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Subject: Re: [PATCH V3 1/3] vDPA/ifcvf: deduce VIRTIO device ID when probe
To:     Zhu Lingshan <lingshan.zhu@intel.com>, mst@redhat.com,
        lulu@redhat.com, sgarzare@redhat.com
Cc:     virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20210416071628.4984-1-lingshan.zhu@intel.com>
 <20210416071628.4984-2-lingshan.zhu@intel.com>
From:   Jason Wang <jasowang@redhat.com>
Message-ID: <efc73829-0209-8144-0426-935b8384b6ad@redhat.com>
Date:   Mon, 19 Apr 2021 11:15:51 +0800
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在 2021/4/16 下午3:16, Zhu Lingshan 写道:
> This commit deduces VIRTIO device ID as device type when probe,
> then ifcvf_vdpa_get_device_id() can simply return the ID.
> ifcvf_vdpa_get_features() and ifcvf_vdpa_get_config_size()
> can work properly based on the device ID.
>
> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
> ---
>   drivers/vdpa/ifcvf/ifcvf_base.h |  1 +
>   drivers/vdpa/ifcvf/ifcvf_main.c | 30 ++++++++++++++++++------------
>   2 files changed, 19 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/vdpa/ifcvf/ifcvf_base.h b/drivers/vdpa/ifcvf/ifcvf_base.h
> index b2eeb16b9c2c..1c04cd256fa7 100644
> --- a/drivers/vdpa/ifcvf/ifcvf_base.h
> +++ b/drivers/vdpa/ifcvf/ifcvf_base.h
> @@ -84,6 +84,7 @@ struct ifcvf_hw {
>   	u32 notify_off_multiplier;
>   	u64 req_features;
>   	u64 hw_features;
> +	u32 dev_type;
>   	struct virtio_pci_common_cfg __iomem *common_cfg;
>   	void __iomem *net_cfg;
>   	struct vring_info vring[IFCVF_MAX_QUEUE_PAIRS * 2];
> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
> index 44d7586019da..469a9b5737b7 100644
> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
> @@ -323,19 +323,9 @@ static u32 ifcvf_vdpa_get_generation(struct vdpa_device *vdpa_dev)
>   
>   static u32 ifcvf_vdpa_get_device_id(struct vdpa_device *vdpa_dev)
>   {
> -	struct ifcvf_adapter *adapter = vdpa_to_adapter(vdpa_dev);
> -	struct pci_dev *pdev = adapter->pdev;
> -	u32 ret = -ENODEV;
> -
> -	if (pdev->device < 0x1000 || pdev->device > 0x107f)
> -		return ret;
> -
> -	if (pdev->device < 0x1040)
> -		ret =  pdev->subsystem_device;
> -	else
> -		ret =  pdev->device - 0x1040;
> +	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
>   
> -	return ret;
> +	return vf->dev_type;
>   }
>   
>   static u32 ifcvf_vdpa_get_vendor_id(struct vdpa_device *vdpa_dev)
> @@ -466,6 +456,22 @@ static int ifcvf_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>   	pci_set_drvdata(pdev, adapter);
>   
>   	vf = &adapter->vf;
> +
> +	/* This drirver drives both modern virtio devices and transitional
> +	 * devices in modern mode.
> +	 * vDPA requires feature bit VIRTIO_F_ACCESS_PLATFORM,
> +	 * so legacy devices and transitional devices in legacy
> +	 * mode will not work for vDPA, this driver will not
> +	 * drive devices with legacy interface.
> +	 */
> +	if (pdev->device < 0x1000 || pdev->device > 0x107f)
> +		return -EOPNOTSUPP;


So this seems useless, id_table has already did that for us:

The driver supports:

#define IFCVF_DEVICE_ID         0x1041

and

#define C5000X_PL_BLK_DEVICE_ID        0x1001

I think we can never reach the condition above.

Thanks


> +
> +	if (pdev->device < 0x1040)
> +		vf->dev_type =  pdev->subsystem_device;
> +	else
> +		vf->dev_type =  pdev->device - 0x1040;
> +
>   	vf->base = pcim_iomap_table(pdev);
>   
>   	adapter->pdev = pdev;