: Create subfunction for data reading

[Alex Williamson]

On Tue, 2 Apr 2024 11:24:30 +0800
Longfang Liu <liulongfang@xxxxxxxxxx> wrote:

> During the live migration process. It needs to obtain various status
> data of drivers and devices. In order to facilitate calling it in the
> debugfs function. For all operations that read data from device registers,
> the driver creates a subfunction.
> Also fixed the location of address data.

Cédric noted privately and I agree, 1) fixes should be provided in
separate patches with a Fixes: tag rather than subtly included in a
minor refactoring, and 2) what does this imply about the existing
functionality of migration?  This would seem to suggest existing
migration data is bogus if we're offset by a register reading the DMA
address.  The commit log for the Fixes patch should describe this.

> 
> Signed-off-by: Longfang Liu <liulongfang@xxxxxxxxxx>
> ---
>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 56 +++++++++++--------
>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |  3 +
>  2 files changed, 37 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> index 45351be8e270..bf358ba94b5d 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> @@ -486,6 +486,39 @@ static int vf_qm_load_data(struct hisi_acc_vf_core_device *hisi_acc_vdev,
>  	return 0;
>  }
>  
> +static int vf_qm_read_data(struct hisi_qm *vf_qm, struct acc_vf_data *vf_data)
> +{
> +	struct device *dev = &vf_qm->pdev->dev;
> +	int ret;
> +
> +	ret = qm_get_regs(vf_qm, vf_data);
> +	if (ret)
> +		return -EINVAL;
> +
> +	/* Every reg is 32 bit, the dma address is 64 bit. */
> +	vf_data->eqe_dma = vf_data->qm_eqc_dw[QM_XQC_ADDR_HIGH];
> +	vf_data->eqe_dma <<= QM_XQC_ADDR_OFFSET;
> +	vf_data->eqe_dma |= vf_data->qm_eqc_dw[QM_XQC_ADDR_LOW];
> +	vf_data->aeqe_dma = vf_data->qm_aeqc_dw[QM_XQC_ADDR_HIGH];
> +	vf_data->aeqe_dma <<= QM_XQC_ADDR_OFFSET;
> +	vf_data->aeqe_dma |= vf_data->qm_aeqc_dw[QM_XQC_ADDR_LOW];
> +
> +	/* Through SQC_BT/CQC_BT to get sqc and cqc address */
> +	ret = qm_get_sqc(vf_qm, &vf_data->sqc_dma);
> +	if (ret) {
> +		dev_err(dev, "failed to read SQC addr!\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = qm_get_cqc(vf_qm, &vf_data->cqc_dma);
> +	if (ret) {
> +		dev_err(dev, "failed to read CQC addr!\n");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
>  static int vf_qm_state_save(struct hisi_acc_vf_core_device *hisi_acc_vdev,
>  			    struct hisi_acc_vf_migration_file *migf)
>  {
> @@ -511,31 +544,10 @@ static int vf_qm_state_save(struct hisi_acc_vf_core_device *hisi_acc_vdev,
>  		return ret;
>  	}
>  
> -	ret = qm_get_regs(vf_qm, vf_data);
> +	ret = vf_qm_read_data(vf_qm, vf_data);
>  	if (ret)
>  		return -EINVAL;
>  
> -	/* Every reg is 32 bit, the dma address is 64 bit. */
> -	vf_data->eqe_dma = vf_data->qm_eqc_dw[1];
> -	vf_data->eqe_dma <<= QM_XQC_ADDR_OFFSET;
> -	vf_data->eqe_dma |= vf_data->qm_eqc_dw[0];
> -	vf_data->aeqe_dma = vf_data->qm_aeqc_dw[1];
> -	vf_data->aeqe_dma <<= QM_XQC_ADDR_OFFSET;
> -	vf_data->aeqe_dma |= vf_data->qm_aeqc_dw[0];
> -
> -	/* Through SQC_BT/CQC_BT to get sqc and cqc address */
> -	ret = qm_get_sqc(vf_qm, &vf_data->sqc_dma);
> -	if (ret) {
> -		dev_err(dev, "failed to read SQC addr!\n");
> -		return -EINVAL;
> -	}
> -
> -	ret = qm_get_cqc(vf_qm, &vf_data->cqc_dma);
> -	if (ret) {
> -		dev_err(dev, "failed to read CQC addr!\n");
> -		return -EINVAL;
> -	}
> -
>  	migf->total_length = sizeof(struct acc_vf_data);
>  	return 0;
>  }
> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
> index 5bab46602fad..7a9dc87627cd 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
> @@ -38,6 +38,9 @@
>  #define QM_REG_ADDR_OFFSET	0x0004
>  
>  #define QM_XQC_ADDR_OFFSET	32U
> +#define QM_XQC_ADDR_LOW		0x1
> +#define QM_XQC_ADDR_HIGH	0x2
> +
>  #define QM_VF_AEQ_INT_MASK	0x0004
>  #define QM_VF_EQ_INT_MASK	0x000c
>  #define QM_IFC_INT_SOURCE_V	0x0020