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Subject: Re: [PATCH 3/3] virtio/vdpa: Clear the available index during probe
From:   Jason Wang <jasowang@redhat.com>
To:     Eli Cohen <elic@nvidia.com>, mst@redhat.com,
        virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org
References: <20210531160502.31610-1-elic@nvidia.com>
 <2a0a106c-af92-37b7-84de-5754b8ac645b@redhat.com>
Message-ID: <70d6217d-3722-156b-fac0-620129bc3e56@redhat.com>
Date:   Tue, 1 Jun 2021 13:40:49 +0800
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在 2021/6/1 上午10:20, Jason Wang 写道:
>
> 在 2021/6/1 上午12:05, Eli Cohen 写道:
>> Clear the available index as part of the initialization process to
>> clear and values that might be left from previous usage of the device.
>> For example, if the device was previously used by vhost_vdpa and now
>> probed by vhost_vdpa, you want to start with indices.
>>
>> Fixes: c043b4a8cf3b ("virtio: introduce a vDPA based transport")
>> Signed-off-by: Eli Cohen <elic@nvidia.com>
>> ---
>
>
> Acked-by: Jason Wang <jasowang@redhat.com>
>
> Note that we probably need a follow-up fixes for vp_vdpa driver.
>
> I will post it soon.
>
> Thanks


Hi Eli:

Rethink about this, it only works for the case of split virtqueue.

I will post a series that makes it work for both packed and split 
virtqueue (with some tweak on this patch).

Does this work for you?

Thanks


>
>
>>   drivers/virtio/virtio_vdpa.c | 6 ++++++
>>   1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
>> index e28acf482e0c..32fb121a6ec4 100644
>> --- a/drivers/virtio/virtio_vdpa.c
>> +++ b/drivers/virtio/virtio_vdpa.c
>> @@ -142,6 +142,7 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, 
>> unsigned int index,
>>       struct vdpa_callback cb;
>>       struct virtqueue *vq;
>>       u64 desc_addr, driver_addr, device_addr;
>> +    struct vdpa_vq_state state = {0};
>>       unsigned long flags;
>>       u32 align, num;
>>       int err;
>> @@ -191,6 +192,11 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, 
>> unsigned int index,
>>           goto err_vq;
>>       }
>>   +    /* reset available index */
>> +    err = ops->set_vq_state(vdpa, index, &state);
>> +    if (err)
>> +        goto err_vq;
>> +
>>       ops->set_vq_ready(vdpa, index, 1);
>>         vq->priv = info;