在 2021/6/24 下午5:16, Yongji Xie 写道:
On Thu, Jun 24, 2021 at 4:14 PM Jason Wang <jasowang@xxxxxxxxxx> wrote:
在 2021/6/24 下午12:46, Yongji Xie 写道:
So we need to deal with both FEATURES_OK and reset, but probably not
DRIVER_OK.
OK, I see. Thanks for the explanation. One more question is how about
clearing the corresponding status bit in get_status() rather than
making set_status() fail. Since the spec recommends this way for
validation which is done in virtio_dev_remove() and
virtio_finalize_features().
Thanks,
Yongji
I think you can. Or it would be even better that we just don't set the
bit during set_status().
Yes, that's what I mean.
I just realize that in vdpa_reset() we had:
static inline void vdpa_reset(struct vdpa_device *vdev)
{
const struct vdpa_config_ops *ops = vdev->config;
vdev->features_valid = false;
ops->set_status(vdev, 0);
}
We probably need to add the synchronization here. E.g re-read with a
timeout.
Looks like the timeout is already in set_status().
Do you mean the VDUSE's implementation?
Do we really need a
duplicated one here?
1) this is the timeout at the vDPA layer instead of the VDUSE layer.
2) it really depends on what's the meaning of the timeout for set_status
of VDUSE.
Do we want:
2a) for set_status(): relay the message to userspace and wait for the
userspace to quiescence the datapath
or
2b) for set_status(): simply relay the message to userspace, reply is no
needed. Userspace will use a command to update the status when the
datapath is stop. The the status could be fetched via get_stats().
2b looks more spec complaint.
And how to handle failure? Adding a return value
to virtio_config_ops->reset() and passing the error to the upper
layer?
Something like this.
Thanks
Thanks,
Yongji
