Re: [PATCH v13 05/13] vdpa: Add reset callback in vdpa_config_ops

Michael S. Tsirkin
2021-09-06T05:56:09Z

On Tue, Aug 31, 2021 at 06:36:26PM +0800, Xie Yongji wrote:
> This adds a new callback to support device specific reset
> behavior. The vdpa bus driver will call the reset function
> instead of setting status to zero during resetting.
>
> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>

This does gloss over a significant change though:

> ---
> @@ -348,12 +352,12 @@ static inline struct device *vdpa_get_dma_dev(struct vdpa_device *vdev)
> return vdev->dma_dev;
> }
>
> -static inline void vdpa_reset(struct vdpa_device *vdev)
> +static inline int vdpa_reset(struct vdpa_device *vdev)
> {
> const struct vdpa_config_ops *ops = vdev->config;
>
> vdev->features_valid = false;
> - ops->set_status(vdev, 0);
> + return ops->reset(vdev);
> }
>
> static inline int vdpa_set_features(struct vdpa_device *vdev, u64 features)

Unfortunately this breaks virtio_vdpa:

static void virtio_vdpa_reset(struct virtio_device *vdev)
{
struct vdpa_device *vdpa = vd_get_vdpa(vdev);

vdpa_reset(vdpa);
}

and there's no easy way to fix this, kernel can't recover
from a reset failure e.g. during driver unbind.

Find a way to disable virtio_vdpa for now?

> --
> 2.11.0