RE: [PATCH v2 3/5] hisi_acc_vfio_pci: bugfix cache write-back issue

[Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>]

> -----Original Message-----
> From: liulongfang <liulongfang@huawei.com>
> Sent: Thursday, December 19, 2024 9:18 AM
> To: alex.williamson@redhat.com; jgg@nvidia.com; Shameerali Kolothum
> Thodi <shameerali.kolothum.thodi@huawei.com>; Jonathan Cameron
> <jonathan.cameron@huawei.com>
> Cc: kvm@vger.kernel.org; linux-kernel@vger.kernel.org;
> linuxarm@openeuler.org; liulongfang <liulongfang@huawei.com>
> Subject: [PATCH v2 3/5] hisi_acc_vfio_pci: bugfix cache write-back issue
> 
> At present, cache write-back is placed in the device data
> copy stage after stopping the device operation.
> Writing back to the cache at this stage will cause the data
> obtained by the cache to be written back to be empty.
> 
> In order to ensure that the cache data is written back
> successfully, the data needs to be written back into the
> stop device stage.
> 
> Fixes:b0eed085903e("hisi_acc_vfio_pci: Add support for VFIO live
> migration")
> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
> ---
>  drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> index 4c8f1ae5b636..c057c0e24693 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> @@ -559,7 +559,6 @@ static int vf_qm_state_save(struct
> hisi_acc_vf_core_device *hisi_acc_vdev,
>  {
>  	struct acc_vf_data *vf_data = &migf->vf_data;
>  	struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
> -	struct device *dev = &vf_qm->pdev->dev;
>  	int ret;
> 
>  	if (unlikely(qm_wait_dev_not_ready(vf_qm))) {
> @@ -573,12 +572,6 @@ static int vf_qm_state_save(struct
> hisi_acc_vf_core_device *hisi_acc_vdev,
>  	vf_data->vf_qm_state = QM_READY;
>  	hisi_acc_vdev->vf_qm_state = vf_data->vf_qm_state;
> 
> -	ret = vf_qm_cache_wb(vf_qm);
> -	if (ret) {
> -		dev_err(dev, "failed to writeback QM Cache!\n");
> -		return ret;
> -	}
> -
>  	ret = vf_qm_read_data(vf_qm, vf_data);
>  	if (ret)
>  		return -EINVAL;
> @@ -1005,6 +998,13 @@ static int hisi_acc_vf_stop_device(struct
> hisi_acc_vf_core_device *hisi_acc_vdev
>  		dev_err(dev, "failed to check QM INT state!\n");
>  		return ret;
>  	}
> +
> +	ret = vf_qm_cache_wb(vf_qm);
> +	if (ret) {
> +		dev_err(dev, "failed to writeback QM cache!\n");
> +		return ret;
> +	}
> +
>  	return 0;
>  }

Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>

Thanks,
Shameer