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Subject: Re: [PATCH v8 09/10] vduse: Introduce VDUSE - vDPA Device in
 Userspace
To:     Yongji Xie <xieyongji@bytedance.com>
Cc:     "Michael S. Tsirkin" <mst@redhat.com>,
        Stefan Hajnoczi <stefanha@redhat.com>,
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From:   Jason Wang <jasowang@redhat.com>
Message-ID: <e4cdee72-b6b4-d055-9aac-3beae0e5e3e1@redhat.com>
Date:   Wed, 23 Jun 2021 11:30:52 +0800
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在 2021/6/22 下午4:14, Yongji Xie 写道:
> On Tue, Jun 22, 2021 at 3:50 PM Jason Wang <jasowang@redhat.com> wrote:
>>
>> 在 2021/6/22 下午3:22, Yongji Xie 写道:
>>>> We need fix a way to propagate the error to the userspace.
>>>>
>>>> E.g if we want to stop the deivce, we will delay the status reset until
>>>> we get respose from the userspace?
>>>>
>>> I didn't get how to delay the status reset. And should it be a DoS
>>> that we want to fix if the userspace doesn't give a response forever?
>>
>> You're right. So let's make set_status() can fail first, then propagate
>> its failure via VHOST_VDPA_SET_STATUS.
>>
> OK. So we only need to propagate the failure in the vhost-vdpa case, right?


I think not, we need to deal with the reset for virtio as well:

E.g in register_virtio_devices(), we have:

         /* We always start by resetting the device, in case a previous
          * driver messed it up.  This also tests that code path a 
little. */
       dev->config->reset(dev);

We probably need to make reset can fail and then fail the 
register_virtio_device() as well.

Thanks


>
> Thanks,
> Yongji
>