Virtualization - Aug 2021 - [PATCH v10 10/17] virtio: Handle device reset failure in register_virtio_device()

? 2021/8/4 ??4:50, Yongji Xie ??:
> On Wed, Aug 4, 2021 at 4:32 PM Jason Wang <jasowang at redhat.com>
wrote:
>>
>> ? 2021/8/3 ??5:38, Yongji Xie ??:
>>> On Tue, Aug 3, 2021 at 4:09 PM Jason Wang <jasowang at
redhat.com> wrote:
>>>> ? 2021/7/29 ??3:34, Xie Yongji ??:
>>>>> The device reset may fail in virtio-vdpa case now, so add
checks to
>>>>> its return value and fail the register_virtio_device().
>>>> So the reset() would be called by the driver during remove as
well, or
>>>> is it sufficient to deal only with the reset during probe?
>>>>
>>> Actually there is no way to handle failure during removal. And it
>>> should be safe with the protection of software IOTLB even if the
>>> reset() fails.
>>>
>>> Thanks,
>>> Yongji
>>
>> If this is true, does it mean we don't even need to care about
reset
>> failure?
>>
> But we need to handle the failure in the vhost-vdpa case, isn't it?

Yes, but:

- This patch is for virtio not for vhost, if we don't care virtio, we 
can avoid the changes
- For vhost, there could be two ways probably:

1) let the set_status to report error
2) require userspace to re-read for status

It looks to me you want to go with 1) and I'm not sure whether or not 
it's too late to go with 2).

Thanks

>
> Thanks,
> Yongji
>